I have been considering getting a solar panel for maintaining our 2 12v deep cycle batteries when parked at home.i usually back the TT in behind our garage and plug in the 30 amp shore power cord into a 20 amp 110 outlet with adapter to charge and maintain the batteries which has worked fine.i would like to park the TT in our back yard which would place it a good distance from the garage. solar panel would be in full sun all day unless its cloudy. the TT already has a solar connector wired.We do not dry camp or boondock but do have a residential fridge that we always load the night before camping and leave it running while on the road so the batteries do get used.wondering if a single 100 watt panel would be enough for charging and maintaining the 2 batteries while at home. i found this on amazonRenology 100 watt 12v panel with controller included in the kit169.99 (expandable to 4 panels )looking for thoughts or advice

As long as the fridge is off, the 100 watt panel will keep the batteries charged just fine.

I use a 30-watt Renogy solar panel and controller to keep my 4 6-volt batteries charged when stored over the winter near Seattle. I connect the charge controller's output directly to the batteries, and use the battery disconnect switch to remove any possible current draws. It works great!Note: I put the solar panel on the roof in the fall and remove it in the spring.

What are the amp-hrs of the batteries and what is the draw of the fridge? Storage: it would be simpler to disconnect the battery.Fridge the day before: Good chance it kills the batteries before you leave. That's where you need to check the amp-hr and draw. Don't plan on using more than 50% of the rated amp-hr if you don't want to damage the batteries. Probably simpler to run some extension cords for the day before. As long as you aren't running the air/con, household extension cords should be fine even for pretty long runs.

valhalla360 wrote:What are the amp-hrs of the batteries and what is the draw of the fridge? Storage: it would be simpler to disconnect the battery.Fridge the day before: Good chance it kills the batteries before you leave. That's where you need to check the amp-hr and draw. Don't plan on using more than 50% of the rated amp-hr if you don't want to damage the batteries. Probably simpler to run some extension cords for the day before. As long as you aren't running the air/con, household extension cords should be fine even for pretty long runs.last year to test how the batteries would do powering the fridge.not sure of the official draw from fridge but last summer in 90 heat with ac not running the fridge ran late afternoon till next morning off the batteries showed 12.5 volts after maybe 18 hours. (nothing but fridge running and other parasitic draws) i didn't want to discharge batteries below 50 percent.

100 watts is way more than you need to maintain your batteries. There are plenty of trickle chargers in the 7-10 watt range that would serve your purposes.

Solar panel question for 12v battery charging | Good Sam Community

sgfrye
Explorer
May 29, 2018
CarnationSailor wrote:
I use a 30-watt Renogy solar panel and controller to keep my 4 6-volt batteries charged when stored over the winter near Seattle. I connect the charge controller's output directly to the batteries, and use the battery disconnect switch to remove any possible current draws. It works great!

Note: I put the solar panel on the roof in the fall and remove it in the spring.

thank you, the 30 watt renogy kit on amazon would be more cost effective for battery charge maintenance.

im a solar newbie forgive me. i understand the controller's function. how would you wire from controller directly to 2 12v batteries? positive to positive and negative to negative on 1 of the 2 batteries.

my tt has the "factory installed" zamp solar plug. from what i understand its wired with the polarity reversed. it would be convenient to use it with a non zamp controller but wondering if there are adapters available other than splicing and changing wires on zamp plug
sgfrye
Explorer
May 29, 2018
BFL13 wrote:
Solar idea would work. Or bring batteries to garage and put them back on the trailer for trips.

Depends on the scenario at the OP's place, but we just use really long extension cords from stick house power. Doesn't matter about voltage drop on the 120 to run the converter at such low amps. Forget about the A/C, MW or WH though -voltage drop too much for high wattage items.

Trying to get away from the cords across the yard deal and we usually camp couple times a month so removing batteries to charge would get old.

Good simple advice though.
fitznj
Explorer
May 29, 2018
Renology 100 watt 12v panel with controller included in the kit

This is what I have been using for several years to keep the 2 batteries charged while parked in my backyard. Works perfectly.
The batteries are disconnected during storage.

I have another 100W panel which I take with me when camping
Lwiddis
Explorer II
May 29, 2018
Like CarnationSailor I use a small solar panel...25 watts/1.4 amps...to keep my two Trojan T125s charged when Winnie is home Then I can cover the TT with the 300 watt solar system on the roof. Works just fine. WindyNation sells a 10 amp weatherproof PWM controller for twenty bucks.
BFL13
Explorer II
May 29, 2018
Solar idea would work. Or bring batteries to garage and put them back on the trailer for trips.

Depends on the scenario at the OP's place, but we just use really long extension cords from stick house power. Doesn't matter about voltage drop on the 120 to run the converter at such low amps. Forget about the A/C, MW or WH though -voltage drop too much for high wattage items.
ppine
Explorer II
May 29, 2018
100 watts is way more than you need to maintain your batteries. There are plenty of trickle chargers in the 7-10 watt range that would serve your purposes.
sgfrye
Explorer
May 29, 2018
valhalla360 wrote:
What are the amp-hrs of the batteries and what is the draw of the fridge?

Storage: it would be simpler to disconnect the battery.

Fridge the day before: Good chance it kills the batteries before you leave. That's where you need to check the amp-hr and draw. Don't plan on using more than 50% of the rated amp-hr if you don't want to damage the batteries. Probably simpler to run some extension cords for the day before. As long as you aren't running the air/con, household extension cords should be fine even for pretty long runs.

last year to test how the batteries would do powering the fridge.

not sure of the official draw from fridge but last summer in 90 heat with ac not running the fridge ran late afternoon till next morning off the batteries showed 12.5 volts after maybe 18 hours. (nothing but fridge running and other parasitic draws) i didn't want to discharge batteries below 50 percent.
valhalla360
Navigator
May 29, 2018
What are the amp-hrs of the batteries and what is the draw of the fridge?

Storage: it would be simpler to disconnect the battery.

Fridge the day before: Good chance it kills the batteries before you leave. That's where you need to check the amp-hr and draw. Don't plan on using more than 50% of the rated amp-hr if you don't want to damage the batteries. Probably simpler to run some extension cords for the day before. As long as you aren't running the air/con, household extension cords should be fine even for pretty long runs.
CarnationSailor
Nomad
May 29, 2018
I use a 30-watt Renogy solar panel and controller to keep my 4 6-volt batteries charged when stored over the winter near Seattle. I connect the charge controller's output directly to the batteries, and use the battery disconnect switch to remove any possible current draws. It works great!

Note: I put the solar panel on the roof in the fall and remove it in the spring.
time2roll
Nomad
May 29, 2018
As long as the fridge is off, the 100 watt panel will keep the batteries charged just fine.

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