Switch off Orion to bring battery to winter storage charge

Q&A and troubleshooting
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1

I have an Orion 30 A DC-DC charger between alternator and cranking battery on the input side, and a 230Ah LiFePO4 battery on the output side.

In order to bring the charging level down to around a preferred winter level of around 50%, I wanted to switch the Orion to off.

However, the app gives a warning:

Charger will be disabled and battery will stop charging.
This is intended for maintenance purposes only.

Does this hold in my situation?

The only configuration I can think of, in which this could cause damage, is when there is no (cranking) battery between the alternator and the Orion. Then, the alternator wouldn’t have a reference voltage and could be damaged.

2

If there is no cranking battery, then presumably, you won’t be starting the engine - so no problem with the alternator…
An alternative to turning off the Orion would be to pull the fuse between the Orion and the house battery.

3

Is the cranking battery permanently connected to the alternator? Is the lifepo4 charged from the starting battery? If so, assuming you want to charge the Lifepo4 to 50pct SOC (I’d suggest anywhere between 50 and 80% SOC for storage), you can just manually switch off the Dc-dc converter (through the app) once you reach the desired SOC.

I usually prefer fully charging and then I discharge to about 75 pct SOC (3.3V per cell with no load).

4

Unless you would switch it off when the engine were running.

The point is, the warning is there, but why?

5

Yes, I did just switch it off. It is now at around 70%, which seems fine then, thank you.

I was hoping Victron employees were monitoring this forum and would explain why they implemented the warning in their software.

6

best storage for Lithium is around 25% SOC, about 3.0V per cell. This reduces internal corrosion rate.

7

I think that was the guidance we used when I first started using Lifepo4 (when they first came out). Nowdays, most quality Lifepo4 manufacturers don’t specify a lower SOC for storage. Victron for example says to store them at the float voltage. Epoch considers the environmental conditions (temperature) to be the key factor during storage.

Here’s Battleborn’s recommendation:
With our LiFePO4 batteries, we recommend disconnecting all potential power draws from the battery and letting them sit with a full charge, or at least a 50% charge minimum. On a full charge, our batteries have been proven to last at least a year in proper storage conditions with a 2–3% depletion each month. If left at a half charge, the batteries have the potential to not last as long in storage.