Making the right call on batteries

[Mountain Gnome]

Originally Posted by LargeMargeInBaja

.
We built our Concorde LifeLine AGM bank new in early-2003 ('2002' is molded into the cases)

Nearly two decades, four of our original eight are still puttering along.
I think the key to longevity is using a couple-three percent during peak photovoltaic hours, then immediately re-filling.

Interesting life span that I wouldn't expect.


FWIW, I'm using FLA starter batteries for my deep-cycle house bank.


I had one single one at first and worked it hard, down below 12VDC many times. I would charge it with a Black & Decker 15-amp charger. It would run 15 amps for maybe an hour, then slowly drop down to 1 over another 30-60 mins, and then shut off. After a few months of that, the battery would only show 12.5VDC after charging and then sitting a few hours.


But when I charged it while using the stereo, pulling 5-12 amps (depending on listening volume), it might take a bit longer, but the battery would then sit at 12.7-12.8 VDC.


I think maybe the charger would cut out at 1-amp, but the battery would still take 0.5 amps and charge more, and got what it needed when the radio was on. Cheapo-creapo charger? Fact about lead-acid batteries?


My alternator would charge it in 20-30 minutes, from below 12VDC. In just 5 mins, it would be at 12.6VDC, but drop to 12.5VDC in an hour. Like it wanted that last half-hour of trickle, but would fill near-full pretty quick.


I like that fill-up-quick with the alternator thing that FLA batts have.. It suits my drive-daily lifestyle.


For now, I think that keeps me happy with regular FLA for deep-cycling. Then I just put new starter batteries in on a regular basis, and rotate the old ones to house-service. Then I feel better about parking in remote areas, with a nice, new starter battery, not waiting until it dies.


Maybe when I get money for solar (will I ever stop putting $$$ into fixing this beast and get back to upgrading it?) I'll go LiFePo or something. As it is now, tranny dead and waiting for a fix, I wish I had choke solar and a big bank. Don't want to idle the big diesel beast just to charge batts.

[john61ct]

[QUOTE=jawild;456632]According this [URL="https://www.skoolie.net/forums/Lithium batteries provide 100% of their rated capacity, .[/QUOTE]This is categorically false.

Disregard that source, has no credibility.

[john61ct]

Originally Posted by jawild

Do I understand correctly that, for example, a 100Ah lithium battery will last longer than a 100Ah wet battery at the same high rate of discharge? In other words, at high discharge rate, a lead-acid battery's SOC will decline faster than the lithium battery?

I assume high rate of discharge would result mostly from the inverter trying to supply an AC unit, etc.

Do not try to run loads like big aircon off stored energy, foolish rich man's game. Use an inverter genset.


You do not want to inflict a high rate of discharge on any bank.

The correct unit is C-rate so 100A from a 100Ah battery is 1C

40A is 0.5C, and that is as high as I would reco for lead, unless for a peak draw for just a few seconds.

Since lead should normally only be discharged to 50% SoC only 50Ah is available, so you would only get maybe 20min at 40A.

LFP 100Ah say 80Ah is usable for good longevity, maybe 90-100min.

You could go to 1C or 100A, but that would then only last a bit over one hour

[HamSkoolie]

Originally Posted by Rwnielsen

I'm close to buying batteries too. My main issue is that they have to be inside the bus ss I don't have the room outside. I can get lifepo4, 600 Ah for around $2400 ,possibly less if I assemble them myself. I wouldn't feel safe with an FLA bank venting inside not to mention leakage. I had not considered AGM batteries but at about 1/3 the price....
My main usage will be a 12 volt compressor fridge, water pump, diesel heaters and misc LED lighting. I have on-board generators and a 4500 watt backup and 900, or so, watts of solar (3 panels).

I sent you a message with the link to the ones we're considering. You can get 5.12kWh of lithium for $1500

[john61ct]

Originally Posted by cadillackid

good stuff.. since I have room for 2 more batteries it sounds like the idea would be to install them as to reduce the depth of discharge overall for the same amount of Watt-hours I pull.. that should help me with longevity. also makes sense to continue plugging into shore power every night that I can for top-off with these batteries..

yes, with shore power readily available every night can get away with smaller bank size

really just gives you a buffer while off grid

Ah per 24hrs input must always exceed output, averaged over say 2-3 days if the bank is big enough.

LFP can full recharge in a couple hours if amps are high enough

Lead always needs at least 7+ hours, more at lower currents

[HamSkoolie]

Originally Posted by john61ct

Yes FLA are fine inside the living space, so long as you don't seal up their cabinet, allow the gas/vapors to dissipate.

