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Building my own lifepo4 battery bank to work with solar ! :)

C

Claudio

New Member
Joined
Oct 9, 2019
Messages
8
So, first of all sorry for any mistake but I'm far from being an expert hehe
So, I've found what I think a good deal of 8 x 3.2v 60ah lifepo4 batteries but without any record of how much and where they worked before.
The only information I have is that who is selling them told me that all are working and holding between 3.26 and 3.30v . The deal is arround 400 us dollars. I'm thinking of having 4s and 4p to make 12v and maybe 200ah with losses and the condition of the batteries. Do I need to balance them or the 0.04 diference is good enough and I can skip that process?
Should I go for it ?
And for last what would I need for building a safe battery bank with this ? Bms, low temp cut off ...??

I would love to have some help here and wisdom from who is more experienced . I've done anything like this so any advice is more than appreciated !!!

Greetings,
hope someone can help me and make me a happy off grider person! Eheh
 
Hi and welcome to the club.
First thing that sticks out is that you are looking at 8 60ah cells. In a 4s2p(corrected) 12v battery, that would only be 120Ah with new batteries. Depending on age and cycle count, that could be much less. Also, that seems awful expensive for those cells. I was just able to buy a 12v 100Ah worth of cells for that price that had no cycles on them. There are also some good deals on cells straight from China for not much more which are brand new.
You cannot really determine anything about the battery based on voltage hold. Only a capacity test will tell you if they're any good.
Regardless, you need to determine what your expectations are with a pack that size. At 12v120Ah you won't power AC devices for terribly long, depending on loads.
What are you looking to power?
 
Last edited:
CheezWiz said:
Hi and welcome to the club.
First thing that sticks out is that you are looking at 8 60ah cells. In a 4s4p 12v battery, that would only be 120Ah with new batteries. Depending on age and cycle count, that could be much less. Also, that seems awful expensive for those cells. I was just able to buy a 12v 100Ah worth of cells for that price that had no cycles on them. There are also some good deals on cells straight from China for not much more which are brand new.
You cannot really determine anything about the battery based on voltage hold. Only a capacity test will tell you if they're any good.
Regardless, you need to determine what your expectations are with a pack that size. At 12v120Ah you won't power AC devices for terribly long, depending on loads.
What are you looking to power?
Click to expand...
How do you get 4S4P out of 8 batteries? That would take 16.

4S2P or 2P4S would get 12v. Both at 120ah.

Pass on the deal and order 4 BLS cells off of Allie Express. They have some around 100ah, 130ah and 150ah.

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425.0US $ 15% OFF|4pcs Grade A 3.2v 120ah Lithium Iron Phosphate Cell Lifepo4 Battery Cycle 4000 Times Solar 12v 100ah 176ah 200ah Eu Us Tax Free - Rechargeable Batteries - AliExpress

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CheezWiz said:
Hi and welcome to the club.
First thing that sticks out is that you are looking at 8 60ah cells. In a 4s4p 12v battery, that would only be 120Ah with new batteries. Depending on age and cycle count, that could be much less. Also, that seems awful expensive for those cells. I was just able to buy a 12v 100Ah worth of cells for that price that had no cycles on them. There are also some good deals on cells straight from China for not much more which are brand new.
You cannot really determine anything about the battery based on voltage hold. Only a capacity test will tell you if they're any good.
Regardless, you need to determine what your expectations are with a pack that size. At 12v120Ah you won't power AC devices for terribly long, depending on loads.
What are you looking to power?
Click to expand...
 
Keith_PDX said:
How do you get 4S4P out of 8 batteries? That would take 16.

4S2P or 2P4S would get 12v. Both at 120ah.

Pass on the deal and order 4 BLS cells off of Allie Express. They have some around 100ah, 130ah and 150ah.

