inverter to charge batteries connected to ANOTHER inverter

Discussion in 'General Questions' started by faloolah bananahammock, Jul 2, 2014.

  1. the problem: i didn't read the 'fine print'. just picked up 2 stackable 2500 w modified sine inverters and one 6000w pure sine inverter - i was on a roll, what can i tell you... tax return giddiness. anyways, turns out this 6000w inverter can't be used when the PVs are charging the batteries, it will only act as a battery charger/transfer switch via AC power.... not a HUGE issues since this is for a remote cabin, so i can unhook the inverter when i leave and let the solar panels charge the batteries (12 x 6v golf cart batteries wired as 24v so way more power than i need for a long weekend)... HOWEVER so i don't have to mess with hooking and unhooking stuff when i leave, could i use the 2x2500 watt inverters connected to the solar panels (via a charge controller of course), with a bank of 4x6v batteries, with the ac cable to the IN on the 6000w inverter? technically sounds like it would work, but just seems like there has to be an easier way... maybe simply shutting off the inverter when i'm using it and turning ON the solar panels (i built a charge combiner with breakers) when i leave?
  2. TomT

    TomT WindyNation Engineer

    What brand and model is the pure sinewave 6000 watt inverter ?

  3. Item No.


    Continue Power


    Peak Power


    DC Input Voltage

    DC 24V

    AC Output Voltage



    Pure Sine wave

    Line Low Transfer

    85V±4% /170V

    Line high Return




    Short Circuit Protection

    Yes, shutdown after 10 second

    Power Factor


    Battery Voltage


    Minimum Start Voltage


    Low Battery Alarm


    Low Battery Transfer


    High Voltage Alarm


    Max Charging Current


    Over Charge Voltage


    Battery Mode


    power saver

    Available when the load is less than 25 Watts

    battery charger voltage range

    28v-31v, 3step, manual


  4. No , i would not , i tried that and my pure sinewave inverter was making strange noises , when i connected the non sin-wave unit to its AC-in ..... , as well then the "unclean" power is switched through to your consumers

    I do not understand , why you cannot use the 6000 watt sinwave while batteries are charging via external chargecontroller and PV
    I heard about those inverters , and another possibility is to connect Grid tie inverters on their AC in or AC coupling on the DC side , but i see no reason to go this route in a remote cabin

    Can you tell more about PV panels you have and battery and do you have an external charge-controller ?

  5. talked to the manufacturer - because of the frequency difference, he said most definately don't do it... i can unhook the batteries from the solar when i get there, use the power and hook them up again when i leave, since it's doubtful i would ever use as much power as is stored in 8 220ah 6volt batteries.. and yes I have a xantrex c60 controller... not sure WHY you can't, it's just a 'feature' of this particular inverter i guess. turns out is more of a transfer switch to DC i think, than what i wanted.... thinking i'll just modify a 2 breaker panel in between the inverter and the batteries - i already did a larger combiner panel for the wind and solar panels... so i'll just shut one off and the other on... not a huge deal...
  6. still, i do not understand , why the inverter will not work, when the xantrex chargecontroller is charging the batteries ....

    anyway ther are other methods with this inverter , for example AC-coupling the panels on the AC-out side could work,902.0.html....
  7. nor do I!! actually, i didn't mention to the inverter guy there was a charge controller on the solar side. all i know is when i had the solar panels charging and hooked up the inverter, it made a noise it should not have made! it really didn't like it... take out the solar, noise goes away. since this inverter is a rather expensive piece of kit, at least on my budget, just as soon work around it with a transfer switch of sorts. i don't want to bugger it up, but was thinking normally when you connect an inverter, you hook up the first + in a chain and the last - in the chain... these are 6 volts wired into 24's. what would happen if I connected the solar panels to the + and - 'in between' 2 sets of 24vs, that is to the + and - that ties two sets of 4x6's together - the 'middle' + and - sort of. the inverter gets the last in and out, the solar gets the middle in and out - would that 'fool' the inverter i wonder... i had them on the same posts. just idle thought, as i say, i don't want to screw up an expensive thing just to avoid having to unhook the solar... total bummer though, not being able to charge at the same time, and something i absolutely didn't think to look for - who would have? it's an inverter for crying out loud! ah well, caveat emptor right?

    took at look at that page and may i just say... i understood about three words in there, so i have a LOT of learnin' to do... but what he has for an inverter looks like the big brother to mine, so i'll contact him directly and see what he's got to say... i just plod away following directions, but with only a rudamentary understanding of what it is i'm doing and fervent hope i don't blow myself up!
  8. ... i just think , that you hooked your chargecontroller (xantrex) somehow wrong with this offgrid inverter .... , why the feck , should an off grid inverter have a problem with PV charged batteries ?

    Just charge the Batteries , why did you get those two stackable 2500 w modified sine inverters ? What was the intention ?
  9. the controller/batteries have been working fine with other inverters i had... hey, what can i tell you.. the manufacturer says the only acceptable thing you can having running with this inverter at the same time as the batteries is standard 110 AC...its more a battery charger/transfer switch from AC/DC rather than PV/DC inverter. and i'm not sure you're understanding the issue... the inverter doesn't have an issue with PV charged batteries. it has an issue with the PV's charging the batteries at the same time the inverter is being used to convert to AC. it's not HOW the batteries are charged, it the fact the batteries can't be connected to a PV 'input' at the same time as the inverter is turned on.. i expect it to do with the mhz or cycles or some weirdass electrical thing.

    the stackable ones are for a different bank, for future use in a greenhouse, and the ability to use them as a single 5000w or as two 2500s. and because i wanted them.
  10. TomT

    TomT WindyNation Engineer

    I would be thinking that the PV is PWM charging the batteries. And the frequency from that plays havoc with the inverters input since it should be just DC.
  11. Tom , isnt PWM chargecontrol just happening , when battery gets close to fully charged , in bulk charge there is no charge-control as far as i know ..... , but one could test this by connecting the panels directly to the battery (stay with them and disconnect when voltage too high ) or if its a problem with the xantrex charger , then try it in diversion mode and let the PWM s drive a heater ?????
  12. TomT

    TomT WindyNation Engineer

    I have not had one of those. I just use the one I made a few months ago. It just keeps my battery topped off at 14.4 volts. I have 2 volt telephone batteries. 12 volts. So you maybe right. Leamy might know or Josh from Windy Nation.

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