Need help with LiFePo4 batteries, to replace lead-acid for off-grid system

[imlost]

I have an existing off-grid solar system that currently uses (16) 230ah 6v lead-acid batteries that are near the end of their life. I would like to replace these with some pre-made lithium iron phosphate batteries, and have been making some inquiries on Alibaba. The problem is, I'm relatively clueless of what I need for replacement batteries, and can use your advice. My current system is 48 volt, using a Schneider SW 4048 inverter/controller, and is tied to (12) 330w solar panels. It's in Baja Sur, Mexico.

 

[Supervstech]

How much do you draw down the existing setup?
if only 50% like lead is recommended, 16 of the 170Ah cells would work, and your controller may or may not work, depending on if it is configurable.
If you use the full 280, there are 300Ah sets also.
Also, there are premade GYL setups, or drop ins out there.
David Poz just did a video on the GYL setup.

 

[Steve_S]

You have more or less 460AH gross / 230AH useable at 50% max DOD, in theory, if everything was fresh'n shiny.
So the minimum you'd be looking for is 48V/280AH. Which would be a "direct" replacements, basically. The reason for the bit extra AH is because on average you're using no more than 80-90% of the capacity. One advantage with LFP, is it can take more amps during charge and charges faster than lead as well due to its makeup, so that allows you to add more capacity (being reasonable of course) without really "upgrading" your existing equipment. I'm not familiar with the Schneider Product specs but several people here do have experience with them & LFP.

As suggested above, 280AH+ premade's are available but do due diligence on making sure they are known good and with reliable reviews from folks like David & Will etc. Even better if backed by personal reviews from members of this site. There is also a lot of experience with poor to bad ones here too so it's worth checking/asking.

 

[imlost]

I'm not sure how much I draw down the existing system... Currently, more than it will keep up with.
I typically run 2 refrigerators, some low-watt light bulbs and a fan or two. My water pumps also run off of this system. Sometimes I use a clothes washer, and occasionally a mini-split air conditioner.

I checked - My existing Schneider controller is configurable for lithium batteries.

Steve- I don't want to make a mistake with this purchase, and I'm relatively clueless, but willing to learn. That's why I'm here.

Thanks for the responses - please keep them coming.

 

[imlost]

...So, if I'm reading you correctly, you're recommending at least 48v/280ah. Is there any restriction in using batterie(s) that with a higher amp-hour rating than that? For instance, (2) 200ah batteries, or (4) 100ah batteries?

 

[Steve_S]

Not really, at present I am using 2x 24V/175AH & 2x 24/280AH. I'm just getting ready to complete my setup which includes a reconfiguration to 3x 24V/280AH & 1x 24V/350AH. These are all in Parallel the final config will provide 24V/1190AH/30.4kWh. The battery packs in parallel share the load and charge in balance relative to their capacities. It's highly suggested to keep the different packs at a similar capacity, too much difference and issues start to pop up.

 

[Supervstech]

Higher Ah is recommended to extend the life of the batteries, and to give wiggle room for sunless days...

 

[Jumpee]

I have system currently running at 24 12V 100Ah batteries that i need to replace, and im thinking with going 48V 280-300AH LiFePo4.

 

[Jumpee]

You have more or less 460AH gross / 230AH useable at 50% max DOD, in theory, if everything was fresh'n shiny.
So the minimum you'd be looking for is 48V/280AH. Which would be a "direct" replacements, basically. The reason for the bit extra AH is because on average you're using no more than 80-90% of the capacity. One advantage with LFP, is it can take more amps during charge and charges faster than lead as well due to its makeup, so that allows you to add more capacity (being reasonable of course) without really "upgrading" your existing equipment. I'm not familiar with the Schneider Product specs but several people here do have experience with them & LFP.

As suggested above, 280AH+ premade's are available but do due diligence on making sure they are known good and with reliable reviews from folks like David & Will etc. Even better if backed by personal reviews from members of this site. There is also a lot of experience with poor to bad ones here too so it's worth checking/asking.

Where would I find David and Will reviews/recommendations? Im looking to replace my batteries with LifePo4, and oh boy is there a lot of stuff out there

 

[Steve_S]

48V = 16 Cells, 1 250A capable BMS, 1 250A fuse. + Case/Frame whatever you choose.
EVE LFP, 280AH Matched & Batched with report: $125ea Link to Page (Luyuan)
EVE LFP, 280AH (Bulk, Voltage & IR Matched only)--Old version: $91.50ea LINK to Page (Luyuan)
Assembly & Prep Instructions: https://diysolarforum.com/resources/luyuan-tech-basic-lifepo4-guide.151/

Luyuan is a Known Good Reliable Vendor who has supplied MANY of us. For a proper & accurate quote, you must open a Chat/Messenger session, the shipping charges are shown from a GUESStimator and not accurate.

 

[Jumpee]

Thank you so much, I have looked it over and will concider whether I can build my own packs or have to stick with buying ready to go, time is the issue, i work long hours far from home and with LA traffic its not pretty.

 

[Baughb]

Just a satisfied customer; My reBel 100AH lifepo4 battery is performing great for me. Reasonable prices compared to many and really good customer support from Aric. I have no need for more at this point but when I do, I'll be going back to reBel.

All the best.

 

[Jumpee]

Thats awesome. I need about 26KWH of power though, so it would mean i have to get at least 24 of the ones you have, and in all honesty im trying to downsize it, so looking into 300AH options

 

[Bossrox]

I'm with Steve on your lithium bank size need to replace your old batts. Like others are saying, the Gyll's appear to be a good choice but @ $1500 each, you need about 3 of them for 300 a/hrs to equate to your lead acid's but if you could build your own, you can get a set 280 a/hr lith's for 2 grand delivered & the cost of a bms. A bit more than 2 grand difference from prebuilt compared to DIY.

 

[Steve_S]

Just to add more clarity.
24V/280AH = 7168Wh / 7.1kWh
48V/280AH = 14,336Wh / 14.3kWh

The GYLL (now EG4) 48V/100AH = 5120Wh / 5.1kWh for $1500 USD

HIDDEN

GYLL HAS REBRANDED TO EG4 SAME GREAT BATTERY, DIFFERENT NAME. LEADTIME Details: SHIPPING to customers BY 8/02/21All Orders are refundable prior to shipment This EG4 51.2V (48V) LiFePo4 5.12kWh Lithium Battery with 100AH is a premium battery with only 16 prismatic 3.2V cells in series versus the...

shop.signaturesolar.us

Example: BattleBorn Batteries which most know, (they don't even have 48V YET)
100 Ah 12V LiFePO4 Deep Cycle Battery $899.00
270 Ah 12V LiFePO4 Deep Cycle 8D Battery $2,800.00

You are trying to replace 48V/230AH Useable (460AH gross), 460AH = 23.552 kWh while 230AH = 11.776 kWh
then you say you need 26kWh which is 507.81 Ah

ONE 48V/280AH would replace what you have for Working Capacity NOW

LFP is 99% Efficient while Lead is 82% or so.

Seems you have some more pondering to do.