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Post by klafond on Nov 14, 2017 14:21:04 GMT -8
I have a solar setup in my RV and am trying to understand why my two year old batteries are not fully charging.
I have a 240 watt panel flat on my roof ( I can't remember the brand name, but I don't think that is important). I have a Renogy MMPT 40CC charge controller with an MT5 remote meter. I have 2 Energizer EGC2 6V batteries rated at 208 AH each.
I put the new batteries in on Nov of 2015. I generally watch some tv at night and that is about it. I spent the winter of 2015 in Arizona and California where the system worked fine. My batteries would be no lower than 12.1 and I turn off the inverter when not in use. The batteries would replenish during the day and be good for the night.
In the winter of 2016 I was unable to travel and left the rv parked. I cleaned the snow off the panel everyday when it snowed. I kept an eye on the system, and it was at 100 % charge all winter and summer. I check the electrolyte level once a month and top up with distilled water as required.
This winter I am in California, I noticed that voltage drops quicker now than in 2015, I have let it get down to 11.9.
I had a couple of cloudy days and the solar did not bring the batteries up to 100%, so I used a generator and a battery charger to bring the batteries back to 100%.
I notice now that the charge controller says my batteries are at 100% as early as 11 am or noon. The most I have seen my panel produce was about 36 V and about 8 amps. My batteries seem to drop quickly from 12.7 to abot 12.3 or 12.4.
I also notice the voltage shows about .1 or .2 higher on the charge controller than on the readout on the inverter, I have confirmed with a multimeter that the charge controller is not displaying the correct voltage.
I have also seen a discrepancy betwwen the state of charge between the charge controller (CC)and my battery charger. Today at about 11 am the CC said the batteries were at 100%, I was curious, so I put the battery charger on and it said the batteries were only at 97%, so I have been charging them with the battery charger (the solar is still on) for about 3 hrs and they are still not at 100% as per battery charger, however the CC has been at 100% the entire time.
It would appear to me that the CC is not charging to 100%.
Is there a voltage adjustment on this CC?
I checked the specific gravity when the CC said 100%, and it was about 1.250.
Can anyone tell me what is wrong and how I can correct it?
I was speculating that I would get 4 or 5 years out of the batteries if I did not let them get below 11.9 volts.
Can I bring these batteries back to life or do I need new batteries?
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Post by tattoo on Nov 14, 2017 14:42:47 GMT -8
What is you specific gravity now? I didn't see where you said... Just what is was...
How many hours sun are you getting on your panels everyday?? Direct sun..
The state of charge on your CC means nothing, forget about it like it's not even there... ONLY go by your specific gravity... That's the true test...
Your solar will never get it to 100% unless you don't have any draw for several days because this time of year there just isn't enough sun..... You should top off your battery at least once a week with a AC battery charger for at least 12 hours....
I really doubt that you will get 4 or 5 years out of your battery but I don't think your battery is bad just weak...
How do I know you ask??? I just went through this 3 weeks ago...
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Post by rabird on Nov 14, 2017 17:33:29 GMT -8
research equalize batteries, this is an intentional overcharge to get all the cells equal and to remove sufate from the plates in the battery. A good equlization will also mix the electrolyte. Golf cart batteries need to be equalized regularly to help return to full capacity. Capacity loss from repeated undercharging. The problem is having the equipment to equalize, it requires ~ 5A / 100 ah capacity and to bring the batteries to 16v or so. support.rollsbattery.com/support/solutions/articles/430-corrective-equalization-instructionsI have no idea if you can program your controller to do this. hopefully it is programable and you can adjust the set pts so it charges FULLer in the future. One method is to bypass the controller and let the solar panels charge the battery directly, you monitor batt voltage and sg and need to disconnect when the voltage gets too high www.youtube.com/watch?v=jCl5klSF4tEfor more detail sumbit you post the the tech formum at rv.net www.rv.net/forum/index.cfm/fuseaction/listings/forum/39.cfm |
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Post by tattoo on Nov 14, 2017 17:52:14 GMT -8
My guess by reading his post he can't program his CC........... Like 80% of the people with a solar system...
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Post by klafond on Nov 14, 2017 18:35:24 GMT -8
What is you specific gravity now? I didn't see where you said... Just what is was... How many hours sun are you getting on your panels everyday?? Direct sun.. The state of charge on your CC means nothing, forget about it like it's not even there... ONLY go by your specific gravity... That's the true test... Your solar will never get it to 100% unless you don't have any draw for several days because this time of year there just isn't enough sun..... You should top off your battery at least once a week with a AC battery charger for at least 12 hours.... I really doubt that you will get 4 or 5 years out of your battery but I don't think your battery is bad just weak... How do I know you ask??? I just went through this 3 weeks ago... I am about 6 hrs into charging and can't get past 99% on the generator and charger, too dark to check specific gravity right now. I will consider doing the generator battry charge once a week. Thanks. |
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Post by tattoo on Nov 14, 2017 18:38:10 GMT -8
It takes time to get 100% 6 more hours should do it..
