High Quality 100AH LiFePo vs. DIY 4 - 3.2V Cells

[bear0214]

Looking for some feedback/comments on purchasing a high quality 100AH LiFePo4 (BattleBorn, etc.) vs. building my own 12V LiFePo4 with 4 of these and adding a high quality BMS. https://solarsupplyhouse.com/product-category/lifepo4-high-capacity-cells/

Primary use would be off grid boondocking with truck camper RV, 2000W inverter and 450W of solar panels. I also have a 4500KW genset primarily for AC use.

I am good with electrical/wiring/diagrams etc. and have no problem at all building a high quality battery with all the good instruction from this site.
I am not up to speed with all the current battery technologies and configuration options. The more I read, the more intrigued I become with building my own battery(s) and high quality system for off-grid RVing.

Thanks, John in Montana

 

[ksmithaz1]

If you are going to build it out yourself, I'd find a cheaper cell. $900 for 12v (4x3.2v) 320AH, then you get to buy a BMS, and wire it all up. Discounting the time maybe $1100. Or for $1500 you can get a rack mount 12v 400AH setup with a built in BMS. 1100/320 = 3.43 1500/400 = 3.75. plug and go. If you just want to try it out for fun... You should be able to find your prismatic's for quite a bit less.

 

[bear0214]

If you are going to build it out yourself, I'd find a cheaper cell... You should be able to find your prismatic's for quite a bit less.

Thanks for the comment, for the already assembled 100AH would I be getting double + AHs buy building it myself? (300+ AH)?

One of my quandries if finding quality vendors to source good cells, there are quite a few posts where people are not getting what they paid for. I don't mind paying for quality A grade cells/components, I just do not know where to start looking.
Is there a vendor list or something similar that I can feel comfortable ordering from without the thought of getting scammed?

 

[ksmithaz1]

Thanks for the comment, for the already assembled 100AH would I be getting double + AHs buy building it myself? (300+ AH)?

One of my quandries if finding quality vendors to source good cells, there are quite a few posts where people are not getting what they paid for. I don't mind paying for quality A grade cells/components, I just do not know where to start looking.
Is there a vendor list or something similar that I can feel comfortable ordering from without the thought of getting scammed?

A 5kwh rack mount battery with a built-in BMC is around $1500. That would be 48v/100ah or 24v/200ah or 12v/400ah. Your 4 300ah batteries will get you 12v/300ah roughly 3.8kwh for $900. Kind of depends what you have room for. Personally I'd not have a 12v inverter, it does allow the use of your car generator for charging, but requires a lot of fat power cables. 300A BMC is pricey.

 

[ksmithaz1]

With only a 2KW inverter you could probably get away with a 150A BMC.

 

[Brucey]

Thanks for the comment, for the already assembled 100AH would I be getting double + AHs buy building it myself? (300+ AH)?

One of my quandries if finding quality vendors to source good cells, there are quite a few posts where people are not getting what they paid for. I don't mind paying for quality A grade cells/components, I just do not know where to start looking.
Is there a vendor list or something similar that I can feel comfortable ordering from without the thought of getting scammed?

I think it's safe to say 18650batterystore is safe. US based and shipping from Georgia warehouse, you can pick them up yourself if within driving range.

LifePO4 Prismatic Cells

Discover our collection of high energy density LiFePO4 prismatic cells with long lifespan, high safety, and low cost of ownership. Ideal for electric vehicles, solar energy systems, and backup power systems.

www.18650batterystore.com

That's Eve grade A 304Ah cells for $149+shipping. So $596+shipping for four cells and a 12V configuration. Then add BMS costs etc.

That's three times the capacity of a 12V 100Ah battery (with potentially questionable cells).

 

[Rednecktek]

That's Eve grade A 304Ah cells for $149+shipping. So $596+shipping for four cells and a 12V configuration. Then add BMS costs etc.

Which are great cells and all mine have pulled capacity as best as I can tell. Add in a 200a BMS for $130 and you're looking at 300Ah and 200a max draw for less than $750, and has all the features like low temp protection and such. Compared to a 100Ah/100a discharge Battleborn for $925 it's a pretty easy choice.

Even if you went with the cheapest 12v 100ah batteries without all the protections and bluetooth and such you're still looking at a minimum of $1000 for the same capacity.

A 200a BMS also gets you 2400w of inverter to boot.

Making batteries is a LOT easier than I thought when I did my first, now I'm in the process of charging my 5th home brew battery (my first 24v 8s) but does require a few special tools (lug crimper for the bigger wires) and there are a few other parts that are really nice to have (heat shrink red 1/4" ring terminals) but pretty easy and WAY less scary than I expected it to be when I did my first.

As a pro tip, the Noco DC31 battery boxes fit everything inside quite nicely and are pretty cheap.

 

[Sam Cho TX]

SFK V4 Standard 280 - 304 AH Kit Ready to Build (BMS, CELLS, & CASE) - All items needed to build a battery Kit for RV, Back up Power / Stand by power or power walls using Certified Automotive Grade EVE LF304 or LF280K Cells or REPT 280 Cells. Sunfunk

SFK V4 Standard 280 - 304 AH Kit Ready to Build (BMS, CELLS, & CASE) - All items needed to build a battery Kit for RV, Back up Power / Stand by power or power walls using Certified Automotive Grade EVE LF304 or LF280K Cells or REPT 280 Cells. Sunfunkits.com

www.sunfunkits.com

I have built 3 of these, everything you would need at $950.00 some of the best cells the V3 280K are doing 311AH.

Bluetooth, 300AH, Strong non flexing case.

 

[EastFalcon]

I built the above kit with cells form 18650, its a nice solid kit but I got the heated one with a 150 BMS and it has switch to turn on/off heating.
I would do that again, but SFK has a new version of the 280K in stock and they are getting 311 AH form it. My 280K from 18650 got 278AH so just make sure you understand not all the 280K are the same. I did some price checking right now you will save $24.00 buying the kit from sfk and the 304 cells from 18650 battery store, but SFK has a 2 year warranty on the cells vs 1 year from sfk.

I do have cells form sfk on order shipping from there China warehouse so this will be my first time trying cells form them should arrive in about 30 days or so.

 

[EastFalcon]

304 from 18650 = $149 x 4 = $596
304 from sfk = 695 - 55.6 (coupon) = $639

So correction you would save $39, but if you go with the 280K V3 which is getting 310AH you would be:

665 - 53.2 = 611.38

 

[OffGridForGood]

Personally I have had no issues with Alibaba for my cells (from Amy) but it does take patience and some nerve - at least on the first order or two - until you gain some confidence in their 'pay and pray' system. If you use Alibaba (not aliexpress) for cells, pay with credit card or paypal. The difference in cost and time may not be worth it for you, but it is an option. For your first DIY battery build, I would recommend using N.American source cells, one less thing to worry about, quicker delivery.

 

[Sam Cho TX]

Very little savings going to alibaba now IMHO any vendor with test reports is very close to Luyuan price.

Alibaba probably is better deal if you are buying grade B, I have seen some as low as $69.99 for a 280.