Battery and Cradle contact melting!!

Hey guys, not brand new to the forum but seem to have lost my credentials so I started a new account. I am having an issue with my battery (pics attached, a Luna style bottle batt), and it's cradle. As you can see in the pics, a single contact seems to have softened/melted and is now not making proper contact, resulting in sporadic power delivery, turning on and off. Any ideas? Im just getting into ebikes and have only had this unit for about 6 months from a dealer in Canada. It's a mid drive Bafang, and I've had a ton of fun with it, but can't ride now! Help!

Pics are too large, so here are links to them:
Shark battery cradle https://imgur.com/a/2cxOq
Shark battery pack https://imgur.com/a/59ngz

When you keep using it with the intermittent power it makes a lot of heat shorting out and sparking, this happens with the hard case packs. You can help prevent it by using an extra strap around the battery if it's really rattling around on the bike.

You will need to replace or have those connectors replaced since it's pretty new,

that sucks,

I had the same thing happen on my shark pack. Inside the pack, all 4 terminals are live (2+ and 2–), but in the cradle only the outer two pins are wired. So I fixed it by bridging the pins on each side so I had two positive, and two negative pins to match what the pack had.

I haven't had any issues with the connection since and I haven't had to use any extra straps or anything.

Hey zro-1, that sounds great! How would i go about that? Solder a piece of wire between the relevant contacts on the cradle? If so, what gauge?

Yeah exactly.

If you pop the plastic part of the cradle that the battery slides on to off of the metal part that was designed for a controller, you'll see the plastic moulding that holds the 4 pins that contact the connectors in the battery. If all 4 are already connected, then the issue isn't there, but if only the outer two pins are connected, then you can simply use some wire that's about the same gauge as the wires coming off the pins already and bridge each inner pin to the live pin to the outside of it. Just make sure you solder on the back side of the pins (where the wires are).

Luna has some info in their support forums. This particular link is about repositioning the shark pack, but it shows the disassembly you'll do to access those pins, so it should still be helpful.

https://electricbike.com/forum/forum/knowledge-base/batteries-aa/19174-how-to-fit-a-shark-pack-onto-the-down-tube-if-the-bottle-screws-do-not-line-up

ghostboarder said:

Hey guys, not brand new to the forum but seem to have lost my credentials so I started a new account. I am having an issue with my battery (pics attached, a Luna style bottle batt), and it's cradle. As you can see in the pics, a single contact seems to have softened/melted and is now not making proper contact, resulting in sporadic power delivery, turning on and off. Any ideas? Im just getting into ebikes and have only had this unit for about 6 months from a dealer in Canada. It's a mid drive Bafang, and I've had a ton of fun with it, but can't ride now! Help!

Pics are too large, so here are links to them:
Shark battery cradle https://imgur.com/a/2cxOq
Shark battery pack https://imgur.com/a/59ngz

Click to expand...

Yup, a now old design that has been upgraded. Had resellers told people to use dielectrc grease, boeshield or similar, those connectors may have done better. You’re not alone, FWIW, the latest cases have benn upgraded. But some resellers had really short warrantees.

Thanks for the advice gents, I'm having some fun getting the bridging to work properly. I'm going to desolder the wires on the harness from the outside contacts and move them to the inside, with any luck this will make a cleaner and more reliable fix.

those contacts are joke.
Not designed for the current this battery can deliver.
Also when contact is loose, bad contact all start to heat up really fast even at 20A.

miro13car said:

those contacts are joke.
Not designed for the current this battery can deliver.
Also when contact is loose, bad contact all start to heat up really fast even at 20A.

Click to expand...

I agree. I was unsuccessful moving the wires on the back side of the harness from the outside to the middle. Good solder joint, but no current flowing from the battery. Ugh, terrible as you said. What can i do now guys? Can i replace the harness and the battery contact with something better?

You can try to get a new cradle or new contacts to repair that one, a new case, or even take it out of the case and put it in a bag,

These are all options but none that great, you are kinda stuck with it so might as well make it work,

the solution here is to get rid of those contacts and replace them with quality 4-pin weatherproof min 20Ah rated connector

BTW
my BIONX uses female contacts /plus, minus, communication/ on battery mating with male contacts and I checked them - pristine clean and shine.
but they mate with precision and gold plated also.