12 VDC problems

Red_Stephens · 04-08-2018, 09:52 PM

2017 Windsport 29M; I have no 12vdc power in the coach from the coach batteries. Even though plugged into shore power here at home (120vac), the batteries completely lost charge. I slow charged with my charger for about three hours, then started the genny and ran it for about three hours. If connected to shore power or if the generator is running, everything works as it should. The use/store switch by the step is in use mode, and I can hear a relay clicking when the switch is operated. Both circuit breakers in battery compartment are in proper position (test tripped, then reset). All 12vdc fuses in panel checked with VOM, all check good. With no load, batteries have 12.4 volts at terminals. There is an inline fuse, 30amp, approximately 1" square in the battery compartment; I don't know what this is for. What am I missing? Is there a reset of some sort that I'm missing on the converter?:

javelin · 04-14-2018, 10:21 PM

Hi Red, does your coach use the RV Custom Products BCC (Battery Control Cabinet)? I have helped a couple people recently on this forum that use this BCC and it contains a small grey 50 amp circuit breaker mounted on a circuit board inside this BCC which trips open under certain electrical conditions. If it trips it will not allow your coach batteries to charge via the converter and will not allow the coach battery to power the coach loads......the converter typically works fine powering coach loads other than battery on shore power or gen. If you have this BCC somewhere on your rig (it is in the engine compartment on my 2013 ACE 30.1) check the CB5 grey colored cct breaker and reset it. If you do not have this style BCC there may be some cct breaker that requires a reset.

Redbeard · 05-17-2018, 12:21 AM

Had the same problem you described on my 2018 model. I was able to get the generator started and then the problem "went away" (I hope!) without finding any culprit. My dealer didn't find the problem either. Three trips later and it has not recurred. Please post a followup if you found the problem/solution. Thanks.

Red_Stephens · 05-18-2018, 08:59 AM

Javelin, I don't think I have the BCC. I believe I have resolved that part of the problem by replacing the house batteries. I thought it was the battery isolation relay, (the one that clicks when use/store switch is engaged) but while troubleshooting I found a slight leak in one of the batteries, and they would never charge to over 12.4 volts. When I replaced them and got them fully charged, it resolved the problem. The isolation relay is still acting kind of finicky, so I ordered one from Amazon to have on hand. The batteries going completely discharged while at the dealers didn't help matters any. I'm curious about this BCC, it's possible I have one and just haven't spotted it yet, I keep finding gizmos all over the coach. And the compartment under the bed where the converter and inverter are is a wiring/component nightmare.

Red_Stephens · 05-18-2018, 09:09 AM

Quote:

Originally Posted by Redbeard

Had the same problem you described on my 2018 model. I was able to get the generator started and then the problem "went away" (I hope!) without finding any culprit. My dealer didn't find the problem either. Three trips later and it has not recurred. Please post a followup if you found the problem/solution. Thanks.

I believe the root cause of the issue was the batteries, which had been completely discharged while at the dealer. I thought is was the battery isolation relay under the bed, but that started working when I replaced the batteries. I bought one off Amazon and have it on hand just in case. I wasn't able to get the batteries to charge above 12.4 volts and found a slight leak in one. Thor wasn't any help at all, all I could get out of the guy I was talking to was take it back to the dealer, you have a converter problem. I'm not fond of that isolation relay, it's more of a solenoid than a relay that when engaged it should latch in mechanically until voltage is applied in reverse polarity which disengages; thus it being used as a use/store relay. I suspect the low voltage from the batteries wasn't allowing it to fully engage when the use/store switch was engaged and may have weakened it somewhat resulting in it being finicky.

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