The evolution of a dweller's electrical system

[SternWake]

Here I will outline how my system evolved along with my understanding of it all.  I'll not gloss over the mistakes.  This is long winded. Skip to the end if you want the moral of the story.

: June 2001, I bought my 89 dodge b250 van in SW Florida.  My only electrical loads were the incandescent light fixtures and the Stereo.  I ripped out the door buzzer instantly. The battery was some marine type of battery, group 27 size, I believe.  I had a Jumper pack with a 12AH AGM battery for when I ran the battery dead.  I was completely unaware that one cannot discharge a battery and just let it sit discharged, and not have it degrade quickly.  I also assumed that short trips were enough to fully charge a battery.  I had no idea what the charging voltages were or the amperage either.  My dashboard had an Ammeter which would move 1/16" to the left when cranking the engine, and 1/16" to the right after it started.  If the battery was lower, it would move 1/8" to the right, briefly after engine start.

Added electric loads: 12v Fan, 12v black and white TV

: December 2001, replaced engine battery with the starting biggest I could find off the shelf in a small town in eastern Oregon,  Was a group24 I believe. 

January 2002, Added second battery and Guest brand 1/2/both/off switch with help from my father in Florida.  I was still confused on how this was to be wired  I did not know the ground cables did not have to be switched too.  As a Xmas present, He bought me a group27 Deka marine/deepcycle battery, and enough 2awg cabling to reach my cabinet behind the drivers seat.  2 red cables, and one black to go battery to battery which we put in a marine battery box and just placed in the cabinet, kind of wedged into place, but not strapped down.  There was a nice battery store that made up some professional terminations crimps on the 2 awg marine cable.  Still have them.

  Acquired 120 watt Sony laptop, and 400 watt inverter.
  Found inverter would work OK on Dashboard ciggy receptacles, but not on Back ones.  First glimmering of the effects of voltage drop setting in. And I wired Inverter right to battery terminals.

Until June of 2007, I was replacing wally world batteries every 5 to 7 months The only loads were stereo, TV  and lights and some  internetless laptop use.   In 2006 My 90 amp alternator failed, and I was unaware until the windshield wipers moved really slow, along with the turn signals.  I was in San Francisco.  Only then did I test and find that I only has 11.2 volts with engine running.  Took Bus to nearest AP store, bought biggest deep cycle battery I could get so I could drive to where I could work on it. 

I went to Kragen Autoparts on Mission Avenue in San Francisco and bought a 120 amp alternator with a lifetime warranty.  I installed it, started the engine, and the dashboard ammeter moved 1/2 inch to the right, then centered itself, and I only had 11.1 volts again.  Removed alternator, had it tested, tested fine.  Grrrrrr

A 10awg fusible link on the alternator to engine battery cable had blown,  unknown to me, but I assumed the voltage regulator was bad, which my Chilton/haynes guide told me was in the engine computer, had failed.  Tried to get used engine computer at junkyard .  Got one, it would not start my engine.  Stress.  Had them charge my battery so I could drive.

Went to Automotive electrician.  They found the blown fusible link in 2 minutes and replaced it in 10, charged me 60$ and I tried to return the battery i bought and was denied, rightfully, and left San Francisco that day after adding the new battery in parallel to the other house battery with store bought 4 gauge sae cables.

The two dissimilar house batteries performed badly together.  The newer one, an Exide Nautilus liked to puke battery acid, and it ate the paint on my van floor in the cabinet and was a fume wafter.  I then built a battery box out of steel and mounted it below the floor with an Access hatch from above.  I built it just big enough to hold the 2 group 27 batteries, later kicking myself for not making it just 1 inch longer so I could fit 2 group 31 batteries, and have even more capacity.

Lots of capacity gave me the warm and fuzzies.  I had still not grasped that I was chronically undercharging the batteries.  I did buy a 2/10 amp manual Schumacher transformer based charger,  BUt have recently discovered it maxes out at 6 amps and will never go above 14.2v.  POS!

My electrical loads were still modest.  My laptop did not have WiFi.  Stereo and seldom laptop use, and Often I was still killing my~220 AH house bank completely, But always had the fully charged engine battery to start the engine.

For a few years I had been spending several cumulative months a Year in Baja.  I had a harbor freight 5 watt solar panel with a Ciggy plug on it.  Almost worthless it was, but I would park and not move for 3 weeks and have enough juice for the stereo and occasionally watch a DVD on the laptop.

Later I got a 120 watt DC to DC converter for the laptop.

