Should my system be F MPTT at low power??

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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #92
    Re: Should my system be F MPTT at low power??
    Freewilley wrote: »
    There has GOT to be an issue with the brand new Surrettes, MEthinks....I have been absorbing with solar for a couple of hours, and the genny was absorbing before that....the Manual says they should absorb in 90 minutes and I have not seen any increase in SG...still at 1.240

    Sulphation?
    Whats the Voltage ?? Absorbing at this point is meaningless. Did you ever hit 15.5 volts ?? What are your loads ?? You could have EQ'd a 100 batteries in the time you'v been fooling with 2 batteries.

    A Outback 2512 is not a current Inverter / Charger, what do you have ?? A FX 2012 puts out 80 amps.
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  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    #93
    Re: Should my system be F MPTT at low power??
    vtmaps wrote: »
    Permanent hard sulfation is unlikely if the batteries have been recently manufactured. Someone earlier mentioned the possibility of having been filled improperly or perhaps having had a spill that someone compensated for with water.

    Assuming that there is nothing wrog with the batteries, you really only have two choices when charging a battery: time and voltage. If you can't increase the time, try increasing the voltage by 0.2 volts.

    There are many folks who increase their absorb voltage a bit seasonally, in the winter, to make up for less sunlight hours. Its harder on the battery, but easier on the generator.

    --vtMaps

    I set my absorb high...it was 14.9 for 2 days.
    Now the MX has gone to float, presumably because it has absorbed for 4 hours....
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #94
    Re: Should my system be F MPTT at low power??
    Freewilley wrote: »
    I set my absorb high...it was 14.9 for 2 days.
    Now the MX has gone to float, presumably because it has absorbed for 4 hours....

    Yes; after the time limit is up it goes to Float.

    Now this is where observing the Amps through the Absorb stage is useful; if the current has dropped to 2% or less (8 Amps in this case) then the batteries are likely as full as they are going to get.

    However I did say 14.8 would be a starting point for Absorb Voltage for these batteries; many Surrette users find they need 15 or even more (which is one of the problems with them).

    There is also the possibility that your hydrometer is reading inaccurately, for whatever reason.
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  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    #95
    Re: Should my system be F MPTT at low power??

    hmmmm, I guess I cannot tell the current as I can only read that from the MX, which I believe shows total current from array (which includes the power being used by the house).
    that total current is varying of course, but at this point,
    my mx screen shows
    pv 30.8 v Bat 13.2 v
    o4.4 A 9.3 A
    watts 120 aux off
    kwh 1.0 FLOAT

    I have two hydrometers, one new "pro" grade, and they agree.....I wish it was those instruments that are the problem....
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #96
    Re: Should my system be F MPTT at low power??

    The current at Float is not relevant.

    Tomorrow try charging only from the MX and watch the current during the Absorb stage; see how low it gets before switching to Float.

    I'm sort of assuming here you have nothing better to do with your time than watch the system. :p
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #97
    Re: Should my system be F MPTT at low power??

    Are you temperature compensating the SG readings?

    Otherwise, it may be time to call the battery support line.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    #98
    Re: Should my system be F MPTT at low power??

    I am temp compensating.

    Steve from Surrette is reading this thread, he emailed me and asked about phantom loads, he suspects I have some.... but I only have very very small phantom loads, a couple of clock radios a small internet modem...microwave is plugged in, unused.

    But it is not a phantom load issue in my mind, I have lots of solar coming in, 7-800watts for 4 hours plus. When nothing is running in the house, the MX is only using 140 watts to keep the system at absorb. And for 2 days I ran the genny to no avail, it was only using a tiny portion of capacity to absorb also.
    Mate, VFX 2812, FM 60 & MX 60, 2 Full River AGM 400 6v, 1400 watt Solar Array, Yamaha 3000iSEB inverter gen
    12 volt Flojet water pump
    off grid summer home in northern Ontario
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #99
    Re: Should my system be F MPTT at low power??

    I agree it is not a load issue. There would have to be huge loads to be hindering the charging so much.

    For example I have slightly more Watt hours capacity in my battery bank and a slightly smaller array. Mine is a 24 Volt system, but the same charge controller and an FX inverter. It has no trouble keeping up with my 2+ kW hour daily usage on a sunny day and there is no problem charging the batteries to full with the FX when needed.

    It simply should not be this difficult or time consuming to get batteries up to full SG when you have sufficient charging power, which you do.

    I'm beginning to suspect another set of defective Surrettes.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #100
    Re: Should my system be F MPTT at low power??
    Freewilley wrote: »
    I am temp compensating.

    Steve from Surrette is reading this thread, he emailed me and asked about phantom loads, he suspects I have some....very very small phantom loads, a couple of clock radios a small internet modem...microwave is plugged in, unused.

    But it is no a phantom load issue in my mind, I have lots of solar coming in, 7-800watts for 4 hours plus. When nothing is running in the house, the MX is only using 140 watts to keep the system at absorb. And for 2 days I ran the genny to no avail, it was only using a tiny porting of capacity to absorb also.
    You ran a generator 2 days and have a Inverter / Charger with a 80 amp output and still cannot charge or Equalize 2 batteries ?? I'd say something is wrong, maybe Steve can find it, must be a disconnect somewhere.
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