Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 20,660
I've read AGM has more concentrated electrolyte.
Page 26:
100% charge, -70C, -94F
Page 26:
100% charge, -70C, -94F
Off Grid for small Cabin
- Thread starter pbennison
- Start date
Hmmm bill gave me that number a few years a go ? I could be wrong
I can get to -27f in my area .
My battery box dosent get any where near 0 the coldest I’ve seen is 21o and that is when it’s -15 for a week .
And if I’m cycling the batteries I stay around 45° All winter ?
Horsefly
Solar Wizard
There seem to be lots of numbers, but all of them are low enough that it probably doesn't matter. Here's one that says -80°F:
https://www.usbattery.com/winter-st...tery has,freeze and cause unexpected failures.
Well it has been a while since I posted but here is an update.
I spent a good portion of the spring pulling everything together. I started out with 4 Deep Cycle 12V 75AH batteries. I have an RV that was connected along with a water pump (1HP) along with some LED lights, power tools, fans, laptop/phone chargers, etc. On more than one occasion the inverter would shut down at night due to low battery voltage. I finally realized the RV fridge was a power hog which was causing this. Late spring I added 4 more of the same batteries for a total of 8 Deep Cycle 12V 75AH batteries. I also bought a new refrigerator for the cabin and from that point forward I never had an issue. I actually ran an air compressor on and off all day when I built a deck (nail gun). All in all I believe I had a very successful first year with my install. I brought the batteries home because I did not want to take the chance of having them discharge and freeze.
In researching the best way to connect them for balanced charging, I found a thread that is close but I wanted to update this and figured that would be best. I have come up with what I think is the best alternative and below is a diagram.
Would love to get some input on this.
Bottom line is that my system is working fantastic and I have to thank everyone for all their input. I would be glad to answer any questions anyone has about my system. I could never have done this without all the input from people on this forum that have done this.
I spent a good portion of the spring pulling everything together. I started out with 4 Deep Cycle 12V 75AH batteries. I have an RV that was connected along with a water pump (1HP) along with some LED lights, power tools, fans, laptop/phone chargers, etc. On more than one occasion the inverter would shut down at night due to low battery voltage. I finally realized the RV fridge was a power hog which was causing this. Late spring I added 4 more of the same batteries for a total of 8 Deep Cycle 12V 75AH batteries. I also bought a new refrigerator for the cabin and from that point forward I never had an issue. I actually ran an air compressor on and off all day when I built a deck (nail gun). All in all I believe I had a very successful first year with my install. I brought the batteries home because I did not want to take the chance of having them discharge and freeze.
In researching the best way to connect them for balanced charging, I found a thread that is close but I wanted to update this and figured that would be best. I have come up with what I think is the best alternative and below is a diagram.
Would love to get some input on this.
Bottom line is that my system is working fantastic and I have to thank everyone for all their input. I would be glad to answer any questions anyone has about my system. I could never have done this without all the input from people on this forum that have done this.
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12VoltInstalls
life passes by too quickly to not live in freedom
I’m seeing two 24V arrangements, but as far as balance I wondering if a 12V-4Px12V-4P arrangement might be better? But overall I can’t criticize that very much.
And I could be off base?
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The original photo did not have the blue connection, which takes the two parallel 12V and puts in series for 24V. I just edited and updated photo.
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 20,660
That's now 4P2S, a bit unusual.
Somewhat longer wiring (higher resistance) than 2S4P. Maybe it provides a benefit if each 2S would be mismatched?
Maybe more difficult to do equalizing charges on 12V battery individually without breaking the pack (not sure if that is a good idea anyway; don't try it while charging/discharging entire pack at same time.)
2S4P is what we would normally see.
Somewhat longer wiring (higher resistance) than 2S4P. Maybe it provides a benefit if each 2S would be mismatched?
Maybe more difficult to do equalizing charges on 12V battery individually without breaking the pack (not sure if that is a good idea anyway; don't try it while charging/discharging entire pack at same time.)
2S4P is what we would normally see.
That makes sense. I literally just took the example for perfectly balanced charging and then put them in series. I just did a quick sketch and as you stated there is less wiring going 2S4P. I am really glad I posted this. I will update with a better drawn sketch. Thank you so much.
12VoltInstalls
life passes by too quickly to not live in freedom
So that 2S2P2P for eight batts
That should be ok I’d think
That should be ok I’d think
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