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Old 03-25-2016, 09:44 AM   #1
2006 T1N 2500 Long & Tall
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Default Charging chassis battery from house batteries

On a 2006 LTV Free Spirit 3S, where do I find the relay that connects house batteries to the engine battery so house batteries charge while engine is running.

I do have a LR9806 relay, I've checked the voltage on both large lugs, the voltage is exactly the same on both lugs (the house battery voltage). Shouldn't one be the chassis battery voltage and the other lug be the house battery voltage?

Would this be where I would install a Trik-L-Start (battery charger/maintainer) so the solar charging from house batteries can also charge chassis battery?

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Old 04-02-2016, 01:43 AM   #2
2006 T1N 2500 Long & Tall
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Default Re: Charging chassis battery from house batteries

Here is the answer to the above question. Hopefully it will benefit someone that has a desire to temporarily connect the chassis and house batteries. or install a Trick-L-Start. I have found the elusive factory MB isolation relay (it isolates chassis from house battery). It is under driver's seat pedestal, at the rear portion. See pictures.

If I park for a week without starting the engine I find the using my transceiver radio along with my MP3 dash radio I would deplete the chassis battery quite quickly. Aside from that I also have a parasitic load which I've not been able to find. So I decided to charge the chassis battery from the house batteries that are connected to a 170W solar panel system.

Disconnect the ground terminal on the house battery and on the chassis battery. The relay has 2X10mm nuts, one for the house and one for the chassis battery. I secured a 10GA wire on each terminal long enough to install a switch on the outside of the seat pedestal. Or you can connect your Trickle L Start to this relay.

You will have to remove six T30 torx screws, first four, just rotate the seat a few inches to access the head, the other two of which you will have to rotate the seat 4 more inches so the 1" diameter hole is over the 2nd torx screw.

Disconnect the seat belt alarm wire, mine was wired through the center pivot bolt and cutting it would have been the only way to remove the seat from the pedestal. Instead I just moved it over as far a I could without cutting the wire and managed exposing the isolation relay.

One thing I really like about solar charging, my batteries are always operating in the top 20-25% of the battery capacity. Where before I was always around the 25-50% range.

Good luck
Attached Images
File Type: jpg 1 MB Relay.JPG (126.6 KB, 103 views)
File Type: jpg 2 MB Relay.JPG (158.5 KB, 102 views)
File Type: jpg 3 MB Relay.JPG (153.0 KB, 100 views)
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Old 04-02-2016, 10:27 AM   #3
UK 2004 T1N 313CDi
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Default Re: Charging chassis battery from house batteries


A nice way of recharging your chassis battery but you really should put a fuse in this new connection just in case you forget to turn the switch off before cranking the engine. The fuse will blow and prevent damage to your switch and/or new and existing wiring.

2004 UK Spec 313CDi (OM611 2.2 litre 4 Cylinder Manual Non-ABS)
Auto-Trail 'Cheyenne' Coachbuilt Motorhome
36,000 miles from New

Sprinter reference info site http://diysprinter.co.uk/reference/
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solar power

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