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diy solar

4 AWG wire vs 4/0 AWG wire

I’m trowing away the cheap battery that came with the trailer and replacing it with 3x drive motion 75ah AGM batteries. Initially the only battery was at the front of the trailer near the propane tank. I’m puting everything inside under the table seats

If you are getting 3X 75aH AGM batteries that only gives you about 115ah of useable power ... I could not find those exact batteries but are they deep cycle or starting??
 
Two things ... TemCO (on Ebay) makes GREAT copper wire at a good price .. we have NEVER had an issue with their stuff at all ...
Got the wires this week at a local battery store. US made wire so it should be better than what's already there
And OP if i understand you correctly u you are going to get 3X 75aH AGM new batteries??
I bought those 3 75ah batteries.
 

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Oh yes sure, I'll keep monitoring that with my battery monitor.

SO actually these being AGM you can drop them to 80% with no issues .. the 50% rule is really for WET CELLS ... NOW technically 50% DOD on AGM will give you the best life expectancy BUT typically we drop our AGMs to 70-80% and the manufacturers tell us that we should be fine ...

The biggest killer of AGMs is HEAT followed by OVER CHARGING ...
 
SO actually these being AGM you can drop them to 80% with no issues .. the 50% rule is really for WET CELLS ... NOW technically 50% DOD on AGM will give you the best life expectancy BUT typically we drop our AGMs to 70-80% and the manufacturers tell us that we should be fine ...

The biggest killer of AGMs is HEAT followed by OVER CHARGING ...
Thanks for that info, I’ll make sure to monitor my batteries. I always have my 2200 watt generator in backup
 
SO actually these being AGM you can drop them to 80% with no issues .. the 50% rule is really for WET CELLS ... NOW technically 50% DOD on AGM will give you the best life expectancy BUT typically we drop our AGMs to 70-80% and the manufacturers tell us that we should be fine ...

The biggest killer of AGMs is HEAT followed by OVER CHARGING ...

I stand corrected.
"AGM offers a depth-of-discharge of 80 percent" -- https://batteryuniversity.com/learn/article/absorbent_glass_mat_agm
Thanks ghost.
 
Check out this hydraulic crimper:

Thanks, I already got the hammer crimper from amazon and did the job! I attached a picture of the project so far, everything works perfect.
 

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I bought 10" 4/0 wires from an e-Bay vendor, with ring terminals already crimped and sealed (heat-shrink with glue). Those go between eight 405 Ah 6V AGM batteries, also from the end batteries to (-) buss bar and two (+) fuses. Due to the undersized battery bank, will only carry full load for about 30 minutes, not your typical off-grid installation.

I used the hydraulic crimper to terminate 2/0 cables connecting four SI-6048 battery inverters (ring terminal at battery, ferrule where the fine-strand wire goes under a screw). The inverters could produce almost 6 kW each continuously, twice that for seconds to start motors so just an IR drop concern and not ampacity/heating.

AC wire is 6 AWG in screw terminals from the Sunny Islands to circuit breakers. Could have fit 4 AWG, which would allow more derating for a higher temperature location, but 6 AWG is sufficient for my application.

Ground wires for AC and DC don't need to be as large as the current carrying conductors, just sufficient to trip the breaker or fuse in case of a short.
 
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