Battery tender in 2008 Phaeton left rear bay?

[DrBob7762]

We're the 2nd owners of our 2008 Phaeton 36QSH.

I find an operating (green light is on) Battery Tender in the left rear bay. It's plugged into an outlet, and the outbound cable disappears through the wall.

Is this an OEM device? If so, what battery is this tending? My guess is the engine batteries - but why? Periodically, do I need to check that it's operating properly? If so how?

Thanks!
B

[vsheetz]

Yes, OEM
Yes, maintenance charger for chassis batteries.
The outlet it's plugged into is powered when on shore/genny power.
Check voltage with a test meter.

It's a fairly common item to fail with age. Often replaced with a LSL AmpleStart diversion charger (easily installed at the charge/aux relay in PS rear compartment).

[vettenuts]

My neighbor in Florida had theirs fail over the summer and had to replace the chassis batteries. I installed a Trik-L-Start that uses the charger in the inverter and connects to the charge solenoid, which is likely in your right rear compartment.

[DRM901]

Ours failed as well on our 2014 Allegro Bus and killed the chassis batteries.

I went with a Blue Sea ML-ACR. This replaces the boost solenoid. I think it is a much better solution. When you are driving, it keeps the house batteries charged via the alternator, the solar panels charge both banks, and both battery banks when on shore power.