The depth of knowledge about all things solar on this forum is formidable indeed. So I want to take advantage of a small amount of it.Can a 10 watt solar battery charger keep an average RV 12 volt battery fully charged over the winter? The charger will be facing south, and not in the shade. And will it require a charge controller? And lastly considering the question what should I use to keep a single 12 volt deep cycle battery charged from mid-November to mid-March? The toyhauler is in storage about 10 miles away. I've always pulled the battery, brought it home, and hooked it up to my Battery Tender. But this is a new-to-us toyhauler and I'm wonder if I need to move into the 20th Century. Yeah I know, but I'm always a step behind. :)TIA

Not sure about 10 watts. I use 30 on top of the cover when in storage and it keeps my two 6s at 100%. If I do maintenance and run the radio and some lights it will recharge them.

Spend the extra money and get at least 100 watts. It's the same labor to install.

Easiest way, charge the battery fully and remove the negative battery cable. The battery will fine, it will not freeze, the self discharge rate will be minimal. Charge it up before next use.I have done this on my motorhome 6v and 12 vote batteries for years.

Now this is a serious question, and not a just "I don't want to spend the money" response. Although I really don't want to spend the money. :)The 100 watt runs around $75-$90, and I understand I'd also need a controller, about another $25, I think. A 10 watt maintainer is around $25-$30, with no need for a controller as long as it has the blocking diode, I think.Now what do I get for that extra $100? Bear in mind I'm just thinking of keeping the battery charged in the toyhauler over the winter. When we travel we have a generator, which is rarely used, and stay at full hook ups almost invariably. But I am open to suggestions that can be used to justify the extra expenditure.

garym114 wrote:Easiest way, charge the battery fully and remove the negative battery cable. The battery will fine, it will not freeze, the self discharge rate will be minimal. Charge it up before next use.I have done this on my motorhome 6v and 12 vote batteries for years.About what I do, but since I only had one battery and it was easy to get to, I pulled it and put it on the Battery Tender. The reason I brought this whole thing up is the new-to-us toyhauler came with a 5 watt solar maintainer, which in all honesty, didn't seem to do much to keep the battery charged. But, anyway, it fell over and broke the glass, now I'm trying to decide if I want to replace it or just forget it.

Solar maintainer. | Good Sam Community

19 Replies

2oldman
Explorer II
Aug 13, 2021
garym114 wrote:
Easiest way, charge the battery fully and remove the negative battery cable. The battery will fine, it will not freeze, the self discharge rate will be minimal.
this
fj12ryder
Explorer III
Aug 13, 2021
Thank you all for the information. Right now I'm leaning toward going with a cheap 10W maintainer. If I regret it, I will pass that along, and you all can say "I told you so". :)
valhalla360
Navigator
Aug 13, 2021
As long as there aren't any parasitic draws, yes, a 10w panel should do fine.

Disconnect the battery from the rest of the system and directly connect the panel.

Self discharge can run down a battery over 6-8 months and lead-acid batteries are only happy sitting at 100% charge.
wanderingaimles
Explorer
Aug 13, 2021
I have a spare group 27 rv marine battery that i leave out on my deck, it only gets used in power failures with an inverter. I have a small solar panel maintaining it and it has always been charged when needed. Which is only two or three times a year for Cpap and or refrigerator.
fj12ryder
Explorer III
Aug 13, 2021
garym114 wrote:
Easiest way, charge the battery fully and remove the negative battery cable. The battery will fine, it will not freeze, the self discharge rate will be minimal. Charge it up before next use.
I have done this on my motorhome 6v and 12 vote batteries for years.
About what I do, but since I only had one battery and it was easy to get to, I pulled it and put it on the Battery Tender.

The reason I brought this whole thing up is the new-to-us toyhauler came with a 5 watt solar maintainer, which in all honesty, didn't seem to do much to keep the battery charged. But, anyway, it fell over and broke the glass, now I'm trying to decide if I want to replace it or just forget it.
fj12ryder
Explorer III
Aug 13, 2021
Now this is a serious question, and not a just "I don't want to spend the money" response. Although I really don't want to spend the money. :)

The 100 watt runs around $75-$90, and I understand I'd also need a controller, about another $25, I think. A 10 watt maintainer is around $25-$30, with no need for a controller as long as it has the blocking diode, I think.

Now what do I get for that extra $100? Bear in mind I'm just thinking of keeping the battery charged in the toyhauler over the winter. When we travel we have a generator, which is rarely used, and stay at full hook ups almost invariably. But I am open to suggestions that can be used to justify the extra expenditure.
garym114
Explorer II
Aug 13, 2021
Easiest way, charge the battery fully and remove the negative battery cable. The battery will fine, it will not freeze, the self discharge rate will be minimal. Charge it up before next use.
I have done this on my motorhome 6v and 12 vote batteries for years.
jdc1
Explorer II
Aug 13, 2021
Spend the extra money and get at least 100 watts. It's the same labor to install.
Lwiddis
Explorer II
Aug 13, 2021
Not sure about 10 watts. I use 30 on top of the cover when in storage and it keeps my two 6s at 100%. If I do maintenance and run the radio and some lights it will recharge them.

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Solar maintainer.

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