Hey all, I know this has probably been asked and answered many times, but is it more advisable to store 2 T-105's inside on a trickle charger or leave them in the trailer which has solar charging over the winter? A few details...- solar charging is a 260watt panel with sunsaver MPPT 15 amp charge controller, setpoints tweaked to match the Trojan battery specsheet. I have a 3 way battery cutoff switch installed such that I can keep solar charging connected with all trailer circuits disconnected ie. no parasitic draws.- winter temps here can hit -40C.Is it best to pull the batteries and keep them inside? Or keep them connected to solar and just clean off the panel when the snow falls? Inconvenience isn't a worry, I'd just like to get the most life from these. Thx!

Winterize batteries Oct2009Stay plugged in in storage?Stay plugged in roast batteries?

If I were doing it, I would bring them inside and put a good maintainer on them instead of having to brush snow off the panel every time it snowed.If you have a good charge controller that will not over charge them then doing it either way is OK for the batterys.

With Alberta, winter temperatures, I would fully charge the batteries and let them sit totally disconnected from everything for as long as five months. -10c temps dramatically slows down self-discharge. That way you have *zero* chance of anything going wrong. Make certain a hydrometer reading confirms the battery electrolyte is temperature corrected to 1.275 specific gravity.

What could be better than inside on a good maintainer ? But for me, they are too heavy,....they'd stay outside,.....if you have charging that will not fail.I would never leave them outside w/o dependable maintainer charging.

Mine stay on the tongue of the trailer outside, connected to 150 watts of solar. My last set of generic 6v batteries lasted about 8 years. My current T105s are over 11 years old and winter over just fine.Why bother brushing off snow unless you expect it to stick around for an extended period? My panels still charge even with a couple inches of snow on them.

Winter storage or solar for 2 T-105's | Good Sam Community

15 Replies

Almot
Explorer III
Dec 02, 2015
I think the question was not whether a panel would be able to maintain 2*T105 in storage. Any panel over 20W would.
OP wanted to know if this is better than not leaving it on controller. Again, the answer is - Yes, with (minor) chance of controller failure.
vermilye
Explorer
Dec 02, 2015
Mine stay on the trailer, and are kept fully charged (as indicated by a Trimetric monitor) by a 95 watt panel through a white Tyvek cover. Temperatures down as low as -15°F, and I do brush the snow off the cover when it gets more than 6" deep.
buzzard616
Explorer
Dec 02, 2015
TT in signature has two T-105s, 290 W Solar, and cheap crappy PWM controller. Batteries get topped up every Spring, but get no other special attention. Checked last Winter and after having lights on for a few minutes, panel was showing 13+ Volts and .3 Amp charge at -30C with 4" of snow on the roof and panels. I have'nt bothered to brush the snow off since. Batteries are coming up on 5 years old.
DrewE
Explorer II
Dec 01, 2015
Almot wrote:
Do you math, try to estimate how much charge it will lose over winter. It will not be -40C all the winter. From top of my head, with temps consistently below 25C you will lose less then 30% of charge in 3 months. How bad is 30% discharge dragging for several weeks (i.e. slowly dropping from 0 to 30% over 3 months)? Don't know. Let chemistry gurus here chime in.

At least around here, the temperatures are cold enough that it would be considerably less than 30% self-discharge over the winter. A rule of thumb is that battery self-discharge doubles for a 10C increase in temperature, and conversely halves for a 10C decrease in temperature. Assuming a 5C winter average temperature (which sounds not too unrealistic, perhaps a bit warm), I'd lose something like 7-10% over the winter.
westend
Explorer
Dec 01, 2015
I'm just a bit South of the OP and keep my banks charging with a single 235W module through the Winter. My panel is tilted at about 60 degrees. Snow only stays on the module for a day at the most. I have no parasitic loads on the batteries and I don't choose to schlep any more weight than I have to. YMMV.
Almot
Explorer III
Dec 01, 2015
MEXICOWANDERER wrote:
A Question Not A Statement

Disconnect whatever it is maintaining your batteries, be it panels, a maintainer or a converter/inverter.

The for MILLI-amp draw by the disconnected from shore power charger. Is there any?

No entiendo, senior. You must be working too much. Doesn't do any good, at this age.

There is no milliamp draw from charger as long as it's functional. Whatever bad and cheap it is, the net current is "into" the battery, not "out". In my 30A MPPT 3048 the power consumption in resting mode is 11 mA @12.6V. Consider that it's resting only in the night or if panel is covered with snow.
Almot
Explorer III
Dec 01, 2015
Do you math, try to estimate how much charge it will lose over winter. It will not be -40C all the winter. From top of my head, with temps consistently below 25C you will lose less then 30% of charge in 3 months. How bad is 30% discharge dragging for several weeks (i.e. slowly dropping from 0 to 30% over 3 months)? Don't know. Let chemistry gurus here chime in.

Leaving it on either solar or 110V maintainer is what I would normally prefer, but electronics might fail at -40C. Losing a cheap maintainer is one thing, losing more expensive MPPT controller is another. But, at least, you'll have batteries fully charged until (whatever is charging them) will have failed. Heck, your MPPT might even survive -40.
MEXICOWANDERER
Explorer
Dec 01, 2015
A Question Not A Statement

Disconnect whatever it is maintaining your batteries, be it panels, a maintainer or a converter/inverter.

The for MILLI-amp draw by the disconnected from shore power charger. Is there any?
SkiSmuggs
Explorer
Dec 01, 2015
I leave mine in the fiver, use the Disconnect switch and connect a Battery Minder. However, this is the first winter with solar panels and am not sure whether to disconnect the panels or not.
ktmrfs
Explorer II
Dec 01, 2015
I just disconnect mine. Have done that for over 10 years now. Self discharge rate when cold is low, One set is still going strong after 14 years, other set on newer trailer is only 6 years old.