Should jump cables be soldered and/or crimped?

Ulf wrote:

Hello, Yesterday, when I was rummaging in the trunk for my jumper cables, I noticed that one of the clamps (made of plastic with copper strips) was broken. Now, it's only usable if you manually connect one end to the car's chassis. At the opportunity, I measured the resistance of a cable: 5 mΩ over 3.2 meters corresponds to a copper cross-section of approximately 11 mm². On the packaging, it prominently states 25 mm² - presumably, they calculated that including the insulation . If this cable set is loaded with the 350A as indicated on the packaging, it will dissipate approximately 1.2 kW of power . Therefore, I am looking for a jump starter cable with a genuine 25mm² copper cross-section (or an equivalent aluminum cross-section) and metal clamps. "Does anyone know a source for something like this?" Alternatively, I'm considering building one myself, using cable in meter lengths (e.g., H07V K) and solid connectors. Diese Klemmen sind nur für 120A konzipiert, unsere Anlasser ziehen bei ca. 13°C Motorblocktemperatur aber ca. 260A. Weiß jemand, welche konkreten Probleme mit den Klemmen dabei zu erwarten wären?

Hello Ulf,

Do you have any industrial supply or welding equipment stores in your area?
At least in a welding supply store, you can find the corresponding cables and (probably uninsulated?) connectors. Usually, they can also crimp those types of things.

Hi, Jockel.

The tip is good; you can have such cables custom-made at a good welding supply store. I got 22 sq mm, but unfortunately, the insulation isn't quite the standard pink and black. The 22 sq mm is because the devices they offer come with cable drums and winding aids designed for 25 sq mm cable cross-section, including the insulation.

Hutfahrer wrote:

The tip is good, because in a good welding supply store, you can have such cables custom-made to your specifications. I got 22 qmm. . .

Interesting!
How much did you pay for all the parts, including the connectors (or the complete cable set), and how long is your set?

Ich fand 5,5 m fuer normale PKW ausreichend, bekam die Plusklammern mit schlauchisolierten Klammern, die nur vorn im eigentlichen Kontaktbereich rundum unisoliert sind. Die Masseklammern sind komplett unisoliert. Kabelbefestigung durch Verpressen, Oxidationsschutz durch anschliessendes Kunststoffvergiessen. Damit wurde auch die aufgesteckte Schlauchisolation der Plusklemmen "befestigt". As I said, the cable colors are not entirely compliant with the standards, but I can live with them just fine.

In the garage, I have a permanently installed 7.5-meter cable run with the same configuration at the charging unit, with the cables stored on a garden hose reel mounted on the wall. At the charging unit, there are threaded connections from the welding supply section, and the other end has the usual clamps.

@Hutfahrer: Thanks for the private message.

Meanwhile, I compared my cables with datasheets for 25mm² meter goods, and they seem to actually have a 25mm² copper cross-section.
240g of copper per meter results in 770g for 3.2 meters, and one of my cables weighs 860g (including connectors) -> so the order of magnitude is correct.

The excessively high resistance measurement was caused by contact resistances at the crimped ends, which appear visually to be brand new and undamaged. When I apply the measurement current between the crimps, I get approximately 0.75 mOhm per meter, which corresponds to approximately 24 mm² of copper.
So, I'm just going to get some more robust connectors and re-terminate the cables.

Sure, with pleasure!

Quote:

Also werde ich mir nur stabilere Klemmen besorgen und die Kabel neu konfektionieren.

Look at this: http://www.werkzeugeonline.eu/batterie-servicegeraete/klemmen-starthilfekabel.html


The two lower terminals are crimped -- it should be something like that.

It should be possible to transmit current from both ends of the terminals. Often, battery terminals don't make a good connection, so you need two conductive ends to ensure a proper connection.

Autoservice wrote:

Quote: Also werde ich mir nur stabilere Klemmen besorgen und die Kabel neu konfektionieren. Look at this: http://www.werkzeugeonline.eu/batterie-servicegeraete/klemmen-starthilfekabel.html The two lower terminals are crimped -- something like that is what it should be.

Well, around €75 + shipping would already be a reasonable price for a complete set of jump starter cables. Paying that much just for the terminals of a simple emergency cable is too much for me.

A screw connection would fit well with the copper inserts of the old plastic clamps: Cut it to the length of a cable lug, drill a 6mm hole, screw it in, and it's done -> a "new" jump starter cable for 20€.

Sorry, ich dachte, du suchst was Gescheites.

Quote:

I could befriend someone like this: http://www.conrad.de/ce/de/product/734435/

I've already had terminals like these melt.

Possibly: http://www.conrad.de/ce/de/product/734472/Ladezange-480-A-Schraubanschluss-fuer-Kabelschuhe-ueber-Ringoese-M6-480-A-Rot-SZ40-SET/?ref=detview
Bitte gib mir den deutschen Text, den du übersetzt haben möchtest.

Autoservice wrote:

I've already had terminals like these melt.

Wow
At what load level / what should be started?
Is it only the plastic that has melted, or the metal as well?

Quote:

Crimp tool - 480 A - screw terminal for cable lugs - via Ringoese

Well, that would still be more affordable than the first suggestion.

Quote:

Wow icon_eek.gif At what load level / what should be started? Ist nur das Plastik geschmolzen, oder das Metall?

Ist schon ewig her. Das war noch zu Zeiten, wo ein Anlasser länger standhielt, als die Batterie, man also eine Batterie noch leer orgeln konnte, ohne das der Anlasser vorher schmilzt/abraucht.

The problem is that, depending on the polarity and unfavorable conditions, only one terminal end might make proper contact, and the current has to flow through the hinge pin and spring to the other side... etc. If you're not careful, it will start to smell like plastic.

