Hot Weather Battery Charging via Solar

[markcee]

Disclaimer: This may be a simple/dumb question, but I do not have solar, nor do I keep my battery in my trailer when it's in storage.

A buddy of mine just purchased a new trailer with factory installed solar. He plans on keeping the battery in the trailer and keeping it charged via his solar while the trailer is parked in outdoor storage.

We live in Arizona. As summer temps routinely top 100+, I'm assuming even keeping the battery in a trailer stored outdoors, not to mention running the charging system, is a big no-no during the hot months.

I'm assuming people in similar situations just remove the battery and maintenance charge at home when the heat sets in but just wanted to get some feedback to provide him.

[flybouy]

Doesn’t your battery in your truck stay in the truck when it's hot outside? Doesn't your truck charge the battery when it's running?

[markcee]

Originally Posted by flybouy

Doesn’t your battery in your truck stay in the truck when it's hot outside? Doesn't your truck charge the battery when it's running?

Thanks....I guess it was a dumb question then.

Since my truck doesn't sit outside, unused, in direct sun in 100-120 degree temps for extended periods of time, I thought there might be other considerations. Plus batteries tend to have a much shorter lifespan here, due to the heat.

On a side note, I just found my friend's charge controller manual online and specs indicate an operating range up to 104F.

[snoobler]

Originally Posted by markcee

Thanks....I guess it was a dumb question then.

Since my truck doesn't sit outside, unused, in direct sun in 100-120 degree temps for extended periods of time, I thought there might be other considerations. Plus batteries tend to have a much shorter lifespan here, due to the heat.

On a side note, I just found my friend's charge controller manual online and specs indicate an operating range up to 104F.

Not a dumb question. Concerning charger operating temps, that's part of the charger specification and varies. Many are good into the 120°F range.

Concerning battery charging in hot temps, a good charge controller includes a temperature probe and compensates for temperature changes by lowering the peak voltage.

Your friend's plan is acceptable if the charger is good to operate in that temperature, and the charger is capable of temperature compensation.

[JRTJH]

Two things I'd consider as "complications that need to be resolved" are:

1. Off site storage that's unattended is an excellent way to lose batteries or other equipment to people who want your stuff more than you do... Devise a means to secure the batteries and if visible, the solar panels.

2. High temperatures, especially when in direct sunlight, can put a battery inside a black battery box in the "very high temperature range" very easily. Evaporation of water in the battery electrolyte is going to be greater because of the low humidity and the increased temperature. Don't forget to check battery fluid levels frequently....

As a note, we've seen a lot of "solar farms" in areas where the "wind farms" aren't easy to build... When we were in Las Vegas, there's a couple of HUGE solar farms between Nellis AFB and the speedway. I don't think I've seen as many "dead panels" (cloudy, drooped, broken or otherwise non-functional) in any solar farm than in those two. Las Vegas was the "hottest and most unfriendly "solar environment" we stayed in. I don't know the correlation between those panel failures and the desert environment around Las Vegas, but your friend might want to do some research on how to best maintain, clean and protect his solar panels from the environmental issues they might encounter when "in storage for a week or two with dust and dew settling on them and baking into the panel surface"... I don't know for sure if it would be detrimental, but worth addressing before losing a panel without realizing there was a problem.....

[markcee]

Originally Posted by snoobler

Not a dumb question. Concerning charger operating temps, that's part of the charger specification and varies. Many are good into the 120°F range.

Concerning battery charging in hot temps, a good charge controller includes a temperature probe and compensates for temperature changes by lowering the peak voltage.

Your friend's plan is acceptable if the charger is good to operate in that temperature, and the charger is capable of temperature compensation.

Thanks Snoobler. In reading his manual, his controller does compensate for temp, however its 104 degree operating range appears to make this a part-time solution.

[markcee]

Originally Posted by JRTJH

Two things I'd consider as "complications that need to be resolved" are:

1. Off site storage that's unattended is an excellent way to lose batteries or other equipment to people who want your stuff more than you do... Devise a means to secure the batteries and if visible, the solar panels.

2. High temperatures, especially when in direct sunlight, can put a battery inside a black battery box in the "very high temperature range" very easily. Evaporation of water in the battery electrolyte is going to be greater because of the low humidity and the increased temperature. Don't forget to check battery fluid levels frequently....

