Proper stock battery charging

[davidrrand]

Picked up our 2016 FC25 in May and have spent six nights so far plugged in with full hook ups. When at home, I park trailer near my house and plug it into to 115 volts every few days to charge the batteries, usually for 4-6 hours. Notice that when its plugged in charging, the Sea Level monitors usually shows around 13.6 volts. When I unplug and maybe run the fans at low speed to ventilate the trailer with the summer heat, the stock Interstate batteries seem to discharge rapidly, down to 12.3, maybe in as few as 4 or 5 hours.
Checked the batteries for fluid level and all are good. I am assuming that if the converter is only charging at 13.6 volts, the batteries are not getting charged fully. I have read that wet batteries should be charged at closer to 15 volts to receive a good charge. I charge the same type of batteries used in my two small boats with a 10 amp multi-stage charger, one at a time and these batteries seem to hold charge very long. The charger shows voltage at times well into 14 volts approaching 15.
These are my questions:
1) If I kept it plugged in longer charging with the stock converter, would they receive a full charge?
2) Should I charge the AS batteries with my auxiliary charger periodically instead of the converter to get a full charge? If so, can I charge the two batteries at the same time with this charger in the battery box with the alligator clips. If so, what is the best way to hook up the clips or should I take the batteries out and charge them individually?
Thanks for your responses and you can see my DC knowledge is limited.
Dave

[alano]

Sounds like you have a pretty good idea of what's going on. Your stock converter only includes a single-stage battery charger. You should avoid using your converter for extended periods, otherwise you might damage the batteries. An external three-stage charger from time to time would keep them healthy and fully-charged. Many folks replace the stock converter with a proper three-stage battery charger. It's not difficult to do yourself and the cost is just over $200. Some folks avoid replacing the stock converter by installing a solar charger which includes a three-stage battery charger.

If you're careful by not excessively charging your batteries with the stock charger, check the fluid levels from time to time and only charge when required, there are folks who get many years of battery life.

[OTRA15]

Welcome to the forum!

The OEM charger will show that 13.6 volts as standard. It is possible that your batteries were not stored/charged correctly at the dealer, and that they are shot.

After charging (with the Use/Store switch in the Use position), unplug from shore power, wait an hour, and start logging the battery voltage over time, say every 4 hours or so. The first reading should be about 12.8 or 12.9. Make sure all 12 volt functions are off, including any sub-woofer under the bed, stereo/radio in cabinets, lights in exterior storage areas, etc.. You can leave the propane detector on, but know that it is a small parasitic draw on the batteries FYI.

Our 2014 FC20 batteries will stay above 12.5 for 3-4 days, with no use of the trailer. Our stock Parallax converter is fine (for now -- upgrade contemplated for the Fall), if actively managed, as you seem to be aware might be needed.

Let us know what you log for battery voltage over time, and you will get better feedback. When you have more complete data, you can also contact the dealer for feedback. Interstate stores will often replace the batteries without having to involve the AS dealer.

There are many threads here on this topic. Stand by for a few links:

http://www.airforums.com/forums/f37/...ns-153861.html
http://www.airforums.com/forums/f449...ry-148901.html

Or you could peruse the list of threads in this Battery sub-forum for similar topics:

http://www.airforums.com/forums/f449/

Good luck!

Peter

PS -- It should not be necessary to use an auxiliary charger.

[OTRA15]

Originally Posted by davidrrand

. . .
Thanks for your responses and you can see my DC knowledge is limited.
Dave

Just wondering if you sorted this out, and whether you had to get new batteries (hopefully under warranty)? Or maybe you upgraded to a new converter/charger?

We are considering the upgrade, but are gathering as much info. as possible first.

Thanks,

Peter

[davidrrand]

Originally Posted by OTRA15

Just wondering if you sorted this out, and whether you had to get new batteries (hopefully under warranty)? Or maybe you upgraded to a new converter/charger?

We are considering the upgrade, but are gathering as much info. as possible first.

Thanks,

Peter

Peter, thanks for your follow up. Found out the light in one of the storage compartments that normally stays locked up was turned on and was probably contributing to a rapid discharge. I have been hooking up power for a couple of days at a time then putting switch in store mode for 3-4 days then repeating with decent results. Checking fluid level each week and no added water, yet. Leaving this week for a 4-6 week trip out west and will find out how good my batteries really are! Have a generator to charge also when necessary. Wish me luck and thanks again for your follow up!

