Lithium Batteries Help (Allied)

[TheQMiami]

Thanks!! Can you repost that item or link, as it doesn't seem to bring up anything?

How's your experience for purchasing on aliexpress?

[augiedoggy]

https://m.aliexpress.us/item/3256801...andl_shipto=US yes I've bought many things there you can pay with PayPal as well which gives you added protection.

[TheQMiami]

Originally Posted by augiedoggy

https://m.aliexpress.us/item/3256801...andl_shipto=US yes I've bought many things there you can pay with PayPal as well which gives you added protection.

HUGE Thanks.... I'm looking around now. The on you put the link to doesn't seem to specifically say LITHIUM and I'm still figuring out how to contact the seller. That one seems good and there are a few others, just need to find the right combo of 48V 58.4 15A Waterproof with the Anderson connector (I ordered a joining Anderson connector on Amazon and will remove my current snap plug).

[LukeL]

There are options for LifePo4 in the “color” selection under the listing.

[DaveTM]

Originally Posted by LukeL

You need a battery meter with a shunt like the Renogy battery monitor to accurately gauge the SOC on those batteries. A regular 2 wire voltage meter won’t work with a lithium setup because voltage doesn’t drop as the charge goes down as much as lead batteries.

Just reading through this post and noticed this statement.

While (from everything I've read) this is true with LifePO4 chemistry, batteries with Lithium-Ion (Nissan Leaf) chemistry do not react the same.

When I built my Leaf pack I kept my FLA dash volt meter. The Dash VM is usually .1-V less than what my BMS monitor says. That and under a hard acceleration, the voltage of Lith-Ion will drop 2-3V vs what the actual pack voltage is "at rest."

[Volt_Ampere]

I built a meter that estimates SOC on my Leaf pack that is probably good to a couple %.
I got the discharge curve online and made a table lookup routine to linearize the SOC vs Voltage curve. There is enough of a curve to do this with Leaf chemistry but for LiFePO4, you really can't do this. The discharge curve is way too flat for most of the discharge.