GoldenMotor.com Forum
General Category => General Discussions => Topic started by: sock2828 on June 27, 2007, 04:24:34 AM
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I want to make a lead acid battery pack but don't know how to wire it I do have basic soldering skills
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Take (3) 12V batteries and solder them in series:
| + - | | + - | | + - |
myelectric bike is recommending 14ga or 16ga wire for the connections. Wire the outstanding ends to the + and - of the controller.
I was wrong on the wire gage size, see myelectricbike's comment below
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K thanks thats what I thought but I wasn't sure
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Actually the controller uses a 16 AWG equivalent for the power leads to the motor and 12 AWG equivalent for the power supply leads going to the battery. (Go figure!) At 700 watts peak you will also need a fuse that can handle 700 watts at 36 volts, i.e., 20 amps at 36 volts. The difference in wire size to the motor is that power per motor power lead is less per lead ??? ...can you say that again?
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Thanks for the wire gage correction. Don't want anyone melting through their battery leads.
-Mike
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No problem. I've heard but have not confirmed that some of the original kits used 14 and 12 in the same lead. There are all kinds of tricks used in electronics such as a solder bridge used as an internal fuse or splicing in a higher guage to protect windings in place of an internal fuse. Even if your controller is wired with 10 AWG going to the battery pack the math is what you should rely upon since on that day at the factory they may have simply used up the last spool of 12.
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so wait I need to use fuse ???
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Yep.
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where?
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I think it should be ~30A fuse on the Red (+) lead from battery pack to controller. The motor is unlikely to be fed much more than ~20 amps (720W) before the controller's protection logic shuts it down. The controller has self protection built in. The 30A fuse should give you room to spare, yet still blow before melting down the wires, creating a fire hazard, or harming the battery.
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should I just solder it to the wires directly or is there a socket for it or something
and to be clear I use 12AWG wire for the battery pack?
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You should use 12AWG or larger wire. If you use connectors they should be sized large enough to handle the current that the wire can handle. Connectors will allow you to disconnect the batteries much easier in the future.
Dale
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I meant the fuse.
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I use pigtail fuse holders with the pigtails soldered inline. As an added precaution I do not twist the ends to be soldered together but rather overlay them for about 3/4 of an inch and then slide up the piece of shrinkwrap I did not forget to put on the wire before soldering when I'm done.
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on the instructable that tells you how to put one of these things together he uses a male computer power plug thing does the kit come with this and if so does it come with a female one ?
oh and ime not familiar with the term pigtail in electronics
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The last rear wheel kit I got had both the male and the female plugs plus the inline fuse holder and fuse so I think this is the new trend but you may get a kit with only the male connector (female pins). Most techs at a local computer store can help your get the right one.
Also if you are not familar with the term pigtail in electronics you may want to brushup on basic electronics before working with battery packs since minor things like not including a fuse can result in serious trouble including personal injury although possibly not death.
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i mostly work in small electronics with things like ICs and PCBs stuff like that
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I'm pretty sure pigtail is just referring to short wire leads coming from the socket. In antenna parlance it is a short piece of coax that has been terminated with the right ends, rather than a long piece of coax you terminate on installation.
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Pigtails should be self explanatory. If not then you need to brushup on electrical circuits more so than electronic circuits.
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oh you mean a pigtail? connector like the ones with the plastic caps
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Pretty much. In wiring (not antenna coax) the pigtail probably ends in an unfinished end for you to strip & solder to whatever you need to connect it to. In antenna coax work it usually means terminated with standard sockets. Silly difference, yes?
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Ok I understand it now I knew what it is I just didn't know it was called that
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The front wheel drive kit that I just received has a three prong AC plug connected on the battery input wires. The instruction pictures you download from the GM web site show this plugged into the custom built battery box. So it will take a chassis mount female connector (not included) to make this happen. The battery charger also has this same plug on the DC side, which indicates to me that you unplug the motor controller assembly and plug in the charger to charge the batteries. Better yet have two battery boxes, one in use and one being charged.
Dale
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You can of course use heaviy duty battery supply connectors some APCs and ebikes use but they are expensive. You can also make some pretty heavy duty connectors yourself since this is one place where even a small amount of resistance can cause thermal problems. To save cash on my 48 volt mod I used a double wire lead and standard double socket house wire recepticles for each battery although its very bulky and requires extra room in the case. Doubling up makes the mod very heavy duty at still the very lowest price. The only problem is that when people see the standard recepticles they think is is powered by 120 volts and therefore can not be provided by the factory although I'm surprised the current connectors did not suffer the same fate.