# Hell-raiser 48V Electric Go Kart



## Functional Artist (Aug 8, 2016)

I re-used some of the orange ~4g. battery cables from a Chevy Volt. (cut to "size" & added terminals)

They work really well & look kool too 
...but, after crimping some of the terminals could be "pulled off" 
















Most are good-n-tight
...but, I've had a few that, came right off, when "pulled-on" to check "tightness"

I thought, "welding" them on (actually solder) would "do the trick" 
(like you do, to attach terminals, on Anderson Connectors)
...so, after crimping, I drilled a small hole, heated the terminal up & then, filled it in with solder.
















Now, their good-n-tight 

But...
Then, I noticed in the FSAE Rules (I refer to this rule book as a "best practices guide") 
*EV.6.2.4* Soldering electrical connections in the high current path is prohibited. 
Soldering wires to cells for the voltage monitoring input of the AMS is allowed, these wires are not part of the high current path. 

So, did I do good? (can't have terminals just sliding off)
...or was this a bad decision? (if the cable heats up, the solder could melt & the terminal could slide off?)
(there's a lot of "if's" & coulds in there)

* Other options in this situation?
... would have been an acceptable remedy?


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## rubinstu (Aug 25, 2019)

I'm not an electrician or an expert on electrical codes in any way (but I am an Electrical Engineer by training). I suspect the code has a few reasons. (1) In general, wires heat up when current passes through them. I don't know how much in your case, but in general, if you had a failure mechanism (overloaded current, some other heat source like an engine, etc.), the solder could melt and your connection break free. (2) A soldered connection is a lot less conductive than the copper you're connecting. 
In your case, it looks like you made a mechanical connection with the crimp, and your solder "fill in" reinforced it. I think the soldering may have ironically made the electrical connection worse (even if only nominally), but I do appreciate that it would make it a stronger mechanical connection.
Regardless, your kart looks awesome. Have fun!


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## remy_martian (Feb 4, 2019)

The rules are for the HV wiring, so interpretation must be in that context.

1. Temperature cycling will crack a solder joint. This would lead to arcing within the joint.

2. Leaving a tadpole tail as you pull the iron away also can create a high electric field that may breakdown air, leading to a dangerous arcflash

3. One of the basic rules of solder joints is to never use it as a mechanical fixation. It's there to create a low resistance contact between conductors and prevent oxidation of that contact.

If you're at the point of melting solder you have bigger problems than the solder joint.

And most non-Pb solders have silver in them, which is more conductive than copper.

You need a better and properly sized crimping tool & lugs, imo.


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## Zieg (10 mo ago)

I hate to ask, but are you sure the lugs are the correct size for the wire gauge? I've had very mixed results with hammer crimpers (which look to be what you used?). They seem to be even less effective when the lug is big on the wire.


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## Functional Artist (Aug 8, 2016)

Zieg said:


> I hate to ask, but are you sure the lugs are the correct size for the wire gauge? I've had very mixed results with hammer crimpers (which look to be what you used?). They seem to be even less effective when the lug is big on the wire.


I was using standard 4g lugs
...& they seem to fit very snuggly on the cable (these Chevy Volt battery cables aren't labeled but, seem to be 4g.)








Yes, I was using a "hammer style" crimper
...so, anyone have any recommendations on a "better" cable lug crimper?


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## remy_martian (Feb 4, 2019)

@gregski recommended one in his build thread he seems happy with. I seem to recall @windraver got something as well.


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## windraver (Aug 29, 2021)

I used a hydraulic crimp tool

10 Ton Hydraulic Wire Battery Cable Lug Terminal Crimper Crimping Tool 8 Dies Fit for Crimping wires 


https://a.co/d/8LzM7A1



And the lug ends I got all came with heat shrink wraps

TKDMR 10pcs 1/0 AWG-3/8" Battery Lugs,with 10pcs 3:1 Heat Shrink Tubing,Battery Cable Ends,Heavy Duty Copper Wire Lugs,Tubular Ring Terminals,AWG Crimp Wire Ring Lugs,Battery Terminal Connectors 


https://a.co/d/eAIRcrO



Note that my application was for a car so I used 1/0 gauge but you can easily find 4g equivalent. The crimp tool works at multiple gauges.


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## TT-Man (May 28, 2015)

Hi Guy's, I was in electricity supply in the old days of solder sweated joints. They had to carry prospective fault currents of sevetal thousand amperes.
These were replaced by a variety of hydraulic compression connectors. The object then is to get a "compression weld" in the connector. The flexible cable with a large number of fine strands has a lot of give. A good hydraulic compression tool is desirable. 
When it comes to soldering I think it is necessary to tin the cable first to ensure that all strands are wetted and make connection.
The risk that I see in the mechanism used is that the solder may be acting to stop the lug pulling off, but may not have enhanced the connection between cable and lug.
Having said all that ... suck it and see. Have a non-contact thermometer handy. Give the kart a few high current accelerations, then check for temperature rise at the connections. If little rise above the cable temps then enjoy!
Hope this helps,
Joe


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## Functional Artist (Aug 8, 2016)

Thanks for the info 
I 've checked temp (manually) several times & didn't notice any significant rise

I think it may be "the lugs" (cheap Chinese junk?)
Here are (2) different 4g. lugs (diff mfg.) that I installed on 4g. cables with my "hammer style" lug crimper








Here are the ends
...& a "cross section" (cut-off) of the (1) with a "good compression" 








* Notice, on the "good compression" the "stamping" is crisper 
...& you can't even tell that there are individual strands in there anymore. 

I'd say that's a "compression weld"


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## TT-Man (May 28, 2015)

Hi Functional,
Agreed the strands look well compressed, and 'pressure welded'. The connection to the lug looks good. If there is a bad connection, some resistance in the conection / lug, under high current there will be temperature rise, and voltage across the connection. Measing either under high load would be an indication. Non contact, point and click thermometers are cheap enough, not highly accurate but might help. I got one to check tyre temps on my camper van when on long trips.
Is there a problem somewhere else?
Cheers, Joe


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## Functional Artist (Aug 8, 2016)

No problems, so far (It's a Beast of a go kart) 

I was just concerned about the "fitment" of these lugs
...& my DIY "fix"

If your (or anyone) are interested, I first "test ran" my Hell-raiser with a little 48V 1,000W motor (~1.2HP) 

It was actually pretty peppy 
...but, it didn't last 

It didn't show up "too good" in the video
...but, I saw FLAMES "shooting" out the back side of the motor 




Also, I noticed that this little 1,000W motor, which should only draw ~20A (1,000W/48V = 20.83A)
...was "pulling" over 100A a couple of times
...& even the constant draw seemed to be over 30A (~50% higher than usual)

This was only a test
...but, had some interesting results


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## thinkpad4by3 (Sep 30, 2019)

haha you're FA from over on diy go karts....now using some bigger and better batteries than the SLA packs I saw you using last


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