Sunsaver MPPT output vs link 20 reading

buchhla
buchhla Registered Users Posts: 4
in Off Grid Solar & Battery Systems #1
Hi, I have a new install on my boat that consists of two kyocera kd135 panels wired in parallel to a sunsaver mppt. I also have the pc interface for the controller, and a seperatle xantrex link 20 monitoring by two battery banks, the house being 400Ah @ 12v

my question is, today, one of the first days with some sun since i have installed the solar, i was monitoring both the charge going into the batterys on both the link 20 and via msview. my questions is that the numbers did not match. I know my boat draws < 1 amp at rest for bilge pumps, propane sniffer etc. MS view said the array power was 195 watts, which seems close as I am in seattle and it was 4pm. it also said that is was charging the bank at ~12 amps, but the link 20 was only showing about 6.5 amps going in. msview did say the batteries were in bulk, and were at 13.8v

Any idea why there is a descrepancy? The way i am reading the help file from msview, charge current is the power going into th batteries. is that correct?

Thanks!
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Comments

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    Re: Sunsaver MPPT output vs link 20 reading

    your 260Watts, is not going to do much except trickle charge a 400A battery pack.
    260 /15 = 17A under very best conditions and less under normal conditions.

    You do have another charger that can top those batteries up before they sulphate.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • RWB
    RWB Solar Expert Posts: 168 ✭✭✭✭✭
    #3
    Re: Sunsaver MPPT output vs link 20 reading

    I bet the MSView Amperage Output is dead accurate.

    You sure there just was not something eating up the difference between what the Sunsaver was putting out vs what the Monitor was reading?

    I bet there was just some load running causing the loss, specially if your battery monitor has been accurate up till now.

    Test it again and see if the same thing happens, if so then you might have something failing that's drawing more current than normal.
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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #4
    Re: Sunsaver MPPT output vs link 20 reading

    The most common cause we see for what you are experiencing is that somewhere not all the current is going through the Link shunt for some reason, usually because of some kind of tap or power takeoff from the wrong side of the shunt. We have also seen the wrong size shunt, or the Link configured for the wrong shunt, but not common.
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  • buchhla
    buchhla Registered Users Posts: 4
    #5
    Re: Sunsaver MPPT output vs link 20 reading

    Thanks everyone, I just got back from a week in Mexico on a friends boat and I will take a look to make sure I don't have anything running off the batteries that is not going through the link shunt...
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