It's better to invest a few more euros in that case.

I like the crimped terminals because the cables don't stick upwards when you clamp the terminal onto the pole from above. With heavy cables and straight terminals, they tend to tip sideways. For example, with a Renault Modus, it's already difficult because there's hardly any space above.

Hi,

Quote:

On this occasion, I measured the resistance of a cable: 5 mΩ over 3.2 meters corresponds to a copper cross-section of approximately 11 mm². The packaging states in bold "25 mm²" - presumably they calculated that including the insulation

.
You probably measured the transition resistances between the measurement clamp and the cable (2x) and between the cable clamp and the cable (2x). If there are oxidation layers present, you will quickly see values in the milliohm range. Your multimeter also contributes to the readings in that measurement range.
The weaknesses of the cable lugs being discussed are the M6 connectors with ring terminals. This leads to contact resistance issues, especially when the cable is crimped to the ring terminal at home.
When it comes to a high-quality cable for frequent use, choose one with cable lugs where the cable is directly and solidly crimped.
hg
Herbert.

Autoservice wrote:

The problem is that, depending on the polarity and unfavorable conditions, only one terminal end makes proper contact, and the current has to flow through the hinge bolt and spring to the other side..., etc. If you're not careful just once, it already smells like plastic.

OK, that makes sense.
However, this can be prevented by carefully feeling the individual keys after a few short organ playing attempts to see if any of them become noticeably warm. If a key does become warm, try pressing it in different ways until it no longer heats up.

Quote:

Die verkröpften Klemmen gefallen mir deshalb gut, weil die Kabel nicht nach oben wegstehen, wenn man die Klemme von oben über den Pol klemmt. Bei schweren Kabeln und geraden Klemmen kippen diese gern mal seitlich weg. Hat man zB. einen Renault Modus, wird´s schon schwierig, weil nach oben kaum Platz vorhanden ist.

Auch das ist verständlich, aber bei unseren Wagen ist die Batterie gut zugänglich. DFor me, the risk of getting a donor car with a battery that's difficult to access doesn't justify paying an extra ~50€ for the terminals.
Especially since you'll likely encounter terminals that are straight but angled, and sometimes you might need to carefully cut away a bit of the plastic casing to access them.

Herbert wrote:

Hi, Quote: Bei der Gelegenheit habe ich mal den Widerstand eines Kabels gemessen: 5mOhm auf 3,2 Meter . . . You probably measured the contact resistances between the measurement clamp/crimping tool (2x) and the crimping tool/cable (2x).

If there are oxidation layers present, you will quickly see values in the mOhm range. The measurement was performed in the mV range with a test current of 5A from a laboratory power supply. For the positive cable, the sum of the crimp resistances was even ~ twice as high as the total cable resistance -> a case for resoldering.

Quote:

The weaknesses in the cable lugs being discussed are the M6 connections with ring terminals.

This is where the contact resistances reappear, especially when crimping the cable to the ring terminal at home. }Therefore, I want to modify the copper strips that are factory-crimped to suitable ring terminals (by soldering them).
Then, using copper paste as a contact area enhancer and corrosion protection, screw it firmly onto the pliers – this should, in my opinion, provide sufficient contact.

ulf wrote:

... Therefore, I want to modify the copper strips that are factory-crimped by soldering them and converting them into suitable ring terminals.

To then obtain the attached image as a result:


That was a fuse holder used to connect a car radio (4*6W !!).
The cable is 1.5mm² in diameter and has been tinned with solder at the ends. And that's where the trouble began. Over time, the screwed and tinned cable weakens and develops a "break point." This eventually creates a huge resistance, and the cable will eventually burn out.

The cable piece shown here was installed in the car for exactly two weeks before the customer came to me and complained about the incompetence of the previous installer. His radio was constantly cutting out. Of course... with that connection .


Soldering and electrical wires is an absolutely useless (and even forbidden) combination!

Bertil wrote:

Soldering and cable wires is an absolutely useless (and even prohibited) combination!

That's why I'm not surprised that currently 4 vehicles in my care (G3 AFN, Ibiza ALH and BUK, Polo ASZ) with preventatively resoldered factory crimps on the high-current cables between the alternator, battery, and starter, some of which are up to 9 years old (then resold), have not shown any problems that could be attributed to poor cables.I am aware that solder can gradually melt away under stress, which is why even well-tightened wire connectors can loosen over time when used with stranded wire that has been soldered (as in your radio example).
I allow the tin to flow into the spaces between the strands of an existing crimp afterwards, in order to maximize the contact areas between the cable and the connector, so that no corrosive substances (water, etc.) can creep in. In my opinion, this is a significant difference compared to a tinned cable that is subsequently crimped with solder .

ulf wrote:

... However, I allow the tin to flow into the spaces between the strands of an existing crimp afterwards, in order to maximize the contact area between the cable and the connector, so that no corrosive substances (water, etc.) can creep in. ...

Und den korrosivsten Stoff bringst du mit dem Lötzinn ein ..... The flow agent!!



EDIT: It was quite visible on that cable, actually... unfortunately, I didn't photograph the 10cm section next to it.

Quote:

That's why I'm surprised that, so far, 4 vehicles in my care (G3 AFN, Ibiza ALH and BUK, Polo ASZ) with proactively re-soldered factory crimps on the high-current cables between the alternator, battery, and starter motor, some of which are up to 9 years old (then resold), have not exhibited any problems that could be attributed to poor cables.

Da hast du bisher wohl einfach nur Glück gehabt .... bis dir mal so eine Karre abbrennt.

It's not always the case that this action has to go wrong, but the probability is high... too high!