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Post by Kevin h on Feb 14, 2017 19:22:53 GMT -8
I have 4 100 watt solar panels a 40 amp charge controller and I want to build a 12 volt battery bank useing 6 6volt batteries wired series and parallel will the batteries charge ok with out any problems
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Post by johann on Feb 15, 2017 18:10:28 GMT -8
How many ahr do your batteries have?
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Post by Kevin h on Feb 16, 2017 15:53:37 GMT -8
235 amp hour batteries
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Post by johann on Feb 19, 2017 16:46:16 GMT -8
To charge your 700 ahr batteries completely you need about 70 amps of current.
Usually the charging current should be about 10% of your total ahr. A lower current is ok if your discharged amp hours are lower.
A 100watt panels give you 5.29 amps max, so about 20 amps for 4 panels. That would take care of a 200 ahr battery if you draw 50% of the capacity daily from it. But it will not charge 700 ahr of battery propperly.
If you use very little battery power at a time then you could have a bigger battery bank since there may be less power required to recharge them.
700 ahr battery will give you 4200 watts safely on a daily basis if you discharge your batteries to 50%. It will take about 5460 watts to recharge that battery bank because of losses. With your 400 watts of panels, it would take about 2.73 days to fully recharge your batteries if no other load is applied while charging.
If you take those 4200 watts on a daily basis, then you would need about 1100 watts of panels to recharge your batteries in one day.
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Post by Kevin h on Feb 22, 2017 18:54:52 GMT -8
Thanks for the help Johann
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Post by upnorth on Mar 28, 2017 5:02:32 GMT -8
not sure if this is where I should be asking this question or not but here it goes. I just bougt 2 vmax tank batteries to make a 12 volt system. Than I read on their website that I need at least a 150 watt system to charge them. I only have a 100 watt panel will this still work? Why would it make a difference? I have a 20watt mppt charge controler
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Post by johann on Mar 29, 2017 19:34:18 GMT -8
not sure if this is where I should be asking this question or not but here it goes. I just bougt 2 vmax tank batteries to make a 12 volt system. Than I read on their website that I need at least a 150 watt system to charge them. I only have a 100 watt panel will this still work? Why would it make a difference? I have a 20watt mppt charge controler Batteries like to have that optimum charging amperage and/or voltage to extend the live of them. Any thing higher or lower can affect how long they may be good. A mppt works good with higher panel voltage, not so good with an 12 volt panel especially in the summer when heat will lower the panel voltage output. If I remember right, the bulk charge is the only charge that uses mppt and all the other stages are using pwm with an mppt controller. |
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mel
New Member
Posts: 31 
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Post by mel on Jun 3, 2017 14:37:55 GMT -8
KEVIN
I have a 400 watt system just recently insalled on our 32' 5th wheel, Renogy ecipse premium kit 40a Commander CC, MT-50, 4 6v flooded 120ah=480 with 240ah (50%). I'm shocked at how good this system works, Even on a rainy day a few weeks ago it charging away. Bottom line for us is I can run two LED 26" & 28" TV'S each with a DVD playing two 60 watt LED lights and a big ceiling fan from 7:00 P.M til 6:30 the next morning and my monitor read 12.5 Volts. So I turned off the TV's DVDS and lights and took out our brand new $20 Mr. Coffee and brewed a full pot of coffee and still read 12.5v and was already charging as the sun was rising on a cloudy morning. I just don;t think you need that many AMPS
Mel
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