I have lithium batteries fitted to our motorhome. Have a Victron dc-dc charger that governs the charging from the alternator. When the batteries are fully charged and I’m driving, I’d understood that the batteries wouldn’t be overcharged due to the management system and the dc-dc charger. Why then do some people fit isolation switches to turn off the dc-dc charger when driving?
If the battery/charging parameters are correct, a switch is not needed. The Orion will shut down automatically. I'm not really sure why people fit switches, unless it's because they can't configure the Orion properly.
I think some people install switches so they can cut the charging when they need "max power" from the engine (e.g. going up a long hill) and don't want the extra alternator load on the engine. I suspect it's a minuscule load, and doesn't really make a difference, but I have seem some people comment that is why they want to be able to cut off the DC-DC charger.
Not a Victron product but a good friend with a well known brand 50A DC-DC charger was thankful recently for the easily accessible inline switch when the smoke was rapidly released from inside the metal box. The connected 80A fuse link remained intact.
We direct charge our 300Ah LiFePO4 battery from the alternator at c90A.
Another reason to disable a B2B charger would be for people with lots of PV and good weather.
Sunlight is free... :)