Dave

[MarkR]

no expert here but I'm pretty sure it's normal for battery voltage to drop, sort of rapidly, from the charge voltage (in the 13's) down to mid 12's . . . then is should stabalize there (in the mid 12's) for an extended period (assuming no, or very little use).

[OTRA15]

Originally Posted by davidrrand

Peter, thanks for your follow up. Found out the light in one of the storage compartments that normally stays locked up was turned on and was probably contributing to a rapid discharge. I have been hooking up power for a couple of days at a time then putting switch in store mode for 3-4 days then repeating with decent results. Checking fluid level each week and no added water, yet. Leaving this week for a 4-6 week trip out west and will find out how good my batteries really are! Have a generator to charge also when necessary. Wish me luck and thanks again for your follow up!

Dave

Thanks Dave. Did you ever get the battery voltage readings over time, as suggested earlier? [no shore power for days at a time] If your batteries went seriously below 12 volts for any length of time, they may be damaged already IMO. Better to know now than in the middle of a trip maybe?

For storage in the future, we intend to follow a recent comment by the expert lewster in another thread, which you might also consider -- the simple added step of disconnecting the negative-to-negative jumper cable between your two batteries [click on arrow to go to that thread]:

Originally Posted by lewster

If your battery connections are factory stock, the should be wired with the positive load to battery 1 and load negative to battery 2.

If that is the case, simply remove one connection from the parallel cable between the negative battery posts and that should act as a complete disconnect, as it will isolate the two batteries from each other.

Lew Farber

Have a great trip!

Peter

[Adventure.AS]

Originally Posted by OTRA15

... For storage in the future, we intend to follow a recent comment by the expert lewster in another thread, which you might also consider -- the simple added step of disconnecting the negative-to-negative jumper cable between your two batteries...

The Airstream owner's manual it warns against this procedure.

Section 2-3

YMMV

[dznf0g]

Originally Posted by Adventure.AS

The Airstream owner's manual it warns against this procedure.

Attachment 269116 Section 2-3

YMMV

While this is true, and it always has been, I have never had a false alarm due to contamination. I re-wired my detector to only be on when the store switch is on. It sits every winter disconnected...for 5 months.

[LY007]

I'm not advocating a particular unit, but here the voltage specs on a Powermax 35 amp charger.



35 amp 3 Stage Charger
KEY FEATURES:
Automatic three-stage battery charging maintains your battery's life with three nominal voltage output models:
* 13.2 Vdc range "float" mode
* 13.6 Vdc range "absorption" mode
* 14.4 Vdc range "bulk" mode
* Electronic current limiting automatically shuts down power during overload or short-circuit conditions.
* Quiet operation in a wide range outputs. Convenient deck mount installation.

[Adventure.AS]

Originally Posted by dznf0g

While this is true, and it always has been, I have never had a false alarm due to contamination. ...

As I previously posted, YMMV, however, I have had the false alarm. It is a bit disconcerting as one doesn't know if is false or real until it goes away (and of course I was hoping that it would stop so that I wouldn't have to disconnect it and loose the safety factor of having the sniffer.)

For safety's sake, I turned off the propane in the meantime and it did eventually stop alarming, which was a good thing as I was travelling in winter and needed the furnace on for the night.

[OTRA15]

Ah choices . . .



The risk of a false positive propane alarm may be outweighed by the benefit of having batteries maintain their charge during storage.

As was said earlier, your mileage may vary . . .

[davidrrand]

Thanks again for the great comments and suggestions. Much appreciated. I think my batteries are fair as they seem to gradually discharge over about four days from 12.6 to 12.3 with the with the switch on "store". I have generators to keep them from getting too, low. If it appears they have been damaged, I will find an Interstate dealer to load test them and exchange if necessary. If that becomes necessary, what do you folks think about going to Interstates 6 volts golf cart style batteries in series? Would the stock converter be compatible with these?

I , too hope to upgrade converters/batteries this winter and maybe chase down Lewster in FL to do the job.

thanks! Dave

[OTRA15]

Sounds like a good plan! We also anticipate many upgrades along those lines.

Happy Trails!

Peter