Jumper Cables

RE: Jumper Cables

neuromodulator — Thu, 20 Sep 2018 13:01:55 GMT

As others suggest 4 wire should be good to measure resistance. But I would like to add that to measure high currents you can do it without robbing a bank through shunt resistors. One that supports a max of 200 A costs 8 usd on ebay... at max current it just drops 75mV, which is pretty insignificant.

RE: Jumper Cables

jennifert — Thu, 20 Sep 2018 06:11:30 GMT

Quite helpful piece of writing, thanks for the post.

RE: Jumper Cables

mcb1 — Thu, 02 Nov 2017 05:24:40 GMT

While I was responding here, I thought I'd pass on some information regarding modern batteries.

The newer breed battery is "calcium" which I presume means the chemical makeup is different.

They can remain in a charged state and don't loose any charge for nearly a year, but the recharging when flat is much different.

These batteries require a special charger that pulses the voltage to over 15 volts during the charging process.

Jumper starting a car with a seriously flat battery and then driving around charging it is unlikely to charge it as the alternator voltage is not high enough.

Once you stop it's likely it will be the same as before.

Because these are just about the only battery you can buy, when you add them into older cars with regulators set at 13.6v, they don't seem to last.

So in reality the alternator or regulator needs to be changed as well.

We had a discussion here when [mention:b0bc65b9ecdc4307bd967592f00e340a:e9ed411860ed4f2ba0265705b8793d05] was having issues with his battery.

Keysight U1282A Vehicle/Automotive and Industrial Applications

This comment shows the voltage

https://www.element14.com/community/community/applications/industrial-automation-space/blog/2016/05/16/keysight-u1282a-v…

So just be warned that jumper starting the car might get it going, but I'd be heading home or to the Auto Electrician .....

Mark

RE: Jumper Cables

shabaz — Wed, 01 Nov 2017 23:59:08 GMT

Hi Mark,

Nice post, and timely too since it is getting cold here.. a lot of the car stores here sell fat cables that are all insulation and little wire.. I wish there was a culture of more moral behaviour by retailers and thus not allow such "bad bargains", because people are so dependent on jumper cables and cannot test it easily until they really need it.

Excellent fix with the ring crimp and nut/bolt!

RE: Jumper Cables

dougw — Wed, 01 Nov 2017 21:55:30 GMT

[View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-a453313d-0941-45ae-959c-551f51151a48/contentimage_5F00_938.png:16:16][View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-a453313d-0941-45ae-959c-551f51151a48/contentimage_5F00_938.png:16:16][View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-a453313d-0941-45ae-959c-551f51151a48/contentimage_5F00_938.png:16:16] I mean what a comical crimp[View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-a453313d-0941-45ae-959c-551f51151a48/contentimage_5F00_403.png:16:16].

Obviously it is no fun to have this type of product performance in a product intended to save the day.[View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-a453313d-0941-45ae-959c-551f51151a48/contentimage_5F00_1577.png:16:16]

Its a good thing you are a clever guy - this would be a lot more costly for someone less astute.

RE: Jumper Cables

three-phase — Wed, 01 Nov 2017 21:40:25 GMT

Great post Mark

Fairly standard crimping technique adopted by jump lead manufacturers as the croc clip is too big for the cable when it is stripped so they do what you have found, tuck it under the complete cable and crimp it down.

Whilst what you did was a great fix, it increases the manufacturer's cost in both time and materials so it just isn't done in the cheaper jump lead sets.

For testing them I would use a four wire resistance technique injecting a few amps down the lead and then measuring the voltage. The alternative is again putting amps down the lead and measuring temperature. The higher the amps, then the easier it is to find a bad joint. In the power sector we have micro ohmmeters and thermal imaging cameras to help with this, so if you know someone in that field you may be able to scrounge.

RE: Jumper Cables

DAB — Wed, 01 Nov 2017 19:06:06 GMT

Nice post.

It makes you wonder what passes for quality control at some places.

Crimping insulation has to be an epic fail on somebodies part.

DAB

RE: Jumper Cables

ntewinkel — Wed, 01 Nov 2017 16:55:16 GMT

Great upgrade job! I've never really looked at how they're put together.

I have a pair of jumper cables that hasn't been used in nearly 2 decades.

Good thing you didn't find out about that issue somewhere remote. I suppose you could leave them on to slowly charge the main battery for a few minutes before starting.

I've noticed some of the cheaper little low voltage patch cables with alligator clips on them are cheaply crimped in the same way, and have soldered up a fair number of them already. Looks like they're all trying to do things as quickly and cheaply as possible these days!

Would a small solar panel help keep the old 4WD charged up?

I've also wondered about the little Lithium boost packs - they tend to run just under 100 bucks here and claim to be able to give a few boosts on a charge. Saves packing and moving a heavy battery and dealing with booster cables [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-a453313d-0941-45ae-959c-551f51151a48/contentimage_5F00_1.png:16:16]

I bought one mainly to use as power in the little trillium trailer.

I have a big-battery booster-pack version too. I use it mainly for testing though.

Cheers,

-Nico

RE: Jumper Cables

rsc — Wed, 01 Nov 2017 15:39:01 GMT

Hi Mark,

The best wire I've found for jumper cables is from an arc-welding supplier. The more strands, the more flexible it will be.

00-1 AWG works well.

I've had many of the cheap cables melt or catch fire, so I made my own.

Scott

RE: Jumper Cables

jw0752 — Wed, 01 Nov 2017 14:42:10 GMT

Hi Mark,

Thanks for the information. I have always suspected that my jumpers were like this but I have never looked closely. I am too cheap to buy a quality set for the once a year application that I seem to have. I am thinking of a way to test your leads but haven't had a good idea yet.

John

RE: Jumper Cables

kas.lewis — Wed, 01 Nov 2017 12:53:25 GMT

Good job on the fix there.

Kas