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Bast

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I am very confused. 

1) Aren't lead acid batteries inherently dangerous in an enclosed space like a van. 

2) Since I am not certain what I am looking at can somebody ballpark (for the U.S.) what a 6 volt and 12 volt lithium battery should cost. 

3) Also please recommend one (lithium battery). 

4) Also why are people recommending 6 volt golf cart batteries when 12 volt batteries are available. 

5) Also do the batteries connected to solar power charge when the car is driving or when hooked up to shore power. 

Sorry
Bast
 

jimindenver

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Bast said:
I am very confused. 

1) Aren't lead acid batteries inherently dangerous in an enclosed space like a van. 

Yes there can be a danger of corosive and even explosive gas. It doesn't much of a vent to the outside of a enclosed battery box to mitigate it.

2) Since I am not certain what I am looking at can somebody ballpark (for the U.S.) what a 6 volt and 12 volt lithium battery should cost. 

3) Also please recommend one (lithium battery). 

2 and 3, sorry but I have no experiance with Lipo, their battery management or cost.

4) Also why are people recommending 6 volt golf cart batteries when 12 volt batteries are available. 

Generally two 6v will have much more Ah than your basic 12 volt battery. They also tend to be more suited for long term deep cycling as they have thicker plates and last longer. Then again it does take two and two 12v can be close to the same Ah.

Another way of looking at it is two 6v in series have the same Ah's as one of my huge 8-D's, just much easier to lift one at a time.

5) Also do the batteries connected to solar power charge when the car is driving or when hooked up to shore power. 

Batteries that are connected to multiple charging sources continue to charge. Each source sees the same battery voltage and will not be in conflict as long as they are set to achieve the same voltage points.

Sorry
Bast
 

TMG51

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Bast said:
I am very confused. 

1) Aren't lead acid batteries inherently dangerous in an enclosed space like a van. 

2) Since I am not certain what I am looking at can somebody ballpark (for the U.S.) what a 6 volt and 12 volt lithium battery should cost. 

3) Also please recommend one (lithium battery). 

4) Also why are people recommending 6 volt golf cart batteries when 12 volt batteries are available. 

5) Also do the batteries connected to solar power charge when the car is driving or when hooked up to shore power. 

Sorry
Bast

1) Sort of. Maybe. Technically, probably. So is running a propane stove/heater in an enclosed space. That's definitely dangerous, with carbon monoxide and such. We all do it. We just take responsibility for ourselves and crack a window to provide ventilation. The van life is a life of compromise and common sense... Yes lead acid batteries will have to off-gas at some point. How much they gas and how likely it is to affect someone can be debated, but, most people around here report no issues unless they are sensitive to smells.

2 / 3) I don't have a number, but lithium batteries get pretty expensive. Cell tower batteries are a solid lithium platform...

4) Because most (not all) 12v deep cycle batteries you see marketed are not really deep cycle batteries. "Marine deep cycle" batteries are an oxymoron as a marine battery is a compromise between a starter battery and a deep cycle battery. A true deep cycle battery is going to give you the best performance in a house electrical system and 6v golf cart batteries are true deep cycle batteries. If you find a true deep cycle 12v battery it's likely going to cost more than 2x what these golf cart batteries cost.

5) They can do either, or both of those things, depending on how they're wired. For charging off the car (alternator) you'd need something like a continuous duty solenoid to swap over. For charging off shore power you'd need a charge converter. Typically ideal setup is alternator + solar.
 

cognitive dissonance

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Bast said:
I am very confused. No worries. So are many of the people in the solar business!

1) Aren't lead acid batteries inherently dangerous in an enclosed space like a van. They can be, but as others have said, housing those batteries in a sealed/vented box is an easy solution. It's done all the time.

Personally, I use AGM lead acid batteries. AGM stands for "absorbed glass mat" and the battery itself is sealed so no need to worry abut venting.  These are true deep cycle, and are used by the truckload in commercial uninterruptible power supplies. You can buy take-outs in any big city for 25 cents on the dollar, and often they haven't been discharged more than once a year in testing. 

