Sunseeker house and chassis batteries drained in 7 days

[Phrogdriver]

Hi all,
My family and I are enjoying the 2014 Sunseeker 3170DS we've had for about a month. After taking in to the dealer for some warranty work, and to install the awning lights they didn't have when we took delivery. I picked it up last Saturday. When I got the the dealer to pick it up, they had the engine and generator running and said the battery had run down a bit. Drove it back to my storage lot, checked the house batteries were fully charged, turned off the generator, and turned the battery disconnect switch to off. Locked up and left. Went back today (7 days later), to pick it up for a quick trip tomorrow, and all the batteries (including chassis) were completely dead. Called the service department and they said they had never heard of all the batteries draining. Ultimately, I used jumper cables to get the engine, and then generator, running, brought the RV home and plugged in. Batteries are showing completely charged again. I checked the fuses in the battery control area... Any ideas on what might be causing the simultaneous battery drain of all batteries? Thanks for any help y'all can provide!

[ependydad]

I think you need to check the batteries with everything off. If you have 120v, when you check the battery- the converter is pushing a charge to them and are giving you a falsely high reading.

In fact, I think you're supposed to leave the batteries off for a bit before checking them for any "residual something or other to equalize" or something.

[RamblerGuy]

As ependydad stated, the coach batteries are deep cycle which must be charged at a slow rate overnight to fully recharge. They will quickly show good voltage after charging a short time, but it takes a while for the charge to “soak” into the thick deep cycle plates. To get a true reading of the state of charge, you have to leave it with no charger or load for several hours. They would not have been fully charged in a few hours.

It sounds like the isolation relay that connects the coach batteries and the chassis battery is staying energized. It is controlled by a black box in the battery control center behind a panel on the left side of the steps. The box is called a Bi-directional Relay Control (BIRD). The relay itself takes about 0.5 amps to hold in, and over 7 days that would be 84 amps. That isn’t enough to drain two coach batteries (assuming you have two) and a chassis battery, but they may not have been fully charged and there may be some other current drain. After four months in storage our Sunseeker started instantly and the coach batteries still had lots of charge.

Normally, the BIRD will energize the isolation relay to connect the coach and chassis batteries when either the coach system (from the shore line through the convertor) or the chassis system (from the alternator) is charging.

I’ve attached the product information sheet on the BIRD which explains its operation. The Sunseeker is not wired quite like the diagram illustrates. It does not have a chassis disconnect relay and it has a disconnect switch for the coach batteries instead of the coach disconnect relay, which the company just happens to sell. The “AUX” wire comes from the emergency start switch that is mounted on the side of the driver’s seat.
Regardless of the problem, the dealer should fix it under warranty, but it is good to understand show things like this work so you can troubleshoot them when you’re on a trip.
By the way, there is one thread on this about what tools and supplies to carry that may be helpful if you are at all handy fixing things. At the very least I think you should have a digital voltmeter, even if you plan to camp plugged in all the time.

[Phrogdriver]

Thank you both for the responses. RamblerGuy - the BIRD data sheet was very useful. I wonder if it fails, if it fails with the circuit closed, keeping the batteries connected? The good news is, I am a fairly handy guy. The bad news is, I allowed myself to have a false sense of security thinking that a one month old RV certainly wouldn't have any problems yet, and hadn't bothered putting together a tool kit yet. I also found a recall on 2014 Sunseekers for a 'Battery Interface Module' last night. Either way, it looks like it is back to the dealer on Monday, with hopes that it can be diagnosed/fixed before our camping trip next weekend.

[garbonz]

Originally Posted by ependydad

I think you need to check the batteries with everything off. If you have 120v, when you check the battery- the converter is pushing a charge to them and are giving you a falsely high reading. In fact, I think you're supposed to leave the batteries off for a bit before checking them for any "residual something or other to equalize" or something.

It's called the "surface charge" and it takes several hours without drawing any current to come down to a full resting voltage. OR you can draw a couple of amps for a couple of minutes and it will do the same thing, sort of.