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-   -   4mm bullets in battery too small? (https://www.rctech.net/forum/radio-electronics/961999-4mm-bullets-battery-too-small.html)

bmx_ican92 09-16-2016 12:37 AM

4mm bullets in battery too small?
 
I purchased a couple shorty pack lipos from a guy at the track. I'm having a problem getting my 4mm bullets from my esc into them. I'm 95% sure the the female bullets in the battery are 4mm but it is a really tight fit, like tight to the point I have to pry it out with a flathead screwdriver.

Do they make batteries with 3.5mm bullets? (Would I be able to even fit the 4mm bullets in if they were this size?

Can I bore out the bullets with a file to ease the fit?

http://i.imgur.com/njkTu7m.jpg

http://i.imgur.com/AfrxWqM.jpg

SickNT760 09-16-2016 12:52 AM

I looked up your battery and it does say that they are a 4mm female bullet connector on the site. I have not heard of any problems with that end being too small. I have only heard of 4mm and 5mm bullets but could be wrong. The site does show a updated version of your battery on there. Maybe the older model runs 3.5mm? Others would have to chime in there. But I would not recommend filing out the insides.

Phillip F 09-16-2016 01:04 AM

Measure your bullet connector with a caliper. I had a bullet connector that is labeled 4mm when i boight it but when measured really it is 4.25mm.

rannblod 09-16-2016 01:10 AM


Originally Posted by SickNT760 (Post 14672383)
I looked up your battery and it does say that they are a 4mm female bullet connector on the site. I have not heard of any problems with that end being too small. I have only heard of 4mm and 5mm bullets but could be wrong. The site does show a updated version of your battery on there. Maybe the older model runs 3.5mm? Others would have to chime in there. But I would not recommend filing out the insides.

Older ones are 4mm

dtr 09-16-2016 08:35 AM

Those are probably regular 4mm bullets, just showing their age. Arcing when pluging in and friction roughens up the surface to a point when plugging in a new connector is a real PITA. This is why I prefer wired packs to inline ones; switching connectors is easy with a simple iron.

bmx_ican92 09-16-2016 09:13 AM


Originally Posted by Phillip F (Post 14672389)
Measure your bullet connector with a caliper. I had a bullet connector that is labeled 4mm when i boight it but when measured really it is 4.25mm.

They are 4mm for sure, I have 4 other shorty packs that they fit in perfectly

bmx_ican92 09-16-2016 09:15 AM


Originally Posted by dtr (Post 14672659)
Those are probably regular 4mm bullets, just showing their age. Arcing when pluging in and friction roughens up the surface to a point when plugging in a new connector is a real PITA. This is why I prefer wired packs to inline ones; switching connectors is easy with a simple iron.

I would have no problem doing that but my space and weight are very precise. No real room for more wire, not to mention I don't think the b6 body would clear a pack with wires coming out of the side

brew99 09-16-2016 10:20 AM

I have the same battery packs and find that my 4mm bullets are tight also. I mostly get my bullets from HK, and just assumed that these cheap bullets were a little oversized.

I have filed downed a couple of bullets which helped some, but I wouldn't advise doing this as a regular fix.

Have you tried different bullets from a different manufacturer to see if they fit the SMC better?

bmx_ican92 09-16-2016 10:50 AM


Originally Posted by brew99 (Post 14672756)
I have the same battery packs and find that my 4mm bullets are tight also. I mostly get my bullets from HK, and just assumed that these cheap bullets were a little oversized.

I have filed downed a couple of bullets which helped some, but I wouldn't advise doing this as a regular fix.

Have you tried different bullets from a different manufacturer to see if they fit the SMC better?

That's probably what I'm going to try.

gigaplex 09-16-2016 06:34 PM

Wouldn't filing the bullets remove the gold plating?

brew99 09-16-2016 11:28 PM


Originally Posted by gigaplex (Post 14673176)
Wouldn't filing the bullets remove the gold plating?

Sure it will remove some, but I would hazard an educated guess and say that it probably won't effect your ability to transfer power from the battery to a point that you would notice any difference. That is also why I said it's not an ideal solution.

Grizzbob 09-18-2016 12:25 AM

I agree that it does happen here & there, I've had a couple of shorties that had one connector barrel ok, & the other a bit too small(measured with my calipers at about 3.9mm or so, while the good ones were more like 4.1mm). Doesn't sound like much of a difference, but using those newer male plugs(like these: http://www.tqrcracing.com/shop/produ....asp?p_id=7358 ) it's incredibly tight in the small dia. barrels(one one shorty, I even accidentally tore the casing of the pack apart slightly trying to get that one out of the barrel). Best solution I could find for it was to use the older style banana male plugs on the end with the small barrel(for me, I've almost always found them on the neg. side of the pack).


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