Auiliary battery needs solenoid 2003 Eurovan

[2wander]

converting my 2003 Eurovan to a camper setup and need a solenoid for auxiliary battery and a restraint. It fits under the driver's seat. The battery is 12v 200ah

[mikemtnbike]

If you have an AGM or other lead acid battery, you need to wire in something like this:

https://www.victronenergy.com/upload/documents/Datasheet-Cyrix-ct-120A-230A-EN.pdf

and you can be done with the alternator to starter battery to aux battery part. Housing wiring will depend on your specific needs.

If you have a li-ion battery, you need something like this:

https://www.renogy.com/dcc30s-12v-30a-dual-input-dc-dc-on-board-battery-charger-with-mppt/

I've used both those products successfully, so that's why I mention them.

I'm not going to try and explain how to wire things up, first I'm not qualified to post that kind of advice, secondly there are many many sources for that information out there, including some that are Eurovan specific- but I've found various RV sites and the vanagon forum equally if not more helpful for true expertise on the electrical details.

Don't burn your van or your self- do your research, test at each stage, fuse adequately, etc. Electrical work should always be approached with all possible cauton.
_________________
1991 Vanagon GL 2.1 AT Westfauxlia. "Frankie" Totaled https://www.thesamba.com/vw/forum/viewtopic.php?t=764510&highlight=carnage
1995 Eurovan Camper "Marzivan"
2020 GTI SE manual

[orbeamike]

Victron DC-DC charger can handle everything you need, it provides proper charging profiles as well as battery isolation between the house and engine batteries.
https://www.victronenergy.com/dc-dc-converters/orion-tr-smart-non-isolated

[bigfoot_ev]

I agree with what's already been posted since over time I have done both a smart battery isolator and then moving to a DC-DC charger. Personally, I really like the advancements that have been made to DC-DC chargers. I have been really happy with my CTEK for the past 5 years and it does battery isolation, MPPT solar charge controller, and specific battery chemistry charge profiles. Here is the model I use: https://www.amazon.com/CTEK-Overlanding-Maintainer-Alternator-Compatible/dp/B07X4YTP1P.

[kourt]

Just to help others interpret what's being said in this thread (because it's not totally clear):

The original EVC, and some other VW campers, were built with an isolating solenoid that ensured that the 12VDC circuit to the aux battery was disconnected when the engine was turned off. In the EVC it was located in the engine bay, just behind the starting battery, mounted on the firewall.

I think the OP is asking about an isolating solenoid to build a camper conversion with a DC aux battery system, to achieve the same result as the original design. That design is now obsolete, so suggestions are being made for alternatives.

The DC-DC chargers of today (2024) are usually built with isolating capabilities, so it's not necessary to have the isolating solenoid in the circuit path anymore. In fact, in some cases, it is undesirable, because some DC-DC chargers will accept solar inputs and send the excess current to the starting battery, which wouldn't be possible with the stock EVC isolator in the way.

The suggestion to get a DC-DC charger also assumes that the original EVC aux battery charger, located in the back of the van, is obsolete and should be removed. For shore power charging, a Victron battery charger is recommended.

TLDR: forget about the isolating solenoid, and buy a DC-DC charger to manage the relationship between your starting battery and aux battery.

kourt

PS: we might never see OP again...