Battery Charging Questions

[WanderingCanuck]

So I'm thinking that if I limit the scope to FLA for now, perhaps the most cost effective option to charge from shore power would be a power converter/charger. With that I should be able to keep the fridge on the same circuit while charging too - if I understand the function correctly.

Links to some of them I'm interested in:

45A, CDN$ 291.78 + ~$12 shipping
https://www.amazon.ca/Progressive-Dynamics-PD9245CV-Inteli-Power-Converter/dp/B000GANZZ6

45A, CDN$ 198.24 & FREE Shipping
https://www.amazon.ca/IOTA-Engineering-Converter-and-Charger/dp/B0030GA42A

45A, CDN$ 205.14 & FREE Shipping
https://www.amazon.ca/PowerMax-PM4-45A-Converter-Battery/dp/B01ER3LH3O

Seems to me any of the above should be better than the poor excuse for a charger I have now. I've looked at some of the high end recommendations, and although I really like the idea of being programmable I have trouble justifying CDN$ 500 or more for something that may become surplus to my needs before long. I'm sure that the electronics constitute a lot of the cost, but I think the pretty packaging has to be a big factor as well, catering to the high end boat market as they do. Any reason not to let the lowest price make the decision for me? Any similar options that I'm overlooking, maybe better value? (which doesn't necessarily mean lower price).

Am I processing this correctly? It meets the needs of my current situation, with easy shore power availability and in the future I should be able use any of the above on a generator to do the 50% -> 80% (or thereabouts) charge if/when needed. I'd still need the other feasible power sources like solar and alternator and figure this could work for me. If not, that's when I go lithium - mostly for the high rate of charge. But that's another topic, and at least a few years distant.

One final question to tack onto this. I get it that these batteries like to be returned to full SOC "after discharging", but what does this mean? If I'm running only my fridge on it constantly for 4-5 days before charging it back up to 100% is that going to be a factor limiting the battery longevity? Or is it when they sit at a partial discharge state that the problem exists? I'm still collecting data, but I don't think I'm dropping below 50% after this period of time. I'll know more by the end of the week.

Again, thanks (John61CT in particular), and I'm glad to see that this is helping some others too (Max).

 

[WanderingCanuck]

Hmmm.... what about equalizing? I don't think those will let me do that.

 

[John61CT]

SternWake is alive and well, just left this forum sick of being told how to post.

You can find him elsewhere by googling.

 

[WanderingCanuck]

Here's another one similar to the other three listed above:

https://www.amazon.ca/Go-Power-GPC-45-MAX-4-Stage-Converter/dp/B007GN4VKY

It describes the fourth stage of charging as equalization. At least one of the above said "four stage", but didn't elaborate. It says the charger does this automatically when the battery needs it. Forgive my skepticism, but should I really trust that?

One commenter (first one when I read it) talks about being able to tweak the output voltage. I didn't see anything like that on the others. Is this a common feature?

 

[WanderingCanuck]

SternWake is alive and well, just left this forum sick of being told how to post.

You can find him elsewhere by googling.

I guess it's better to be thought dead and found alive than the other way around.  I don't remember what got me thinking this way.  Maybe a comment about him being "gone now" or something like that.

Thanks for setting me straight.

 

[WanderingCanuck]

I've been continuing to think about this and I'm wondering about using a DC-DC charger with various less-expensive power supplies for voltage/current sources. For example, I have a computer power supply in front of me with about 16A @12V. I'm not sure if these can happily run in parallel, but they're cheap as dirt - often freely obtainable. I'm pretty sure I can come up with some other creative ideas for higher current supplies at voltages close to this as well. I have a feeling this isn't a new revelation, so are there any snags that others have run into with this approach?

 

[John61CT]

Excellent path.

Check out iCharger 4010-Duo.

Usually used with PC style PS in series to get 24 V.

Can work with any voltage any chemistry cells, balancing LFP, automated load testing. . .

Otherwise Sterling BB series

 

[WanderingCanuck]

I logged the voltage, temperature and specific gravity of my batteries this week.  As mentioned before, there is no built-in charging system yet so this is only the drain from my fridge running 24/7 off 2x US Battery 2200 GC2 in series.

