Rad Power Batteries are now UL certified and fully potted

[docw009]

That's a hard life for a 2P 50S, having to power a 30A BBSHD at 15A per cell peak.

I had a battery where they ran the balance wires over the tops of the cells, I took this battery, a 21700 13S-2P apart, and repackaged it with cell holders, new PVC wrap, and BMS.plus rubber shrink wrap. This one now runs my wife's ebike at a typical 100 watts on the average. It's well built, but still have the uncertainty of cheap cells,




Refinished. Still might be a bomb.

 

[nervagon]

That's a hard life for a 2P 50S, having to power a 30A BBSHD at 15A per cell peak.

I had a battery where they ran the balance wires over the tops of the cells, I took this battery, a 21700 13S-2P apart, and repackaged it with cell holders, new PVC wrap, and BMS.plus rubber shrink wrap. This one now runs my wife's ebike at a typical 100 watts on the average. It's well built, but still have the uncertainty of cheap cells,

View attachment 349205
View attachment 349206

Refinished. Still might be a bomb.
View attachment 349209

That's a nice clean up job. I will do the same eventually.

That's a hard life for a 2P 50S, having to power a 30A BBSHD at 15A per cell peak.

The Samsung 50S will do 20A continuous no problem, and 30A-45A bursts no problem. Samsung lists a continuous discharge of 25A. On topic, the 50S is a cell that would really benefit from potting. It is a powerhouse, but runs warm. But the operating discharge temps are within spec up to 80C! But any non-programmable BMS will shut down the pack before that point. The default is usually in the low 70sC.



Dude, I should pot this pack when I rebuild it.

 

[2old]

I have one of those batteries under the boom of an HPV FS26 powering a Phaserunner and MAC 10T @ 40A.
I fabricated a locking slide mount rattle free and stout yet only 340 grams.
Its gets stressed. 180 Charge Cycles so far still at 97% State of Health. Its a keeper. And looks really cool - clear case.
Impressed by the fire retardancy of potting.

I attached mine with the magnetic mount Luna supplied and an extra strap tightly wrapped around it. It's too bad Luna stopped selling them since mine is going on five or so years and still functions perfectly (qualitatively).

 

[Doctorbass]

Epic Resin are making potting for ebike battery. They make a special formula developped with parthnership of electric godness ( do your search on that company please!) and it has endothermic feature which absorb the heat.

My opinion on ebike battery repair is that only 1% or less know really how to make it properly and safely which mean not using hot glue, duck tape, fish paper and spagetti wirring etc) So ebike battery poting is probably safer than battery repair and poting also reduce the need for repair as it block moisture inside the battery which is a big contributor of cell and BMS failure.

I have the UL2271. All I can say is that it will not yet solve the problem of ebike battery fire for many reasons:

1. it does not adress the need for MINIMAL cell spacing !!! this is a scandal!! there are alot of papers on insuffisent cell spacing relationshop with thermal propagation after initial thermal runaway of the first cell.
2. And it does not adress the proximity of busbar sharp edges to the cell skin.. HOW many battery I ahve seen that have the nickel busbar edges at less than 0.2mm from the cell fragile skin!
3. and maximum mosfet voltage requirement to have a proper margin in case of bad charger use. Yes the BMS can protect against cell overvolt but at a certain point if the voltage is too high ( a 72v charger on a 48V battery for instence it will short the mosfet close! and the battery will no more be protected and get overcharge anyway!
4. It also not adress the water ingress which is one of the main cause of ebike battery fire due to BMS protection function compromized
5. It does not adress the fuse DC voltage rating!!! YES the UL will certify battery with a 32V fuse on a 48v battery which mean it can arc!! I saw 32V fuse on 48V bms PCB blowing a hole in an aluminum battrey casing because of the plasma ejection when it blow!!

I have contacted the UL 2271 people about the cell spacing that is not adressed and they had no answer for me... it is still not adressed in the lastest revision.

