Mysterious 4th battery (1 Viewer)

[KittyTabbert]

I was hoping if anyone could shed a light on why my old German motorhome would have a 4th battery, haven't tried too hard to see where the wires go but it's not part of the leisure battery bank and its not for ignition. We've not had it long so I asked the previous owner, who hadn't been aware there was a 4th ( factory fitted by the look of it, boxed in the passenger footwell) its.1998 LHD Tabbert based on a Sprinter 412.
Appreciate any thoughts

 

[daveandsan]

Auxiliary battery, runs the radio and alarm, leaving the engine battery just for starting the engine.

 

[KittyTabbert]

Thanks, that would make sense, will it take charge from the alternator rather than the panels do you think?

^{_{Subscribers  do not see these advertisements}}

 

[daveandsan]

If it is the auxilary battery the alternator should charge it but i have fitted one of these http://leisurelines.net/battery-charge-manager-leisure--main-battery-3334-p.asp to mine so that the solar panel via the leisure battery keeps it topped up when it is parked up.

 

[KittyTabbert]

Thanks, useful website link too

 

[Tootles]

It powers the rotating key on the roof........

^{_{Subscribers  do not see these advertisements}}

 

[KittyTabbert]

New stereo fitted today and it seems this is drawing power from the "auxiliar" battery. Thanks for your thoughts (even the really bad photo shopped wind up key)