June 2007, I was back in Florida, and gutted my van internals again.  I bought a 130 watt solar panel, a battery monitor, A NorCold 12v/120V compressor fridge, and rebuilt my interior just How I wanted it.  No wasted space, Minimal insulation. maximum utility and comfort for my intentions to spend several months a year In Baja in comfort, and be able to freeze the fish I caught, and not have to buy any damn ice ever again.

I went back to the place which sold my Dad the Deka battery and the 2 awg cable, but being foolish, I went with 3 New wal mart group 27 marine batteries instead to save 40$, one for the engine, 2 for the house.  I also bought a Schumacher sc2500a smart charger, 2/12 and 25 amps settings.

I went back to Baja, Right When The Narco wars were heating up, Saw the proliferation of Crystal Meth ruin the small fishing villages and turn some Mexican friend's into Lying thieving *********s who lost all sense of a moral compass, left after 2 months and have never returned.

I was in the soothing green light camp then.  I was unaware of the float threshold setting on my charge controller, and the relationship between voltage and current on a fully charged battery. Basically I had it programmed to drop to float as soon as amps per 100AH of capacity dropped to 5 amps.  I thought I was telling it to pump 5 amps into the depleted battery at float voltage.

I was unaware that one cannot pump 5 amps into a fully charged battery at 13.2v.  headsmack.

 When my Solar controller went to float, I assumed my batteries were full. In fact, as soon as the 130 watts were getting all three batteries to 14.4v, it would drop to 13.2v and not spend any time at all at 14.4 absorption voltage.  I was unaware 130 watts for 345 AH of battery is way too little. I almost never bothered isolating the engine battery with that much overall capacity, and having a battery monitor too. Despite setting absorption duration for 3 hours, the controller would instantly goto 13.2v float.  The first battery failed at 13 months.  A shorted Cell, after 380 very shallow discharges, and a blinking green light every day. 


I took the engine battery out and paralleled it with the remaining house battery, and used house bank for both engine and house duties.  No dedicated engine battery at all.  Never needed one.

The next wally world battery failed at 23 months.  My battery monitor showed me 0.3v less one day than I expected to see, and I unparalleled the batteries.  They both read 12.7v.  I put my 16 amp air compressor on one and it held 12.5v, and quickly rebounded to 12.7 after I turned it off.

The other battery instantly dropped to 10.4 volts under the 16 amp load, and then instantly rebounded to 12.7 when the load was removed.

I took the good battery, moved back into my engine compartment, and bought 2 Crown group 27'deep cycle' batteries for my house bank.  Arizona Wind and Sun praised these batteries, and All I knew was that I would not buy another Wally world battery again, and All I could fit was two group 27's and these were the best flooded batteries that I could get my hands on.

After 2 years of very light cycling, rarely more than 25% discharged, I let them get low on water as I did not know that water usage increases with Age, and getting to them to water them was a chore, and I am the master procrastinator.  When refilled and charged they performed Abysmally, dropping to 12.1v with only 30AH removed.

I went back to get two more Crown batteries, and the distributor said yes we have Crowns, but we now put our own stickers on them.  They felt a bit lighter, but I was shown the Crown stickers as they were removing them.

These batteries never impressed me.  I had by this point found out how to keep my controller in absorption voltage for longer, but I still did not own a hydrometer.  I had also begun to explore alternator charging more.

While I can see alternator current on my battery monitor, I always saw it max out at 62 amps cold, never go any higher no matter how depleted the batteries or how fast the alternator was spinning, and these amps would quickly taper downward.  I reinvestigated the Fusible link the Auto electricians installed, and saw it was 4 inches of 14awg equivalent.  After starting my engine with depleted batteries, this length of fusible link got so hot I could not hold it in my fingers.

I took some 4awg jumper cables whose clamps were useless and cut them off, and ran the wires doubled, from ALT(+) Stud to my 1/2/both/OFF switch's common stud.

Now, 62 amps cold idle shot upto over 100 amps at 3000 rpm.  When hot it could maintain 65 amps at 800rpm, but only 32amp at 525 rpm.  I later got a smaller alternator pulley in a futile attempt to increase hot idle speed amperage.  I Added a heatshield in between the rectifier and the nearby exhaust manifold and this was good for 3 to 5 extra amps when hot.

I found that these short lived blasts of high amperage, on my drive to the ocean in the morning, really woke up my batteries, they would hold higher voltage that night, and I started researching the maximum recommended currents that Crown recommended, which was 12 to 18% of battery capacity.

By this time I was drawing 40 to 65 AH each night from my battery bank, and again at around two years I let them get low on water, and after refilling got another 6 months or so from them.  I knew this was not a very good lifespan, and needed to know why I was not getting anywhere near the cycle life I expected from the batteries.  I was not cycling them deeply, they were getting charged every day, not sitting discharged, and the alternator was able to really return some AH in relatively short drives.
  
