Lithium SOH percentage (state of health)

[dg0603]

So I brought the Tellaro home from the dealer Monday and the SOH was at 87%.

Had to return it to the dealer because a part failed (Southwire unit) and it would not charge. Got it back last night. SOC (state of charge) is great at 100%, but the SOH is still at 87%.

Can the SOH improve over time? Or is it a countdown to battery death? What exactly is that showing?

[dg0603]

And why when I have the master switch off and the inverter off, does the Balmar meter still show a small constant draw of like -.8 ?

Thanks!

[DavidEM]

I have never heard the term State of Health (SOH). Could you explain.

The 0.8 draw could be lots of things: inverter standby current, propane solenoid valve, CO monitor, etc.

David

[Judge]

SOC is typically a calibration of a Smart Shunt based on the total Ah and voltage at full charge where 100% SOC is 13.6 - 14.4V for LiFePO4 batteries. I assume SOH would be a calculation that the BMS is doing based on the number of charge / discharge cycles of the battery and the state of the cells from the time they were put into service as new.

You may want to do some research on your specific BMS for the LiFePO4's to be sure how SOH is being determined.

If this is a brand new coach and it has been on the lot for a while, it sounds like the batteries may have cycled quite a bit for the SOH to be down to 87% already.... or maybe there is a defective cell / battery?

[dg0603]

As I knew it would be - GREAT info.

I feel better about the draw, that all sounds dead on. And I will do some research. I'm not too worried more curious.