Solar Battery Tender

[nighthawk87]

Would something like this work as long as batteries are isolated? 210Ah will be put in storage at 90% charge. Prefer to take out at 100%. Trailer kept at storage lot in open sun.

Eventually a 200W $400 solar setup is in my future but this is cheap and I can afford it now.





ECO-WORTHY 20W 12V Solar Panel Kit: 20 Watt Polycrystalline Solar Panel & Battery Clips & 3A Charge Controller https://www.amazon.com/dp/B00PFGP0EA..._1kiMAbR5APTGM


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[Mustang65]

That 20 watt system may keep a single standard 85Ah battery, that is fully charged, when connected. These systems are not for charging batteries (less than 100%). Even with the batteries isolated 1Amp is not enough. Look at the sky in the picture you are already producing less than 100% with a thin wisp of clouds. That 1Amp is in FULL sunlight, maybe 2 hours a day and the rest of the time you will probably be pushing out a 1/2 Amp.

My (2) T145 6 volt batteries (260Ah) are pulling 4-5 amps when the sun first comes up each morning (granted they are 5 years old)... then it drops to 2 then around 1 amp for the rest of the day.

You are already looking at $59 for this system. You are planning on going with 200watts, why not look at a Renogy 100 watt kit for $169, you can always add a 2nd and 3rd panel when you save some money again in the future. It is a system you can build on.

Don

My Registry

RVing with SOLAR

[nighthawk87]

Originally Posted by Mustang65

That 20 watt system may keep a single standard 85Ah battery, that is fully charged, when connected. These systems are not for charging batteries (less than 100%). Even with the batteries isolated 1Amp is not enough. Look at the sky in the picture you are already producing less than 100% with a thin wisp of clouds. That 1Amp is in FULL sunlight, maybe 2 hours a day and the rest of the time you will probably be pushing out a 1/2 Amp.



My (2) T145 6 volt batteries (260Ah) are pulling 4-5 amps when the sun first comes up each morning (granted they are 5 years old)... then it drops to 2 then around 1 amp for the rest of the day.



You are already looking at $59 for this system. You are planning on going with 200watts, why not look at a Renogy 100 watt kit for $169, you can always add a 2nd and 3rd panel when you save some money again in the future. It is a system you can build on.



Don



My Registry



RVing with SOLAR

Haha. Good point. Problem is I have to spend $219 after factoring in the $189 kit that comes with brackets and wiring, plus a entry cover for roof and 40A fuse. I can skimp much more than that.

Then another 100W panel is $139. Might be a good compromise.

Will one 100W panel be worth the effort though?


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[Mustang65]

Originally Posted by nighthawk87

Haha. Good point. Problem is I have to spend $219 after factoring in the $189 kit that comes with brackets and wiring, plus a entry cover for roof and 40A fuse. I can skimp much more than that.

Then another 100W panel is $139. Might be a good compromise.

Will one 100W panel be worth the effort though?


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(1) 100 watt panel will do the trick (with mother nature holding to her part of the bargain). Does it have a SOLAR charge controller with it?

The other issue is that in the future, adding additional panels, the new panels must be within 1% of the existing panel voltage.
Don

My Registry

RVing with SOLAR