ABSOLUTELY WRONG


Flooded Lead Acid batteries off gas Hydrogen gas in addition to acidic vapors. Hydrogen is EXPLOSIVE.
FLA batteries can be inside living spaces ONLY if they are sealed from the living space and ventilated to the outside. They cannot be near sources of ignition including flames, sparks, or heat.


Putting FLA batteries inside a rig is a recipe for disaster as well as begging your insurance to deny any claims resulting from fire.

[john61ct]

Originally Posted by HamSkoolie

I sent you a message with the link to the ones we're considering. You can get 5.12kWh of lithium for $1500

Post that link publicly please, suspiciously low.

Quality barely used secondhand can fetch more than that.

plus delivery costs.

[HamSkoolie]

Originally Posted by john61ct

Post that link publicly please, suspiciously low.

Quality barely used secondhand can fetch more than that.

plus delivery costs.

It's the best deal out there unless you build your own (which is a horrid idea for anything except an isolated building due to insurance balks). AFTER we get ours we'll post the url publicly but I was okay trying to help out an individual.....there's a serious supply/demand issue in this country and these batteries are seriously in demand. If you'd like I can PM you a review link from a popular YouTuber.

[john61ct]

Originally Posted by HamSkoolie

Flooded Lead Acid batteries off gas Hydrogen gas in addition to acidic vapors. Hydrogen is EXPLOSIVE.
FLA batteries can be inside living spaces ONLY if they are sealed from the living space and ventilated to the outside. They cannot be near sources of ignition including flames, sparks, or heat.

Putting FLA batteries inside a rig is a recipe for disaster as well as begging your insurance to deny any claims resulting from fire.

Poppycock and balderdash.

The only danger risks from lead batteries beyond general electrical ones

A. letting the fumes concentrate inside a sealed up box

B. continuing to use them at high C-rates long after they've reached EoL, they should be replaced at 70-80% SoH%

which last is just as true for AGM and GEL.

Obviously venting to the outside is a good idea, but following the guidelines in the post you responded to, totally optional.

[john61ct]

Originally Posted by HamSkoolie

It's the best deal out there unless you build your own (which is a horrid idea for anything except an isolated building due to insurance balks). AFTER we get ours we'll post the url publicly but I was okay trying to help out an individual.....there's a serious supply/demand issue in this country and these batteries are seriously in demand. If you'd like I can PM you a review link from a popular YouTuber.

No interest in YouTubers especially prats like Prouse.

No interest in drop-ins.

Putting an LFP bank together from cells is not DIY and not at all risky in fact an easily replaced BMS is much safer and better for longevity

never trust BMSs they destroy so many banks

never fly blind without access to per-cell voltages

[HamSkoolie]

Originally Posted by john61ct

Poppycock and balderdash.

The only danger risks from lead batteries beyond general electrical ones

A. letting the fumes concentrate inside a sealed up box

B. continuing to use them at high C-rates long after they've reached EoL, they should be replaced at 70-80% SoH%

which last is just as true for AGM and GEL.

Obviously venting to the outside is a good idea, but following the guidelines in the post you responded to, totally optional.

Allowing EXPLOSIVE GASES (and acidic vapors) into the living environment is asking for trouble and violates any and all safety codes. There is NOTHING that justifies doing so except total disregard for safety and human life.
Its simply not up for debate. I have my educated and professional opinion as a formally trained and formerly ASE certified mechanic in ELECTRICAL SYSTEMS as well as a about a decade as a safety inspector at the federal level.
You have your opinion based upon whatever makes you think its okay.

[john61ct]

Farts can be explosive in specific circumstances too, but it would simply be fear-mongering to claim they are dangerous.

The quantity of gasses released by FLA batteries is very very small.

The box being ventilated means they are dispersed / diluted so that they are no longer harmful.

Cooking a spicy dinner would cause more discomfort than even 800Ah bubbling away toward end of the CV cycle

but just the same if you felt discomfort, the solution is easy, just crack a window or turn on your vent fan.

If you are sensitive to the smell by all means vent to the outside

but preventing explosions is not the reason to do so.

[cadillackid]

Originally Posted by HamSkoolie

ABSOLUTELY WRONG


Flooded Lead Acid batteries off gas Hydrogen gas in addition to acidic vapors. Hydrogen is EXPLOSIVE.
FLA batteries can be inside living spaces ONLY if they are sealed from the living space and ventilated to the outside. They cannot be near sources of ignition including flames, sparks, or heat.


Putting FLA batteries inside a rig is a recipe for disaster as well as begging your insurance to deny any claims resulting from fire.

THIS is what i was always told about FLA batteries.. and in my business where FLA batteries were used in UPS systems there was always a pretty elaborate venting system and system that monitored the ventilation as well.



