Batteries: How do I charge both while driving?

[Patches]

Sent: 5/12/2002

What do I have to do to have my alternator charge both batteries while driving?
We have a 76 Chieftain? Not sure, it was a classroom, we were told it was a brave, but we saw anM500 and someone said it was a chieftain.
It seems we can only charge motor battery off of alternator, must plug into land line to charge house battery, or the portable generator will charge it also, but want to charge off of alternator, any help will be greatly appreciated.
Thank you

[HAL]

Sent: 5/13/2002

HAL HERE. ON MY 79 BRAVE THERE IS A BATTERY SWITCH ON THE DASH THAT YOU MOVE TO DUAL POSITION TO CONNECT THE BATTERIES TOGETHER. THROUGH A BATTERY ISOLATOR..
BATTERY ISOLATOR CIRCUIT, CURRENT FROM THE ALTERNATOR FLOWS TO EACH BATTERY THROUGH THE DIODES, BUT CANNOT FLOW IN REVERSE OR FROM ONE BATTERY TO THE OTHER. HOPE THIS THE INFORMATION THAT YOU ARE LOOKING FOR.

[DUHDave]

Sent: 5/13/2002

You can wire your house batts into the charging circuit. Be sure to use a good "Battery isolator" and just follow the instructions that come with it.

But before you do that...how much alternator output do you have? In other words...is your alternator of sufficient size to charge all these batteries at one time? If not, you should upgrade to a larger capacity alternator.

A good auto electrical shop should be able to look up the part number and tell you what it is...and what you need, to do what you want to do.

Hope this helps,
Dave