Alternate aux battery installation

An easier way to add an isolated aux battery where you want it and without going under the driver's seat is to use a battery combiner ( marine ) which has only three connections ( 2 battery cables and ground ). They sense increased charging voltage and then connect aux battery with a high current relay. Don't forget to fuse new cable at existing battery terminal block and use a heavy enough cable to handle large charging current. One source is defender.com .....
Bob

If I add an aux battery under the passenger seat and use the battery combiner, where would I tap into for the power source? Directly from the battery or somewhere from under the driver's seat electronic hell hole?

Regards.

On the main battry is a fuse block. I have one position empty (no rear AC).I ran #4 cable with a 70 amp fuse to the combiner and a battery box under the sofa bed I built. Put the battery vent thru the floor. I think I will fuse the interconnect cable at the aux battery as well.All feeds from the aux battery should be fused.

This might sound dumb but I can't find the answer anywhere.

I have added an aux battery in the rear of my van (with a combiner). to run a 2500 watt inverter. The combiner uses 6 gauge wire to connect the batteries together and has a spot for an 18 gauge ground wire which I connected to the body (West Marine Combiner 150). The inverter is also grounded to the body. Should the aux battery be grounded to the body also or just connected to the inverter? Although I only plan on useing it to power the inverter it seems as if it should also be grounded to the vehicle.

Thanks,

pgr

Hi PGR
I swear there is a thread for this in detail, on the forum
Master Seek will drop in when he sees this as he is the electronic expert
If you missed this thread it may help you.
Alternate aux battery installation - Sprinter-Forum.com
However this link below is for what we do down under and it's great to read as it covers most inverters
Installing an Inverter
Richard

From the West Marine pdf manuals I find online, you have to connect that ground terminal to a common ground, meaning, if the batteries are connected to the chassis, you connect that terminal to the chassis. If the batteries are NOT connected to the chassis you connect the ground wire to the common negative terminal.

The ground wire terminal is used as a ground reference for voltage sensing. It says in the instructions to disable the combiner, put a switch in series with the ground wire. To me if you don't connect it, you're essentially disabling the combiner.

My take...connect it. It's only a 18AWG (manual says 16AWG) wire. It's very easy to handle and it doesn't costs much to install. Make it as short as possible since it is a voltage sensing line.

Seek

I guess I should connect the house battery to the chassis then.

Thanks,

pgr

pgr said:

I guess I should connect the house battery to the chassis then.

Thanks,

pgr

Click to expand...

I reread you post. Sorry it's early.

Yes, you need to connect that second battery to Chassis.

Seek

Thanks - I'm working on it right now!

pgr said:

The inverter is also grounded to the body. Should the aux battery be grounded to the body also or just connected to the inverter?

Click to expand...

If the inverter is grounded (with 6AWG) to the body, connecting the Aux Battery (with 6AWG) to the inverter is the same as grounding the battery (with 6AWG) to the Chassis.

You don't need to connect the Aux Battery to the Inverter AND Chassis ground.

Yeah, I know. I'm just trying to dig myself out of a hole.

Seek

Hi as a lot of things are given different names in Australia I some times think what it is called IN THE LAND DOWN UNDER so wait for a few more WHAT ARE YOU ON ABOUT questions from me ..................
West Marine Combiner 150 ???????? is this our duel battery charging system...... after starting the engine the charging volts need to be above certain volts before the second battery is charged !!!!!! ......
So if you are charging the aux battery from the vans alternator you will need to complete the circuit by grounding it back to the chassis
Inverter ...I am installing a 300w pure sine wave and the user's manual 110V models Neutral Grounding....connected to the safety ground ..This conforms to National Electrical Code requirements............So most electrical appliances have a Earth wire that goes back to power source inverter/house fuse box than to ground (metal rod in the ground near your fuse box) So I will find out more today about it we have rubber tires and no grounding rod
What size and type battery are you using as this inverter could run a small house ..........my two 180amp deep cycle battery system is to run a 12volt fridge and lights for a few days if there no sun on the solar panels......

Thanks for the info.

I ended up connecting the aux battery to the chassis as well as the combiner and the inverter. I've only had time to test out the microwave, but it seems to work fine. Tomorrow I will install the fridge and test that out.

pgr

Here is my contribution to the sprinter nation. Works perfectly , and is how I have my work van setup.