Headway battery pack FIRE! <lot pics>

[deVries]

As AlanB points out, the Maxis were not the cause of the problem, but after two concurrent Maxi failures in conventional holders, I could not with conviction say that chroot's Maxi/holder offered adequate protection to prevent matters from cascading. I am personally looking for an alternative for pack protection in the general vein of the ANL design...

Thanks for pointing out the issues you've had with this fuse holder. Is there a way to seal/glue it to prevent the holder inserts from resistance failing? Maybe a slightly higher amp fuse might have helped? Or, two lower amp ones?

Let us know what you find to be a better fuse solution. Thanks.

 

[teklektik]

Is there a way to seal/glue it to prevent the holder inserts from resistance failing? Maybe a slightly higher amp fuse might have helped? Or, two lower amp ones?

The Faston is molded into the rubber fuse holder and it seems the friction junction with the fuse leg became electrically compromised somehow. This bike doesn't see foul weather, so it's unlikely to be moisture related -- better sealing does not look like a promising solution. There are a couple of threads on ES about fusing strategies, including Doc B's multiple-small-Amp fuse approach.

This particular failure mode has been reported before - I knew about the potential problem but thought I could beat the odds with a relatively low powered 50A rig. I guess not...

 

[Alan B]

I agree that some of the Maxifuse holders are pretty low quality. They seem to be something along the lines of fast-ons cast into soft plastic. (I started this post before the previous one).

I'm moving to ANL fuses for the main current. They are a bit larger though.

 

[teklektik]

I'm moving to ANL fuses for the main current. They are a bit larger though.

Yep - thanks for the lead - it got my attention as an alternative. The ANN looks faster. With some leads w/ring terminals bolted up and sheathed in heat shrink, the size seems manageable.

Here's a rundown of auto-style alternatives. The mini-ANL and Mega fuses looked promising but are only available in 32vdc rating compared to 80vdc for the ANN/ANL.

chroot - oops, sorry for the thread hijack

 

[Alan B]

If your purpose is to protect wires, then quick fuse action is probably not so critical.

If you are trying to protect a semiconductor the faster fuses would be helpful.

Thanks to chroot for this thread that is helping improve battery safety knowledge for the readers.

 

[deVries]

If your purpose is to protect wires, then quick fuse action is probably not so critical.

If you are trying to protect a semiconductor the faster fuses would be helpful.

But one of these two might have longer lasting "contacts" for the fuses, seal better, or have a lower resistance for connections.

 

[Alastor]

Rapping one every two cells with shrink material should also help with vibrations and will provide more short circuit protection for the individual cells.I think that hot glue should be mandatory in building this kind of packs even if it will make it more difficult to repair it afterwards.Having cells rubbing one to another is not fun.

 

[veloman]

I have some old inner tubes separating my headway pack, but after reading some of this thread, I'm going to beef it up.

 

[dnmun]

I have some old inner tubes separating my headway pack, but after reading some of this thread, I'm going to beef it up.

you should consider putting a fuse on the charging wire at the battery terminal if you want to "beef it up".

there is no evidence the headway cells shorted out and started this fire.

it started when the charging lead shorted out and overheated and caught the nylon bag on fire.

 

[veloman]

I have some old inner tubes separating my headway pack, but after reading some of this thread, I'm going to beef it up.

you should consider putting a fuse on the charging wire at the battery terminal if you want to "beef it up".

there is no evidence the headway cells shorted out and started this fire.

it started when the charging lead shorted out and overheated and caught the nylon bag on fire.

Okay. My entire pack is homemade, no BMS, just balance leads and a separate charge lead using 14g wire. I charge at 3amps max. It wouldn't be a bad idea to check on everything though.

 

[dnmun]

sorry you have no BMS. these batteries are expensive to waste. but the red wire to the plus terminal of the battery is where you need to put the fuse. at the battery terminal. you have no, as in none, short circuit protection on the output since there is no BMS and you have no short circuit protection on the charging wire either. so twice as likely as chroot to have a fire.

 

[dnmun]

headways are like a pickup truck. almost unbreakable. heavy and slow. i bet that some of the headway cells in chroot's pack still functioned after the fire.