24v lead acid battery upgrade

[eddie49]

Searching for "15ah LiFePo4" cells, most of the images show tubular cells - like 18650s but bigger ( e.g. "4680", 46mm diam, 8cm long ). Very few are rectangular ( "prismatic" ), and they are heavy - 0.5kg - so the 8 x 3.2v cells needed to make 25.6v plus the BMS would exceed the 2.6kg of this Ultramax battery. So with the literature available:

Ultramax LI15-24, 24v 15Ah LiFePO4 Lithium Iron Phosphate Battery

Ultramax LI24-15, 24v 15Ah LiFePO4 Lithium Iron Phosphate Battery for Solar Panel, Motorhome, Caravan, Off-grid, Inverter, Large Electric Vehicle: Electric golf carts, Buses, Electric Cars, Sightseeing Cars and Hybrid vehicles. Light Electric Vehicle

batterymasters.co.uk

and:

https://batterymasters.co.uk/pub/media/sebwite/productdownloads//s/l/slaumxli15-24-tech_wb-xam-v1c24.pdf

and probably tubular cells, orientation is definitely not going to be a problem.

 

[reb78]

So what have I bought? Surely they can't say it's a LiFePo if it isn't?!

 

[gaz1]

its a lithium battery

you can use it on its side, upside down, or standared it wouldnt make any difference

it wont leak either the only issue they have is a fire risk

so be ready if need to be but otherwise there fine to use

 

[reb78]

So is it something I shouldn't put in a kids toy? My boy will be sat on top of it.

 

[gaz1]

you have enough room in the back of the vehicle for it to be fitted

and thats where id fit it with a cover over it for protection and charging it as well as access to do the charging with it

its up to you but if i had any concerns about a lithium battery which i do then thats where id fit it

 

[eddie49]

that type of cell chemistry is inherently safer regarding fire risk than basic Li-ion.

LiFePO4 is a safer battery type than other Li-ion chemistries ( e.g. NMC ), and acc to the Spec sheet linked above, the BMS has thermal protection - probably thermistors that monitor cell temperature and shut down current flow in either direction.

 

[reb78]

LiFePO4 is a safer battery type than other Li-ion chemistries ( e.g. NMC ), and acc to the Spec sheet linked above, the BMS has thermal protection - probably thermistors that monitor cell temperature and shut down current flow in either direction.

I'm getting confused now. You said your quote about the cell chemistry being safer regarding the battery I have bought. But have since said the battery I have bought may not be what it is?

 

[eddie49]

All the documentation for the battery, and the Company that supplied it, seems legitimate, so I do not doubt that it is what it claims to be.

 

[reb78]

All the documentation for the battery, and the Company that supplied it, seems legitimate, so I do not doubt that it is what it claims to be.

Ok. Thanks! I was getting worried. They seemed legit. I contacted them about whether it'd be a suitable replacement. They accidently sent the wrong charger but rectified that immediately.

 

[m_c]

LiFePo4 is probably the safest commonly available lithium battery, as unless you do something stupid with them, they won't explode/ignite, unlike LiIon or LiPo that will explode/ignite if not used safely. The main risks are still overcharging, and the battery being physically damaged.
Lead Acid will also explode if abused, and has the added danger of acid running out if damaged, it's just that Lead Acid is more tolerant of being overcharged, and won't (usually) explode in a ball of flames.

@eddie49 most LiFePo4 battery cells are prismatic. I think the construction has more in common with a LiPo cell, rather than a metal cased LiIon.
I didn't even know tubular cells existed until I just searched for them!

 

[Gragson]

tubular cells

Mike Oldfield