crud
Solar Newcomer
Posts: 10
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Post by crud on Sept 29, 2018 14:05:55 GMT
what device can anyone recommend for me to see how full my battery is. A charge controller is not good because it doesn't give a true reading. It only tells you how much charge you are getting from your panels.It won't say how full the battery is otherwise. If you don't believe me then charge your battery all day,then see what the charger tells you at night.It never says it's full,no matter what.Even when you have not used any power from the battery after charging it.
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Post by tattoo on Sept 29, 2018 14:20:55 GMT
what device can anyone recommend for me to see how full my battery is. A charge controller is not good because it doesn't give a true reading. It only tells you how much charge you are getting from your panels.It won't say how full the battery is otherwise. If you don't believe me then charge your battery all day,then see what the charger tells you at night.It never says it's full,no matter what.Even when you have not used any power from the battery after charging it. If your talking about SOC % forget about it.... It's useless and shouldn't even be there....
The ONLY thing that matters is, What the voltage is in your battery at the end of the day with no load on it checked with an Amp meter? 12.7 is fully charged.....
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Post by bupkis on Sept 29, 2018 14:43:03 GMT
freasglass.com/Freas_Glass_Catalog_Dec2013.pdf for a flooded battery. What does your battery maker suggest full is? one or two will suggest you charge to some specific battery voltage, hold that constant as the amps taper to some low level, this they would call full. renogy doesn't say when a battery is full but they have this info which is confusing www.renogy.com/template/files/Specifications/RNG-BATT-AGM12-100.pdf1, they suggest charging 14.4-15v for cycle use, current?, for how long??? 2. their charging charateristics graph is hard to understand but states 20% of capacity (or 20A) @14.1v for how long?
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Post by tattoo on Sept 29, 2018 15:35:10 GMT
^^^ Yep Renogy tells you just enough to be confusing...^^^^
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crud
Solar Newcomer
Posts: 10
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Post by crud on Sept 29, 2018 16:22:04 GMT
thanks for the input. I was wanting to know because they say not to deplete your batteries too much,or they won't refill to the max capacity. I guess I just need to buy five or six more batteries so I can use some power at night.
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crud
Solar Newcomer
Posts: 10
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Post by crud on Sept 29, 2018 16:30:48 GMT
also,If I check it with the multimeter,What reading would one know not to discharge it any further. I'm guessing 11.4.
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Post by bupkis on Sept 29, 2018 17:25:17 GMT
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crud
Solar Newcomer
Posts: 10
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Post by crud on Sept 29, 2018 18:55:19 GMT
geeez..that doesn't make a lick of sense. I say this because .6 is only 5% of 12 so that would mean if I have 11.4 out of 12 volts then I would have 95% of the voltage. nevertheless I will laminate my own frickin copy from that link, like the guy did, and stop obsessing about batteries too!
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Post by bupkis on Sept 29, 2018 20:17:13 GMT
AGM, last few columns, note DEAD is 11.8v!!!  |
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Post by tattoo on Sept 29, 2018 21:11:13 GMT
also,If I check it with the multimeter,What reading would one know not to discharge it any further. I'm guessing 11.4. 12.2 max......If you keep killing your battery down to 11.4 it won't last very long...
Remember you need to fully charge your battery everyday for it to stay healthy...
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Post by jsb2000 on Sept 29, 2018 21:56:47 GMT
As tattoo said: 12.2VDC (which equates to 50% capacity of the battery) is the absolute lowest you want to go.
Also, you want to minimize the number of times you take it down that low. Most discharges should be shallow (to 75% or so, which is around 12.4VDC or so). That will maximize the lifetime of your batteries.
I like to visualize it this way: Each time you discharge your battery, you shave some metal off the plates. Deeper discharges shave more metal than shallower ones, but each time shaves some. And as the plates thin, the amount of energy you can store decreases. So, over time, the situation exacerbates itself, since less capacity tends to lead to deeper discharges, which in turn leads to even less capacity.
A properly sized system keeps the batteries fully charged most of the time for this reason. When you have sunlight, a properly sized system should be able to supply enough energy to run your typical loads AND charge/maintain your batteries at the same time.
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Post by Admin on Sept 30, 2018 3:31:22 GMT
freasglass.com/Freas_Glass_Catalog_Dec2013.pdf for a flooded battery. What does your battery maker suggest full is? one or two will suggest you charge to some specific battery voltage, hold that constant as the amps taper to some low level, this they would call full. renogy doesn't say when a battery is full but they have this info which is confusing www.renogy.com/template/files/Specifications/RNG-BATT-AGM12-100.pdf1, they suggest charging 14.4-15v for cycle use, current?, for how long??? 2. their charging charateristics graph is hard to understand but states 20% of capacity (or 20A) @14.1v for how long? For cycle use our general recommendations are to charge at 10-20% of the battery capacity 20Hr-Rate, So 10-20 Amps comfortably. -Renogy Team |
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