I don't have a SG chart specific to this battery, but extrapolating from the T-105 chart I get the following:

SOC        SG
~~~       ~~
100        1.270
90          1.251
80          1.231
70          1.210

60          1.188

50          1.165

40          1.141

30          1.117

20          1.091
10          1.066

My final reading prior to charging was 1.15, so as best as I can figure I was just below 50% SOC, which seems like it should be ok.  Now, doing this over four days before charging back up is still something of an unknown in terms of battery longevity.

The voltage isn't represented well on this chart due to the scale of the right axis, but it also isn't that important.  I was just interested to see how it tracked the SG.  It seems the drop was fairly linear.  More interesting is to see the SG drop more quickly after a period of high temperature.  Of course this makes sense but it's still neat to see the chart.  The resolution of my data isn't great, but since I was logging morning, lunch, and evening it should still be quite valid.

Data from this chart covers the period between Sept 17, 8am and Sept 21, 6:30pm

P.S. - Anyone care to explain why my hydrometer has labels starting with a decimal (eg. 0.1275) while the rest of the world refers to this as 1.275 ?

 

[Weight]

SpGr changes by temperature. It may relate to voltage but must be SpGr at Temperature number.

 

[jasper]

Background: I have 2x 6V FLA GC batteries only running a fridge/freezer. Charging is completely manual from shore power at this time. I've had them two weeks (or one?) and have been trying to get them back to full SOC as often as I can, mostly by intelligent guessing. 
 
I've purchased a battery hydrometer and received it a few days ago. After taking readings at different times I've discovered I'm never getting the battery up to full charge, based on the battery spec sheet.

Battery:
http://usbattery.com/products/6-volt-batteries/us-2200-xc2-lf/

Hydrometer:
https://www.amazon.ca/E-Z-Red-SP101-Battery-Hydrometer/dp/B000JFHMRU

It says SG at full charge should be 0.1270 but I can't seem to get it there. I've seen max 0.1240 and min 0.1225.

The charger is a cheap one with 2A/12A "auto" settings, autotransformer type. I know it's crap, but I thought I'd have the opposite problem - overcharging.

So, where do I go from here? I can get a better shore power charger but would prefer not to spend a fortune on the "best". Is there one that will do a decent job without breaking the bank?

Or, is there something different I can do with this charger to get better results?  So far I've been putting it on the 12A setting for a few hours (3-5?) in the evening then the 2A setting overnight (7-9h).

Also, recommendation for DC current measurements so I can tell what's flowing, maybe the clamp style. Something accurate but not NIST cert level.

Thanks

Cheap, as in the first word in the green rectangle in the upper left corner of this page?  I can relate.  I also relied on shore power charging only, before going vehicle alternator along with solar charging.  Also, two 6v golf cart batteries, mainly for refrigeration.

My smart so-called 30A charger cycled on and off for that rating.  Somewhat false advertising.  It would also turn off before getting specific gravity high enough.

I decided to go dumb, which for me is not difficult.  I have been using one of these Chinese 30 amp switching power supplies for two years. It has an adjustable output voltage slot at the end of the terminal strip.  I've bought three more, and all adjusted to 15vdc. I use a lamp cord with a thumb wheel switch for the AC input.

https://www.ebay.com/itm/12V-DC-30A...pply-For-LED-String-Strip-Lights/321990514901

No wiring or on/off switch.  You have to do your own wiring, and install terminals.  Two AC in, two DC out.

Wiring one of these cheapos in series will show charging current. I've tested them against digital ammeters and am happy enough.

https://www.ebay.com/itm/DC-30A-Ana...-QW/253394604719?_trksid=p2485497.m4902.l9144

An accurate DC voltmeter is required to monitor battery/power supply/charger voltage.

For my two golf cart batteries, it's turn the voltage adjust screw to minimum, hook the power supply and the ammeter to the battery, then plug the charger into shore power.

Adjust the voltage adjust screw until the charge current reaches 30 amps (or whatever recommended) or the adjust screw is at maximum.  If 30 amps is reached before reaching adjust maximum, come back however many times it takes before the adjust screw is at maximum,  approximately 15vdc.

The current (amps) will decrease until barely readable.  I generally leave it charging overnight when on shore power.

The crude setup has kept specific gravity up to acceptable levels, but later trials with a PWM solar controller brought the specific gravity up on a couple of long sitting golf cart batteries with the PWM controller that the crude power supply could not.

After hearing the popping noises in various electronic devices, and looking at waveforms of PWM controllers, it seems that could be a plus.

I may have missed it.  AC or DC refrigerator?  Amp draw when running?

 

[WanderingCanuck]

SpGr changes by temperature. It may relate to voltage but must be SpGr at Temperature number.

The hydrometer I purchased (and linked to earlier) claims to be direct reading, temperature compensating. I'm trusting it functions as advertised because I have nothing else with which to calibrate it.

 

[WanderingCanuck]

I may have missed it.  AC or DC refrigerator?  Amp draw when running?

Thanks for sharing your experience, and adding to the mounting evidence that really expensive electronics may not be needed to get the job done. Yes, they may do it better, but that's for another thread and for future system improvements.

