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Author Topic: Solar panels wired to 12V batteries in parallel  (Read 961 times)
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Earth
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Please help me connect these batteries correctly and reach my inverter TARGET = 1000WATTS. My current setup only gives me 600W-630W. my inverter is not used and has been off since the summer 5months ago. but sitting in front of me is my 42" Sharp Aquos mocking me and motivating me. it needs 950watts to turn on. i got 600w. i dont need an isolator cause my trailer dont move and theres no engine. so, with that new information we will go with all AGMs with the current wire diagram. we dont need to isolate anything. right? Here is what my current setup looks like with four batteries outside and five inside. if its not correct then download my attachment and draw the lines in and post it here. Thank you.


ps: delete that other thread, thx


* batterysetup5.jpg (108.27 KB, 717x648 - viewed 29 times.)
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Webmaster living off grid in a camper with 300watts of solar panels charging 9 absorbed glass mat 12V batteries. i own about 40 dot coms. i

Earth
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i know the five inside should be connected like this. but i cant fit under my bed anymore.  smiley-grin
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Webmaster living off grid in a camper with 300watts of solar panels charging 9 absorbed glass mat 12V batteries. i own about 40 dot coms. i

Ontario
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You've got about 390 AH of batteries lined up there.
To pull 1,000 watts from the inverter, assuming the inverter is 90% efficient, you will need to supply about 100A @ 11.5V.  Your batteries *might* be able to do that.
But that is a discharge rate of C/4 -- a quite rapid discharge rate.
Your battery string could maybe do that for an hour or so before reaching 50% SOC.

If you want to add a generator to the mix, you should find an inverter-charger.  I have one of these, and it works okay:
http://www.xantrex.com/power-products/inverter-chargers/freedom-hf.aspx

It has an integrated transfer switch and charger.  When you have an external source of power running, it swaps the loads over automatically and starts charging the batteries.  It has a decent, but not very powerful charger in it.

Can you remind me what this has to do with Arduino again?
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Earth
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good, i wired it right. some people almost talked me into getting an battery isolator.

"Wake up Arduino, how much voltage do i have?"
have you ever seen that tv show called Eureka?
the sheriffs bunker home can sense everything.
i will have sensors everywhere and see it on my droid when im away.
this thread can better explain my evil plan.
http://arduino.cc/forum/index.php/topic,144152.0.html
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Webmaster living off grid in a camper with 300watts of solar panels charging 9 absorbed glass mat 12V batteries. i own about 40 dot coms. i

Ontario
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If you are married to 12V, you are married to 12V.  But you may find that an off-grid setup is more efficient of you can run the DC part at 24V, 36V or 48V.  Higher voltage means smaller conductors, longer conductor runs, if needed, and less dangerous currents moving around.  For 12V, you are just going to be paralleling up all your batteries, so the wiring you have is fine.

You do have three different battery types combined in your battery string: flooded, AGM and Gelled VRLA.  I would wager that they are all different ages and conditions.  This is definitely sub-optimal and will affect the overall performance.  Especially, it will not be possible to equalize this string together.  Estimating overall SOC will not be remotely accurate.  One or two dodgy batteries could easily suck the life out of the good ones.

With so many batteries you will need a lot of fuses.  If you do not have 100A fuse on each battery's (+) post, I do not want to hear about it.

I do not understand what you mean that you get only 600W from your 3,000W inverter.  Why is that?  Does it overheat or over-current shut down? or experience low input voltage or what?  I would expect your battery string could supply 100A for at least a few minutes.

Battery University is a good place to read about batteries.  They have a lot of stuff on Lead-Acid:  http://batteryuniversity.com/
Also have a look at all the alternative energy and off-grid forums.  There's a lot of good info about the ins and outs of battery system design and care and feeding.
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