emergency starting rv

[lotus7]

I have a 2018 Georgetown Class A motorhome GT31L5 I am confused last week on a 5 month old coach, my engine battery was completely dead... I could not access the coach batteries because the relay switch (next to the steps) is powered by the engine battery....what kind of catch 22 is this? was it wired wrong during mfg??

[ScottBrownstein]

It is entirely possible that your unit was wired with the coach feeding what should have been the chassis connection. I have heard of this recently but cannot remember the manufacturer. Of course the whole idea of an emergency start switch is to overcome a dead CHASSIS battery. I would have someone look at it.

[bubbles]

The emergency start switch on the instrument panel energizes the interconnect relay in the BCC and that puts the chassis and coach batteries connected together. The battery disconnect switch at the steps has no input to accomplish this. There is a fuse in the BCC that the emergency start switch goes through to the interconnect relay. Incidentally, the interconnect relay is the same one that ties both batteries together for charging. This is the set up in my 2012 GT and see no reason it would have been changed for later years.

[Bayouownbeer]

Originally Posted by bubbles

The emergency start switch on the instrument panel energizes the interconnect relay in the BCC and that puts the chassis and coach batteries connected together. The battery disconnect switch at the steps has no input to accomplish this. There is a fuse in the BCC that the emergency start switch goes through to the interconnect relay. Incidentally, the interconnect relay is the same one that ties both batteries together for charging. This is the set up in my 2012 GT and see no reason it would have been changed for later years.

Does this emergency start switch in my coach it’s called battery boost have to be active for the alternator to charge the coach batteries going down the road?

[ScottBrownstein]

OK, I have re-read your post and perhaps understand your problem better. You are saying that your coach battery is dead and you cannot use your boost start since your house batteries are disconnected via the switch by the door. The battery disconnect switch will prevent boost from working since the house batteries remain disconnected and cannot be brought on line.

I do not know which BCC FR used in your coach but from the Intellitek manual that is used on many of these coaches, it appears that the disconnect should be powered by either coach or chassis battery. I do know of a "catch 22" case where the house batteries could not be brought back on line to charge since they were totally dead and would not fire the disconnect, which seems to indicate that some are powered by the house only. The solution to that problem was to charge them with a separate battery charger a little to enable them to fire the disconnect and then use the converter to bring them back. You could use the same strategy to charge the chassis a little to see if that is in fact your problem.

The disconnect is a wild card in your situation. Boost start would work if the house bank was not off line though the disconnect as the two have nothing to do with each other.

The real question is why is the chassis bank dead already. That shouldn't happen and I leave my coach for weeks at a time with the house disconnected and have never had a dead chassis battery or insufficient power to use the disconnect.

[bubbles]

Originally Posted by Bayouownbeer

Does this emergency start switch in my coach it’s called battery boost have to be active for the alternator to charge the coach batteries going down the road?

No. The switch is only used when the chassis (engine) battery will not start the coach. The switch is held on while starting the engine and released when started. The start power comes from the coach batteries so the coach batteries must have enough charge in them to start the coach. The engine alternator will charge all the batteries if the coach batteries are not disconnected. If the coach batteries are disconnected they also will not be charged when connected to shore power. If the coach batteries are disconnected that will not prevent the emergence start switch from tying the batteries together, assuming the coach batteries are of sufficient charge. There is a fuse in the Battery Control Center (BCC) box that the emergency start switch input goes through to energize the interconnect relay for the emergency start and a fuse battery HOT output fuse. You should pull the cover off the BCC and check the fuses that are inside. What I have written here is assuming your power setup is like the standard FR Georgetown power distribution. Remember, for the emergency start function to work the coach batteries must be sufficiently charged. One other input; the battery disconnect switch at the steps is not powered by the chassis battery and if it is not working then your coach batteries may be depleted as to not allow switching.