I've since discovered that if I switch this charger from "Charge" to "Start", the voltage increases from the too-soon float level (~13.4) up to the "too high, but more effective" 15-16V. When the batter was still very low, this voltage was lower and it would keep putting 12A or so into the battery as long as it would take it. I was even able to heat it up a little (slightly warm on the casing), and let it rest a bit when I noticed this. I've been manually swapping around the settings the past two days and have managed to bring the batteries back up to 1.270, maybe even a little higher than that. Due to the higher voltage I'm thinking I was probably doing some equalizing too since I kept going even after it was near full.

With the higher voltage I do notice bubbling in the electrolyte, but it isn't that vigorous. At what point does higher than recommended voltage start doing damage, and of what nature? There's still lots of liquid. Actually, I was surprised how much the levels come back up from discharged to charged. Can anyone explain this property?

The fridge in question is a 12V DC, 80L (~80 quart) that I've talked about in another thread. The draw varies, and I'm not yet setup for great current monitoring. The max at startup seems to be up to about 3A but that easily drops down to maybe 1.5 to 2A depending what it's doing. Then of course there's the duty cycle. I want to set up some logging capability in the future but I'm not there yet. I'm pretty handy with digital electronics and intend to cobble together my own solution, but suggestions to this effect are appreciated and will be considered.

I never realized there was quite so much to FLA batteries. I just considered them "old technology" that's quickly being replaced by others. Though that may still be true, I think there may always be a place for this tried-and-true technology.

But I have to admit, they take FOREVER to charge. Maybe I can improve this a little with better charging equipment, but I understand it will still take some time.

 

[John61CT]

You need an ammeter.

As trailing amps drops, it becomes more important to get the voltage right, so you can stop at the defined 100% Full point.

If you have more than enough amps, that should be within 6-7 hours, but longer if the charger is small.

How many AH is the bank?

Being the regulator yourself manually will quickly get old, and very likely you will at some point accidentally overcharge to the point of reducing longevity.

Although with FLA that is not so critical, compared to chronic undercharging, long as you keep them well watered.

 

[jasper]

My reason for replying was that your situation so closely paralleled mine.  I have used my inexpensive power supply set up on a pair of 205ah and a pair of 225ah golf cart batteries.  I have also used it on cranking batteries in an emergency.

My prior post made the charging operation seem more aggravating than it is.  For my similar situation, at a beginning charging voltage of greater than about 12.2vdc, the adjustable voltage screw would be at max to get the 30 amps.  I just hook it up, adjust usually to maximum, walk away and come back up to twelve hours later and stop charging whenever charging current was barely readable.

Below about 12.2v, the voltage adjust is required to keep power supply current below 30 amps to keep it from getting angry.  Usually, within less than an hour, cranking the adjust screw once to maximum was all that was required.

Well, that and keeping check on fluid levels and specific gravity.

I have one of these voltmeters installed so that I can easily see it.  I first ordered five blue ones for ten bucks, then discovered how much they illuminated the interior after dark.  Red is not as bad, but I also can switch it off.  All ten I have ordered matched themselves and my digital multimeters.

https://www.ebay.com/sch/i.html?_fr...Xdc+voltmeter.TRS1&_nkw=dc+voltmeter&_sacat=0

Then I found a Renogy 100 watt suitcase model solar panel on Craigslist for 125 bucks, and have seldom needed my shore charger since.  For mainly a fridge, it's been wonderful.  The solar charger comes mounted on the panel, and to limit losses from long wires from it to the battery, I removed it from the panel and mounted it close to the battery. The controller is smarter and more observant than me and my crude power supply could ever be.

My Edgestar fridge has an amp draw of about 2.5A when it runs.  My data logging has been listening to when it runs and keeping an eye on the voltmeter, especially in the morning. Your fridge hopefully shuts down before the voltage lowers to battery damaging levels.

After discovering my 100 watt panel would output about 1 amp on cloudy days, with an occasionally running fridge drawing 2.5, I  got another solar panel to charge the batteries quicker. I've seldom needed more than 100 watts.

Did I mention how much I really like the solar setup and controller smarts? Cost me less than the two batteries and maintains them MUCH better for longer life.

I didn't mind battery maintenance in industry for decades when someone else paid for them, but view them differently now that they're my babies.

Let's don't even mention golf cart battery banks in golf carts. Nothing beats having a wonderful smartypants controller losing its mind and cooking the entire bank during your absence. That means I still look at things regularly due to trust issues.

 

[WanderingCanuck]

Yes, being the automatic charger has definitely been taking up more of my time than I'd like. I've almost pulled the trigger a couple of times on better dedicated shore chargers. But every time I'm stopped by the feeling that I'm not going to be needing it after I get into my "full" setup. Accordingly, I just keep using what I have - which is already paid for, and didn't cost a lot in the first place. As long as voltages up to 16V aren't likely to harm the batteries too quickly I may stick with this for a little while longer.

