Leaving batteries in trailer during winter

[MelGoddard]

Here's an update on my New converter/battery issue.
This morning, I shut the batteries off at the 'switch', and installed my 'Genius 3500' battery tender. (Purchased from Canadian Tire, several years ago.)
The indicator inside showed 14.1 V. in progress.

I left it to go for about four or five hours; switch 'on' ,13.8 V.
Switch 'off' 13.0 V. with one tender clamp removed from (-).
So I then rechecked the specific gravitys.

They were right up in the green at about 1.275-1.300. Full Charge!
So the batteries are good.

So I guess that it's back to CanAm again to resolve the PD4655 not doing it's job.
DAMN!

[Caffeinated]

I pull my batteries from the trailer, bring them home, and use a battery tender to keep them charged over the winter. It works for me.

Mike

[Rocinante]

Ah, sorry, I somehow missed that you had already installed a PD4655. Definitely have the installer take a look, something must be amiss there.

[MelGoddard]

Originally Posted by eawotr

This is such a timely and helpful thread. I was getting ready to ask for help on the very question. We have a 2017 Classic that will be stored in an enclosed garage this winter just outside of Boulder, CO. There is a120v outlet available and I was thinking of using a battery tender to keep the batteries charged and freeze free this winter.

My question, and I'm a bit embarrassed that we don't know this, is how do I connect the battery tender so that both batteries are charged? Do I use a single tender and connect to the positive on one and negative on the other battery since they are set up in parallel?

Thank you for all the help and advice. This forum has saved us numerous times since taking delivery of our AS and we're super grateful.

Attachment 273487

Yes. The single tender should be attached to Positive on one and Negative on other battery. the one tender will usually keep both batteries in charge.

I used a 'Genius' 3500, set on the propane bottles, with the leads going through the access hole at the side of the battery box.
In four hours, it took two uncharged batteries from 1.125 up to fully charged 1.250-1.300 specific gravity.
The damned thing worked as promised.

"Trailer Trash squatting in a Tin Shed."

[MelGoddard]

Originally Posted by AIRHEDS

I've got a 1.25A Battery Tender specifically for charging my Honda EU6500 generator battery, which is a small motorcycle battery whose manufacturer states that a 1.25A charger should be used to maintain a charge during non-use periods.

Our Group 24 and Group 27 AGM batteries deliver many, many times more current. I don't see how a 1.25A tender can exercise such a battery (ref. the other threads calling out use of a 1.25A charger).

BatteryTender makes a bunch of tenders.

http://www.batterytender.com/Chargers/

There's the 1.25A tender already otherwise discussed ... (too small for these batteries????)

There's the 3A tender.

There's the 5A tender, as well as a 5A weatherproof tender ...

But they also make a twin 20A charger (40A total), which explicitly states that it will charge a depleted Group 27 AGM in 4 to 5 hours--the only charger that calls attention to Group 27 AGM's, by the way.

So, if all we're looking to do is maintain the pair of already charged batteries, and a small motorcycle battery gets a 1.25A charger to maintain a charge through non-use periods ... and ... if the most common car battery chargers throughout history are 10A for charging a single 12V battery, why wouldn't our large Group 24 and Group 27 AGM batteries get at least 5A, if not 10A to maintain their charges, especially when wired in parallel, which effectively requires twice the current to maintain both batteries at the same rate you'd charge one battery, all things being equal? How can we even consider a 1.25A charger in dual-battery configurations? And who's the best source for knowledge? The battery manufacturer or the company that makes the chargers?

Sorry if this appears critical ... it's not intended that way ... just asking questions that have been nagging since I started reading about charging...

Thanks,
Rich

What's all this talk about a multitude of different size chargers??
Charging a battery or three is the same as charging an air tank with an air compressor.
A big tank can be charged up by large or small air compressors.
A small compressor (little amperage)will take a lot longer to charge the tank than a large compressor, (lots of amperage);but BOTH will fill the tank to it's set pressure. (voltage)
Then the compressor (tender) will maintain the pressure (voltage) as the regulator demands.

It depends on how fast you need the batteries, (air tank) to charge up.
"K.I.S.S".

Trailer Trash squatting in a Tin Can Shed.

[MelGoddard]

Originally Posted by Wazbro

These trailer batteries when in good condition loose less then 1amp per day so a charger that provides more then 1 amp per hour can easily maintain 2 charged batteries. It can even charge them from dead, even if it takes a week.

See comment to Airhed back one.

[Wazbro]

Originally Posted by MelGoddard

See comment to Airhed back one.

Not sure why you are pointing out that you just agreed with me but OK.

[Philip Jones]

Originally Posted by Caffeinated

I pull my batteries from the trailer, bring them home, and use a battery tender to keep them charged over the winter. It works for me.

Mike

Is it safe to leave them on the tender in the garage when it is super-cold? I presume with non-AGM batteries that leaving them inside could be dangerous because of hydrogen sulphide gas? Thanks.

[AIRHEDS]

Thanks Mel ... I got the same reply from the folks at Battery Tender a while back. I just wrongly assumed a bigger battery might require a bigger charger... not the case...