I note that http://www.cloudelectric.com/product-p/pk-me1004.htm includes 300A ANL fuses and 2 awg cable so 2x4 or 1 awg with 400A ANL fuses seems vaguely in line, just as another sanity check from something someone else may have done. ☺
On Sat, Nov 2, 2013 at 1:03 PM, Michael K Johnson <[email protected]> wrote: > That's a really interesting idea. Thanks! > > 2 x 4 awg is the same cross-sectional area as 1 x 1 awg (42.4 mm²) so > I should be able to put 2 x 4 awg wire into a single 1 awg lug for my > connections. I'm using a pair of SB350 andersons for an emergency > disconnect; those lugs are sized for 1/0 awg but I was going to use a > pair of 10 awg solid pieces as core to ensure a snug fit in those > connectors; that would be even easier to do between two pieces of > stranded 4 awg than introducing them into a single 1 awg. I might need > to buy different heat shrink tubing but that's easy to check... > > No conduit in my application, just grommets for any through-holes > required to route, and anchored cable ties to hold them in place. If I > route them not touching each other, that will keep them coolest. > > (Leaving the 4 awg in place would involve letting it sit in the box; I > haven't started the conversion yet—need to keep using the ICE to > vacuum up leaves until the trees are bare; then I'll have enough time > to do the conversion as a novice... I had planned to re-purpose the 4 > awg for welding purposes. But I can just buy more 4 awg instead.) > > > On Sat, Nov 2, 2013 at 12:38 PM, Roland Wiench <[email protected]> wrote: >> Hello Michael, >> >> Just leave the 4 gage in place and install another 4 gage in parallel with >> the existing wire. We do this all the time in old and new installations. >> Two 4 gages in parallel will run cooler than one 1 awg cable because of more >> surface area. >> >> If you installing these wires in a conduit such as a water proof flexible >> plastic or metal conduit, it is best that the conduit is 60 percent larger >> than the wire to allow air flow. Do not seal the end of the conduits, >> unless it is connected with seal tight box connectors to a ventilated >> enclosure. >> >> The current capacity of the wire should at least 1.25% larger than the >> continuous current in the wire. Example: If you draw 100 amps continuous, >> then a wire good for 125 amps should be used. >> >> Two 4 gage wires with a temperature rating of 75C is about 80 amps per wire >> or 160 amps total for a standard insulation wire in conduit. Not in conduit >> suspended in air for 100 feet is closer to 200 amps allowing for a 3 percent >> voltage drop. >> >> Roland >> ----- Original Message ----- >> From: Michael K Johnson<mailto:[email protected]> >> To: [email protected]<mailto:[email protected]> >> Sent: Saturday, November 02, 2013 9:06 AM >> Subject: [EVDL] Wire gauge for 48V lawn tractor/mower conversion: >> sanitycheck >> >> >> I'm new to the list. I expect this has been discussed before but I >> haven't found the right search terms. I apologize if so and would >> appreciate a pointer. >> >> I'm also entirely new to EV conversions. I've been scouring the net, >> and have purchased most of the items to convert my lawn tractor to an >> EV this winter. I'm using the ME1004 as a "drop-in" replacement for >> the ICE in my existing hydrostatic-drive donor tractor, not doing >> separate deck motors. I know several of the things I'll want to do to >> reduce loss (belts, bearings, lube, new sharp blades, etc.) and I >> understand the single motor/multi motor tradeoffs and already have the >> ME1004... ☺ >> >> From what I've seen so far, ME1004 conversions on lawn tractors at 48V >> consume 70-100 amps while actually mowing, and may momentarily consume >> up to 200 amps while spinning up the mower deck. >> >> I misread something somewhere (I don't even remember where anymore) as >> indicating that since I expect to have 20 feet or shorter, I could use >> 4AWG fine-strand welding cable, so I bought some. Then I learned that >> this might have been somewhat optimistic, so I'm expecting to chalk >> that up in the "mistakes" column. I found the helpful articles at >> engineeringtoolbox.com and a few references on resistance of copper >> wire and am trying to calculate real voltage drop instead of following >> rules of thumb. In particular, I'm looking at >> >> http://en.wikipedia.org/wiki/American_wire_gauge<http://en.wikipedia.org/wiki/American_wire_gauge> >> and >> >> http://www.engineeringtoolbox.com/copper-wire-d_1429.html<http://www.engineeringtoolbox.com/copper-wire-d_1429.html> >> which both >> have similar numbers for ohms per thousand feet for copper wire. >> >> I intend to fuse the conversion no larger than 400 amps and possibly >> at 200 amps using an ANL fuse. So I've been calculating voltage drop >> over 20 feet (and also, pessimistically, at 30 feet in case it takes >> more cable than I expect) at 100 amps, 200 amps, and 400 amps. >> >> My understanding is that I want to keep the voltage drop below 2%, so >> with some room for error it seems like I want less than 0.9V drop in >> normal operation, and not go much above it momentarily. >> >> I'd like a sanity-check on my math, as well as the wisdom of the list >> on recommended wire gauge... >> >> For resistance per Kft, I am using: >> 1/0 awg: 0.09827 >> 1 awg: 0.1239 >> 4 awg: 0.2485 >> >> (I see no point in buying smaller than 1 awg if I replace the 4awg I >> bought, so I'm ignoring 2 awg in my calculations.) >> >> It looks to me like the voltage drop per 10 feet at 100 amps is the >> same as ohms per Kft, since I divide by 100 to get the resistance of >> 10 feet, then multiply by 100 amps to get the voltage drop, so it >> cancels out. Multiplying by 2 should give me voltage drop at 20 feet >> at 100 A (my expected normal operation) and by 8 should give my >> voltage drop at 20 feet at 400A. >> >> Since 1/0 awg is more than twice as expensive as 1 awg as well as >> harder to work, I'd prefer to use 1 awg. I calculate that 1 awg >> (0.1239 Ohms/Kft) should drop about 1/4V at 100A at 20 feet (max >> normal load) and about 1V at 400A at 20 feet (max momentary load). >> >> Am I missing anything? >> >> Thanks much! >> _______________________________________________ >> UNSUBSCRIBE: >> http://www.evdl.org/help/index.html#usub<http://www.evdl.org/help/index.html#usub> >> >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org<http://lists.evdl.org/listinfo.cgi/ev-evdl.org> >> For EV drag racing discussion, please use NEDRA >> (http://groups.yahoo.com/group/NEDRA<http://groups.yahoo.com/group/NEDRA>) >> >> -------------- next part -------------- >> An HTML attachment was scrubbed... >> URL: >> <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20131102/9df4410d/attachment.htm> >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA >> (http://groups.yahoo.com/group/NEDRA) >> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
