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old243
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# Posted: 3 Jan 2014 11:07pm
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I have 3 deep cycle batterys 12v, 2 are out of my camper are similar but not the same age. The third is older, but still seems to be charging. I want to just not let them discharge over the winter.
I hooked them in parallel, have 5 watt solar panel connected to them . When I disconnect the solar panel and test the voltage of the 3, I am reading 12.8 volts. There is no charge controler in the circuit. They have been connected about a week.
Am I going to damage my batterys with this setup?
Is this a safe way to charge?
Would anyone recommend a better way?
Thanks for any help Old 243
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Just
Member
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# Posted: 3 Jan 2014 11:19pm
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I think it will be fine make sure you check the water
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MtnDon
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# Posted: 4 Jan 2014 12:14am
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For a pv panel with no controller a rule of thumb is to choose a panel that will give a maximum output of about 1/300th to 1/1000th of the amp-hour capacity of the battery. So with three batteries in parallel, add the amp-hours up, then do the 1/300 and 1/1000 math. For sunnier locations use the smaller value; for cloudy locations use the higher value.
Personally I like using a charge controller at all times; I just feel better. There are some very inexpensive low powered ones. But if you keep an eye on the fluid levels and do not see excessive bubbling you should be okay. When getting set to check the state by voltage readings disconnect the panel the day before taking the reading to ensure the surface charge has dissipated. That 12.8 could be higher than it is in reality if it was taken with the panel connected or if within a few hours of the panel producing power.
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old243
Member
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# Posted: 4 Jan 2014 09:48am
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After posting this request, I saw a discussion where they recommended not connecting battery's of different ages. An older battery , or one in not good shape, could deteriorate the newer battery's. Two of my battery's are relatively new. The third is quite a bit older. I wonder if I should disconnect it. and charge it separately. Don't want to end up with 3 old battery's.
I really like the discussions here , just found you , a short time ago. We are off grid at our hunt camp, use propane lights, cooking etc. Coolers for food, wood stoves. Use generator to pump water from a river, to overhead tanks. I have been looking at the discussions on LED lighting, This might be useful at the camp. Something I have never seen discussed is coal oil lights, We light a small one ,
before going to bed, turn it down low, this gives you enough light to move around , nature calls etc, no stubbing your toes, on something. lamp will run about a week on a refill. I enjoy the peace and quiet, think I am turning into a loner old 243
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Truecabin
Member
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# Posted: 4 Jan 2014 08:25pm
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Quoting: MtnDon Personally I like using a charge controller at all times; I just feel better.
also cc will prevent power outflow to the panel at night
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CabinBuilder
Admin
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# Posted: 5 Jan 2014 01:05pm - Edited by: CabinBuilder
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Quoting: Truecabin also cc will prevent power outflow to the panel at night
I think most (if not all) solar panels these days have a build-in diode to prevent that.
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Truecabin
Member
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# Posted: 5 Jan 2014 01:40pm
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yes thats a better way
everyone says im years behind
if the panel is old then check at night with an ammeter if there is any flow out
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