I retrieved my RV from storage today where it had been for 14 days. When I entered the RV I immediately saw that the interior lights (LEDS) were on. Yikes! They were on for 14 days straight. I do not have solar. I have three 12v deep cycle batteries in the RV living quarters that were all purchased new about 6 months ago. These batteries were all fully charged prior to putting away in storage 14 days ago.I checked the battery voltage on the battery terminals (I've got a bluetooth monitor on them) and it said 11.4v. On the short drive home (about 1 mile) the voltage went up to about 12.4v while the engine was running (as the chassis alternator was trying to give them some charge). When I got home I plugged the RV in to shore power so the converter can give it a charge overnight.After about 5 hours of being plugged in, the voltage on the batteries is at 11.7v. Seems like it has been there a while. Is this common/expected?I've got a WFCO 75amp converter that is only about 6 months old. Very often over those 6 months when I plug into shore power it was common to hear the converter fan kick on and it sometimes would stay on for a couple hours before finally shutting down. So far, being plugged into shore power for about 6 hours now trying to charge the dead batteries I have not heard the converter fan come on at all. I thought that when under a heavier load and trying to charge the batteries it was common for the converter fan to kick on...but so far it hasn't.From your knowledge/experience, what sort of damage did I do to my batteries? Is it reasonable to expect that they will mostly recover if I charge them for a very long time? How long should I expect to recharge them?Thanks!

Give it another 24 hours before sending up the balloon IMHO

Given how poorly the WFCO converter works, I'd go for 168 hours.

The batteries will be fine. The wfco was a mistake in my opinion. Let it charge on the wfco and monitor it in case wfco isn't bringing it up. Maybe get a new progressive dynamics arrives.

You'll be fine. Just keep your camper plugged in. You don't need fancy instruments to determine the health of your battery. Just unplug the camper from shore power. Turn on a light and see how bright it is. Now turn on a second light. If the lights dim noticeably, the battery is either weak or not fully charged. It's just that simple.Keep it plugged in. It will be fine.

On the short drive home (about 1 mile) the voltage went up to about 12.4v while the engine was running (as the chassis alternator was trying to give them some charge). When I got home I plugged the RV in to shore power so the converter can give it a charge overnight.After about 5 hours of being plugged in, the voltage on the batteries is at 11.7v. Seems like it has been there a while. Is this common/expected?No... Seems the wfco is not charging. You should be up over 11.7 because the truck was charging @12.4. And yes the wfco fan would come on non stop at that low level.Possibly the breaker/fuse on the frame rail is blown? Need more info.You need to do some testing on the wfco. Ill post a link, but in mean time get those batts on an external charger ASAP.http://wfcoelectronics.com/wp-content/uploads/2015/11/New-Flow-Chart-for-WF-8900-Series.pdf

Batteries drained because lights left on...how bad is it?

25 Replies

MEXICOWANDERER
Explorer
May 06, 2018
Fully Automatic Charger

Where do I stick in the wires?
Harvey51
Explorer
May 06, 2018
When a battery is charging it’s voltage is the voltage of the charger. Disconnect the charger for at least a couple of hours to get an indication of state of charge from a voltage reading.

I have a smart charger with equalize mode but in this case I would use my little bench variable power supply because I can set it at 14.8 volts for a few hours. Dumb can be better than smart because the charger doesn’t know what happened to the battery.
pianotuna
Nomad III
May 02, 2018
If you wish to eliminate generator use, 400 watts of panels would be the minimum I would install. I did 256 watts--but that was went panels were $5.50 per watt, now the lowest price I've seen is 26 cents per watt.

The wfco is NOT going to finish charging the batteries. The voltage is too low. You need to equalize the jars and that requires at least 14.4 volts and 14.8 would be significantly faster and better.

SJ-Chris wrote:
Update: Yes, my RV does have a battery disconnect switch. This was the first time ever that I accidentally left it on, draining the batteries for 14 days down to 11.4v. The only thing on was about 6 LED bulbs.

I took off the stand-alone battery charger once the batteries were up to about 12.5v. I plugged back into shore power and the WFCO converter fan kicked on and started charging the batteries. I left it on overnight and when I went out this morning it was charging at 13.8v. Seems like they should be good and charged now (3 12v deep-cycle batteries in my bank).

One thing I'm thinking about doing is adding 100w (or 200w) solar. This seems like it would be a great way to keep the batteries charged when not camping, and when camping they would provide much less need for plugging in and/or generator usage.

Thanks all for your suggestions!
-Chris
MEXICOWANDERER
Explorer
May 02, 2018
Those batteries MUST SEE 14.4 to 14.8 volts. Or they are going to suffer a short lifespan. 13.8 is Tickle Me Elmo
SJ-Chris
Explorer II
May 02, 2018
Update: Yes, my RV does have a battery disconnect switch. This was the first time ever that I accidentally left it on, draining the batteries for 14 days down to 11.4v. The only thing on was about 6 LED bulbs.

I took off the stand-alone battery charger once the batteries were up to about 12.5v. I plugged back into shore power and the WFCO converter fan kicked on and started charging the batteries. I left it on overnight and when I went out this morning it was charging at 13.8v. Seems like they should be good and charged now (3 12v deep-cycle batteries in my bank).

One thing I'm thinking about doing is adding 100w (or 200w) solar. This seems like it would be a great way to keep the batteries charged when not camping, and when camping they would provide much less need for plugging in and/or generator usage.

Thanks all for your suggestions!
-Chris
MEXICOWANDERER
Explorer
May 02, 2018
The batteries will be damaged unless they charge until they bubble. Hopefully your little charger has an equalize setting. BTW this is not guesswork you must revert as much of the material on the positive plates as is reasonable.

WFCO maintainers are only useful when connected full time in a permanent RV park.
MEXICOWANDERER
Explorer
May 02, 2018
The batteries will be damaged unless they charge until they bubble. Hopefully your little charger has an equalize setting. BTW this is not guesswork you must revert as much of the material on the positive plates as is reasonable.

WFCO maintainers are only useful when connected full time in a permanent RV park.
red31
Explorer
May 02, 2018
put the portable charger back on to charge.
Wild_Card
Explorer
May 02, 2018
Its possible the converter went into fail safe or something. Diconect and reconect reset the converter. Most would have stopped diagnosis at failed converter and spent some wasted money. Good job.

As stated above get a disconect for when its in storage. Surprised there isnt 1 already.
westend
Explorer
May 02, 2018
It may be a good time to install a battery disconnect switch. Even if you turn all the lights off, there are parasitic draws that will draw down the batteries while in storage.