Charger and engine/alternator at the same time

[sndbowen]

We have one battery charger charging both house and starting batteries.

When cruising we often have the generator running while underway and leave the charger on.

Is this ok or should the charger be turned off when the engine/alternator is running?

 

[toocoys]

This doesn't answer your question, but we have our engine alternators wired in such a configuration that they charge the starter batteries first, and then a relay kicks over and they charge the house batteries. If the starter batteries fall below a certain point, it kicks back over to charge them.

Good question though, I'll be looking forward to the answers.

 

[sndbowen]

I believe our's is wired the same way. Thanks

 

[DavidM]

It will be fine to leave them both on.

The engine alternator unless it is a high output one with an external regulator has a fixed voltage output. As the batteries charge, the alternator's fixed voltage is below what the batteries require to charge so the charger dominates. The charger is almost certainly is a three step type. No problem whatsoever with that.

David

 

[Ski in NC]

Alts and chargers work together all the time on all sorts of boats. No issues.

I think the concern is a vestige from like 50yrs ago when there were mechanical regulators, parallel those and they could do weird things.

 

[diver dave]

Alts and chargers work together all the time on all sorts of boats. No issues.

.

But sometimes a tach will go nuts if ur near full charge.