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Post by klafond on Nov 14, 2017 18:43:47 GMT -8
research equalize batteries, this is an intentional overcharge to get all the cells equal and to remove sufate from the plates in the battery. A good equlization will also mix the electrolyte. Golf cart batteries need to be equalized regularly to help return to full capacity. Capacity loss from repeated undercharging. The problem is having the equipment to equalize, it requires ~ 5A / 100 ah capacity and to bring the batteries to 16v or so. support.rollsbattery.com/support/solutions/articles/430-corrective-equalization-instructionsI have no idea if you can program your controller to do this. hopefully it is programable and you can adjust the set pts so it charges FULLer in the future. One method is to bypass the controller and let the solar panels charge the battery directly, you monitor batt voltage and sg and need to disconnect when the voltage gets too high www.youtube.com/watch?v=jCl5klSF4tEfor more detail sumbit you post the the tech formum at rv.net www.rv.net/forum/index.cfm/fuseaction/listings/forum/39.cfm I will read up on the equalization, I was wondering if I might be getting stratification (I think that is the correct term) of the electrolyte, I was trying to mix it with the specific gravity tester. I am not sure I have the equipment to equalize, but I need tobread up on it. Thanks. |
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Post by klafond on Nov 14, 2017 18:48:36 GMT -8
It takes time to get 100% 6 more hours should do it.. How many years would you speculate I should get out of my inexpensive batteries if maintained correctly, I know there are a lot of factors but is 2 or 3 years more reasonable? |
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Post by tattoo on Nov 14, 2017 19:07:41 GMT -8
It takes time to get 100% 6 more hours should do it.. How many years would you speculate I should get out of my inexpensive batteries if maintained correctly, I know there are a lot of factors but is 2 or 3 years more reasonable? I would say if you start charging them fully once a week I would think you could get another year or two.... And I don't think you will be able to do what bird suggested... |
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Post by klafond on Nov 14, 2017 19:52:07 GMT -8
How many years would you speculate I should get out of my inexpensive batteries if maintained correctly, I know there are a lot of factors but is 2 or 3 years more reasonable? I would say if you start charging them fully once a week I would think you could get another year or two.... And I don't think you will be able to do what bird suggested... My panel puts out 36V on a good day, so I am not going to try and equalize that way. My gen and charger has put out as high as 15 v (it's a newer model, not like my old stand by from the 1980's), so I will try and bring them back with that. Regards. |
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Post by klafond on Nov 14, 2017 20:11:58 GMT -8
I would say if you start charging them fully once a week I would think you could get another year or two.... And I don't think you will be able to do what bird suggested... My panel puts out 36V on a good day, so I am not going to try and equalize that way. My gen and charger has put out as high as 15 v (it's a newer model, not like my old stand by from the 1980's), so I will try and bring them back with that. Regards. Here is something else I don't understand what is happening. The generator with the battery charger got to 100% and went into maintain mode, I am not sure for how long, could have been as much as an hour. I turned the charger off and back on again and it said battery was only at 77%. I have next to 0 for a load on it, a couple of 12v phone chargers and the propane detector, so why are the batteries not holding their charge? Once again it was too dark to check the specific gravity. |
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Post by tattoo on Nov 15, 2017 5:25:55 GMT -8
^^^^^ I go back to what I said above.. Forget about what your state of charge is it means NOTHING....What does your Hydrometer say the batteries are at??
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Post by rabird on Nov 15, 2017 8:12:06 GMT -8
any panel connected directly to the batt will draw down to battery voltage. A '12v' panel operates between zero and 22v, a pwm controller connects the panel directly to the batt during bulk and switches on/off during absorb/float.
So ya ain't gonna try that, how about taking the 2 batts to a autozone or the like and let them 'test' them, they will recharge them and then do a load test. passing a specific load test would be an indication they have good capacity. A pair of golf car batteries should have 1000 or more 50% cycles if recharged FULLY. @ 300 cycles a year that is over 3 yrs.
% meters are useless
For a generic pair of 6v flooded golf car battery, I'd wanna see at least 14.8v (temp corrected) at the battery terminals, once a charging source gets them there, I'd want them to stay at the voltage until the amp flow has reduced to ~2A.
^^^ That would be the daily routine after (if) they can be corrected by equalization.
Your quick drop could be an indication of one cell being shorted and then the pair would be junk.
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Post by tattoo on Nov 15, 2017 9:52:08 GMT -8
Your quick drop could be an indication of one cell being shorted and then the pair would be junk. Glad to see your coming around Bird.... That's why I want to know what the Hydrometer says..... |
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Post by klafond on Nov 15, 2017 11:43:32 GMT -8
Your quick drop could be an indication of one cell being shorted and then the pair would be junk. Glad to see your coming around Bird.... That's why I want to know what the Hydrometer says..... Generator and charger have been on for about 3 1/2 hrs this AM, charger is putting out 15.1V, all cells are gassing, one cell is 1.250, the remainder have come up to 1.265 to 1.275, I am going to continue to charge with gen and monitor. I appreciate the help. |
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