Help with Outback warranty claim requirements for Northstar Battery

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jdobush
jdobush Registered Users Posts: 18 ✭✭
Hi,
I'm in progress of a warranty claim on a Northstar Blue+ battery. By all tests I can do it has a bad cell (drops way down under any load, hardly any charge or discharge current coming from that string). It's part of a set of 3 24v strings. 

I'm more asking if anyone has had experience getting an actual warranty claim done on a battery - specifcally with Outback. I have just sent them a ton of required information. But it looks like they are also requesting that all batterys get a conductance or impedence test and a Siemens value. 

Now, I don't have anything that can measure that, nor can I easily find something that would. But in any case it looks like I would have to spend more than a battery costs, to purchase such a tool (any recommendations?) Or can anyone comment on getting a battery claim approved without this? I mean I have pictures of the battery dropping to 10.6volts on a simple carbon pile tester. ??

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,478 admin
    edited February 2022 #2
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    You have a carbon pile tester... A common method to "estimate" resistance of a battery (or any voltage source) is this equation:
    • V=I*R (standard equation)
    • R=Voltage/Current
    • R= change in voltage / change in current
    • Example: 12.8 volts - 10.5 volts / 50 amps - 0 Amps = 0.046 Ohms
    And Siemens is simply:
    • S = 1/Ohm
    • S = 1 / 0.046 Ohms = 21.7 Siemens
    Note: You can ask the battery vendor what current level(s) to do the resistance/Siemens test at... For example you could use lower current values or even a "change in current" vaules... Making numbers up:
    • R = 12.1 volts - 11.9 volts / 20 amps - 10 amps = 0.01 Ohms
    • S = 1 / 0.01 Ohms = 100 Siemens
    This is not the "fancy" testing with a meter/system that can test at 100 Hz or whatever... But it does the basics.

    And with your carbon pile tester and some sort of current meter (an AC + DC Current Clamp meter is very handy)--You should be able to demonstrate the present state of your batteries. Do this testing with at least two batteries--Your "bad" one and a good one to show that your tests are valid and show the degraded performance of the failed battery (the one bad cell is pretty difficult to miss).

    https://www.amazon.com/gp/product/B019CY4FB4 (mid priced AC+DC current clamp DMM--You can find AC+DC clamp meters down towards $50 too... And Fluke meters for many more $$$).

    In theory, the closer between "high and low" current--The closer you are to measuring the "DC Resistance" of the battery system (i.e., 2 amps vs 1 amp discharge or charging current)--And measuring the "charging" current/resistance may also be helpful (i.e., if it has high resistance charging in the case of an "open" cell)--Would also be a nice confirmation of cell/battery failure--Although, the "numbers" will be less accurate (depending on the number of digits/accuracy of your meters i.e., x.xx vs x.xxxx meter display capabilities).

    Sorry I cannot be more helpful... Just not in my area of experience.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jdobush
    jdobush Registered Users Posts: 18 ✭✭
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    Thanks Bill, this was incredibly helpful. I come from an automotive electrical background, and battery testing beyond pass/fail has not been in my wheelhouse. I was honestly looking for a good explanation of what a Siemen is even looking at and you explained it beautifully. 

    I do have a DC clamp meter as well that I've used to prove that very little current is moving in or out of this questionable string. I've made it to the point where I have a good idea of whats going on, but explaining it and meeting their specific needs is the challenge. 

    I'll wait to hear back if what i have is sufficient, or if they need more. But your ideas of the rough calculations may put me in the right place. I don't think i would even try to go down this warranty road with simply degradation of capacity. Hopefully they cut me a break with an obviously 'bad' battery.

    Thanks!
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    edited February 2022 #4
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    I think that what Bill showed was called dynamic resistance...  So, One over that value would be dynamic conductance.
    Just tell then that number maybe ?    If you call it dynamic conductance they might not know what you are talking about though ?   Might be over THEIR heads ?  😀
  • jdobush
    jdobush Registered Users Posts: 18 ✭✭
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    An update for any interested: I did in fact receive a replacement battery from Outback - no shipping charges either. 
    I ended up just ignoring the conductance/impedance test sections of the forms. I clearly spelled out what was happening, with pictures of all of my testing, on good and the bad battery. And filled in only what I could on the request forms.

    It ended up that who I was talking to was not technical, just taking info to pass along to the tech support people (never had any direct contact). Communication could have been better, as I went from a 'they're working on the claim', to a call from a freight company saying when can we deliver. But no complaints, since I got a free replacement. A positive outcome for anyone else trying to decide if all the battery warranty road is worth the trouble. 
  • BB.
    BB. Super Moderators, Administrators Posts: 33,478 admin
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    I am sorry to hear that you had battery issues... But happy that you got warranty support/replacement.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset