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robbirobson

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Posts: 13
Reply with quote  #11 
I think the problem was that the charging voltage was too low and i had the ampere setting only to 20 amps instead of 30. Also the low and high voltage configuration at the mppt were not correct.. The type of batteries i am using is Tree TRG12-100. Does anyone have experience with it? The batteries are non servicable and the manufacturer told be they can last up to 8 years. How do i know if its AGM or Flooded? I am not too much into batteries, but the charging voltage is printed on it as 14.2 to 14.4V so i guess its agm? What helps against sulfated batteries? Its sufficient to charge them fully with maximum voltage and current? THe batteries are new, like 2 months old.
Also in a full sunny day i get about 30A charging current for at least some 4 to 5 hours (should be almost 900w), i am usually not at home at day and everything is turned off so the batteries receive full power.
Production starts in the morning around 7.30 / 8.00am with around 5 to 10 Amps, from 9.30am to 3.00pm is the best time with 25 to 30 amps sometimes up to 5.00pm when there is really a lot of sun. after 4pm to 5.30 its around 5 to 10 amps.

Another question, the mppt handles a maximum charging current of 30amps, even tho it says up to 60amps on the sticker but there is no option to set it more than 30. Does it makes sense to connect more than 4 batteries as they will never get maximum charging current with that?

Gordy

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Posts: 75
Reply with quote  #12 
Sorry Rick,

But self discharge does not explain why those jeep batteries went from fully functional to totally dead in 24 hours. And no they were not dropped or kicked round.

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Gordy,
Minnesota
stmbtwle

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Reply with quote  #13 
Possible the "low" battery is defective.


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Willie, Tampa Bay
Rick H Parker

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Reply with quote  #14 
But self discharge does not explain why those jeep batteries went from fully functional to totally dead in 24 hours.

My best guess is that the sediment traps where full. Moving the battery brought some of the sediment in contact with the bottom of some plates and shorted them out. That would create a very high self-discharge rate. Did the battery get tipped when removing it from the jeep? That could cause the sediment to slide to one end of the sediment traps and build up to the bottom of the plates.

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Rick H Parker
Kansas, USA
Electronics Engineering Technologist
Rick H Parker

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Reply with quote  #15 
maybe it has been stored to long at the dealer without charging.

That could explain it. The battery may of acquired some semi-hard sulfation which required a good charge to convert back into lead.

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Rick H Parker
Kansas, USA
Electronics Engineering Technologist
Rick H Parker

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Reply with quote  #16 
The type of batteries i am using is Tree TRG12-100.

Did you mean Temrii TGR12-100?  If so, Temrii TGR12-100 are gel cell and are non serviceable.

What helps against sulfated batteries?

Frequent under charging is the number one cause of sulfation. ( Keep in mind, over charging will kill a battery real fast )
Number two is how deep you discharge the batteries (DOD Depth Of Discharge).

Another question, the mppt handles a maximum charging current of 30amps, even tho it says up to 60amps on the sticker but there is no option to set it more than 30.

What is the make and model number of the charge controller?

Does it makes sense to connect more than 4 batteries as they will never get maximum charging current with that?

It makes sense to use more then four batteries.
1. You do not need to charge at the maxim current, you just need to get them charged.
2. The more batteries you have in a bank the longer the batteries will last. As mentioned above, DOD is the second biggest killer of batteries. More batteries = less DOD.

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Rick H Parker
Kansas, USA
Electronics Engineering Technologist
Gordy

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Posts: 75
Reply with quote  #17 
Thanks Rick,

My best guess is that the sediment traps where full.

 Makes sense. Now that you bring that up I do recall seeing busted batteries at a salvage yard years ago. The space at the bottom of some were empty and some were full of crud.
  
Thanks again.

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Gordy,
Minnesota
robbirobson

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Posts: 13
Reply with quote  #18 
Ok i am back, i did some testing on the system. i have the slight feeling that the batteries are not good. My batteries are 4x Temrii TGR12-100.
Whatever i set in the mppt i do not get the capacity out of it as it should be. Here is the manual of the mppt:
https://www.scribd.com/document/314450778/Axpert-MKS-MKS-1-5KVA-manual

it has over and under voltage protection, for example it trips of when the voltage goes below 22v which is 11v per battery, it also goes of when the battery without load is maybe 23 volts and with a load its less than 22 volts it turns off. so i should not have any problem with draining them too much. In the manual in the appendix is a table of the minutes you can get from 100ah or 200ah under certain loads. I do not get anywhere close to it. for example the 1100 minutes for 300w load at 200AH. My fridge has less than 300 watts, i am happy when i can run it 2 hours without sun than the mppt shuts down.

What i also realized the batteries charging very fast, it displays me full bars after just 2-3 hours under full sun which cannot be because the charging power is no more than 870watts (30A*29V) so at least to charge the batteries it should take almost 6 hours under full sun.

I checked the voltage of the batteries "fully charged as displayed" without load, one battery has 13.6v the other 3 batteries have 13.2v. I now disconnected 2 and charge only 2 at a time i also raised the charging voltage to 29v. I do not have much experience with batteries, what do you think are the batteries bad? I want to buy the batteryminder desulfator and charge it with it. Do you think it can restore the capacity? I have the feeling the dealer just stores the batteries and does not charge them or did not charge them fully because i remember when i bought them the voltage was a little more than 12v without load.
robbirobson

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Posts: 13
Reply with quote  #19 
I just realized the battery that had 13.6v after i charged it has now dropped to 12.7v in about 5 hours without anything connected to it. The other battery hsa dropped from 13.2v to 13v in the same time without load.[frown][confused]
Rick H Parker

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Reply with quote  #20 
I just realized the battery that had 13.6v after i charged it has now dropped to 12.7v in about 5 hours without anything connected to it.

~ 12.7V is full charge with the surface charge dissipated.



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Rick H Parker
Kansas, USA
Electronics Engineering Technologist
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