Battery will not charge on shore power

[yldhawg]

I have a 2008 International, 16'. During a recent extended trip (boon docking), when it came time to charge up the battery, I could not get it to charge through the shore power connection via a Honda EU 2000 generator. Up until that time we have not had any problems with the electrical systems (we have owned this trailer until since early 2013), and have successfully charged the battery in this manner many times. Upon returning home and hooking up to grid power, the battery still would not charge through the 30 amp shore power connection. However, I noted that while towing from one campground to another, the battery did take a charge from the tow vehicle.

I have taken the trailer in to a local (reputable... I thought) service center. I was told that they could not find anything wrong. They were able to successfully get the battery to a full charge. I suspect that they charged the battery directly and charged me $50 for the privilege.

I do have 'some' mechanical skills (although I wouldn't trust my skills on someone else's rig). I am looking for some direction on digging in and trouble shooting this issue myself. Any guidance (including the best brew to drink while pondering which direction to twist the wrench) will be appreciated.

Thank you in advance.

PS. My trouble shooting to-date has included installing a new battery, inspecting the fuses, and checking the terminal connections on the battery and buss-strip.

[Mrjkq]

If your AS is like mine it will not charge on shore power unless the store/use switch is on use, if on store no charge even though the red light is on

[yldhawg]

Thanks Joe. I my unit, when it is hooked up to shore power (either the grid or a generator) the store/use switch is automatically held in the "use" mode. Attempting to toggle to "store" just cycles the relay and the system returns to use mode.

[Mrjkq]

Maybe that relay switch is faulty & not recycling a sit should creating a false positive?

[bwaite]

I just got a 2016 International and like yidhawg, when plugged into shore power, the power switch cannot be engaged in the "store" position. I have tested the battery draw with and without shore power and the batteries are recharging automatically when shore power is connected.

[Drathaar]

Get a multi-meter to take with you on all of your travels. They are not expensive, and will save you a lot of $50+ visits to the RV repair shop.

When you have your multi meter, take a voltage reading on the battery without any form of shore power on it. Have the meter on a 15 VDC scale. Assuming the batteries are in good shape, you should see something north of 12ish volts DC. Then, hook up the Honda or Grid, and check it again. If everything is working, you should see over 13.5 volts DC. If not, start checking things... Like is the disconnect switch or converter switch turned on.

If you have a second 30 amp receptacle on the trailer, put your cable on it and try again. Sometimes the switching relay is stuck.

With the Honda or Grid connected, you should have both AC and DC available to the trailer, although the DC will not charge the battery unless the connect (store/use) switch is on. I have not seen an Airstream where when power is connected, the store/use switch is automatically in use. That doesn't mean I'm right, just that I have not seen it.

Hope that helps...

[yldhawg]

Thank you Drathaar & bwaite (and thank you again Mrjkq), I will probably be crawling around with my multi meter this weekend. We have a trip planned for over the New Years so I'm feeling the pressure to get it figured out.

[rmkrum]

Please Understand that the use/store light only tells you you have 12 volt power on the output side of the relay to your 12 system. It does NOT mean you are on battery. It's a special latching relay that consumes no power when it's on. The switch toggles the relay in of off, then it stays that way. You have to remember which way you left it. Press 'use' and it connects the battery. Press 'store' and the battery disconnects. The light only says you have 12 volts available to
Power your 12 volt stuff. It's weird, but that's how it works.

Having 110 shore power connected and a good converter will light the light even if the battery is disconnected.

I have a solar controller and panel connected direct to the battery and only use that to charge batteries in storage. My switch is set to 'store' when I'm not using the AS and solar keeps the battery charged.


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[Drathaar]

When I said you should have at least 13.5 VDC when connected to Honda/Grid, and switch has been toggled to use, that is at the battery.

rmk is correct on operation of switch, and YES on solar to keep batteries charged when not in use.

[rmkrum]

I found data on how it works on the web. Search the part number on the control plate. Can't find the link right now.


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[yldhawg]

Thank you everyone for the input.

