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Zero Motorcycles Forum | 2013+ / Re: DIY Power Tank 2020 SRS
« on: June 11, 2026, 01:40:05 PM »Even though it's boat cable, which has a higher rating than standard building cable, 80 amps is pushing it, unless it's a fairly short run, like a few feet jump to a starter or only intermittent use. otherwise it's typically rated at around 60, would be derated to around 50 or so in an engine compartment due to temperatures being hotter. Given it's boat cable, as you claim, it is being rated using marine standards ABYC instead of normal NEC standards for buildings. nec would rate it only around 30 amps for open 10ga wire.
if you have it up under cowling or in a box, might want to keep that in mind but I don't think that'll really be an issue for you, you won't be seeing those kinds of amps very often at all. No need for switches and stuff, just more stuff to add resistance and corrode on you. Tinned wire is a good thing, fine wire is even better, its easier to work with. personally i love using welding cable when i can get away with it.
it's up to you but a simple Anderson connection might be a quick and easy way to connect / disconnect it, and you can even put the fuse inline with it. that way you are not playing with nuts and bolts, stretching threads and up in that stuff every time you want to use it. an Anderson would also protect the disconnected ends too from most accidental shorting.
the lg batteries tend to be one of the higher grade batteries on the market, so you are good there, and yes, charging, most manu's prefer 0.5 to 1 C but will allow a bit more safely. 10A - 4C discharge, yah that right in range with a standard grade battery,
another place to look for cheap batteries, sometimes you get good finds, is portable tools, people hunk the pack because one cell dies and it kicks the whole pack but the rest of the cells are usable. home depot, lowes, or placesl ike that often have free battery disposal, and a quick talk to the manager, many times they are more than happy to give the old ones for free, because they have to otherwise pay to dispose generally. depending on what brand, size etc, the cells vary but you can build plenty of 'aux power' for essentially free.
aaron
Sorry, I misstated the ampacity of the cable. It's as you say, 60 amps. Remember that the max current draw was 35 amps WOT in sport mode, but in the custom mode I always use, it is only 20 amps max. Of course I'm using an Anderson connector. The SBS75X connector. I use 2 of the small pins to connect the power to the contactor so plugging it in is just one operation. No mistakes. There is plenty of air under the fairing where the wires run for battery cooling. The fairing is open in the front and there is a scoop down low that directs air to the controller and up through the battery so plenty of cooling for the wiring but the compartment that the battery is actually in is not ventilated. I wondered if this would be a heat problem, but I rode 100 miles today and the only thing that was warm at all was the contactor coil. We will see what happens this weekend with 95-degree weather coming. I could always punch a couple of holes in the box and install a 12v computer fan, but I don't really think I'll need it
it's really not something that is 'needed' if one just remembers to check the voltages tween the batteries before connecting them. A good rule of thumb would be either to leave em connected, or install it when both are fully charged as an example, that way you know they both are at the proper volts. im assuming the main reason youd want to put the extra tank on is because you are planning on making a longer trip, in which case you are going to charge it up all the way anyways.
As soon as the contact closes the voltage will become same between packs. Inrush of current will drop fast and be pretty much safe level within few seconds. The batteries Equivalent Series Resistance (ESR) basically does not allow enough current to flow to damage the batteries at these low voltage differences. As long as one battery is not fully charged and the other one is empty.