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toofewweekends
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# Posted: 28 Sep 2020 05:27pm
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I have a small 12v "system" -- 300w of solar, four 6v golf cart batteries, controller and inverter. I've been topping off the batteries in winter (in Alaska) with a 30amp Iota charger that has large alligator clips.
I now have a 55 amp charger with regular wire lugs that fit on the threaded battery posts.
Question: with the other wires filling up most of the two posts I'm using, is there a problem with putting the Iota charger on another +/- pair?
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Brettny
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# Posted: 28 Sep 2020 06:21pm
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With 4 batteries you can connect them on the opposite 2 batteries. I assume your main connections are on opposite strings.
You could also connect them at the inverter if the inverter allows. With all that wireing going from your battery box into the rest of the system maybe it's time to add a neutral and positive bus bar though.
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NorthRick
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# Posted: 29 Sep 2020 02:24pm
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Quoting: toofewweekends Question: with the other wires filling up most of the two posts I'm using, is there a problem with putting the Iota charger on another +/- pair?
That's what I did. Seems to work fine.
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toofewweekends
Member
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# Posted: 30 Sep 2020 07:22pm
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Thanks! I'll put the pieces together this weekend.
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toofewweekends
Member
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# Posted: 30 Sep 2020 07:23pm
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Thanks! I'll put the pieces together this weekend.
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gcrank1
Member
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# Posted: 4 Dec 2020 11:01pm
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Fwiw, rule of thumb is match sorta close the solar array wattage number to the amp hours of the bat-bank.
Assuming your 2s x 2p 6v batteries are a total 12v bank of 400-450ah you in your environment might want to up the array so the bat-bank wont be in a constantly undercharged cycle. That would also min. the gen run time, inefficient for topping off, better for early day bulk charging to replenish the last nights drawdown then let the solar trickle charge it during the peak solar hours.
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Brettny
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# Posted: 5 Dec 2020 05:51am
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That may be true in a full time cabin but really dosnt matter in weekend cabins. Your there 2-3 days a week and the system can fully charge over the next 4-5 days. Really that's prob only 2-3 cycles in a week and even if they get down to 50* and your. Battery cycle life is 500 at 50*DOD then your still looking at just under 10yrs of life.
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Steve_S
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# Posted: 5 Dec 2020 11:10am
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https://www.victronenergy.com/upload/documents/Wiring-Unlimited-EN.pdf
Be attentive to your battery wiring or you can very easily unbalance the batteries.
In Alaska, you will not be doing any Desulphation / Equalization over winter unless by pushing a charger to do. You certainly will not get a Deep Charge with heavy amps either resulting in a surface charge. That fools people a lot.
With FLA you should Equalize at least every 3 months. That's tough up in the North is doing it with solar... short days & low sun, what a PITA, January really sux !
A really good deep equalization in the fall and another first thing in spring is warranted.
Be very aware of any parasitic power draws, including inverter etc. they lurk to get ya.
BTW; folks who have never experienced an Arctic Winter in the arctic have a hard time relating to Sun Issues in the land of Midnite Sun. Lived & worked in Nunavut, NWT & the Yukon...
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gcrank1
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# Posted: 5 Dec 2020 11:57am - Edited by: gcrank1
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Brett, I agree in general with your 'use' assessment but when we get a chance to spend a week straight (oh, could it be!) we will find ourselves short if we havent sized it for pretty steady use, especially if/when much of that week is overcast/poor solar conditions. I wont want to be chasing after/monitoring the bank and running the gen too much. I pretty much would rather be a bit oversized on array than on batteries.
Im still firmly in the camp of only using the top 25-30% of the bat-bank ah's, the life-cycle and health of the bank is so greatly improved over often going to 50%. The balancing act between array, bat-bank and use seems to not be as simple as it appears on first notion.
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Brettny
Member
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# Posted: 5 Dec 2020 04:16pm - Edited by: Brettny
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A quiet generator and charger is something I got and hooked up before I even put the pannels up on my system.
I got one of those $200 sportsman 1kw inverter generators at the end of a 100ft extension cord connected to a 30a charger. A 100ft cord can really quiet a generator. I wouldn't even attempt to do this with a non inverter.
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gcrank1
Member
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# Posted: 5 Dec 2020 08:10pm
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Thinking back to last summer when we got the Lil' Champ was when my approach to my solar changed. To that point I was needing to rewire/revamp the whole 10yr old hacked together by the prev owner system.
By doing the cabin for 110 only rather than the prev 12vdc and 110vac dual wiring, fuse/cb's, etc greatly simplified things.
A marine/rv type input plug at cabin allowed plugging in the inv/gen and 'everything worked'! Then I pulled all the solar apart and started experiments/reassembly. I eliminated the 12vdc run completely, it just made no sense for the run from the array/powerhouse. In fact my array, now sorta portable ground racks, still needs to be farther way to get more sun. By inverting at the powerhouse I get the run without line losses to be concerned about and it plugs right into that cabin input. No transfer box required, just go move the plug for the power supply desired.
By saving pretty big bucks on wiring by not trying to send 12vdc too far the money is better spent on better batteries and/or sine wave inverter.
Ime a small, maybe medium size 12vdc solar can work as long as your power requirements are modest AND the array to cc to cabin can be quite close together. I didnt have that and tried in vain to make something work that was too compromised. I am happy rather than frustrated now.
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Brettny
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# Posted: 5 Dec 2020 08:18pm
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I agree. Alot of people try to send 12v to far or spend big bucks on 12v things in a cabin. I spent a little more on an inverter that's pure sine wave and uses very little stand by power right out of the gate. Everything is ran through an inverter at our place. Although next year I am going to setup a 12v fan and 12v to USB plugs.
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gcrank1
Member
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# Posted: 5 Dec 2020 09:22pm - Edited by: gcrank1
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I suggest driving small 12vdc loads off a portable power pack that you can recharge back at the powerhouse when it needs it (or off the car/truck when driving or even take home). All portable makes it almost too easy.
Im seeing more fancy portable 'boxes' with LFP batteries, usb ports, cig-lighter sockets, even inverters and 110 receptacles. The little one I was just looking at is the 'Expert Power S200', it has 193wh/12v x 16ah Lith bat which translates to some 12+ah of usable power. To get that 12ah from a wet dc battery and stay above the 75% soc you would need a 48ah bat. And this fancy little box is about the size and weight of a 5# bag of sugar. They have the S400 also, about 2x the size & weight.
Neat stuff on the horizon.
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NorthRick
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# Posted: 7 Dec 2020 07:10pm
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Quoting: Brettny That may be true in a full time cabin but really dosnt matter in weekend cabins. Your there 2-3 days a week and the system can fully charge over the next 4-5 days. Really that's prob only 2-3 cycles in a week and even if they get down to 50* and your. Battery cycle life is 500 at 50*DOD then your still looking at just under 10yrs of life.
This. What you really need to have for a full time residence is different than for a weekend cabin.
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paulz
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# Posted: 7 Dec 2021 09:43am
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Quoting: Brettny I got one of those $200 sportsman 1kw inverter generators
Tractor Supply has these on sale for $179, I just bought one.
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