AGM batteries require NO maintenance. For this reason, I think these are superb for people who are new to solar, or mobile.  The number one reason for battery failure is poor maintenance, and I like eliminating that potential problem for people. 

I can't say how long these take out batteries last, because I've only been using them for 5 years. Sizing the battery bank is key to this - the deeper the depth of each discharge cycle the shorter the life of the batteries.  Proper charging is equally important, and unfortunately most people in the business have no clue about this.   


2) Since I am not certain what I am looking at can somebody ballpark (for the U.S.) what a 6 volt and 12 volt lithium battery should cost. These are expensive, and I've never worked with them.  As far as I'm concerned, the only reason to consider them is if your rig can't handle the weight of less expensive alternatives.

Having said that, no one can give you an answer until you figure out how many amp hours of capacity you need. The basic formula for that is as follows: daily load x days of desired autonomy (how many days you can go without charging the batteries) x 2 (if 50% depth of discharge is acceptable) or x 3 if you want only 33% depth of discharge.  (I stick to 33% DOD because, again, batteries last far longer when you don't discharge them as deeply.)

Here it is in round numbers:

Daily Load: 100 amps
        - times -
Days of Autonomy: 2
        - times -
Depth of Discharge: 3 (33%x3)
        - equals -
600 amp hour battery bank.

To calculate daily load, either look up (ok) or measure (better) what each electric appliance draws.  Then multiply by the number of hours it runs each day to get the daily load.

3) Also please recommend one (lithium battery). Don't know enough about them to do this. 

4) Also why are people recommending 6 volt golf cart batteries when 12 volt batteries are available.  As others have said, deep cycle batteries were typically built in 6 volt units.  I usually don't recommend them, unless it's to replace like batteries in an existing system. All of the AGM batteries I have used are 12 volt, which I prefer.

5) Also do the batteries connected to solar power charge when the car is driving or when   hooked up to shore power. This depends on how you hook things up.  I'm an off-grid autonomy kind of guy, so I charge from PV or alternator only.

It's no big deal to charge from shore power as well. Millions of RV's already do that. (This practice strikes me as absurd. It just makes no sense to drive around in a dark colored, poorly insulated RV and then need 50 amps shore power or a loud generator to run 3 a/c's on the roof in order to be comfortable.)

You will have many more questions, but this should help you get started.
 

johnny b

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From some research I've done online...

100 amp hour LiFePo4 (4 x 3.2volt cells) without BMS (battery management system) - $500-600. Needs careful monitoring of charge and discharge to avoid damage and or shortened life. (not too different from what's required of AGM or flooded batteries)

100 amp hour LiFePo4 self contained with built in BMS - $1000.

Claims of 10 year lifespan and thousands of cycles down to 20% vs Lead's 3-5 year span and hundreds of cycles to 50%.**

**[Actual lifespan/usage may vary according to individual's care and maintenance---so don't flame me if you get better mileage!] :D
 

SternWake

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While AGMS do not require watering, and their terminal connections likely never will require removal and cleaning, to say they are completely maintenance free is not quite right either.

AGMs are finicky princesses regarding their recharging. When deeply cycled they really want higher recharging currents, and it is more important to return these batteries to 100% charged more often than their flooded counterparts.

Anyone with a close eye on a voltmeter can notice an AGM's voltage under load dropping a little bit more each night in the same usage, as capacity walks down. Once it begines this capacity walk down, the battery neds a high amp recharge from its most depleted state, followed by a true 100% recharge.

This 1005 recharge on a AGM battery, whose capacity has walked down from many cycles of not quite getting back to 100%, requires that absorption voltage be held for as long as it takes for amps to taper to 0.05% of capacity, 0.5 amps per 100AH of battery capacity. On a healthy AGM battery, this might only take 2.5 hours once absorption voltage has been reached.