I had also added 68 more watts of Solar, Moved the charge controller much closer to the batteries over 4awg cable, and replaced the 12awg to controller with 8awg for the 130 watt panel and the 68 watt panel got 10awg.

Handybob's message mostly got through to me,

But the batteries were still not performing well.
Either they are junk, or I was not charging them properly.  Well, it was both.  The rebadged Crown deep cycles I later found out were only their marine version, not their deep cycle version.

At this point I still did not have a Hydrometer.  I was still relying on Voltage held under a certain load at a certain level of depletion measured by my battery monitor to judge battery performance, noting the trends and tendencies of those parameters as the batteries aged.

I started researching more, asking more questions, and came to the conclusion that I Had too much battery capacity.  Not only did I never need 230AH of house bank, but that my 198 watts~ 11.5 amps, could never even come close to Crown's 12% to 18% recommendation for 230AH of battery, which would be 27.6 amps minimum, or around 450 watts of solar.

My maximum overnight consumption rarely exceeded  70 AH, So I Decided to replace 2 group 27 house batteries at 230AH total capacity with a Single group31 130AH battery.  At least now I was approaching that 12% rate.  11.5 amps is still short of 12% on 130AH, but the ratio was much better.

I went to the same place and bought a Crown group31 battery, and a Northstar group 27 AGM battery to replace the now 7+ year old wally world battery that had been relegated to engine starting duty only at 23 months of age.  I'd actually bought the older blue top Northstar as they took 60$ off of it.

The Crown battery had the battery distributor sticker on it that said super cycling series and all sorts of flowery mumbo jumbo feel good marketing on it.  I fully charged it on my Schumacher, and that night took 65 amp hours from it over 10 hours. Voltage had sagged to 11.7v and rebounded only to 11.92v 3 hours after I removed the loads from it.  This is not a true scientific capacity test, but it was enough for me to rip the battery out and put it on a scale.  What should have weighed 67LBS, weighed 54.  The Effing bastards had put a deep cycle sticker on a Marine battery.

I called the battery store, ranting and raving.  Manager said to bring it back.  I talked to someone at Crown  battery, who knew the manager by name and was surprised they were throwing a deep cycle sticker and claiming a 130AH capacity on a 105AH marine battery.

I went back to battery distributor, foaming at the mouth, and chased the sticker swapping salesmen into the office when they claimed for the third time " A marine battery is a deep cycle battery".

I Paid more for a USbattery, group31, and returned older the BlueTop Northstar for a fresh battery.  The USbattery31 weighed what it was supposed to when I put it on their bathroom scale, and then again when I busted out my own scale, showing my level of trust in them.

I took 65AH from the USbattery that night over 10 hours and it rebounded to 12.2 volts.  Right where it should.
The New Northstar battery, was only holding 12.82 volts, and Northstar says Fully charged resting voltage is over 13 volts I tried several schumacher restarts to force more into it, but it would not take anymore.  The next night I cycled the 90 AH northstar battery deeply, beyond 50%, and voltage never dropped below 12.1, and rebounded to 12.19v.  I recharged it at 25 amps + whatever my Solar was able to contribute, and from then on, full charge resting voltage has been 13.06 volts.  This AGM needed a 50% discharge and a relatively high recharge rate to wake up.

2 months into my   US battery's life, I was unimpressed with the voltage it could hold for the level of depletion and the load on the battery.
NOW, i Finally bought a Hydrometer.  Despite it resting at 12.82 volts after 'fully' charging it, the specific gravity read 1.225 to 1.230 on all cells, when it should have been 1.280.

Long story short This USbattery group31 needed a 14.9v absorption voltage to be held for 3 hours, and then instead of dropping to float, I set float voltage at 15.3v and the solar would hold it there till the afternoon.  Even with these rather obscene voltages held for these extreme durations, the Specific gravity would walk down day after day, and after about 14 cycles i would have to bring it upto 16V for 50 minutes to 2 hours after a normal absorption charge cycle.

I wound up getting about 465 cycles total from this battery before removing it from my Van. The average cycle depth was about 58 Amp hours nightly. I was not conserving/ babying the battery at all.  I do not do that any more.  Those SOBs work for me.

Going from 230 AH total capacity down to 130 total capacity wound up saving me money, not including the gas savings by carrying around ~60 Lbs less weight for a year and a Half.  That group31 battery taught me a lot.  At around 2 months of age when I (finally) bought the hydrometer I swapped it with the AGM battery, putting it into my engine compartment so I could easily check Fluid levels and specific gravity. I'd moved the Northstar AGM battery under hatch below the floor. 