The iCharger you (John) mentioned looks like a neat little piece of kit. but what I'd really like is something I can reuse later with solar + alternator charging (and minimal or non-existent shore power). Prior to getting this all set up I'd just run whatever power supply I have handy into the DC-DC charger. Maybe even the cheapo charger I have now. I can put out amps, no doubt... though there's a thermal overload that shuts it down from running at 70A for long. My understanding is that the DC-DC chargers can take a pretty wide voltage range and convert that to the correct voltage and current for the current stage of charging, as determined by the settings. Do I have this right? The problem I see with the iCharger is that for future use it would not combine more than one input source, and wouldn't automatically take care of battery charging unattended.

I'm beginning to think that there isn't one single device that will fill this niche for me. So, what about two or more? The CTEK pairing of D250SA and SmartPass are looking attractive, other than not being programmable for future LiFePO4 upgrades.

 

[John61CT]

My understanding is that the DC-DC chargers can take a pretty wide voltage range and convert that to the correct voltage and current for the current stage of charging, as determined by the settings. Do I have this right?

I don't buy non-adjustable anymore.

Sterling BB series is pretty future proof. Can stack for more amps.

The CTEK setup is fine for mostly-alternator setups with normal lead, but the solar side is meh.

 

[WanderingCanuck]

I found a somewhat local dealer for Sterling and so far I've learned that the B-B 12V/60A can be had for CAD$ 468.50 + tax/shipping. I was thinking they'd come back with a number nearing or exceeding the $1k mark, so I'm not put off yet. I've been asked for more information on what I'm trying to do, so I think I'll have a chat with the rep and see what can be learned.

I may get this answered in that conversation too, but what about solar? I'm assuming with this you'd need a separate solar controller and it would also connect to the battery bank. I'm also thinking that there wouldn't be much conflict because when the BB is getting power it probably far exceeds the other sources and should get precedence. Just as long as the other sources don't cause it to think the battery is more full than it is. A manual override, or just maybe a clever automatic one, might be needed if that were the case.

I'm just thinking out loud. I'll report back what seems important after talking to them.

 

[John61CT]

I found a somewhat local dealer for Sterling and so far I've learned that the B-B 12V/60A can be had for CAD$ 468.50 + tax/shipping.

Great!

Not everyone selling them knows much about them.

> need a separate solar controller and it would also connect to the battery bank.

Yes, good SCs do not need to be routed tgrough the BB.

Multiple concurrent charge sources do not cause "confusion" problems. Ideally similar profiles but NP if not, gets sorted out, long as no singles sources are set out of spec for the bank.

No priority or overriding needed.

 

[WanderingCanuck]

After having a fairly long telephone conversation with a salesperson from the local dealer, I'm not sure exactly how to feel.  I'm undecided whether he knows better and was trying to steer me down a better path, or didn't know much and was trying to sell me what he knows.  I didn't feel like he was actually listening to what I was telling him, and it seemed like a lot of the conversation was more like an argument.  It might be a case of knowing (or thinking I know) too much going into it, while the sales person expects me to be a complete idiot.  Been there, done that.  Actually, I'm a regular patron.


At every turn of the conversation he was steering me away from the Sterling BB.  From what I recall when I asked why, he seemed to think a "better" solution could be had for less money.  I wasn't presented with any logical argument that convinced me though.

Here is an excerpt from his email following the call:

Here are several documents for you to review:


1)      Victron Cyrix combiner (I have also included Blue Seas ACR data sheet for reference); voltage sensing bi-directional relay for separating and combining start/house.

2)      Iota engineering DLS power supplies/chargers; IQ4 external regulators see (https://www.iotaengineering.com/IQ/#!/ )

3)      Victron BMV battery monitor – provides voltage, current, amp-hours consumed/returned (adjustable peukert value for use with Lithium), time-remaining @ load, can be used for alarms as well as remote communication (has Bluetooth built in).  This unit acts as a real battery ‘fuel gauge’ and typically improves lifespan as well as provides peace of mind.

4)      Solar Regulator (Victron MPPT’s) – these include Bluetooth and if you download the ‘Victron  Connect’ app that is referenced, it has a demo mode to show you capability.

5)      some sample schematics – there’s a lot there, so perhaps have a look and I can provide some follow up later.


…..hopefully not too overwhelming!

I'd love to have been overwhelmed.  But in truth I was quite underwhelmed upon receiving a bunch of brochures that I could have found elsewhere online.  I'm not sure what he's calling "schematics", but there were a few over-complicated setups using lots of expensive Victron components I don't need.

The biggest thing that left me frustrated is that none of this scores well on my "now-and-later" list of criteria.

 

[John61CT]

It is **very** rare to find someone customer-facing in the biz that know half as much as what you find in the forums. Especially local.

Best to know exactly what you want prior to contact & just place your order.

Victron is a great vendor, but the Cyrix line sucks.

There is no competitor to Sterling BB for amps nor adjustability.

Buy from authorized sources to get good support.