Safety charging shrink wrapped battery?

[BrianK]

Hi folks,
I recently picked up a UCC shrink wrapped 48v 20ah battery (because price was, unfortunately, an issue.)

Two questions - 1) is it “safe” to charge shrink wrapped UCC batteries indoors, and 2) does it increase the chances of a fire while charging if I charge it while it’s in its plastic foam shipping protector?

I wrapped the firm foam shipping box in black Gorilla tape and the whole assembly fits perfectly in my pannier bag. If I can charge the battery inside this foam package, inside the pannier, which has a convenient handle, it would make the overnight charging process much easier.

I bought a parallel wire connector to run this battery alongside the original 48v 10.4ah battery on the bike and carrying it in the pannier is the best option I’ve found so far.

 

[J.R.]

I'd be concerned charging or discharging the pack inside all that foam insulation. I'm sure the pack as designed in the shrink wrap is fine. But that type of dense foam, with the addition of the tape and pannier will hold in a lot of heat. I do know people that use shrink wrapped packs inside bags though. I'm no battery expert.

 

[harryS]

My experience is that most of the heat comes from the charger. If it is a small charger, 2 or 3 amps distributed into a battery of that size is not going to heat the cells. The BMS, battery maintenance system circuit circuit board, might get warm, during charging, and in the unlikely event that it is a balance BMS, will stay warm.

My personal habit is to not charge when the home is empty or when we're all asleep. Although I have a smoke alarm in the garage where I do my charging, it's not connected to the house alarm.

Batteries also get warm if you're running a heavy load. If it is a really good BMS, it will have temp sensors, but I think we're talking cheapo BMS here. I would initially check the temperature in the middle of the ride, after some hill climbs or hard runs. As long as you can hold the sides of the shrink wrap, that should be within the 60C (130F) max outside temperature of the cells.

So scope it out. Charge your pack and see if it gets warm,. Use the pack and check it in the middle of a ride after some hills or long acceleration. See how hot it gets. Anyway, you're on your own. Be careful,

 

[BrianK]

My experience is that most of the heat comes from the charger. If it is a small charger, 2 or 3 amps distributed into a battery of that size is not going to heat the cells. The BMS, battery maintenance system circuit circuit board, might get warm, during charging, and in the unlikely event that it is a balance BMS, will stay warm.

My personal habit is to not charge when the home is empty or when we're all asleep. Although I have a smoke alarm in the garage where I do my charging, it's not connected to the house alarm.

Batteries also get warm if you're running a heavy load. If it is a really good BMS, it will have temp sensors, but I think we're talking cheapo BMS here. I would initially check the temperature in the middle of the ride, after some hill climbs or hard runs. As long as you can hold the sides of the shrink wrap, that should be within the 60C (130F) max outside temperature of the cells.

So scope it out. Charge your pack and see if it gets warm,. Use the pack and check it in the middle of a ride after some hills or long acceleration. See how hot it gets. Anyway, you're on your own. Be careful,

Good advice, thanks. I do have a miniature wood stove (about 12”x12”x12”) and out of an abundance of caution I throw it in there while I’m charging it and place the charger in a metal pan on the fireproof hearth pad under the stove. Probably overkill but I live in a trailer so it’s hard to be “too safe.”

 

[Dallant]

Good advice, thanks. I do have a miniature wood stove (about 12”x12”x12”) and out of an abundance of caution I throw it in there while I’m charging it and place the charger in a metal pan on the fireproof hearth pad under the stove. Probably overkill but I live in a trailer so it’s hard to be “too safe.”View attachment 96586

Better to be safe than sorry!

 

[tomjasz]

Good idea. A good shrink wrap pack is no more apt to fail then a cased pack. I charge mine in a large ammo can lid latched and gasket removed. Smoke alarm and a pair of welders glove in case I have to haul a burning pack out.

drilled ports and used rubber grommets to protect wiring.

 

[tomjasz]

Better to be safe than sorry!

Can you share the details on these miniature stoves? I think that’s a brilliant idea.

 

[harryS]

I store my shrink wrapped packs inside cinderblocks on a concrete floor with a paver block over them. I agree..Can't be too safe.

 

[tomjasz]

I'd be concerned charging or discharging the pack inside all that foam insulation. I'm sure the pack as designed in the shrink wrap is fine. But that type of dense foam, with the addition of the tape and pannier will hold in a lot of heat. I do know people that use shrink wrapped packs inside bags though. I'm no battery expert.

A properly sized battery should not overheat. My only hot battery was a 52V 3P small pack pulling 30A, discontinued, from Luna. It’s the problem with small packs and high amp draw.

