Why does generator power work so much differently than solar?

Freewilley
Freewilley Solar Expert Posts: 228 ✭✭
This has been bothering me for a while.
When I have no solar, I turn on the generator for 2 hours or so in the morning.
It charges at 900watts.
As it runs, the voltage increases and charging eventually decreases. Lets say it reaches my max at 14.8, the generator charging has dropped to 100watts and of course it takes care of power demand from the house.
That 100 watts and voltage of 14.8 stay static as long as the generator runs, even with no solar of consequence.

I turn off the generator and voltage immediately drops off. Right now as the day moves on,  I am pulling 320 watts of solar and the voltage reads 13.2, with very little power being consumed.
So the generator seems to maintain the voltage very differently than the amount of charging going on.

To back this up, I know that when I have had a good solar day and have been at 14.8 for hours, when the sun starts to recede that voltage drops quickly. Even 600watts of solar, and probably more, are not enough to maintain that high voltage ....that the generator seems to be able to maintain with only 100 watts with ease.

What is the explanation for that?
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

Comments

  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    Sounds like that charging algorithms are different when running from the different sources.

    I am available for custom hardware/firmware development

  • Freewilley
    Freewilley Solar Expert Posts: 228 ✭✭
    I was going to delete this thread as I feel like a knucklehead....as the day goes on, I see that the system is only drawing 320 watts from the solar alone and is maintaining 15.0 voltage. Given that I am using a little power in the house, this is not the concern I thought it was....the difference is much smaller....

    my bad.
    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
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    edited September 2016 #4
    BUT you should still have a look at the algorithm of/ for your AC charger....  it may be close but not exactly the same and for different battery brands this can be an important thing to know... especially when you have AGMs or ? batteries...  not a bad question, us older forum haunters (may) know about the differences but new folks may not... they might  just assume a charger is a charger, all the same...
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    My generator and charger can only get 64VDC, my solar controller can do 68VDC  Is that the question?
    or is it
    The solar cant run the same loads as the generator can ?   Surge limits and Power Factor are the culprit.

    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 ,