When I removed the USbattery 31 from my Van's engine compartment, My finances were not healthy enough for a new battery.  I also knew by this point that anything in the group 24/27/29/31 Is NOT a true deep cycle battery, not when compared to a Golf cart battery like the 6v trojan t-105 or the 12v T-1275.  I had planned on getting the Trojan Group 31 just to compare it to the USbattery, but saw that the T-1275 cost the same price as the Trojan group31, yet has twice the plate thickness and weighs 25 more Lbs.  A few measurements said a T-1275 would just fit with some modifications.

Anyway, My Northstar AGM was now my House and Engine battery.  I Own a Meanwell Adjustable voltage power supply so I can hold any absorption voltage for as long as needed when I have grid power, and I usually Do.  Since late may of this year, The Northstar AGM has been pulling double duty. 
 I pull 42 to 65 AH from it 4 to 5 nights a week.  Solar does a bulk of the recharging, but a newer reman;d alternator can feed it 50+ amps when hot at 525 rpm( whohoo!) and my meanwell can feed it 40 amps. I do not even need to cycle a battery, but I desire to know how it will perform when worked hard and recharged properly

When I do 4 days in a row of a Solar only recharge, no drivng, no meanwell, then the Northstar's voltage under load starts sagging on night 5.  A high Amp recharge the next morning restores performance, even if it is only 10 minutes of 50+ amps from my alternator, and Solar all day.
But having the Meanwell's 40 amps bring it to 14.46v and hold it there until amps taper to 0.42 is really what determines full charge.  My battery monitor is fairly close.  Sometimes it reads zero AH from full when it still needs another hour or 2 at 14.46, but it is fairly close.

Anyway, I am now rethinking even getting a Trojan T-1275 at all.  No house battery.  This AGM is so capable, It has easily started my engine at 72AH from full!!

Right now it is reading 12.3x at 37AH from full under a 6.7 amp load.

I might just get a small cheap 25$  12AH AGM battery like which comes in jumpstarter packs, and place that in my engine compartment.  If I ever drain the NS AGM battery so much it cannot start the engine, I can flip the switch and have the little jumper battery start my engine.

I went from a total of 345AH of battery capacity at one point, and now only have 90AH total, Yet I have total confidence in my system.

I started out in 2001 with a 100Ah starting battery and a 12AH jumper pack and minimal loads, to having 345AH of total capacity with moderate to heavy loads, and now am  down to 90Ah total capacity, and can use as much electricity as I feasibly can, short of running an electric heater.

It goes to show you how important it is to fully and properly recharge a lead acid battery as soon as possible as often as possible.

This 90 AH Northstar AGM will be 2 years old Next Month, and has close to 200 Deep Cycles on it, many of them well below 50% state of charge,   and in terms of voltage held under load, is outperforming 230 AH of marine battery.  Granted 230AH of flooded marine battery cost less.

Anyway, the moral is, Do not trust blinking green lights that indicate when a battery is fully charged.  Do Not trust the battery monitor, or resting voltage.  Do trust a quality temperature compensated hydrometer.  Raise absorption voltage and duration via an adjustable solar controller until the specific gravity rises to 1.275 or higher.

If you have an AGM battery, you need an Ammeter.  When the battery can only accept 0.5 amps per 100AHa of capacity at the battery manufacturer recommended absorption voltage, then it is fully charged.

Without an Ammeter, or a Hydrometer, you simply have NO idea when the battery is fully charged.  All the regular clues or myths espoused time and again, over and over, mean very little.  Voltage lies, green lights mock you, and 'works Just fine' only means has not yet failed or it has not yet been noticed it is degrading. 

A battery that is truly fully charged will be a happy, long lived battery that will yield a good Cycles per Dollar ratio.  If I knew then what I know now, I would have saved a Lot of Aggravation, And Money.  Well over a thousand dollars I suspect.

 

[ahh_me2]

Interesting read!
I'm a few weeks away from buying some batteries, hopefully I can learn from your mistakes!

Thanks!

 

[highdesertranger]

yep I can relate. I made many of the same mistakes. I started in the mid 90's, a lot of bstterycide has been commited since then. highdesertranger

 

[BobBski]

Interesting read for sure, thanks for you time in writing it. Now I need 3 aspirin, for the headache I have...then read it again to further digest the info....all this is Greek to me

 

[29chico]

Great story of discovery.  Too bad so many expensive lessons are learned about the care and feeding of lead acid batterys.   
 
I would like to add a bit more that is old school as it only applies to flooded cells.

First before changing a flooded cell make sure that the plates are covered by the electrolyte solution.  Just add enough distilled water to cover the plates, no higher.  When a battery that has experienced a significant discharge and then is recharged the level of the electrolyte solution will rise.  If one fills a flooded cell battery to the level indicators when it is discharged and then charges it there is a very high chance that the battery will overflow it's acid solution.