 

[BrianK]

Can you share the details on these miniature stoves? I think that’s a brilliant idea.

Cubic mini wood stoves. Great little stoves, perfect for tiny houses, small hunting cabins etc. I’m currently living full time in a 30’ RV trailer and this wood stove heated my entire trailer all winter. It sits on a corner counter atop a fireproof hearth pad. The only drawback is it needs to be reloaded every 2.5 to 3 hours since the firebox is so small.

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[tomjasz]

A bit lacking in length at 15”. But there are others. Cheap too. Not as well built as yours but I’d never burn wood in one.

wevwanted a Norwegian soap stone stove but our home owners insurance would cancel us. And we’d pay more than double rates.

 

[BrianK]

I’m a huge fan of wood stoves. I was a beta tester for a soapstone wood stove manufacturer in New England and enjoyed it immensely.

 

[J.R.]

A properly sized battery should not overheat. My only hot battery was a 52V 3P small pack pulling 30A, discontinued, from Luna. It’s the problem with small packs and high amp draw.

As noted my concern was with the added dense foam insulation, not the pack. I've known many to use a shrink wrapped pack in a bag with no issue. I use foam like this in my work and it is very dense and insulating. Its adding something to the pack that was not considered by the manufacturer.

As I said I'm no battery expert. I'm a bit over cautious when it comes to batteries. I had a Sure Fire lithium battery explode in my house several years ago. Not charging, not in use, not abused and it was a very small battery with a big bang. Different chemistry than lithium ion, but I've been cautious ever since.

 

[tomjasz]

As noted my concern was with the added dense foam insulation, not the pack. I've known many to use a shrink wrapped pack in a bag with no issue. I use foam like this in my work and it is very dense and insulating. Its adding something to the pack that was not considered by the manufacturer.

As I said I'm no battery expert. I'm a bit over cautious when it comes to batteries. I had a Sure Fire lithium battery explode in my house several years ago. Not charging, not in use, not abused and it was a very small battery with a big bang. Different chemistry than lithium ion, but I've been cautious ever since.

I have mine foam wrapped on three sides. I no longer ride high-speed eBikes. I get absolutely no noticeable heat for 10S 4P 36V packs. Nor from my 20AH 52V or 20AH 48V. I believe heat problems are undersized packs being pushed to their limits.

You've seen my precautions, I'm firmly in agreement with you!!

 

[Gionnirocket]

I agree. Heat is the enemy.
Slow charging (2a-3a)and normal riding of a pack that size shouldn't generate much.
Not a big fan of overnight charging as I think it's better to keep an eye on it and unplug everything as soon as it's done. If you do... SMOKE DETECTOR.
A non contact pistol thermometer is an easy way to take an accurate enough reading here.

 

[BrianK]

I store my shrink wrapped packs inside cinderblocks on a concrete floor with a paver block over them. I agree..Can't be too safe.

When you live full time in an RV trailer, it pays to be paranoid about potential sources of fire. A good friend had one burn down around him and narrowly escaped. They never were able to pinpoint the cause of the fire.

 

[BrianK]

A non contact pistol thermometer is an easy way to take an accurate enough reading here.

Good. That what I use to track the surface temps on my mini wood stove.

 

[Gionnirocket]

Good. That what I use to track the surface temps on my mini wood stove.

As I check my pizza stone before I lay one on'er

 

[Art Deco]

I’m a huge fan of wood stoves. I was a beta tester for a soapstone wood stove manufacturer in New England and enjoyed it immensely.

I am also a soap stone stove fan. Mine runs 24/7 for four or five months annually.

 

[BrianK]

I am also a soap stone stove fan. Mine runs 24/7 for four or five months annually. View attachment 96747

That looks like a HearthStone?

I had three different Woodstock Soapstone stoves, including a beta version of one model before it went into production. A close friend had a huge Hearthstone from the 80s that he heated with 24/7 six months a year for 35 years in upstate New York, till it was so warped and burnt out internally that he finally replaced it with the Woodstock model I had beta tested, their “Ideal Steel.”

I LOVE wood heat and everything about it, so even now after sizing down to a 30’ travel trailer version of a tiny house, I’m still burning wood with this mini version of a wood stove.

I just picked up a battery powered version of a Stihl chainsaw too. Great little saw, and I can charge it with my solar cells via my solar generator. It will easily replace the smaller of the two gas Stihl chainsaws I have. And though I have a hydraulic wood splitter, spitting logs with Fiskar mauls is a great form of winter exercise when my e bike is idle due to weather.