I used to work on these systems and the test procedures we had to go through during yearly system services for the HVAC most definitely required several tests on the VENT system for those rooms..



in the last number of years ive started seeing many UPS systems just installed in the equipment room that is of course A/C'd and ventilated but is not like the old FLA banks were..



FLA seems like the big push buit I dont think its the right tool for everyone


I havent tried to do much A/C with the batteries.. A/C on battery except maybe at night is a futile game for me in this bus.. its almost 32 years old.. has non tinted windows and all factory insulation.. im not willing to ruin its classic-ness by tearing out the inside panels, nor am I willing to turn it into a cold dark drab cave by removing or tinting some / all of its windows.. so for me the right tool to A/C is the diesel engine under the hood...

agaiun at night my portable inverter A/C actually does OK and doesnt run at 100% so my batteries do work with it then..

[HamSkoolie]

Go for it... they're always looking for Darwin contestants.
Having seen batteries explode due to hydrogen in NON SEALED areas and having read lots of accident reports on batteries of various chemistries, I prefer to stick with the expert advice and keep explosive gases as well as corrosives out of the living quarters.
How many commercial RV's do you see built with batteries in the living quarters? There's a reason for that.

[cadillackid]

Originally Posted by HamSkoolie

Go for it... they're always looking for Darwin contestants.
Having seen batteries explode due to hydrogen in NON SEALED areas and having read lots of accident reports on batteries of various chemistries, I prefer to stick with the expert advice and keep explosive gases as well as corrosives out of the living quarters.
How many commercial RV's do you see built with batteries in the living quarters? There's a reason for that.

uhm i think you mis read me... I was agreeing with you about NOT using FLA batteries indoors.. thus why my batteries are AGM....

[kazetsukai]

Originally Posted by HamSkoolie

It's the best deal out there unless you build your own (which is a horrid idea for anything except an isolated building due to insurance balks).

I'm not aware of really any prolific insurance problems exclusive to building one's own battery bank from cells, this seems like nonsense...

Originally Posted by john61ct

Putting an LFP bank together from cells is not DIY and not at all risky in fact an easily replaced BMS is much safer and better for longevity

never trust BMSs they destroy so many banks

never fly blind without access to per-cell voltages

I have to second this.

If you are seriously considering lithium out of need, you're looking at building a pretty high performance system. The end product of a self-built 1P8S or 2P4S prismatic pack is a whole different animal than four "12V" LFP batteries paralleled.... I don't see any sense in building a bank using 12V LFP batteries whatsoever. They are perhaps good as a drop in replacement for a _single_ battery when it will always be under ideal temperature conditions, many people show off banks of these wired in parallel... Nobody nowhere recommends you run lithium cells which are already wired internally in series in parallel, and that is exactly what is happening in that case.

I'll also repeat the analogy- If you cannot monitor cell health you are flying blind and lithium chemistries are not very tolerant of abuse. Under normal operating conditions cell drift can occur and cause abuse to cells within a pack... the overwhelming majority of balancing circuits don't hold a candle to even the most modest of solar charge controllers. For best life, performance and safety you should regularly, manually, check cell health. Not possible with self-contained, sealed packs.

[dzl_]

Originally Posted by kazetsukai

I'm not aware of really any prolific insurance problems exclusive to building one's own battery bank from cells, this seems like nonsense...

I'm not aware of any either. Though when it comes to insurance without positive confirmation I dont have much confidence in anything.



IF the batteries, or the electrical system more generally caused the problem (and were grey market or used cells, or especially non LFP lithium cells meant for EV's and an amateur install), I could imagine an adjuster denying the claim or trying to. But in any other circumstance, I suspect, the insurance company would be completely oblivious to the type of battery used, and not see the need to look into it.


But as with many things skoolie related, and DIY related, there is a big vague grey area that is not clearly defined.


As with everything, but especially with high energy battery systems, everyone should do their due diligence, spend the time to learn and do it right (or pay someone to do so), and don't be negligent/dangerous/pinch pennies on safety. People often debate LFP in terms of cost in $$, but in my opinion, one of the largest deciding factors is whether you are willing and able to should the cost in time/energy/attention to learn what you need to learn to build a system responsibly. This is true of DIY electrical in general, but building LFP battery packs (while not that difficult on one hand) introduces a lot more potential error/danger points.

