charging house batteries

hogasm · 10-09-2015, 09:54 AM

On the 7.3 with only 1 alternator does it matter which van battery, either the battery in the engine bay or the one on the frame you attach the positive cable to to charge the house batteries with this system?

arctictraveller · 10-09-2015, 12:06 PM

A "house" battery usually implys a seperate battery from your starting system so if it goes dead, you can still start the engine. With a diesel, I believe both batterys are normally used for starting, so if you do drain one you may not be able to start, but I'm sure others can clarify. You probably will want to add a third, electrically isolated battery for a house system. As for which start battery to connect to, it shouldn't matter much as long as the cables are big enough to avoid much voltage drop from the alternator to the isolater to the battery.

Scalf77 · 10-09-2015, 01:04 PM

I would tie it into the first starting battery inline with the alternator.

-greg

DCHitt · 10-09-2015, 03:08 PM

I know nothing about the 7.3 but looking at your picture I would say....

The "Trombetta 12 Volt Bear DC Contactor Part No. 114-1211-020" is not smart. The two batterys are only connected together when the switch is on. So to charge the house battery you connect your charger to the house battery.

It also looks like the Contactor will be drawing power for its coil any time the switch is on and will draw power from both batteries if left on. Assuming the alternator is connected to the Van battery the switch must be on, with the engine running, to charge the house battery from the alternator.

With this setup I believe it is common to use "ignition is on 12 volts" to activate the contactor rather than a switch.

hogasm · 10-09-2015, 04:17 PM

Quote:

Originally Posted by DCHitt

I know nothing about the 7.3 but looking at your picture I would say....

The "Trombetta 12 Volt Bear DC Contactor Part No. 114-1211-020" is not smart. The two batterys are only connected together when the switch is on. So to charge the house battery you connect your charger to the house battery.

It also looks like the Contactor will be drawing power for its coil any time the switch is on and will draw power from both batteries if left on. Assuming the alternator is connected to the Van battery the switch must be on, with the engine running, to charge the house battery from the alternator.

With this setup I believe it is common to use "ignition is on 12 volts" to activate the contactor rather than a switch.

On my 97 7.3 the alternator and rear battery and wire to starter connect to the engine bay battery. My plan is to only use the above set up to charge the house batteries when solar needs help and in an emergency when the van batteries will need a jump start. This will require a manually operated switched 12v from the van to energize the contactor.