Second is the fact that in the absence of a good quality hydrometer one can determine when a flooded battery is fully charged by using a manual charging source that will drive the battery to at least 15v.  I have had good, albeit slow, results with  6-8 amp manual chargers on standard starting auto batterys.  So size up the amps accordingly for bigger deep cycle cells.  First follow the instructions above about the acid solution level.  Then just set the caps back on top of their respectve holes.  Begin charging and set a  timer to remind you to check the battery every hour or so.  When the first cell starts to boil note which cell it is and the time it begin to offgas.  Keep adding distilled water to keep the plates from being exposed. If the battery is still in good shape all of the cells will eventually offgas.  Do not be surprised if one cell takes a long time to boil and even longer to get to the point where it is offgasing as much as the other cells.  If a cell never gets to a full boil that cell is weak.  If a cell never boils, even after a day or two of extra charging, that cell is dead and the battery is done for.

Hopefully all cells will eventually boil equally.  Then you can fill the cells all the way to the level indicators and reinstall the caps.  I also like to rinse off the top of the battery at this point as some acid solution will have come out during the process.

Yes the manual charge and equalize process is a hassle.

Please water safety glasses when doing any of the above.  Full body condom optional.

 

[Reverse Engineer]

Quite a tale SW, and once again a lot of GREAT information on the electrics!

My approach has been the reverse, rather than trying to up my storage and charging capacity, I try to minimalize power consumption.  I also don't work with one BIG BATT, but many smaller ones.

My Ewz for instance takes 3 10AH Deep Cycle Batts in series for 36V.  I have 3 sets of those, ~$50 each for $450, 90AH total at 12V.  One small lawn tractor batt (12V), around $40.  One Big Deep Cycle Marine Batt, $100.  Then the vehicle starter battery, whatever it is, but I don't use this for running electrics.

I keep everything charged up at low amp trickle charge throughput, around 2A.  One of the battsets is always in the Ewz, and I have a 36V charger for that.  If not installed in the Ewz, I rewire the batts in parallel for 12V, or I just use them individually as necessary to power my laptop or run a couple of cycles of ice making.  If I drain one, if I am mobile I usually will go to the coffee shop and bring it in with me in a backpack and plug it in with a 12V 4A charger, spend a couple of hours chatting on the net or writing, and it gets recharged that way.  The vehicle does not do the charging of these batts most of the time.  Bonus, the laptop Li-I batt gets charged up during the session also.

I can hook any of the batts to my PV panels, I have 4 30W panels and 3 5W panels, one of which folds up to carry in a backpack.  So if there is good sunshine, some of them are always being charged, while I am using other ones.

In the very worst case scenario, I fire up the Yamaha 2000W Generator to recharge all the batts, including all the little ones used for powering the portable devices.  However, this is almost never necessary.  Why not?

That's what the big deep cycle marine batt is for.  When out on the road, once a week I stop at a motel.  It's the laundry day, shower and cleanup day and recharge day.  I bring the big batt into the motel room and charge off their power outlet.  I also top off all the other smaller batts.  I use the Big Batt to charge the smaller ones later in the week.  It's usually 3 days before I even have to resort to that, and that is without deploying the Solar PV panels.

Basically, I keep my personal electrics almost entirely separate from the vehicle electrics for the alternator and batt there.  I can connect them up if necessary, but it just about never is.  So I am never stressing out the vehicle electrics, and I have never fried an alternator.

It's a fairly pricy setup because the Batts for the Ewz aren't cheap for the 10AH they each will hold.  However, the amount of money you save in gas by having an Ewz is ENORMOUS.  I go shopping with it, they even let me ride it right inside the store!  Which these days helps a lot since I can't walk very well anymore since breaking my neck.  I can ride it from my parking location to the lake with my fishing gear and a cooler.

I'd like to switch over to Li-I for some things to conserve on weight and space and have more recharge cycles, but the prices remain too high to justify it so far.

My total power consumption is very low, usually avg 10-20 AH/day.  I don't run microwaves or TVs or hair dryers, just small electronics mostly.  So this system works well for me.

 

[SternWake]

29 Chico,

Each battery will differ slightly as to when it begins bubbling when voltage has climbed into the mid 14's. Bubbling vs boiling. Semantics, but the casual reader should not believe the electrolyte is like 212f water boiling in a pot.

My previous flooded battery, now taken out of service from my van, is sitting on the floor in my workshop and powering my old TV and lighting and fans requires high absorption voltages and higher finishing voltages, each and every charge. Hours at 14.8 followed by 15.3v, and only by applying these rather absurd voltages after every deep cycle was i able to get nearly 500 deep cycles out of it before removal from my Van.

