Eberspacher 24 volt heater info

[dandywarhol]

Does anyone know where in the archives I can find the wiring for allowing a 24 volt Eberspacher/Webasto heater to work off two 12v batteries.

Could've been done by wryster?????

[Bob]

Do you just wire in series? That would give 24v.

[mikexgough]

Does anyone know where in the archives I can find the wiring for allowing a 24 volt Eberspacher/Webasto heater to work off two 12v batteries.

Could've been done by wryster?????

I thought it was "Yamaha"?....

Also the write up was on bongoogle....but that seems to be down now..... I thought I had saved it as a document but as yet have not dug deep enough to see...

[dave_aber]

Do you just wire in series? That would give 24v.

IIRC it was a bit more complicated than that, as the 2 batteries were a starter & leisure set up, with split charging etc, and a cunning we einterfacce box which derived 24v form them for the eber, but allowed them to carry on as independent batteries in all other ways.

[dandywarhol]

Thats right Dave - it was a cunning box of tricks devised by wryster and used by yamaha. it allowed the main and leisure batteries to connect in series to only operate the eber.
I noticed bongoogle down too - is it only temporary?

[g8dhe]

Its suspended looks like the address is up for grabs or will be shortly, it expired in January 2011.

[briwy]

I'm pretty sure it involved using some hefty diodes to stop the batteries feeding each other but I can't remember exactly how it was done.
I was considering doing it as the 24v ones are a lot cheaper than the 12v but eventually got a 12v at a decent price.

[Yamaha]

I have found some info on my ImageShack account - forgotten I'd uploaded them - hope they help a bit.

http://img220.imageshack.us/i/1224switchll5.jpg/

http://img483.imageshack.us/i/p2080066hp9.jpg/

http://img63.imageshack.us/i/p2080067xd2.jpg/

The relay was a 4PDT 12v jobbie from Maplin - not ideal as only rated at about 12A handling - but unable to source anything heavier at the time - a specialist contactor would be ideal, if a suitable one was obtainable. There are also a bank of 4 fuses in the box - and in use, I have only ever had to replace one on one occassion.
I also used a transistor to switch the relay coil to avoid the charging lamp on the Bongo glowing, but can't find the circuit for it now.

Looking back - I am still glad I went the 24v route - my Webasto AT2000 cost me £330 brand new on eBay - and I really enjoyed the fitting of it (at the time I was more nimble)!!

The only thing I never got around to doing was to replace the internal thermostat with a cabin-mounted one - an easy enough job. This caught me out once when we pulled over one night for a snooze, and the heater wouldn't fire up - I eventually realised that it thought the engine compartment was warm enough - and didn't need any more heat!! One it had cooled down a bit, all was well again.

Bear in mind, though - this installation can ONLY be used when you're parked up, and the engine is stopped, so the relay is off, and the 24v is available for the Webasto.

Mike

[dandywarhol]

Thanks for that Mike.