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Small Cabin Forum / Off-Grid Living / adding to power system
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pabear89
Member
# Posted: 23 May 2021 13:28
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Am currently using a 800w solar array to charge 2 1450 amp hr 12v wet batteries with a gen back up.
They are hooked up to a 6k inverter to provide the 120v outlets.

Considering adding a 2k wind gen and another 2 batteries to the system for longer use time before having to use gen to recharge the batteries.

Is there any problems having both the solar and wind connected to the battery bank together?

trying to limit gen use to keep fuel cost down.

ICC
Member
# Posted: 23 May 2021 14:34
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Quoting: pabear89
Is there any problems having both the solar and wind connected to the battery bank together?


Separate charge controllers for the wind generator and the solar array.... No and yes.

No. If the two separate charge controllers are set with the same bulk/absorb/float values they will get along quite well together.

Yes. Watch the combined maximum amperage output. If that combined value is higher than the maximum recommended for the batteries that could cause problems with batteries.

Also, keep in mind that adding new lead-acid batteries to older lead-acid batteries is not ideal. Basically, the older batteries will make the newer batteries act like older batteries.

pabear89
Member
# Posted: 23 May 2021 18:51
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Yes both will have controllers(12v) and the orig batts are about 10 months old.

gcrank1
Member
# Posted: 23 May 2021 19:48
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Ive 'heard' that if the 1st bat-bank havent been ill treated; ie, only drawn down by 30ish % most of the time, no more than 50% a few, that you can add more new within a year. If they were repeatedly drawn down more than 50% all bets are off.
Curious, what wire gauge and fuse(s) are you using on that 6kw inverter?

Brettny
Member
# Posted: 24 May 2021 05:54
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Do you need 6k all the time? Could you use a smaller one with less stand by and maybe less loss?

Also I dont think 800w is enough for the size of battery bank your useing...guess it depends on sun duration and pannel angle.

I have added batteries to my 1yr old system this year. There are very few places in the US that a wind generator will work 24/7. If you have any trees you can forget about it. Wrong side of a hill forget it. Cant build a high enough tower forget it. I would put up more pannels or batteries prior to buying a wind generator but I dont know your area.

Nobadays
Member
# Posted: 24 May 2021 08:29
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What ICC said....

I'm curious about these 1450ah 12v batteries, didn't know there was such a thing. Who makes these...Wow!

pabear89
Member
# Posted: 24 May 2021 10:29
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Not the need for the 6k all the time but my dealing with these most are overrated as to output.

The battery is napa commercial size equipment very heavy at about 135lbs. Lowest draw down approx to 60% a few times maybe.

300amp fuse with auto size cables connecting power to the inverter.

I'm in the PNW on a hill, Thanks to the timber companies most of the trees blocking the wind have been removed lately and the replacements will not affect flow for probably 20 yrs.

Have found a spot for post/pole that has movement most of the time from pinwheel testing.
The solar panels are set at 42* and have good sun coverage when its out.

Brettny
Member
# Posted: 24 May 2021 15:46
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I believe your talking about a NAPA 8D battery? If so the 1450 your seeing is the cold cranking amps and I dont think that battery is rated nearly enough to support 6kw. I'm not sure on the AH rating of those because there really a marine battery.

Nobadays
Member
# Posted: 24 May 2021 16:15
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Quoting: pabear89
The battery is napa commercial size equipment very heavy at about 135lbs. Lowest draw down approx to 60% a few times maybe.


Thanks.... however I see.... if I'm looking at the right battery....in the specs that battery is rated at 1450 cold cranking amps, that's very different from amp hours. It's rating is 245ah. Again if THIS is the batteries you have.

Wired 12v or 24v? Either way you really only have 50% or less if you can mange. If you are drawing down 60% occasionally you likely do need more storage.

Quoting: Brettny
Also I dont think 800w is enough for the size of battery bank your useing...guess it depends on sun duration and pannel angle.


I was with you Brett! 800w of panel seemed pretty low to charge a 1450ah battery bank, let alone add 2 more! Probably sufficient for the actual 245ah rating, but low if doubling the storage. Hence the wind turbin! (Adding more panels would be helpful as well. Wind is fickle and notoriously unreliable.)

Quoting: pabear89
300amp fuse with auto size cables connecting power to the inverter.


Not sure what you mean by "auto sized cables" but if you are referring to battery cables they are quite often 4awg or 2awg, for heavy equipment sometimes 2/0. Without knowing if your inverter is 12v or 24v it would not be possible to say what size of cable you need for a 6k inverter but... definitely larger that 2awg! Our inverter is a 4k with a 6k surge output and the solar engineer required 4/0 cable. You might want to think about some bigger cable if you have heavy surge loads... like starting a well pump, or large air compressor, etc.

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