On a battery that has seen 30 deep cycles, and only recharged to 98%, and never a high amp recharge, this time required at absorption voltage can require 10+ hours.

If the 100% recharge is not regularly attained, the AGM battery can pack up all its toys, and go home.

They are not an Easy solution to offgassing, if one cycles them deeply( to the 50% range). When cycled deeply night after night, they require the high amp recharge, and the true 100% recharge every so many cycles then becomes mandatory, or their capacity will diminish rapidly, and they will not last as long as their cheap flooded battery would in the same treatment.

AGMS can only achieve the magical battery status that their price fools people into believing, IF their needs are met, or if they are cycled only very shallowly and reach 100% daily.

So while no watering or terminal cleaning need be performed, high amp recharging and ensuring a true 100% charge is maintenance more important to their lifespans. When the capacity has declined, the ability to hold absorption voltage for as long as required until amps taper to the 0.05% of capacity, then becomes a mission, and without the right charging sources available to accomplish this, the battery lifespan is shortened, and can be shortened dramatically depending on just how shy one gets of a true 100% recharge and how often.

AGM batteries can be tickled to death with too little charge current too. Even if a solar system might be able to return all the AH consumed+10% by sundown, the solar might not fulfill the need for the occasional high amp recharge.

My Northstar 90AH AGM battery performance begins to tank after 4 or 5 cycles with only solar as the recharge source. What slaps it across the face back into performing well, is the high amp recharge applied when it is most depleted. Either Via alternator or my 40 amp adjustable voltage plug in charging source.

Without the alternator, and or the 40 amp plug in charging source, this battery would likely be useless at this point, instead of performing very well at 250+ deep cycles( to 50%) + another 150 shallower cycles to 80%, and a couple thousand engine starts in the 2.5 years I've had it.

So I consider the high amp recharge, and the ability to hold absorption voltage for the duration needed for amps to taper to 0.05% of capacity at absorption voltage, to be maintenance. While not cleaning the battery terminals or watering the battery is nice indeed, without the ability to occasionally meet my AGM's high amp recharge from its most depleted state, followed by the true 100% recharge, this battery would not last long enough for corrosion to grow or watering to be required, if it were a flooded battery.

6 volt golf cart batteries do need watering, and their terminals can corrode and need maintenance, and they have to offgass to reach full charge, they will Out perform pretty much ANY lead acid battery in deep cycle usage. They are easier to fully charge, and more tolerant of improper charging than any other lead acid battery. They are simply the best bang for the buck. The only issue is their height, and their offgassing. Cover these two bases and you will be miles ahead in the long run.

If 230AH of capacity is way more than required, then Trojan makes the T-1275 battery, which is a 12v battery at 150AH of capacity, and is one of the ONLY true deep cycle 12v batteries available.

Even the 12v group24, 27 or 31 batteries made by trojan, USbattery, Crown, or Deka, are NOT true deep cycle batteries, but they are top of the line marine/dual purpose batteries, and far superior to the flooded marine batteries sold in wally world or autoparts stores. But their lifespans might be only 25% greater for their 25% greater price in the same usage, so it can be a catch-22. Acquiring a quality marine battery from the manufacturers listed above, and warranty service if needed, usually has most lean in the wally world direction. Which is OK, as long as one is nearby a wally world when it fails, and not too inconvenienced when it does.

I am firmly in the 'never again' category concerning wally world batteries for my usage, but for a newb to 12v, they make a lot of sense, as the Newb is likely to be a battery murderer, overdischarging the battery, never truly fully charging it, and then seemingly totally surprised when it 'no longer takes a charge'
 

cognitive dissonance

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Wow, SternWake.  That's a whole lot to dump on someone admitting confusion and pointedly asking beginner questions - particularly when all you really said is that batteries of any type need to be charged in a manner appropriate for the type.
 
For where Bast is at, I said all that was needed at this stage: "Proper charging is equally important, and unfortunately most people in the business have no clue about this." 

