Transporting 12V 10A over about 10 meters - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: August 30, 2019, 02:15:26 pm
content: I am toying with idea of wiring my solar power (12V 10A) from the garage into the upstairs room where I'm most like to use it running bench supplies and charging my phone etc.I worked out that over 10m of cable, unless I want to run seriously expensive high gauge cable I would probably lose 1 or 2 volts and 10-20W of power over the run at 10Amps.So the other approach is to run something like basic outdoor grade 2.5mm twin and earth but to use a Boost module on the solar end to up the voltage to 48V and a buck module to drop it back to 12-15V for use.Assuming I will hardly likely to actually use the full 10Amps which it's fused for, is it wise to trust the Ebay boost/buck modules for this?(As an aside I'm currently using a whole cascade of batteries to get the power in the house. Solar panel charges a 100A Marine battery. I use my DC-DC bench PSU to then run off that and charge a 26Ah leisure battery which I carry into the house and use the bench supply or a bug converter to charge phones, eCigs etc. I'm estimating I'm losing about 25% doing this... and carrying a 26Ah lead acid and PSU in and out twice a week is getting old)

author: schmitt trigger
author_rank: Super Contributor
timestamp: August 30, 2019, 02:17:31 pm
content: Aluminum railing, perhaps?They can be had relatively inexpensive, and you can obtain some hefty cross-sections.Easy to cut and machine.

author: IanB
author_rank: Super Contributor
timestamp: August 30, 2019, 02:23:01 pm
content: Automotive jump cables can come in fairly hefty gauges and don't seem hugely expensive. Could you use these as a source of cable to bring the power where you need it?

author: bd139
author_rank: Super Contributor
timestamp: August 30, 2019, 02:25:03 pm
content: I would move all my shit to the garage

author: paulca
author_rank: Super Contributor
timestamp: August 30, 2019, 02:32:28 pm
content: Not sure I want to run railings or jumper cables up the walls! I think when I used a voltage drop calculator I was still losing 1 volt of 10 meters of 10 AWG cable. At 48V I don't mind losing 1 volt at lower current over thinner cable.

author: djacobow
author_rank: Super Contributor
timestamp: August 30, 2019, 02:55:32 pm
content: Use reasonable cable, move the charge controller and battery to the load location, add another panel, relax.Losing energy feels unpleasant, but practically and economically, at this point, adding panels is cheaper than most system optimizations.Also, with the right charge controller, you can maintain a 12V system with panels wired in series to 48V OC or even more.

author: paulca
author_rank: Super Contributor
timestamp: August 30, 2019, 03:44:00 pm
content: I get this, but I don't have a "single" load location. I have stuff in the garage running off the panel. I also want stuff in the lab running off it.

author: ArthurDent
author_rank: Super Contributor
timestamp: August 30, 2019, 04:18:29 pm
content: Do what a lot of high end, high current power supplies do, have remote sense. Use 4 wires, the 2 sense leads can be small gauge because they are seeing little current and will compensate for the drop in the 2 larger power leads by measuring the actual voltage at the load point. I believe this is the simplest solution.

author: Zero999
author_rank: Super Contributor
timestamp: August 30, 2019, 04:21:23 pm
content: You'll lose about 10W to 20W of power in the DC:DC converters?How much will the thicker cable cost vs the DC:DC converters?

author: IanB
author_rank: Super Contributor
timestamp: August 30, 2019, 04:25:43 pm
content: Quote from: paulca on August 30, 2019, 02:32:28 pmI've seen 25 ft jump cables in 4 gauge. Just chop the clips off the ends, splice and terminate them neatly, and install them tidily with appropriate clips and fastenings (maybe even inside conduit if you don't want the wires exposed). But I don't see how this is different from coax, telephone or internet cables which I see fixed to outside walls all the time.

author: fourfathom
author_rank: Super Contributor
timestamp: August 30, 2019, 04:33:09 pm
content: Quote from: paulca on August 30, 2019, 02:15:26 pmFor a 10m run (20m of wire), #10AWG wire will drop about 0.6 Volts at 10A. The closest metric wire would be 6mm (even lower resistance). Is that "seriously expensive high gauge cable"? I would think the converters you are considering would be more expensive.

author: David Hess
author_rank: Super Contributor
timestamp: August 30, 2019, 04:39:38 pm
content: Compare the cost for equal efficiency between cable and using converters. 10 AWG is pretty small and those converters are not close to 100% efficient. 1 volt of loss from 12 volts is 8.3% so it would not surprise me that both converters are the equivalent of 2 volts of loss anyway.

author: themadhippy
author_rank: Super Contributor
timestamp: August 30, 2019, 05:05:35 pm
content: Going by the tables in the uk wiring regs , 10 meters of 6mm twin and earth will have a 0.73V drop over 10 meters,and youll get change out of £20 if you buy it from screwfix or tool station.Move up to 10mm and the volt drop is down to 0.44V but the price is almost double.

author: Yansi
author_rank: Super Contributor
timestamp: August 30, 2019, 05:07:52 pm
content: Quote from: schmitt trigger on August 30, 2019, 02:17:31 pmNot sure what you mean by that, but there quite some different alloys there and AlMgSi is nowhere near suitable for current carrying.To OP: Use just some beefy wires/cable.