Also the UL have voltages ranges for live and dead conductive parts spacing requirement but fun fact is that the 48v battery enter into the 50-130V range because when they are recharged they can go to 54.6V ( above 50Vdc).... So for this little 4.6V differences ALOT of parts have their distances requirement doubled!.. and the 48V battery conductive spacing are the same as for a 130v battery!...

For the UL all battery with over 1200Wh ( I think) have more severe constructions rules, like the need to prove that thermal runaway can be controlled and have reduced damages.

 

[CONSIDERABLE SHOUTING]

UL 2271 does not have any puncture or thermal runaway test. It is mostly electrical and software tests to ensure the BMS functions properly. The mechanical tests are shock and vibration (similar to UN 38.3), drop, and a few others. The ingress protection tests are very lax. There are also a bunch of requirements to ensure that all of the materials are from suppliers that are also paying UL.

Happy to see Rad committing to safer batteries, though! Regarding repairability, I have a feeling that of all of the old packs that failed, very few were repaired. Probably straight to the recycler. Not that this is good, its just reality. Few people doing repairs are knowledgeable and careful enough to send out a safe pack.
Also, potting packs makes them much less likely to fail and need repair.

Paul, you gotta step up your past thread on potting compounds! We gotta catch up

For commercial use I feel like the potting is the right call. Do we know what compound they're using for this?

 

[PaulD]

Paul, you gotta step up your past thread on potting compounds! We gotta catch up

For commercial use I feel like the potting is the right call. Do we know what compound they're using for this?

I know! I've been pretty slammed these days. I hope to get back on that research soon.
I figure most brands are using polyurethane because it's cheaper than silicone. I don't have any inside info though.

 

[Chalo]

My opinion on ebike battery repair is that only 1% or less know really how to make it properly and safely which mean not using hot glue, duck tape, fish paper and spagetti wirring etc) So ebike battery poting is probably safer than battery repair

That's about the same as for ANY repair, which isn't a good justification for having a potted car engine, potted washing machine, potted personal computer or anything else really. I venture a guess that the percentage of people stomping their battery hard enough to overheat it isn't any higher than the percentage who can fix their battery reliably (even if not up to OCD standards).

Design for mandatory disposability and stuff gets disposed of when it isn't necessary. That's poor husbandry and unsustainable living.

 

[CONSIDERABLE SHOUTING]

If it's a form of polyurethane that is springy to absorb shock, then it's not absurd to think it would be "squishy" and easily torn apart for opening and recycling. Some urethanes can also be eaten away at using some chemicals or solvents for removal. I don't really see why it's worth shouting about- a pack sealed like this is going to be far more shock resistant since now all the physical structures are now going to act like one "unit", and if your pack suddenly gets a bad cell- say after years of use- its more likely that the rest of the cells are going to follow suit soon after.

Besides, We already have cells that are easily replaced and serviceable with long lifespans- they're LiFePO4 prismatics.

 

[PaulD]

That's about the same as for ANY repair, which isn't a good justification for having a potted car engine, potted washing machine, potted personal computer or anything else really. I venture a guess that the percentage of people stomping their battery hard enough to overheat it isn't any higher than the percentage who can fix their battery reliably (even if not up to OCD standards).

Design for mandatory disposability and stuff gets disposed of when it isn't necessary. That's poor husbandry and unsustainable living.

I used to agree with this sentiment, and I do for pretty much all products EXECEPT lithium batteries, but I think I've seen way too many shoddy DIY batteries and failures to think its a good idea for most people to work on them. And, honestly, there are very few people that WANT to repair anything these days.
What percentage of failed Rad Power batteries do you think got repaired up to this point in time? I don't have the answer, but I'd guess it's very low. We need wide spread, easy recycling collection points.
And I do think all batteries should be built to OCD standards. But I do think having the BMS in a separate compartment, potted in a soft compound is a good idea, so a BMS swap is possible.
Overall, I hope that potting will reduce the number of water ingress and vibration failures far more than it reduces the number of successful repairs.