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Post by Gone on Nov 2, 2016 22:08:01 GMT
Some cable values for you. 15m each way at 10A gives -
Cable mm2 Volt drop 2.5 2.3 6.0 0.9 10.0 0.6 25.0 0.23
If you move the inverter close to the batteries 2m each way at 10A gives
Cable mm2 Volt drop 2.5 0.3 6.0 0.13 10.0 0.08
So as said you either need to move the inverter or run a much heavier cable. Assuming you move it to be close to the batteries I would use at least 6.0mm2 but if I was buying, then for the small extra cost I would get 10mm2 cable.
There will also be a small additional volt drop from the fuse, switch and connections hence use thick cable to keep the total down.
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Post by Deleted on Nov 2, 2016 22:14:01 GMT
By the way, that 'over 2V' that I mentioned wasn't a guess, I worked it out at 2.16V π Wow, no wonder the Icom used to cut out when I transmitted! Ok. So maybe I should look at getting a proper inverter and fit it in the engine room close to the batteries. Then I need to find a suitable way to switch between that and the genny. Then both supplies can be switched into my existing 240v genny circuit. I'll leave the shore line circuit alone. I'll also look at buying some LED lights. That should do the trick. Thanks again Nick & Tony.
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Post by Deleted on Nov 2, 2016 22:22:37 GMT
Just one other question.
Would I have been wasting power with my current arrangement presumably as heat due to the cables not being up to the job?
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Post by Gone on Nov 2, 2016 22:26:05 GMT
Just one other question. Would I have been wasting power with my current arrangement presumably as heat due to the cables not being up to the job? Yes - If 10A with 2v drop would be 20W which is a fair bit.
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Post by Deleted on Nov 2, 2016 22:30:09 GMT
Just one other question. Would I have been wasting power with my current arrangement presumably as heat due to the cables not being up to the job? Yes - If 10A with 2v drop would be 20W which is a fair bit. Great! Thanks Chewy.
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Post by smileypete on Nov 2, 2016 22:39:49 GMT
'amps divided by three' is a good rule of thumb for getting the minimum cable cross section in mm2
So if the inverter draws up to 15A say, that gives 15/3 = 5mm2, or 6mm2 rounded up to the next cable size.
For things like inverters and chargers, they prefer to be near the batts to minimise volt drop, so I'd try to get them within about 6ft to keep the 'round trip' cable distance below 5m.
For most other things if the round trip is more than 10m, the above cable size will need to be increased proportionately.
Some stuff though, like 12V fridges, diesel heaters are a special case and the manufacturers requirements must be met.
That said, as said it wouldn't hurt to use 10mm for the inverter if the price is similar, it would allow a slightly bigger one to be fitted later on if need be.
You'd want fuse near in the inverter feed positive, near but (not in!) the batt box. If the inverter instructions doesn't specify a rating, a 15A one will protect the cable fine. 'Trirated' cable off Ebay or a discount supplier is usually pretty good value.
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Post by Deleted on Apr 12, 2017 12:30:58 GMT
Is it OK to stick 15.4 volts into t105's?
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Post by Telemachus on Apr 12, 2017 14:26:17 GMT
Is it OK to stick 15.4 volts into t105's? Yes. Unless they are very hot. But not for too long, a couple of hours at the end of a charge is ideal, or longer if you are trying to equalise.
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Post by Deleted on Apr 12, 2017 14:34:08 GMT
Is it OK to stick 15.4 volts into t105's? Yes. Unless they are very hot. But not for too long, a couple of hours at the end of a charge is ideal, or longer if you are trying to equalise. Cheers me dear π
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