15.3v alone was not enough voltage, no matter how long it was applied, to maximize specific gravity. It slowed its walk down however.
I was tentative about allowing higher voltages during the often needed equalization charges, but went to 15.5v, then 15.7v, and then eventually to 16v. I found that what took 40 minutes at 16v required 4 hours at 15.7v, and could not be achieved at all at 15.5v. 15.5v was simply not enough electrical pressure to fill the balloon.

So this particular battery required extreme voltages and durations, and gave pretty good cycle life when it got them, but it would have quickly become a paperweight had I not figured out what it needed. In the beginning it got only 2 hours once ti achieved 14.7v, and when 2 weeks old, it measured 1.225 after 2 hours at 14.7v. it would hold 12.78 volts for 24 hours, and most people would think this is fine and dandy, but the hydrometer does not lie, and when i was able to get it to 1.275+ the voltage it held that night under discharge was significantly higher.

I was dismayed about the frequent EQ charges it needed, and after a while I would just turn my solar charge controller to 16v, switch all loads to my other battery, and watch my Ammeter. Once amps tapered to about 4.2a, I knew Specific gravity had maxed out and I did not bother dipping the hydrometer. It usually required 6.2 to 6.4 amps to achieve 16v after ~2 hours at 15.3v and tapered from there.

But right before I took it out of My van, the amps never tapered below 5.5, and then they started increasing again, and a hand on the battery revealed that the cell closest to the negative post, on the bottom of the cell was 20 degrees hotter than the rest of the battery. A soft short had developed from plate sheddings on the bottom of the cell and this cell refused to climb inline with the other cells. 1.255 instead of 1.275+ on the other 5.

I really expected the cell to short out son after, but It has accumulated another 60 or 70 fairly shallow cycles since then and has not showed signs of heating again on that cell, but I do not bother with Manual EQ's on it. I charge it slower on a schumacher sc2500a that I do not trust. It will go as high as 16.4v, when it goes all psycho macher on it, but I do not much care about this battery anymore. Once rated at 130 AH, I bet it only has abut 55 to 60Ah left total.

But using just 25 to 30 AH from it and letting the schumacher loose on it overnight, it is "just fine"

But really the battery is long past its useful service life as I would need it in my Van.

A flooded battery has to offgass to reach full charge. During a 16v equalization charge, the offgassing is closer to the fizzing of carbonated water a few minutes after opening the cap.

The voltages which cause offgassing should only be applied as long as required to maximize specific gravity, or at least to within 0.005 of baseline maximum, compensated for temperature of course.

This will be different on each and every battery, and change as it ages. So for "Ideal" and maximum battery longevity, the user should be able to fine tune their absorption voltage and duration and be able to apply upto a 16V equalization charge for as long as required for Specific gravity to reach this maximum baseline.

A properly performed EQ charged performed when required on a flooded battery, will significantly increase battery longevity, but fully charging/top charging regularly will lessen the frequency at which a EQ charge is required. The EQ charge itself is abusive to the battery, but not nearly as abusive as chronically undercharging it, or cycling it when it only ever achieves 92% charged.

How much effort the battery user decides to employ in getting acceptable battery longevity is upto them. What they should not do however is stick their head in the sand and think everything is 'just fine', while having no Data to back up that assertion. Battery capacity declines with age/ accumulated cycles.. Most people only notice something is wrong when battery capacity has declined to the point where things stop working overnight. This could be 6 months, it could be 6 years. Failure in 6 months is not acceptable, 6 years certainly is.

Heck,if I never use more than 25AH from my previous battery, it can and does still meet this 'just fine' requirement, but in reality the thing has a foot and a half in the grave, and is simply waiting on the most inconvenient time for full failure.

 

[arammarks]

SternWake,

I've been reading through many of your posts here on battery charging and have been learning a tremendous amount.  I've started to grasp your customized use of a Meanwell adjustable voltage power supply. As a user who is vastly less knowledgeable, and perhaps somewhat less motivated to tend to the fine points of charging my house battery, I was wondering if you had thoughts on the use of "smart" charging devices, such as the Meanwell PB-600-12.  I see various other similar products offered by other manufacturers.

This device does not provide overload protection, which you said in another post was a necessity for a battery charger.  I must confess I was not able to understand this point, so I cannot tell for myself whether this is ok.  Also, I notice that this charger can only provide 14.4V. I understand from your posts that you are often prescribing conditioning batteries with upwards of 15V, which would not be possible with this.

