# Lifepo4 Batteries



## Kenny007 (Jan 30, 2016)

Hello,
Battery Experts Need some help-
Looking for some advice, 
Looking to power my marine inverter with a lipo pack 400-600 amp hours 
looking for the best cells for the money 

1) Chevy volt cells 200amp hours 2015 lg cells 
2) GBS cells 4-100 amp packs 
3) Calb cells from electric car parts 400 amp 4 cells
Space and weight is not a issue 
I want the best cells for the money 
Thanks In Advance 
Ken


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## jwiger (Oct 18, 2014)

What do you plan on using for charging?


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## Kenny007 (Jan 30, 2016)

Hello,
plan on using my xantrex sw3012 (second generation) inverter to charge the batteries
It has adjustable charging amps and low and high set points (bulk charge only )
and a bms just don't know which one yet,
Thanks Ken


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## onegreenev (May 18, 2012)

What is your primary voltage going to be? 12v, 24v or 48 volts. Do you have a charge controller that will charge your desired voltage? You will also need a way to shut off your batteries completely from your system when they reach the desired depth of discharge so you don't ruin them in the event of a discharged pack when you are not around. You do not want any drain from your pack if your pack becomes low for any reason. Not even a monitoring device because that will also continue to discharge and when they discharge to a point they will discharge fast even with a tiny load. This goes for all lithium chemistry. Once you do have your system up and running and and you come back to a pack with no power then you should be good to know your pack is discharged and ready to be charged. If you have a good charge controller you should be able to have that charge if the charge goes below a little higher voltage. The low complete discharge device should be the final fail safe. 

Pete 

Leaf cells, Volt cells should do just fine as well as a good set of LiFePO4 cells. I'd go with LiFePO4 myself.


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## Kenny007 (Jan 30, 2016)

Thanks for the advice Pete 
its going to be a 12 volt system


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## onegreenev (May 18, 2012)

So 4 series LiFePO4 Cells will give you a 12 volt system. You can set up as many in parallel as you want then tie 4 of those parallel strings to give you your AH rating you desire. Leaf Modules are harder to use because they are nominal 7.4 volts. They comprise of two parallel two series per module. If they just made each module a set of 3.7 volts nominal it would be much easier to build an off grid system with them. But because they are doubled up in each module you can only fine tune to the tune of 7.4 volts nominal. So it would be harder to do a 12 volt pack with Nissan Modules. So two modules would give you a fully charged pack of 16.4 volts. Well above the 12. But your inverter may still work but most charge controllers do not. I'd suggest you use LiFePO4 cells. Your charge controller should be able to handle that just fine. As for a BMS, you may not need an elaborate one. A way to check your voltage at will and a way to completely shut off the pack from ANY load like I mentioned even from the voltage meter. You can have a setup that will allow the charge controller to keep the battery filled up during normal use but you won't need the float with lithium. If your setup allows your cells to sit for very long periods you don't want them to sit fully charged. If lets say you leave your system unused for like a 4 month stretch you should discharge them half way for storage purposes then have them charge back up when you need to put them into use. For my home, I plan on using my Leaf Modules but I plan on cycling the cells daily.


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## Karter2 (Nov 17, 2011)

A123 12v Ultrphosphate battery. 60Ahr.
http://www.a123systems.com/lithium-starter-battery.htm


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## onegreenev (May 18, 2012)

Karter2 said:


> A123 12v Ultrphosphate battery. 60Ahr.
> http://www.a123systems.com/lithium-starter-battery.htm


Thats only 60 AH. It has a potential of cranking out 900 amps if you need that sort of load.


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## ricklearned (Mar 3, 2012)

Back to your original question, and the three choices you outlined Pete is correct, it might be difficult to configure Leaf cells to a pack voltage that will work with off the shelf charge controllers/inverters. As far as the two other choices, I have heard CALB have a better reputation than GBS. To get prices down to a usable common denominator divide Amphours by dollars to get cost per Amphours. Several years ago I purchased some LIFEPO4 batteries for $1/Amphour. You originally said you wanted 600 Amphours. If you meant that capacity for a 12V system you would need 2400 Amphours of batteries at 3v nominal (approx $2,400). I am a big fan of Battery Management systems but for only 4 cells in parallell you probably only need low voltage and high voltage cutoff relays.

Sent from my SM-N910T using Tapatalk


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## Kenny007 (Jan 30, 2016)

Hello, 
Thanks everyone for the advice-
I was looking at electric car parts 400 amp hour calb cells
they are 400amp hours each they are @ $525.00 a cells I would need 4 cells for 400 amp hours, was just wondering amp hour to amp hour 
what the best cells are 
Thanks Ken


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## Karter2 (Nov 17, 2011)

Kenny007 said:


> Hello,
> ......just wondering amp hour to amp hour
> what the best cells are
> Thanks Ken


You have to define what you mean by best !
Usually "Best". means quality, or performance.
Either of those would point back to A123.
.....but maybe you are looking for something else, like cost ?


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## okashira (Mar 1, 2015)

A123 makes the best /if not only good quality LiFePO4 cells.
I happen to have a bunch of them we're trying to sell
See My FS thread


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## onegreenev (May 18, 2012)

Kenny007 said:


> Hello,
> Battery Experts Need some help-
> Looking for some advice,
> Looking to power my marine inverter with a lipo pack 400-600 amp hours
> ...






Do you want pouch cells or 26650 cells? I purchases some A123 for testing. They are excellent but expensive. Super high output and still LiFePO4 chemistry. I think they would be great for a large pack that needs high output for racing purposes. Not for huge packs unless the cost comes way down per cell. 

http://www.a123systems.com/lithium-ion-cells-26650-cylindrical-cell.htm

50 amp continous discharge and up to 120 amps discharge for 10 seconds. Enough for a quick trip down the track. 2.5 ah each.


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