This is clearly not the time to get all technical on batteries.  It would have been far more humane of you to just chime in that yes, AGM batteries are indeed more sensitive to proper recharging than other battery types, and to really keep that in mind if those are the batteries eventually chosen.

I like to give people some benefit of the doubt, and I rarely try to scare them. It's not at all difficult to 1) read what a battery manufacturer calls for in terms of charging, 2) make sure you have the PV (or alternator) to do it, 3) choose a charge controller that works well in the application, 4) set it appropriately, and 5) include a good meter in the system so you know what is actually happening.
 
Nothing special there.  Fact is, all of these things must be done in any properly designed system, regardless of battery choice. Wouldn't you agree?

Further, almost every system ends up being a compromise of some sort.  Bast is far from grasping any potential compromises, which is why I skipped over them for now. To be helpful, we need to build an understanding of loads before we should address anything else.

Also, absent bad information, there's absolutely no reason for a "newb" to murder batteries. Assuming they care (and Bast seems to) they just need to know what to do. Anytime I help someone who wants to learn something like this, I take them one step at a time. The first step is understanding loads, which was the only thing I was really specific about at this point.  That was deliberate, because, again, you really should build understanding one step at a time.

I note that you use an AGM battery, and that you aren't having all the battery angst you describe. In fact, you say it's performing well. I also note that proper charging was simple for you to arrange. I sure don't see good reason for anyone else to borrow trouble now.
 

SternWake

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Well, inspiring angst is not the goal, my goal here is to prevent batterycide.

Many people assume an AGM battery is some super battery due to being 2 or 3 times more expensive, but the reality is the AGM requires a more finely tuned system, and a higher level of basic requirements be met to get a good lifespan from them.

So they often appear to be a solution to the gassing issue, and their finickyness as to their proper treatment to achieve an acceptable lifespan, # of cycles per $ ratio, is overlooked or glossed over.

Your post glossed over these facts, I brought out the 36 grit sandpaper and went to town. Not trying to scare the OP, just trying to save them headache when their possible pricey petulant AGM battery decides to pack up all its toys and go home, due to less than adequate treatment, which might be adequate for a flooded battery which costs half or 1/3 as much.

No offense.

And Newb's do murder batteries. They do not have to, but until they have a grasp of how much capacity they need to power their items for as long as they need to power them, AND how much recharging is required to keep the battery happy enough, will continue to commit batterycide, until they do grasp the issues of living from 12 volts DC and all the limitations of doing so.


AGMS are a special needs battery, this cannot be glossed over. If one does not know or care about their special needs, then one will pay more just to have them fail early.

Meet their occasional need for a high amp recharge, or do not bother with them, unless ones budget, and lower back, can replace them prematurely without issue time and again.
 

SternWake

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cognitive dissonance said:
Special needs batteries. Who knew?

Do you recommend them for short buses?

I don't think any battery is going to out cycle a 6v flooded golf cart battery.  These are simply the most tolerant of the type of usage typically seen in this lifestyle.

If one wants the AGM, and wants them to last, AND to cycle them deeply, then the high amp recharge needs to be done, every so often.   The less deep the discharge, the less important it becomes to meet the high amp recharge on occasion.

But after many days of cycling deeply, and in incomplete recharge each day, then the battery capacity will have effectively shrunk to a smaller size, than the same size flooded battery treated the same way.

While the flooded battery at this point does not require any special current to return to near full capacity, given enough time at absorption voltage, the AGM battery wants, and craves, a higher initial recharge current to force the migration of electrolyte in the plates.  If the high amp factor is not achieved, the battery will still appear to take a full charge, but if one were to have an AH counter, and notice voltage held for the AH removed, one would easily notice it is lower than expected, the battery is in effect starting out fully charged, but with less  initial capacity.

I've seen this time and again with my own 90AH AGM.  Even cycling to only ~66% state of charge and solar only recharging.  After 5 cycles, the voltage held for the AH removed is 0.1 to 0.15v lower than on night one.  This is even achieving 14.5v and amps tapering to 0.05% of capacity each day before ending absorption voltage and dropping to float.

