floating house ground and xantrex echo charge system?

[Brian Kelley]

Hi, I"m a new owner of a 2004 Beaver Monterey. I was looking into installing a Xantrex echo charge unit to keep my chassis batteries charged off of my solar panels, but I discovered that while my chassis batteries are grounded to the frame, my house batteries are not (they float, it seems). I used a voltmeter, and there is no connection between frame and negative of house batteries. The Echo charge has only one single lead for ground, which indicates I believe that it assumes that the chassis and house batteries share the same ground. In my case, they don't. So, my first question is about the floating/non-frame grounded nature of the house batteries, is the OK/common? and second, can I run the echo charger if they do not share the same ground?
thanks to you all for the great advice and support that you provide this forum, I've learned a tremendous amount.
Brian Kelley, Denver, CO

[Keith Moffett]

While you wait for a good answer for your question, Allow me to welcome you to the Beaver family.

[Edward Buker]

Brian,

You are right that there is only one lead and one ground on the Echo Charger and they have to by design share the same ground. The emergency start button that fires a solenoid only connects the plus side of the two banks, if you have that feature, so that feature requires a common ground.

I would start by measuring between the + of the house bank and the chassis frame. If you measure 12V then your chassis bank is grounded to the frame which I suspect it is. If not then look at the manual for your main charger and see if it has any restrictions about grounding to the frame. I have not heard about not grounding both banks to the frame in the past in a Beaver coach and I cannot see any benefit to not grounding both to the frame.

If you measured voltage between the negative terminal on the house bank and chassis ground that would be 0V. If you measured resistance that should be tenths of an ohm, meaning they are connected, or high resistance meaning they are not.
Hope this helps.

Later Ed

[Gerald Farris]

Brian,
I am under the impression that your 2004 Monterey is equipped with a "Bird" system to achieve battery bank isolation while still charging both battery banks from the same source. If so, the "Bird" system is designed to accomplish the same function as an Echo Charger. Therefore, if your "Bird" is functioning properly, an Echo Charger will serve no purpose, an if the "Bird" system is not functioning properly you will need to repair it to allow the engine alternator to charge the house batteries.

Another explanation for the solar panels only charging the house batteries and not the chassis batteries is that the solar panels are not furnishing enough current to get the house batteries above the voltage threshold that is required to activate the "Bird" system. If that is what is happening, you will have the same problem with an Echo Charger because the two systems use about the same voltage activation threshold.

Gerald