HI guys, my first post - probably not my last as I am just starting my RX8 EV build.
Been building kit cars and fancied a change ;o)
Anyway - first query...
I have been lucky enough to find 30 * Valence P30-36C Lifepo4 batteries from a crashed electric bus!
These have a built in balancer and also the ability to be balanced together in strings using communication cables between the batteries and an additional BMS from Valence.
Forgetting the BMS and focusing on ONE battery, it is essentially a 12S configuration with 144 cells in total. Max charging voltage per S is 3.65 for LifePo4 - giving a max voltage to charge one of these as 43.8v.
My query is that on Valence's website for the 'newer' version of this battery the 'U-Charge' version. They say you can charge it with a standard Lead Acid battery charger.
Really???
But my testing kinda says thats right - currently I am just pumping 30V into one (max of my Variable voltage Dc output!). I can vary the Amperage and slowly increased this over a couple of hours, I left it at 1Amp. Eventually when the battery Voltage reached 30V then Amperage slowly lowered down until it cut off.
My DC bench output does not have that kind of smart ability - I just set an output voltage and current and off you go. But the battery seems to be manipulating the current it draws and the voltage.
That seems pretty bloody clever and if true AWESOME!
Before anyone spots the 'why are you charging below the lowest voltage the battery should hold' It is because ALL the batteries are at zero V - no idea why, perhaps a short when the bus crashed or something that was done to make the pack safe?
The one I am testing is holding 30v merrily, and I have a 50v variable charger coming to see if they are recoverable at full voltage.
I am not leaving it unattended!
Any thoughts greatly received.
Dave