Pull batts in the summer?--1a draw good for batts w/ solar?

[wopachop]

I was reading threads here and came across advice that its good to cycle a deep cycle battery once a month? My trailer has (2) 12v batteries and a solar panel that keeps them topped off, regardless of having my battery shut off switch turned off. Is that good or bad? Keep meaning to buy a disconnect for that positive solar wire to make it easy.

Worried this might become super long and confusing. Let me lay out the situation with numbers.

1. 99% of the time i use the the trailer its plugged into shore power.
2. The trailer has solar panels and there is no disconnect between the solar and batteries.
3. I go out of town for weeks and unplug the trailer and also sometimes the solar charging wire.
4. (here comes the root of the question) I installed a fan that pulls 1amp. I want this fan to turn off and on several times a day using a 12v digital timer while im gone.

So that leads to these questions:
1. Should i power the 1amp fan from the main batteries and let the solar keep them charged? Then do a real cycle on the batts once a month or whatever is recommended?

2. Since the trailer is 99% shore power should i pull the batteries out and put them in the cooler garage? Power the 1amp fan from a small independent solar panel? (will actually be set to 0.25amps so a small 10w panel should power it i hope. no digital timer the sunrise and sunset will be the timer)

[wopachop]

I have a very high quality RC charger. (icharger 308duo)
Might use that every so often to do an equalization charge.
t
Batteries that came with the trailer are two different models of 12v.
Will look up their recommendations but what would you guys set the charger to?

Trying to think if it would be a constant current or constant voltage.
I want both i right? Havnt played with that charger for a good 6 months im little hazy on the methods.

I used it 2 years ago to revive some 6v golf cart batteries in my friends beater golf cart. Gave them a very low amp charge for days at a time using a basic "stupid" mode and it worked. Same batteries are out at the river now and working good enough to cruise around.

[MEXICOWANDERER]

And........looks like my opinion about periodic top charging for flooded units went the way of the woolly mammoth.

[MEXICOWANDERER]

I would yank summer batteries and place inside a structure with cooler temperatures if very warm weather was expected lasting months. Like 90 degree days and almost 80 degree sunrises.

Acids becomes angry and eats things for a living when they are warmed. Their corrosiveness is not linear. 4x activity between 80F and 120F as there is between 20F and 60F.

[BFL13]

wopachop wrote:
Is interstate being a little rediculous then with the spec that says:

3. Equalize every 4 to 8 weeks and always after a normal charge.


We go dry camping so after every charge would be every morning the solar kicks in or at night if we crank on the genny.

Sort of. While off- grid you can't run the gen long enough to get back to full, so you do 50-90s and "recover" the batts once home and have shore power.

On solar, you can get to full sometimes or not depending, so again it means a "recovery session" once home, but with solar you do shallow cycles, so the batts don't get so bad so soon as when doing successive 50-90s.

IMO they mean to follow your Absorption Stage "normal" charge with a higher voltage "finish charge" or over-charge at the same sort of voltage you would use for equalizing. Not to do an actual equalize every time. Badly written IMO. Other brands have similar advice with various wordings. You have to interpret. 😞

[wopachop]

Is interstate being a little rediculous then with the spec that says:

3. Equalize every 4 to 8 weeks and always after a normal charge.


We go dry camping so after every charge would be every morning the solar kicks in or at night if we crank on the genny.

[time2roll]

You really want a Progressive Dynamics or Boondocker converter for hot summer storage as they will consistently drop to 13.2 volts.

I would only equalize once a year unless you suspect some loss of capacity.

Three years out of the common 12v marine deep cycle is normal.

[wopachop]

Thanks for all the info everyone. Im really surprised removing the batteries and storing in the cooler garage is not the best option for a rig on shore power during the summer.

The previous owner only got 3 years out of his batteries and said while camping they would run the genny almost 24/7. I thought maybe his batteries died from being overcharged their whole life by the solar panel. Stored in Chino california where it would get pretty darn hot.

Do most guys buy a separate charger that plugs into the wall to complete an equalization charge every month or 2?

I dont know what converter i have. Its another manual to add to the reading list.

[BFL13]

wopachop wrote:
Is it normal for a modern converter to have equalization voltage built in to its charging brains?

Some do, some don't. The trouble is they call it an "equalization voltage" but it is only to the voltage of their "boost voltage" of 14.x. It is meant for destratification, not equalization.

It gets confusing. They do say to recharge a battery in storage (means not being charged at all) once it drops to 70% SOC and do that with a boost voltage. -followed by an overcharge or "finish"

They also say to give the batts a good goosing every so often when they are on a "storage charge" (13.2 is the usual voltage they have for that)

I find it works best to actually do a deep cycle with a full recharge every so often and not just hit them with a boost from a standing start when they are near full already. sometimes called "exercise the battery"

If you do none of that, your batteries will not die right away of course.

[red31]

wopachop wrote:


I thought the batteries might last longer if they rested undisturbed instead of 13.5v during the hot summer days.

controller temp corrected float voltage will be low during hot summer days not so for the converter. use the disconnect but leave the solar on.

[wopachop]

Is it normal for a modern converter to have equalization voltage built in to its charging brains?

[BFL13]

On periodic charging of a deep cycle battery on a float charge, read Note 3 in both tables here:

http://www.cleanenergybrands.com/shoppingcart/knowledgemanager/questions/98/Interstate+Deep+Cycle+Ba...

[wopachop]

Correct the trailer has a 12v disconnect that i keep turned off.
The solar is wired directly.

I thought the batteries might last longer if they rested undisturbed instead of 13.5v during the hot summer days.

[time2roll]

I would be more inclined to disconnect utility power than solar.
Both connected is not an issue for either.

[wopachop]

Owned the trailer just about 1 year exactly. Meant to read all the manuals. Not doing too good with that.

Lets forget about the 1amp fan draw. If the trailer is parked and on shore power for 3 months in the hot sun would it be wise to disconnect the solar charging?

[red31]

wopachop wrote:
Oh darn i disconnect the controller from the batteries all the time!!!
That can damage the controller?

A common warning in controller manuals.
Plenty of solar suitcases that have PWM controller always attached and occasionally attach to batt with no issue.
Seems more critical for mppt controllers.