My question is essentially, for someone less technically minded about batteries, could you recommend this or other similar smart battery chargers?

Thanks in advance for any comments.

 

[SternWake]

In general I can't recommend any smart charger unless I have used it.  Anybody can read others opinions and parrott them, the internet is full of that.

The charger is listed at 40 amps, that is its amperage limit.  A power supply is able to output UPto its limit, but without constant current limiting on overload, will either shut off, roll back the current, or smoke itself.  

But that Meanwell pb-600 product is designed as a battery charger and will limit it to 40 amps no matter what.

It does have overvoltage protection and over temperature protection






I'd have faith in the quality of the components and workmanship in the meanwell but anything Automatic, Ideally, would, for me, have an adjustable end amps to decide when to end  absorption voltage while knowing how many amps are actually flowing into battery, not powering loads, adjustable absorption voltage, adjustable float voltage, and a battery temperature sensor as well as an Equalizing feature with selectable voltage upto 16.2v and a timer for how long that is to be allowed.

I don't know of any products which fit that bill which are reasonably priced, or even outlandishly priced.

Really battery chargeing is simple. Get the battery to absorption voltage, hold it until amps taper to 0.5% of capacity(20hr rate) for AGMS or ~1 to 2.5% for flooded, verify with hydrometer, then drop to float or unplug charger.


When I plug in I generally choose 14.7v. With a battery monitor I generally know how long it will take to get to full, and  soem time later check on the amperage flowing INTO battery, not total charger output as some of that will be powering DC loads.
   If I am not going to be around to check it, then time to recharge fully is not really a priority either. I lower voltage to 13.6v, the recommended float voltage for my battery  When I come back whenever that might be, I check the amps flowing at 13.6v, then twist voltage back upto 14.7.  If amps do not quickly taper to 0.5% of capacity then I leave it at 14.7v until it does or if I goto bed I lower it back to 13.6v and do the 14.7v thing in the morning, but usually the solar would have already done it by the time I get up.

I release flatulence in the direction of smart chargers.  I can recommend none for use in van dwelling. if it is just for the occassional topping up of an Auto starting battery then any that can do at least 15 amps per 100Ah of capacity will be 'just fine'. But when a deep cycle battery, or a bank of them, is deeply discharged daily, these garage chargers will fall well short of actually fully charging the hard working battery, and cause premature sulfation and demise of the battery and will accellerate the decline on an aged battery as it becomes harder and harder to get a battery full, taking longer and longer, and 'automaitc' will not account for this with theier egg timers, it will treat the new battery the same as an old battery.

Any charging source applied is better than no charging source, but a human with a brain who can spin a dial will always outperform any garage smart charger, no matter how well its marketing is written, and how many glowing testamonials there are by peoplle that have no idea what an hydrometer or an ammeter is or whan a battery is indeed fully charged.  Most don't need to know,  somebody living on a budget and living on 12v, should.

The smart chargers need to be babysat anyway. I have one, and I use it, but I do not trust it, certianly not on any battery I care about.
  When I charge other's batteries sometimes I use this charger overnight as I don't want my meanwell growing legs.  In the morning I find a well undercharged battery, and usually waste a bunch of time loading the battery to drop voltage to get the charger to restart and complete the job.  Usually this is a waste of time and effort and i go get my meanwell, crank it upto 14.8v hook it to undercharged battery, check the amperage, and decide how long to let it go.  My wattmeter usually claims another 12 to 15AH on a 80 to 90AH battery was stuffed into the battery before amps taper to 1 to 1.5% of capacity indicating the smart charger got the battery to % 85 to 90% charged beforer dropping to float voltage.  more than enough to start the car/truck, but nowhere near adequate on a daily deeply cycled battery.
  Usually these batteries are already well compromised, I know the hydrometer is not going to reach 1.275 so I do not bother busting it out.  If I want 1.275+ specific gravity on an old battery this is basically going to require 16.2v for a period of time after a normal 'full' charge, and disconnecting the battery from vehicle, and using the hydrometer and ammeter, and voltmeter, and thermometer.  

That rarely happens on others batteries, but on my previous and still kicking flooded battery was almost a ritual required to get 500 deep cycles from it.

My current AGM is about 570 deep cycles, and to use a much overused term, still going strong.

It is degraded but I am mocking that term and its use by those that could never measure the decline in capacity and voltage retention under load.

 

[MikeRuth]

Thanks SW, I caught on to your info a couple years ago, Since I had already had a good understanding of battery tech your postings accelerated my ability to keep a pair of T-105's running strong now for two years. I surely would have killed them sooner had I not.

Always appreciate your writings on the subject.

