LifePo4 Voltage at .5C - .6C Discharge

StirCrazy wrote:

FWC wrote:

StirCrazy wrote:

BFL13 wrote:
If you did have BMS cut-off, don't forget you will need a way to get the battery bank going again by recharging it. BB suggests you have a charger that can do that. EG my Vector smart charger will not do anything until the battery voltage is above about 5 volts, so it would not work on a cut-off LFP.

wow, man is it good thing we have chargers built into our RV's or we would be totaly screwed..

actualy it would because a BMS cutoff point is above 5V, if I was setting up my own it would cut off at 11.9 but even if you have it cut off at 10.1V that is still above 5V.

Steve

This depends on the battery and the charger. Some batteries have a reset, either a physical button, or a switch in the bluetooth app (what mine has) to reset the BMS. Some BMS will also still show a voltage on the battery terminals, even after cutoff, but won't provide any current - this is often enough to satisfy a 'smart charger' without a lithium mode.

Most converters don't care if there is a battery present and will reset your BMS no problems, and many modern smart chargers (either solar or plug in) have a lithium mode, which will provide voltage even if the charger doesn't see a battery. There is a sub-set of older pre-lithium 'smart chargers' that will have an issue with this, but there is usually a way around this, either through solar, or using the vehicle alternator, or even a jump pack.

all the BMS I have been looking at have automatic reset once the battery charge rises a spicific amount it will turn the discharge function back on. they usaly show disconect at 10.8 and reconect at 11.3 type thing. but they are customizable so you can put them where ever you want. I can see where the older "smart chargers" would be an issue, but if some one is building a functional electrical system on a RV using LFP as a battery, why would you have a smart charger instead of a LFP compatable converter? I imagin we would find issues with any type of set up but a older smart charger would be some one conceniously pick older stuff and takes newer stuff out instead of building the system properly. I believe this is why people have so many issues with LFP, because a lot of systems seam to be throwen togeather haphazardly with out any forthought.

Steve