Batteries discharged

[richeyb]

We own a 2017 Montana HC 380 and use 4 6V batteries to help with boondocking. When in storage I keep it plugged into 50amp 110 service to keep everything charged. Recently went to prepare for spring outings and couldn’t open the slideouts. Check battery lighs in the panel and it show four red lights. However when I checked the 4 batteries they were all drained low.
I immediately disconnected the batteries and began charging to make sure they would accept a charge, all four accepted full charge.
I checked out put of converter and it showed a 13.56v output.
I also checked continuity of the self setting breakers in the battery bay and all showed good continuity.
Not sure if I have missed something but all individual DC Electrical systems appear to be working.
Any suggestions.?
Thank you!

[BB_TX]

Any chance you turned the battery disconnect switch?

[Carl n Susan]

Is there 13.6V at the battery when plugged in? I think Bill has it with the disconnect switch in the convenience center. If the Red Key can be removed, the batteries are not being charged.

[richeyb]

Battery disconnect is in place and will not come out….

[BB_TX]

If you measure 13.56 volts at the converter output then you should find that same voltage at both terminals of all of the auto reset circuit breakers as well as at the batteries. If not then it is a matter of finding the point where that voltage is lost.

[Carl n Susan]

The 12V flow from the converter to the batteries is pretty straight forward. As others have pointed out, here are the places to look. All connections should have 13.5 +/- Volts if the converter is working.

• The converter is part of the power distribution panel -Ensure the CB for it is On
• There are Reverse Polarity Fuses on the converter which protect against connecting a battery backwards. - Ensure they are not blown.
• Check the output voltage at the converter. - it should be in the 13.5V DC range.
• The power then runs to the Disconnect Switch in the Convenience Center. - Ensure the Red Key is in the position where it can *NOT* be removed. If removed, this interrupts the power charging the battery. The Disconnect Switch is not know to fail, but you can remove it to check there is power in and out of it just to be sure.
• The power next flows to the group of 50 amp self-resetting CBs behind the battery. We all know about the one that hiccups and interrupts the hydraulic system. That one also passes power to/from the converter and batteries. You want to check it and it's brother (it is in the current flow to the battery) to ensure there is 13.5V on *EACH* side of the CB.
• The last connection is the one from the 50 amp CBs to the batteries. Ensure you have clean connections and the cables are not corroded (watch out for internal corrosion under the shrink wrap).

Somewhere along this path there will be the problem. A simple VOM should find it. I hope this helps.

The most common causes are :
o - the Battery Disconnect Switch in the convenience center is in the wrong position (the Red Key should be in the position where it can't be removed)
o - The red plastic covered self resetting 50 amp circuit breakers behind the battery have failed.

[richeyb]

Check for power at the battery connections and showed zero volts. Am I missing a connection or fuse in thE crawl space between the Converter and the battery box area?

[richeyb]

Carl, Thanks for the good info. Everything has checked ok xcept checking for power in and out of fuses, only check continuity. Will test for voltage in the mornin.

[richeyb]

Thanks. I’ll check those for voltage in the morning.

[richeyb]

I connected batteries following charging them all…
Checked battery disconnect switch post 1st reads 13.76 (same as converter)
Other post reads 11.76
Each post on all the battery bay fuses read 11.76
Disconnected batteries
Disconnect switch 1st post Rea 13.76
2nd post read 000
Each fuse post read 000

It appears to me disconnect switch has failed not allowing converter power to pass and entergize each fuse and charge the batteries.

[richeyb]

Carl or BB_tex any thoughts?

[BB_TX]

Sounds like a bad battery disconnect switch. You are reading converter voltage on one side and battery voltage on the other. That would indicate an open switch. If you turn the switch to the other position does it make any difference?

Might try working the switch back and forth several times to see if it will make contact. Not a normal failure item, but sounds like you got one.

[Carl n Susan]

I assume your are referring to the Disconnect Switch in the convenience center. I have never had someone say the switch has failed but it sounds like yours has.

You can either connect the In/Out power cables on one post or just bolt the two together (be sure to insulate) to bypass the switch altogether. That will pass the 13.6V on to replenish the 11.6V (aka discharged) batteries. Hopefully the batteries will recover.

[BB_TX]

I agree with Carl. Just put both wires on one terminal of the switch and call it good until you replace the switch. In 14 years the only time I ever used that switch was when replacing the battery. And even that is not necessary if not on shore power.

[twindman]

Don't think it has been mentioned, but you really need a true battery disconnect switch in the battery compartment. Completely disconnect the battery ground (I don't think you do the positive side).

Then when you disconnect it, the batteries should only very slowly drain while in storage (unless you plan on keeping it plugged in somehow). I leave mine disconnected (in AZ where winters are pretty warm) for as long as 5-8 months and they work good for raising the front jacks when hooking up to truck in the spring.

[WaltBennett]

Originally Posted by BB_TX

Any chance you turned the battery disconnect switch?

That 'disconnect' switch does not disconnect everything.

[BB_TX]

Originally Posted by WaltBennett

That 'disconnect' switch does not disconnect everything.

True. But it does disconnect the main wire from the battery to the converter.

[steiny93]

suggestion

When in storage, don't have the trailer plugged into shore power. Rather have a disconnect switch that breaks the negative side of the batteries. Those batteries will sit for an incredibly long time (many months) if they are 100% disconnected (which your current switch doesn't do).

It's simple, reduces risk (fire, equipment failure), less power consumption; it's a win-win all the way around.

[richeyb]

I have connected both wires to a single post of the disconnect switch and allowed converter power to charge my batteries. Have ordered a replacement battery cutoff switch. Not sure why since I leave in the on position at all times. thanks for all the replies and suggestions.