Mike R

 

[user 37446]

The sad thing for me to have read is that SW cannot recommend an automatic battery charger. Just when I had a glimmer of hope previously about the Schumacher 25 amp charger, he says its not trustworthy. Darn it, that and a Black and Decker are the only two chargers I have found that will put out barely enough amperage (C20) that come "recommended" on the Amazon reviews.  Sigh.

My hope was to be able to quick charge a smaller (150 Amp or less) house battery bank by using a friends ac plugin on a weekly basis, with one of these chargers. I knew that my old Schumacher 10/2 from Walmart ($32) was not capable of those kinds of loads in a reasonable timeframe (12 hours). I had hoped there was something that was reasonably priced with a few safety features built in that was capable but it doesn't seem to be true.

I'm not (as yet) interested in fiddling around as much as SW does with ammeters and hydrometers, so am concerned that a good 2:1 solar to battery ratio combined with a good quality MPPT controller and thick wired cabling from the alternator won't be adequate for maintaining the expensive (Northstar) AGM battery life.  Poo.  :-/

While I don't have the van yet, I am trying to prepare. I have regretfully tossed the idea of having a small 700 watt microwave as it seems that the extra cost ($600 plus) in batteries, cabling, and a 1500 watt PSW inverter exceed the utility. That little appx 1.5 amp hour per minute microwave doesn't seem like it should tax batteries that much yet startup voltage sag really seems to affect them, thus my desire for the 12V AGM verses two 6V golf carts. Someone please school me here if I am incorrect.

 

[SternWake]

2 12v agm batteries should maintain higher voltages under load than 6v gc-2 golf cart batteries.  BUt Not all AGMS are made equally in this regard.  


The Northstar AGM battery wants to be high amp recharged every so often.  I give my 90Ah battery 40 or 65 amps when plugged in, or when using the alternator, whatever it can make.

Solar alone might not keep an amp hungry agm battery happy but the ability to high amp recharge from a well depleted state ever so many cycles( more frequently in winter), to a true full state of charge,  appears to be how I extracting excellent service from mine.

My Schumacher is Not reliable, i have not tested them all but have read many reports of them overvoltaging batteries.

The progressive dynamics 92XX series of converters at least allow the user to override automatic via their 'remote/pendant.  My electronic repairman contact has opened up his new PD9270 his only complaint  after inspection was the heavier toroids were not supported well and would likely develop solder cracks at the circuit board with enough vibrations and time.

A converter is usually a much better choice as a deep cycle battery charger, but they lack a sexy casing and buttons and LEDS which the garage chargers like to include.

Any charging source applied to a battery, is better than no charging source.  Just do not believe the garage charger marketing material.  I say have the ability feed a Van dweller's  100AH AGM no less than 20 amps initially when one has the ability to plug in. I also think it is wise to plug in when the batteries are at their very lowest and when they can accept the full output of the charger for a good period of time. A few hours of low sun then my charger are not as effective as if I get 40+ amps to my battery before the sun rises.

While having a green light showing automatic source say the battery is full, will give those human required warm and fuzzies, they simply lie.  A hard working battery needs to reach true full when the opportunity is there to plug in, and the garage chargers will not be able to do this unless the person unplugs charger, loads battery and restarts the charger a few times. Or if they can plug in for 5 days and allow the battery to come upto full at the chargers low float voltage.
 I find when I need to get a  neighbor'/ friend's battery full, it is more work to use my schumacher  and attempt to get the battery full, than it is to just set my Meanwell loose on it until I decide the battery is indeed full. Granted the schumacher would get the battery charged enough to actually start the vehicle, but the vehicele will have little chance of getting such a battery truly full. Better to ensure truly full before removing charging source.

No one needs to use a hydrometer every time, but don't think that glancing at an ammeter and the voltmeter, and making an accurate enough guess as to state of charge requires a degree in rocket science.

100Ah AGM battery accepting ~10 amps at 14.7v. not full. Likely around 85%
100Ah batery accepting 5 amps at 14.7v likely around 93% charged
100AH battery accepting only 1 amp at 14.7v likely arounf 98.5 to 99% charged
100Ah batery accepting 0.5amps or less, battery can be considered full

it is easier to determine state of charge of a battery when charging with a voltmeter and ammeter, than it is to guess accurately at state of charge when discharging it.

Flooded batteries require a bit more Amps to be held at absorption voltage, but one can double check with a hydrometer occassionally.

And don;t give up because one cannot achieve a perfect lab grade recharge, Batteries are meant to serve their owner, not the other way around.  Accepting less overall battery longevity is often much easier than worrying about achieving excellent recharging each and every cycle.

Just don;t believe that getting only to 80% every single rechrge is 'just fine' Such a battery is doomed to a premature failure.