proper SLA wiring

[ebkr]

Just figured out the best replacement for the standard wiring of SLA batteries. Instead of standard AWG10 or AWG12 wires it's much better to use AWG8 speaker wires. Those can be picked at only $1 a foot in surplus stores. If they fit in your battery case you'll see much less of the voltage drop. For main power wires I use AWG4 speaker wire. Those aren't easy to solder, but you can just crimp them. Speaker wires are much softer, then any other type of cables I've worked with and don't brake that easy at terminal's crimping.

 

[texaspyro]

Be VERY wary of cheap/surplus (and even not-so-cheap, from well known brands) audio cables. I have seen 8 ga audio power cables with a resistance greater than proper 12 gauge copper cables!

 

[ebkr]

Thanks, that is very important! I've seen some wires made from steel (!) just plated by copper But where I get them the problem was that all the wires of diferent colors and of the same gauge were of different gauge as a matter of fact when you compare them visually. So that was the reason for them to end up in the surplus store and get to my hands I didn't measure the resistance, but the copper is very nice and soft, and all my old batteries now drop far less voltage when I'm starting my bike from the still stand point or go uphill. Thanks for pointing out about resistance! :wink:

 

[ebkr]

Here are some pix of my newly rewired old battery pack...

 

[texaspyro]

One of the cables that I tested was plated aluminum. Another was some mystery metal... not magnetic, but three times the resistance of copper. Another "100% pure oxygen-free copper" cable was magnetic. All were made in China...

Also, I hope your crimps are good... I use a hydraulic crimper that produces 8 tons of pressure. I cut off some terminals and the surface of the crimped strands appeared to be solid even under magnification. You can't do that with a hand or hammer crimper...

Also, do you have good lock washers on those connections?

 

[ebkr]

Yes, the steel wires I saw were also made in China. Ingenious China really rocks when it comes to saving on copper! What comes to crimping, you are right, you can't do the same with bare hands as you can do with 8 tonnes hydraulic press But for some mysterious reason the guys selling Anderson connectors once didn't suggested crimping at all when I mentioned I'm going to crimp them and strongly suggested soldering them instead. I'm still not sure why tough. Maybe because crimping changes the shape of the cross section of terminal when squeezing them thus shrinking the effective cross sectional area making it sort of a bottle neck for the current inrush. Obviously there's lots of other bottle necks for in rushing current i.e. connectors etc. but that might be why soldering is more important then crimping, so I don't crimp a lot, just enough to make the copper sit tight in the terminal, but I do solder properly inside the terminal channel instead. Strong crimping is very good when there is, or quite possible great mechanical load on terminal-wire junction, like vibration etc. which in my case is almost nonexistent since the cells sit quite tight in the the box and the box lid is closed

 

[texaspyro]

The hydraulic crimpers that I use are actually hand crimpers. Rather cheap (and also inexpensive) Harbor Freight things I got off of Ebay (strange, it looked like you were buying from an individual, but they are shipped directly from Harbor Freight). When I bought them the set was around $35. It is nearer to $50 now. They do seem to work rather well. They come with several sizes of crimping dies.

 

[ebkr]

Hm... maybe I should get one like those ... Thanks for the info anyways!

 

[scoot]

The hydraulic crimpers that I use are actually hand crimpers. Rather cheap (and also inexpensive) Harbor Freight things I got off of Ebay (strange, it looked like you were buying from an individual, but they are shipped directly from Harbor Freight). When I bought them the set was around $35. It is nearer to $50 now. They do seem to work rather well. They come with several sizes of crimping dies.

Checked them out on HF site TP. and am definitely intrigued despite the mixed reviews. Mating the dye to the job at hand is always a challenge, but am encouraged that it is a least, if not more, equal to the Paladin line of leverage crimpers and their extremely expensive dies. I have had a few bad crimps on my APP 75s pieces with the Paladin crimper (user error and die selection probably, but still) . Thanx for dropping the tool suggestion. 8)