I have a canal boat (barge) in France. Engine and generator have 12v starting batteries. House bank is 24v. 1500w Solar running thru a Victron mppt controller charges the 24v AGM batteries.
Barge is unplugged from shore electricity for 6 months of the year while we are back home. The only device hooked up to the 24v system while we are gone is a bilge pump.
The 12v start batteries are often flat when we return even though battery switches are turned off.
Was thinking of using the Victron Orion 24v-12v 20 amp charger that would be hooked up while vessel is unattended.
Questions
Would the Orion be able to be used to charge both engine and generator start battery? Both 12v but different amperage.
You could either use a diode splitter - or a FET splitter to charge the 2 batteries separately from the 12V output, or use 2 smaller converters. The volt drop of a diode splitter would ensure a float voltage depending on the voltage set from the 24/12v converter. You would need a splitter to keep the 2 starter batteries isolated.
Ive used bridge rectifiers for this in the past. Use the negative pole of the BR to connect the chargers positive (its counterintuitive, but correct), the AC connectors go to each starter battery positive, the BRs positive terminal remains unconnected (or use it to supply a load from both batteries redundant)
BRs are available in nice square packages with a bolt hole for mounting, faston flat connectors and many ratings