[RE-wrenches] How Best to Load Test 2 V Cells
Tump
tump at swnl.net
Wed Jul 14 18:17:58 EDT 2021
IT is actually a MIDTRONICS, designed to test the Siemens & record.
Fluke 500 Series Battery Analyzer is another one.
I would call Bert Rohas @ 972-456-4626 TRS rentco. 730 central time. I have found this company great to deal with. I often use there power analyzers for problem clients & utilities.
> On Jul 14, 2021, at 5:49 PM, Tump <tump at swnl.net> wrote:at
>
> I do have a Megatron battery tester that does test internal resistance whit voltage present. The battery Manu usually has that information. When I get my Unigy II battery banks they supply the sheet w/ those #. Did you say what the battery charge settings were? Not much use at this point as it is tough to clean up AGM cells.
>> On Jul 14, 2021, at 5:43 PM, Jeff Clearwater <jeffc at villagepowerdesign.com <mailto:jeffc at villagepowerdesign.com>> wrote:
>>
>> Yes good thought Chris -I doubt if there is an IR tester anywhere on the island - but when I go I will for sure look at that - thanks for that.
>>
>> How would one measure battery resistance with voltage present? I guess with a known voltage applied and current held constant one could calculate? but then how do you know you are measuring resistance vs storing energy? I don't think that's possible - others?
>>
>> jc
>>
>>> Chris Worcester <mailto:chris at solarwindworks.com> July 14, 2021 at 2:14 PM
>>> Has an infra-red thermometer been used on every battery's terminals to check for resistance? I recall, although this might be my own thoughts, that internal resistance of each cell can be measured with an ohm meter...
>>>
>>>
>>>
>>> Chris Worcester
>>> chris at solarwindworks.com <mailto:chris at solarwindworks.com>
>>> 530-448-9692
>>>
>>> Sent from my Samsung Galaxy s9.
>>>
>>>
>>> -------- Original message --------
>>> From: Jeff Clearwater <jeffc at villagepowerdesign.com> <mailto:jeffc at villagepowerdesign.com>
>>> Date: 7/14/21 1:42 PM (GMT-08:00)
>>> To: RE-wrenches <re-wrenches at lists.re-wrenches.org> <mailto:re-wrenches at lists.re-wrenches.org>
>>> Subject: Re: [RE-wrenches] How Best to Load Test 2 V Cells
>>>
>>> Hey Jay,
>>>
>>> Yes the Sunny island Master of this Quad SI AC-coupled off-grid system has been giving automatic Eq and Full charge charges perodically as appropriate to this 48 V EnergyCell RE2700 pack.
>>>
>>> We are getting whole pack volt drops way before we should at 600 well- maintained cycles. When we do whole pack testing - when the voltage drops off there are 5 of the 24 cells lagging - their voltage drops faster than the rest - but they operate well between 50%-100% - all busbars have been triple checked for corrosion and tourque.
>>>
>>> So it looks like they just aged prematurely - so I'm in the process of collating data from EnnexOS to get exact numbers on how they've been treated. But even with a few hard cycles they should held up better than they have. So perhaps a warranty claim - I've gone through charge settings with SMA etc. I did have the AHrs programmed slightly below rated AHrs due to confusion of whether the SI uses the 20 hr or 10 hr rate (in Europe they use 10 but apparently - unbeknowst to me - the US SI uses the 20 Hr - I swear SMA tech support years ago told me 10 hours) but now they are claiming that might be the culprit - I have a hard time believing that setting the Ahour rating in the SI to 2100 instead of 2288 as rated would lead to pack failure - but they are claiming that could have contributed.
>>>
>>> Thoughts?
>>>
>>> Best,
>>>
>>> Jeff
>>>
>>>
>>>
>>>
>>> Jeff Clearwater <mailto:jeffc at villagepowerdesign.com> July 14, 2021 at 1:42 PM
>>> Hey Jay,
>>>
>>> Yes the Sunny island Master of this Quad SI AC-coupled off-grid system has been giving automatic Eq and Full charge charges perodically as appropriate to this 48 V EnergyCell RE2700 pack.
>>>
>>> We are getting whole pack volt drops way before we should at 600 well- maintained cycles. When we do whole pack testing - when the voltage drops off there are 5 of the 24 cells lagging - their voltage drops faster than the rest - but they operate well between 50%-100% - all busbars have been triple checked for corrosion and tourque.
>>>
>>> So it looks like they just aged prematurely - so I'm in the process of collating data from EnnexOS to get exact numbers on how they've been treated. But even with a few hard cycles they should held up better than they have. So perhaps a warranty claim - I've gone through charge settings with SMA etc. I did have the AHrs programmed slightly below rated AHrs due to confusion of whether the SI uses the 20 hr or 10 hr rate (in Europe they use 10 but apparently - unbeknowst to me - the US SI uses the 20 Hr - I swear SMA tech support years ago told me 10 hours) but now they are claiming that might be the culprit - I have a hard time believing that setting the Ahour rating in the SI to 2100 instead of 2288 as rated would lead to pack failure - but they are claiming that could have contributed.
>>>
>>> Thoughts?
>>>
>>> Best,
>>>
>>> Jeff
>>>
>>>
>>>
>>>
>>>
>>>
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>> Tump <blocked::mailto:Tump at swnl.net%22%20%5Co%20%22blocked::mailto:Tump at swnl.net>3391 at gmail.com <mailto:3391 at gmail.com> www.SWNL.net <blocked::http://www.swnl.net/%22%20%5Co%20%22blocked::http://www.swnl.net/>
>> Solarwinds Northernlights
>> Serving Mid Coast Maine & Northern California
>> 207-832-7574 Cl. 610-517-8401
>> Blair "TUMP" May
>> ******** MAINE'S CHARTER ********
>> NABCEP "Certified PV Installer"
>>
>> ******** MAINE'S CHARTER ********
>> Trace Xantrex "Certified" Dealer / Installer"
>>
>
>
>
> Tump <blocked::mailto:Tump at swnl.net%22%20%5Co%20%22blocked::mailto:Tump at swnl.net>3391 at gmail.com www.SWNL.net <blocked::http://www.swnl.net/%22%20%5Co%20%22blocked::http://www.swnl.net/>
> Solarwinds Northernlights
> Serving Mid Coast Maine & Northern California
> 207-832-7574 Cl. 610-517-8401
> Blair "TUMP" May
> ******** MAINE'S CHARTER ********
> NABCEP "Certified PV Installer"
>
> ******** MAINE'S CHARTER ********
> Trace Xantrex "Certified" Dealer / Installer"
>
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