[cadillackid]

I fail to see the problem with series-parallel systems? if you want 12 volts and not 48 volts why wouldnt you series the cells till you reach 12 volts then parallel the banks?



monitoring at the cell level could still be obtained.. but you arent working with 48 VDC and having to convert everything thats non standard or stuck having to order any piece that fails..



ie if I have a 12 volt 'bank' then I dont need a DC-DC converter to run my 12 volt accessories .. a 12VDC to 120VAC inverter is much easier to find if I was out on the road and had one go bad vs having to be stranded up waiting on a 48 VDC to 120VAC inverter to show up wherever you are.. or having to just deal with not having any 120 VAC appliances till you got home..



I suppose if someone is Geeked out about their batteries like I get Geeked-out about A/C then they can build the perfect system which is perfeclty monitored.. and that person knows how to properly read all the data they get.. but the average joe has X,Y,Z amount of space with which to put batteries.. and if they can get much more WH from LFP and afford them then thats what they are gonna stuff in the space, turn it on and go... thus why 12 volt batteries are sold and paralleled together.. id say 99% are in the category of wire it up, turn it on and go..



then there are the 0.1% taking chevy volt or Prius batteries and building an elaborate system that more than likely works much better and lasts longer.. but poor average joe wouldnt have a clue how to know whan it brioke if it did..

[Rwnielsen]

Just for clarification...FLA is flooded lead/acid is it not? A "car" battery?

[kazetsukai]

Originally Posted by cadillackid

I fail to see the problem with series-parallel systems? if you want 12 volts and not 48 volts why wouldnt you series the cells till you reach 12 volts then parallel the banks?

You parallel first. Parallel the cells until you reach desired capacity and then series for voltage. For 12V with LFP this would be 4S. If you parallel multiple 4S packs instead of doing lets say, 2P4S or 4P4S, every pack needs its own BMS and cell drift is easier than in a parallel-first configuration. A single cell failing the wrong way could lower the voltage of one battery, causing the others to dump energy into it uncontrollably, raising the voltage of the other three cells in the bad pack. Finally, as energy moves in small amounts between paralleled packs, that is a form of micro-cycling that will reduce the usable lifespan of the bank.

Originally Posted by cadillackid

Monitoring at the cell level could still be obtained.. but you arent working with 48 VDC and having to convert everything thats non standard or stuck having to order any piece that fails..

Not for sealed 12V packs without opening them, voiding warranties/etc. Also if you have 4x 12V packs paralleled, you have 16 voltages to check rather than 4x voltages to check in a self-built 4S pack with cells paralleled, 4 BMSes that can fail, etc.


Pieces failing: I have 4 spare cells and relevant hardware on hand for that purpose.

Originally Posted by cadillackid

ie if I have a 12 volt 'bank' then I dont need a DC-DC converter to run my 12 volt accessories .. a 12VDC to 120VAC inverter is much easier to find if I was out on the road and had one go bad vs having to be stranded up waiting on a 48 VDC to 120VAC inverter to show up wherever you are.. or having to just deal with not having any 120 VAC appliances till you got home..

Maybe you misunderstand- my argument is instead of using "12V" lithium packs in parallel to get capacity, use 3.2V (LFP) cells paralleled and then series to get desired voltage. If you want 12V, great. 2P4S, 4P4S, 8P4S.... whatever capacity you need, you can get using paralleled cells. Parallelizing packs is just not a great idea.

Originally Posted by cadillackid

I suppose if someone is Geeked out about their batteries like I get Geeked-out about A/C then they can build the perfect system which is perfeclty monitored.. and that person knows how to properly read all the data they get.. but the average joe has X,Y,Z amount of space with which to put batteries.. and if they can get much more WH from LFP and afford them then thats what they are gonna stuff in the space, turn it on and go... thus why 12 volt batteries are sold and paralleled together.. id say 99% are in the category of wire it up, turn it on and go..

The problem is, paralleling 12V LFP batteries is just not recommended. There are problems with parallelizing already series-wired lithium packs which I outlined above.

Originally Posted by cadillackid

then there are the 0.1% taking chevy volt or Prius batteries and building an elaborate system that more than likely works much better and lasts longer.. but poor average joe wouldnt have a clue how to know whan it brioke if it did..

"Average joe" has a few options- run the 12V premade packs in series for higher voltages, that's fine... or use lead acid in parallel, also fine. You generally cannot combine ignorance and high performance. Maybe as chemistries like LTO become more common or solid state or some other low maintenance tech takes over... modern EVs have an insane amount of monitoring built into the energy systems of the car. Failure is taken into consideration in the design of those systems.



Average joe can build and be successful using lithium in solar setups that require the performance/capacity, they cannot do it remaining ignorant. Lithium systems require a level of understanding to operate, I'd argue any solar setup really requires a level of understanding by the operator to be remotely successful, and that's before adding in things like AC power systems / inverters/etc.