Adding a iota charger to current system

kd7irm
kd7irm Solar Expert Posts: 39 ✭✭
in Off Grid Solar & Battery Systems #1
Does anyone have any experience with adding a iota dc charger to a system that currently uses a outback inverter/charger? 

This would not replace the inverter/charger by any means, just a different way to get the batteries charged with a smaller generator. So the charger control on the outback would be turned off, outback solar charge controller would stay the same, but when needing to charge the batteries the iota out be used. The thought is that by doing it this way the random and sometimes large draw from loads starting (refrigerator) would be handled by the inverter and not effect the small wattage gen. Additionally the fluctuation in generator voltage would not felt by sensitive electronics as they would only see voltage from the sine wave inverter, thus another level of protection. 

The generator is 120/240 and rated at 3800/4750. So I could run a iota of either voltage. Looking at the info it looks like the biggest iota doc charger is 120 volts @40 amps. 

Any thoughts?
Outback MX60 charge controller, Outback VFX3524 inverter, Deka 95-25 1140 Ahr (8hr rate) 24v batteries, Champion 3.8kw generator, and about 2000 panel watts. (Honda EU6500is inverter generator in for repair) 
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #2
    Are you saying that a 3800 watt generator can't start your refrigerator?

    To answer your question, yes you can charge with the Iota while inverting with the vfx3524.  Beware that Iota chargers have very high inrush currents.... not very friendly to small generators.  Most of the Iota chargers have poor power factor, but Iota does have a new model with power factor correction.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Mountain Don
    Mountain Don Solar Expert Posts: 494 ✭✭✭
    #3
    How often do you have to run the generator?  Any particular thing that triggers the need to run a generator to charge batteries? If generator charging is a frequent need then maybe you would get more good from more solar PV.  

    Northern NM, 624 watts PV, The Kid CC, GC-2 batteries @ 24 VDC, Outback VFX3524M
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  • kd7irm
    kd7irm Solar Expert Posts: 39 ✭✭
    #4
    vtmaps said:
    Are you saying that a 3800 watt generator can't start your refrigerator?

    To answer your question, yes you can charge with the Iota while inverting with the vfx3524.  Beware that Iota chargers have very high inrush currents.... not very friendly to small generators.  Most of the Iota chargers have poor power factor, but Iota does have a new model with power factor correction.

    --vtMaps
    Yes it will start and run it fine, it's more about the vfx3524 being sensitive to voltage from small non inverter Gensets and then adding in things like the refrigerator starting and it seems a little slow in reducing amps to the charger to supply the loads, thus almost over amping the Genset. Never had this issue with the inverter Genset. And the power from this new Genset is "dirty" and sets off my UPS for the electronics in the house. So I would prefer to find a way to charge the batteries without having to use the same power to supply the loads at the same time. At least that's the way it seems to me, I may be wrong.

    Now with that said I should not have to use the Genset to charge very often at all, only when it's cloudy for multiple days. And even then with power conservation we do ok without even worrying about starting the Genset. We use it to pump water from the well to the holding tank about once a week. This little Genset seems like a perfect match for the well and would love to find a way for it to work well with the house. I'm afraid to use it right now because of how everything acts. 

    Are the new iota chargers you mentioned the sdc1 series? For the 120volt 40 amp model They show max AC amps as 19.5 but list an inrush of 40amps. Is that an inrush of dc amps to the batteries or inrush of AC amps from the Genset?

    Mountain Don said:
    How often do you have to run the generator?  Any particular thing that triggers the need to run a generator to charge batteries? If generator charging is a frequent need then maybe you would get more good from more solar PV.  

    Basically only to power our 240 volt well pump, but need to be able to use it for battery charging if needed for extended bad weather. Swapping out old panels for new would be money well spend no doubt, but looking for a solution for "dirty" power issues on the cheap right now until our inverter Genset is repaired. Or to replace it all together if that's the outcome. Looks like an iota 40 amp is about $260, not to bad compared to other options. 40amps is not as much as I need, but it's not bad. I could live with it for as often as it would be used. 

    Anything special I need to conect the charger to the batteries? Simple positive to positive and negative to negative on the battery pack? Looks that easy from the iota website :) 
    Outback MX60 charge controller, Outback VFX3524 inverter, Deka 95-25 1140 Ahr (8hr rate) 24v batteries, Champion 3.8kw generator, and about 2000 panel watts. (Honda EU6500is inverter generator in for repair) 
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,688 admin
    #5
    Pretty much... You need a breaker/fuse in the positive lead (close to the battery/battery bus) and wiring rated to carry the charging current (i.e., 1.25x the max continuous current from the charger).

    Keep cables short. For a 24 volt battery bank, try to keep the voltage drop to ~0.1 to 0.2 volts maximum in the charging cables. You can use a voltage drop calculator to figure the drop:

    http://www.calculator.net/voltage-drop-calculator.html

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #6
    I've found my newer genset is really a power factor wimp.  doesn't like poor PF loads at all.   I suspect they have "thinned the alternators" down too far. 3Kw rated cont (3.3KW for 10 min)  but actually works more like a 2KW genset
    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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  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
    #7
    I've used an Iota 75A charger with my setup for years.  Very reliable and simple to use, but as mentioned, the PF isn't ideal.

    At full capacity, it will supply 74-75A (measured), but takes 13.56 Amps @ 120VAC to do so. 



    The charger itself does have fuses built-in, but I put a fuse close to the bus bars where it connects.  This was done to protect the wiring between the two.





    I have run this from my Yamaha EF2400iS generator many times.  This generator is rated at supplying 16.7A continuous, and has no problem with the Iota.  It should be noted that the charging nature of batteries causes the current to drop off rather quickly to a much lower level.  I also leave the solar panels connected and charging when I use the Iota.  Everything plays nice together, and even with the small array I have, I can get a combined charge rate of 125A.


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