Batt switch without AFD

[LAC_STS]

So I added a second battery. I have one regular marine flooded acid battery for starting and the second battery I added is a marine AGM.

I want to use the AGM for listening to music and stuff while the engine is off at the sand bar or whatever.

But say after using the AGM for a while I want to charge it. Can I start the boat on the reg battery then switch to the AGM with the engine running? I know I could start off the AGM and charge it but what if I use it enough where I cant start off of it?

I looked up my batt switch and it has make before break but does not have AFD.


Much thanks in advance

 

[UncleWillie]

You can safely start from BOTH, or Either Battery of your choice.
And then select BOTH, or just One battery with the engine running.

Be sure to NEVER select the OFF Position on the the Battery switch with the engine running.
Most switches cycle as #1 > BOTH > #2 for this reason.
Selecting BOTH will have no ill effect on the batteries.
Both batteries will only accept as much current as they normally would if the other battery were not present.
The Physics and Chemistry of the batteries will work in your favor in this situation.

 

[LAC_STS]

You can safely start from BOTH, or Either Battery of your choice.
And then select BOTH, or just One battery with the engine running.

Be sure to NEVER select the OFF Position on the the Battery switch with the engine running.
Most switches cycle as #1 > BOTH > #2 for this reason.
Selecting BOTH will have no ill effect on the batteries.
Both batteries will only accept as much current as they normally would if the other battery were not present.
The Physics and Chemistry of the batteries will work in your favor in this situation.

Thank you

Another thing is I heard from someone that you shouldnt charge lead acid and AGM batteries together. Have you ever heard that?

 

[UncleWillie]

AGM Batteries ARE Lead Acid batteries.

However they do not like to be charged to as high of a terminal voltage as Flooded Cell batteries because the Gas Bubbles get trapped in the Glass Matting.
If you charge both batteries together, treat them as if they were AGM. The Flooded Cell battery will appreciate the TLC.

 

[LAC_STS]

AGM Batteries ARE Lead Acid batteries.

However they do not like to be charged to as high of a terminal voltage as Flooded Cell batteries because the Gas Bubbles get trapped in the Glass Matting.
If you charge both batteries together, treat them as if they were AGM. The Flooded Cell battery will appreciate the TLC.

Yea obviously thats what I meant.

By charging I meant via the engine. As in charging both batteries via the alternator. But now that I have been thinking about it I probably wouldn't do that anyways I would probably just switch to one or the other.