As a note, we've seen a lot of "solar farms" in areas where the "wind farms" aren't easy to build... When we were in Las Vegas, there's a couple of HUGE solar farms between Nellis AFB and the speedway. I don't think I've seen as many "dead panels" (cloudy, drooped, broken or otherwise non-functional) in any solar farm than in those two. Las Vegas was the "hottest and most unfriendly "solar environment" we stayed in. I don't know the correlation between those panel failures and the desert environment around Las Vegas, but your friend might want to do some research on how to best maintain, clean and protect his solar panels from the environmental issues they might encounter when "in storage for a week or two with dust and dew settling on them and baking into the panel surface"... I don't know for sure if it would be detrimental, but worth addressing before losing a panel without realizing there was a problem.....

Thanks for the info John. Its an AGM battery so no fluids to check. He also purchased some type of battery box locking mechanism that I've yet to see. In ant event, due to the temp limit on his controller, this doesn't look like something he can do year round.

[travelin texans]

I stored mine in southern Arizona also.
I disconnected the negative cable from the battery going directly to ground thereby completely disconnecting all parasitic drains.
I then connected, IIRC, a 3 amp solar charger facing west, that was about a foot square in size, with + to battery #1 & - to battery #2. This setup kept the batteries at 12.3+v every time I checked the water levels.
The little solar charger was $35-40 @ Batteries +.
The batteries were left in the boxes with the lids off inside the front storage compartment of the 5er & I never noticed it being overly hot inside that compartment.

[wiredgeorge]

Originally Posted by flybouy

Doesn’t your battery in your truck stay in the truck when it's hot outside? Doesn't your truck charge the battery when it's running?

Real trucks have two batteries!

[snoobler]

Originally Posted by travelin texans

I stored mine in southern Arizona also.
I disconnected the negative cable from the battery going directly to ground thereby completely disconnecting all parasitic drains.
I then connected, IIRC, a 3 amp solar charger facing west, that was about a foot square in size, with + to battery #1 & - to battery #2. This setup kept the batteries at 12.3+v every time I checked the water levels.
The little solar charger was $35-40 @ Batteries +.
The batteries were left in the boxes with the lids off inside the front storage compartment of the 5er & I never noticed it being overly hot inside that compartment.

12.3V is a very unhealthy voltage for lead acid. Proper float should be 13.2-13.8 depending on battery, and overnight resting voltage after a full charge should be 12.7+.

A solar panel of that size is at best 15-20W - well short of 3A@12V.

Whether you would detect it or not during normal usage is uncertain, but that storage period of 12.3V caused a likely noteworthy and permanent loss of capacity.

[travelin texans]

Originally Posted by travelin texans

I stored mine in southern Arizona also.
I disconnected the negative cable from the battery going directly to ground thereby completely disconnecting all parasitic drains.
I then connected, IIRC, a 3 amp solar charger facing west, that was about a foot square in size, with + to battery #1 & - to battery #2. This setup kept the batteries at 12.3+v every time I checked the water levels.
The little solar charger was $35-40 @ Batteries +.
The batteries were left in the boxes with the lids off inside the front storage compartment of the 5er & I never noticed it being overly hot inside that compartment.

Originally Posted by snoobler

12.3V is a very unhealthy voltage for lead acid. Proper float should be 13.2-13.8 depending on battery, and overnight resting voltage after a full charge should be 12.7+.

A solar panel of that size is at best 15-20W - well short of 3A@12V.

Whether you would detect it or not during normal usage is uncertain, but that storage period of 12.3V caused a likely noteworthy and permanent loss of capacity.

Fat fingers! The voltage was 13.2 not 12.3! I'm no electrical wiz by a long shot.
I had no problem running the front jacks every time I hitched it up after sitting for a couple months whatever the wattage or amperage may have been, the rv & charger are gone now.

[snoobler]

Originally Posted by travelin texans

Fat fingers! The voltage was 13.2 not 12.3! I'm no electrical wiz by a long shot.
I had no problem running the front jacks every time I hitched it up after sitting for a couple months whatever the wattage or amperage may have been, the rv & charger are gone now.

WHEW! That's awesome!

[Mic]

just keep teh water level maintained and he shall be all set.

his TV sits out side in same temps...right ???


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