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murphy-r asked

Smart BMS 12/100 - Alternator Cutin Voltage Adjust

Hello All,

I have had a Victron SmartBMS 12/100 setup in my Sprinter Van for a year and it has been running great.

Question for the community: I could not see an option to change the BMS alternator cut-in voltage? Does anyone know if this is tunable?


The Sprinter vans are pretty bad about vampiric amperage load on the starter batteries. Leave it sitting for a a few weeks and it can drain the battery. So to rectify the issue I decided to install a Victron IP67 battery charger just on the starter battery and feed it off our Victron Lithium house battery.

The problem I ran into after install is that it causes a feed loop. When the starter battery charger kicks in it jumps the voltage up to 14+V and the BMS thinks the alternator is running.

A temporary workaround I have done is to put in a custom charge profile on the IP67 starter battery charger of 13V absorption, 12.9 float and like 12.85V storage. It appears to me with testing that the Smart BMS 12/100 has a cut-in voltage of 13.0V. So this just sneaks in and works for my setup.

So this is not ideal for charging profile but, really the starter battery charger is there just to offset the onboard parasitic draw from the Sprinters systems.

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