However the focus on the use/store switch is obfuscating the point of my inquiry. When my battery becomes drained, while I am using the trailer, and I connect to shore power via a generator or grid, the battery will not charge. The switch is in the "use" position to begin with because I had been using the trailer. I don't touch the switch, maybe I should? Toggle it to "use" even though it was already being used, not stored. If this is a needed step, it is a new step. I have been using the trailer for almost 3 years now and this condition is different. Something changed. Perhaps the relay switch which has been discussed is failing or failed.

[rmkrum]

Check that the relay is in fact closed. If you put your voltmeter across the relay with the the AS disconnected from shore power, and the switch punched to use there should be no voltage across the heavy relay terminals. If there is some voltage (over a tenth of a volt or so) the contacts are possibly toast.


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[bwaite]

Thank you both Drathaar and rmkrum as both of your posts were helpful to me in explaining how the store/use relay switch works. I knew it wasn't switching the power source to 12V, but the light staying on when connected to shore regardless of switch position was confusing. So one clarifying question. Is it correct that if I keep the trailer plugged into shore power and wish to have a maintenance charge on the batteries, the switch must be in the use position? I am planning to do this in lieu of connecting to battery tenders if the system is designed to maintain the batteries in this mode. Thanks all.

[Drathaar]

Brad, there is a good chance that you will harm your batteries if you leave it plugged in and charging all the time. At a recent dealer sponsored maintenance clinic, the lead tech said it was ok to do that IF AND ONLY IF you checked water levels on a frequent basis. Weekly? The battery tender or solar would be a better idea. I prefer to charge my batteries fully, remove shore power, then disconnect the negative terminal to the trailer. That way, there is no phantom load on the batteries, and even though it's under cover, the solar gets enough light to keep up with normal voltage decrease.

[PecanMan5]

I bought a digital volt meter from Amazon that plugs into the 12v recepticle (cigarette lighter). I can instantly check my voltage. It I switch it to store with shoe pwr. It goes blank. Quick & simple.

[bwaite]

Thank you Drathaar. Battery Tender it is.

[ijustlee]

Just so people know, the cheapo battery tender from Harbor Freight will over charge your battery in storage. I tried 2 of them and both were not shutting off. As far as the lack of charge on shore power, I'd suspect the contacts in the relay. It usually helps to toggel or flip the switch of electrical things when troubleshooting, as well as giving it a few good "thumps" to see if there are some questionable connections moving around. A bad connection will run hot so that can be a clue. I like to start any troubleshooting with a factory wiring diagram if you can get one or often I draw my own as I go to help me understand exactly how the current flows. Use caution not to short anything when poking around as there is a lot of current available in a battery. This should be a simple fix. Leland

[cuyeda]

Yes, on everything suggested so far. I find that if the battery drains completely, the relay tends not to function. It needs some type of voltage source to the battery enough to engage the relay circuit. If the battery charges with the tow vehicle connected, then you shouldn't have a problem after, because the relay should get energized then.

Also, check the relay, there are fuses on each contact lead.

However, if your battery is not holding a charge that will be another issue.

[rmkrum]

Yup. The control relay that connects the battery won't work unless there is enough charge on the battery. That's why my solar system is hard wired to always charge the batteries.


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[Bash]

Hi guys I read through the posts here. It’s late and I don’t have a multimeter handy. Heres my story. We left our AS plugged into 110 shore for about 3 weeks while we were gone in the “store” position. We didn’t know that was a no no. So anyways the battery was dead. We drove it about 2 hours the dropped it at a storage facility for about 3 weeks. The batteries seemed to have a little charge from being connected to the truck. We left it in “store” again not connected to any power. We just picked it back up (discovered someone stole our propane tanks from a gated storage facility) drove it home plugged back to shore put it on “use” popped the AC on and some outside lights and went to dinner. Came home to 0 power in the trailer and the breaker flipped on the outlet in the house it was plugged in. it will barely light the digital battery monitor when toggling the use/store switch. Tried flipping breakers in the AS. No luck. Any thoughts?