Small Cabin

Small Cabin Forum
 - Forums - Register/Sign Up - Reply - Search - Statistics -

Small Cabin Forum / Off-Grid Living / 3 deep cycle 12 volt batterys - maintain over winter
Author Message
old243
Member
# Posted: 3 Jan 2014 23:07
Reply 


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

Just
Member
# Posted: 3 Jan 2014 23:19
Reply 


I think it will be fine make sure you check the water

MtnDon
Member
# Posted: 4 Jan 2014 00:14
Reply 


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.

old243
Member
# Posted: 4 Jan 2014 09:48
Reply 


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

Truecabin
Member
# Posted: 4 Jan 2014 20:25
Reply 


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

CabinBuilder
Admin
# Posted: 5 Jan 2014 13:05 - Edited by: CabinBuilder
Reply 


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.

Truecabin
Member
# Posted: 5 Jan 2014 13:40
Reply 


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

Your reply
Bold Style  Italic Style  Underlined Style  Thumbnail Image Link  Large Image Link  URL Link           :) ;) :-( :confused: More smilies...

» Username  » Password 
Only registered users can post here. Please enter your login/password details before posting a message, or register here first.