Day 5 or 6 early morning, this battery, I drained to ~12.2v overnight, gets either 40+ amps from the alternator, and or my Meanwell 40 amp power supply, and the solar can then hold the voltage at 14.5 until amps taper to 0.4, and then it returns to full performance.  It cranks my engine with a gusto it had lost in a solar only recharge regimen, and during discharge that night, the voltage held for the AH removed from the battery is back up in the impressive territory.

The Northstar is a high$$ AGM, like Odyssey and Lifeline.  These batteries have no upper limit on charging amperage, as long as voltage is not allowed to exceed 14.4(LL)14.46(NS) and 14.7(Odyssey).

Lesser $$ AGM batteries exist.  Like the Vmaxtanks on Amazon and the often rebranded Deka intimidator AGM sold at sams club and costco and elsewhere.

These lesser AGMS have a limit on charge amperage.  no more than 30 amps per 100Ah of capacity.  While exceeding this briefly is no big deal and hardly an instant battery killer it should be realized that these batteries, given a basically unlimited charging source, like a well wired cool vehicle alternator spinning fast, these batteries can drink faster than they should.  These lesser $$ AGMs still appreciate the higher initial charge rates approaching this 30% rate.  They 'might' also be more tolerant of a low and slow, solar only, recharge regimen.

They are certainly less painful to replace if they are killed prematurely.

Basically, the AGM battery, to live anywhere  near the manufacturer's  claimed cycle life, requires a more exacting recharge regimen, and the harder the battery is used( depleted deeper) the much more important proper recharging becomes.  The 6v GC battery is simply more tolerant of less than ideal recharging.  It is the easiest battery to keep happy. and costs the least if one needs 220AH of house  battery capacity.  Dealing with the offgassing, occassional watering, and their increased height, is the only downside with them.

But one can get 220Ah of GC battery for 200$. 220 AH of AGM is looking at 375 to 650$ just for the batteries, and a solar controller with programmable settings is more$$.  Wiring up the alternator becomes more necessary, more time and $$, and a plug in charging source likely should be factored into the equation too.  One which can approach a 30% rate, or ~ 65 amps for 220AH of AGM battery and whose absorption voltage  is close to that recommended by the AGM manufacturer.

So no only do the AGMS cost more, the charging accoutrements required to meet their peculiar desires cost more too. 

While AGMs are considered a no maintenance battery, if they were a person one is in a relation ship with, they would be considered high maintenance., and only with a surplus of everything they want, could they be kept happy.

http://www.allbatterysalesandservice.com/browse.cfm/4,576.html

If I ever buy another deep cycle flooded battery again, I am getting this one:

http://www.trojanbattery.com/product/t-1275/

I could stuff it underhood where the original battery mounted, with some modification.


  My Van cannot tolerate the height of 6v GC batteries, without sacrificing ground clearance and much other modification.  I am not willing to lose interior space or share the air with them either.

 If it/I could, No way would I be cycling this 325$ Stubborn princess  AGM.

My plan is to make this AGM last until I have a Solid grasp of LiFepo4 and the funds to set them up properly, and more trust in the purveyors of these prismatic cells.
 

akrvbob

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I think we've hashed out that particular part (AGM charging) of his questions pretty well.

Let's get back to his other questions.
Bob
 

ccbreder

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from SW, "6 volt golf cart batteries do need watering, and their terminals can corrode and need maintenance, and they have to offgass to reach full charge, they will Out perform pretty much ANY lead acid battery in deep cycle usage. They are easier to fully charge, and more tolerant of improper charging than any other lead acid battery. They are simply the best bang for the buck. The only issue is their height, and their offgassing. Cover these two bases and you will be miles ahead in the long run."
I have to second this about golf cart 6 volt batteries. Except to add, don't be over worried about off gassing. Get a pair of GC batteries.
 

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