BLS Official Store - Amazing products with exclusive discounts on AliExpress

Discover the wide range of products from AliExpress Top Seller BLS Official Store. Enjoy ✓Free Shipping Worldwide! ✓Limited Time Sale ✓Easy Return.
m.aliexpress.com

www.aliexpress.com

425.0US $ 15% OFF|4pcs Grade A 3.2v 120ah Lithium Iron Phosphate Cell Lifepo4 Battery Cycle 4000 Times Solar 12v 100ah 176ah 200ah Eu Us Tax Free - Rechargeable Batteries - AliExpress

Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com www.aliexpress.com
Click to expand...
Thanks for catching that! I'm multitasking atm.
 
Thanks for the welcome and fast response.

So my main goal is to power a future off grid van, I will be travelling for a few years like that . My total spent will be around 600w a day . So I'm thinking of getting maybe 300w solar and 100ah lifepo4 battery minimum. Sorry but I still don't understand the why only 120 ah for more 4 cells? Wouldn't be 4 x 3.2v in series equal 12.8v and the other 4 in pararell 240 ? 60+60+60+60 .
Sorry if I am missing a really basic thing but we are here to learn eheh

So apparently I will have to search a little more ahah any recommendations ? :)
 
Claudio said:
Thanks for the welcome and fast response.

So my main goal is to power a future off grid van, I will be travelling for a few years like that . My total spent will be around 600w a day . So I'm thinking of getting maybe 300w solar and 100ah lifepo4 battery minimum. Sorry but I still don't understand the why only 120 ah for more 4 cells? Wouldn't be 4 x 3.2v in series equal 12.8v and the other 4 in pararell 240 ? 60+60+60+60 .
Sorry if I am missing a really basic thing but we are here to learn eheh

So apparently I will have to search a little more ahah any recommendations ? :)
Click to expand...
Batteries in series, the voltage adds up and capacity stays the same. Batteries in parallel, capacity adds up and voltage stays the same. Others here will have better advice than me for a Van install but 100Ah seems to be a size I see mentioned a lot for vans on YouTube.
 
4 in series X 3.4v = 13.6v
4 in series X 60ah = 60ah
However:
4 in parallel X 3.4v = 3.4v
4 in parallel X 60ah = 240ah
So:
8 cells arranged 2p4s = 13.6v @ 120ah

If you have limited space look at the various cell offerings & determine if each option can be configured to produce your needed capacity @ the voltage you require, in the space you've defined. I drew out my space & then laid out each cell option in various ways (stacked, booked, top up, etc.) to confirm they would fit.

Tedious but enlightening.
 
Once again thanks for all the help.
So I think I will pass this one after the valuable information you have me and because I am a rookie in this matter I should stick with a already built lifepo4 battery .
I've found this one
https://www.ebay.co.uk/itm/VALENCE-LiFePO4
For the price also looks good but I can't find a lot of information about it which keeps me in doubt.
I know valence is a good brand but a usually see them with green colour witch this isn't, what do you think about it ? Is it a good deal of a big flop ?
Any advice ?
I'll keep your advice in mind ScclockDr :)
Thank you everybody !!
 
Update : received a mail from the person saying this
"
There is an internal BMS.
They have Cycle count of 417 to 1966.
They are at 13v to 13.4v"

So the cycles that they may have is uncertain, even with let's say 1500 is it a good deal ? They are at around 380 USD dollars.
 
Thanks for the reply .

12v Valence Lithium uCharge XP Battery 130 Ahr (u27-12xp) Integrated BMS for sale | eBay

Find many great new & used options and get the best deals for 12v Valence Lithium uCharge XP Battery 130 Ahr (u27-12xp) Integrated BMS at the best online prices at eBay! Free delivery for many products!
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Here is the number of the item

264491335248

If doesn't work just write valence lifepo4 130ah, it's by a person named "funkeyshit " he has several of them in different posts .
I've heard that valence usually are very good and so even being a maybe more used and hopefully more well treated they can last long time 4000 cycles or more .
Give me your thoughts !! :)

The one you sent even seeking a more reliable business is more expensive and the major thing is space, which I will not have in the van lol .

Thanks again
 
Any help ?? :cool: I honestly think that this could work for what I am looking for . And the seller lives like 50miles from me so I can get it personally !
Any wisdom from that side ? Eheh
 
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