New Batteries…new system?

[robbertwilliams]

I’ve been living off grid for the last 6-7 years - system is 24v Schneider Electric Sw2524 with Midnite Classic 150, 1600w solar, and 740ah battery bank (L16’s wired series/parallel).

So, the batteries are at end of life - still holding good charge but their shapes are deforming thus giving me some concerns. So, I’d like to replace with Lithium. Been eyeing many options over the last year or so but haven’t committed. Ideally looking to just get batteries. With that said, would 400ah of lithium (2xEG4 200ah v2) be adequate for replacement? Or could I potentially get by with just one? Or are there other batteries at this price point that anyone would suggest.

Also, been wondering if it’s a smart decision to stick with my 24v system or switch to 48v. I am trying to spend as little as possible but there seems to be less and less of 24v stuff available every year.

Thanks in advance!

 

[Rednecktek]

It really depends on how much battery you have now. 1ah of LFP is ~2ah of lead acid, so if you've 740ah of lead now and it was enough, then about 400ah of LFP will give you about the same.

As for converting to 48v, if your 24v system works, why mess with it?

 

[robbertwilliams]

@Rednecktek - Thanks. Any experience or suggestions on 24v LFP? Best bang for buck?

 

[Q-Dog]

No need to switch to 48volt unless the existing setup isn't meeting your needs. And I agree, 400ah LiFePO4 should give you similar capacity to your existing lead acid bank.

 

[42OhmsPA]

If you're already comfortable with series / parallel I'd recommend 16 EVE LF230s and 2 JBD 200a smart BMS. Make 2 8s packs, parallel them together with bus bars and hook them up to the existing system after reprogramming/ tweaking the 150 and SW voltages.

You should be able to easily do this for under $2500, $2750 if you want to get really fancy with an enclosure for the cells and extra additions.

For a size reference 16 of those cells would be one row in the photo attached.
Don't forget the class T fuses for each pack.

 

[robbertwilliams]

@42OhmsPA - Building a battery from scratch may be over my head but I know I'm capable. How many Ah's do you get for $2500?

 

[42OhmsPA]

I thought I was over my head... it's really not that difficult, just take your time, triple check your work and ask questions here if you aren't sure.
You'd have at least 460ah @24v for under $2000 in battery cells, add ~$150 for a BMS, ~$100 for class t fuses and holders, ~$50 for disconnects.

All of the cells in that photo came from the link below, I used the threaded terminals but they are not in stock in the US.

DOCAN POWER

Brand New High Quality LiFePO4 Battery Cells SupplierDocan is TOP10 battery and battery suppliers in China. We supply TOP1 service of Lifepo4 Prismatic Cell and Battery Pack for variouse area, 12 years+ focus on high capacity, high wattage, high voltage, high dicharge current battery cells and...

www.docanpower.com

There have been a lot of mixed reviews on Docan but I haven't see any complaints on the 230ah cells and wouldn't hesitate to order them again.
Another great source for cells is 18650 battery store, I recently ordered 17 of the 305ah cells to expand my capacity.
Ezealco also seems to be popular here but I haven't ordered from them, they are shipping from the same address as Docan.

If you don't want to build your own I'd recommend Current Connected for pre-built batteries along with the rest of your components.

 

[Q-Dog]

I don't know the differences, but these (v1) are $1400 each, ready to go. 2 of them would be 400ah.

EG4 LL Lithium Battery (V1) | 24V 200AH | Server Rack Battery

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL

signaturesolar.com

 

[AHTrimble]

I was at 24v and decided to go LifePo4. After crunching the numbers and wanting more power for house usage I went with a complete upgrade to 48v.
1xLifePo4 200ah @48v gives you 160 - 180ah of usage (80 - 90% DOD).

I found that a single LifePo4 battery is not a good idea. At least 2 would be a good start whether 100ah or 200ah.
I personally found Trophy Battery units to be excellent and a great price point. Their tech support is really, really incredible. And a 10-year replacement warranty is hard to beat.

 

[AHTrimble]

I am not a fan of building batteries for my house to depend on. I have been doing this for 15 years and am still not comfortable doing it. I would rather depend on the pros and experts...along with their warranty

 

[Rednecktek]

@Rednecktek - Thanks. Any experience or suggestions on 24v LFP? Best bang for buck?

Well, if cold weather is a concern then you can't beat Trophy batteries. Rolling your own is the preferred method, but if you're not up for it then anything 24v with low temp protection is about the same as any other.

 

[SamDeleted]

I am not a fan of building batteries for my house to depend on. I have been doing this for 15 years and am still not comfortable doing it. I would rather depend on the pros and experts...along with their warranty

If only you could actually trust mainstream manufacturer ! Often it's more about profit than it is about making top quality products

 

[robbertwilliams]

I don't know the differences, but these (v1) are $1400 each, ready to go. 2 of them would be 400ah.

EG4 LL Lithium Battery (V1) | 24V 200AH | Server Rack Battery

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL

signaturesolar.com

These are the exact batteries I’ve been eyeing for the last year. Thanks