What the heck is wrong with UPP packs!?

[ClintBX]

Hi ESFMs,

I've been using a few packs from Unit Pack Power (UPP) lately and I've been having some bad experiences.

I do Uber eats with my ebike, so I need a lot of energy to get me through the day. I have a 35 Ah pack (not UPP), a 14Ah pack (from UPP) and more recently a 7 Ah pack (also UPP). I've been able to work all day without having to schedule charging sessions between shifts.

I was pretty happy with my set up that I went to buy a second 14 Ah pack as a spare.

Prior to my second purchase of the 14 Ah pack, I did have the nickel strip that connected the red positive along with the first bms wire to the pack snap on me. I managed to patch that to get it working again but upon examination and research, I discovered that the strips used are nickel plated steel and susceptible to corrosion. There are definitely some rust marks that I'll probably have to deal with in the future. I've had this pack since January and used it everyday from full to empty through to October.

After receiving the spare pack, I decided to swap out the 10 month old one. It performed well up until today, when I discovered the bms burned out on me. When I started my day, it didn't quite fully charge and when I came home the charger wouldn't work at all. It wasn't until I was about to change my charging connector that I noticed a hole burnt through the bottom of the bag and some tiny sparks happening. There was also some dampness on the cardboard insulator. And yes it had the blue heat shrink over it. And this pack was inside a seemingly strong water proof bag.

I just reinstalled the previous pack but now I'm nervous of having to rely on it for the long term, so I'll be searching for a reputable brand that also meets the form factor requirements of my frame. I have this pack strapped on the down tube. This is a full suspension frame, so there is a little more clearance from the front wheel.

I'll be attaching several pics in the next posts.

[ClintBX]

Here's some images of the fried bms.
As you can see, it just totally cooked on the left.

[Tommm]

Here's some images of the fried bms.
As you can see, it just totally cooked on the left.

If it was damp it was damp. Most of this china stuff aren't waterproof even if they claim it to be. Double bag it or something next time.

[tomjasz]

https://www.youtube.com/watch?v=JCaDz_2YcGQ

[ClintBX]

Here's some images of the fried bms.
As you can see, it just totally cooked on the left.

If it was damp it was damp. Most of this china stuff aren't waterproof even if they claim it to be. Double bag it or something next time.

I'd agree with you except, I've had a pretty good experience with keeping water out with various packs. And I ride through some potent rains.

No, I have a different theory. I think that the hole burned through first and then I rode through some sprinklers and puddles recently that may have flicked up into that opening. As I said, I have this pack strapped on the downtube. The front wheel probably flicked some of that moisture.

[ClintBX]

https://www.youtube.com/watch?v=JCaDz_2YcGQ

Yeah, I saw that video.

[ClintBX]

Wouldn't you know it. My 10 month old pack that I swapped in last night wouldn't work today. When I plugged her in, my throttle indicator had it sitting on 4.3v. which happened to me a couple of days ago with the recently fried pack but I assumed it was my connector. It was back to normal when I ensured proper contact them. I had no such luck this time. Wouldn't resume charging either.

When I opened her up, nothing looked physically damaged (except for the corrosion on the strips). However, when I went to volt test each series, the first one was at 0.2v while the rest were at a healthy 41.v. I'll post more pics when I get home.

[ClintBX]

Here are some pics of the 10 month old pack. I checked each series' voltage. There all around 4.1v except for that first one by the court wire bodging. It is on 0.33v

The month old pack is around 3.6v with the first series at 1.36v

[ClintBX]

Here's a shot of the "new" pack after I ripped open the packaging.

I suspect that the cardboard insulator used acts as a sponge and only serves to spread any moisture that happens to get in. I prefer it when they use the hard plastic like insulator.

[ClintBX]

The autopsy continues. Here a shot the bms that didn't burn. Well I guess it did.

[ClintBX]

And on the top side of the bms, I noticed 5 modules with the first 3 looking singed at the back. What are those things? This is my first bms autopsy.

[www.recumbents.com]

Those are the power FETs. It looks like you are putting a higher continuous load on the BMS than the FETs can handle without overheating. Sometime you can add a heat sink to resolve that but the better resolution is to use a higher power BMS. What amperage is the pack rated at?

[ClintBX]

Those are the power FETs. It looks like you are putting a higher continuous load on the BMS than the FETs can handle without overheating. Sometime you can add a heat sink to resolve that but the better resolution is to use a higher power BMS. What amperage is the pack rated at?

I was wondering about that but I'm using a 35A max controller with a 17A continuous. The bms is supposed to be fit for 30A continuous and 90A max.

[goatman]

looks like you get to try and salvage some cells and make a new pack. i use cell holders and plasti-dip to waterproof

[ClintBX]

looks like you get to try and salvage some cells and make a new pack. i use cell holders and plasti-dip to waterproof

I like that idea. How do you recommend I should approach the dismantling process? How do I break the spot welds?

[goatman]

i usually roll the nickel strip off the cells, kind of like how you open a can of spam. on the negative end some batteries have weak metal and it rips a hole in the bottom where the spot welds are, try rolling the strip off the dead cells to see.

you might be able to cut the packs in half and connect the two good halves together in series to get up and going right away

[ClintBX]

I have a question about the UPP's BMS compatibility with my controller/motor setup.

The BMS in these 14Ah packs are rated at 30A continuous and 90A peak.

My controller is rated at 17A continuous and 35A peak.

And my motor is 500 watts. I don't know what that means in terms of how many amps it can take or whether it pulls any additional itself (I had an experience with a1200 watt motor pulling my controller's peak as continuous for some reason, still can't wrap my head around that one)

My question is, even though the continuous ratings of 30A of the BMS exceeds that of my controller's continuous 17A, is it still likely that the fewer times I might hit peak (30-35A) can lead to the type of failure I experienced here?

[kcuf]

motor wattage continuous

not peak rating


never seen 30a bms peak 90a

more like 40-50a if that


multiple problems here

overloading is bad as evidenced here

water only makes things worse

[HK12K]

Saw this not too long ago which completely turned me off to UPP, not that I wasn't already skeptical.

https://youtu.be/JCaDz_2YcGQ

[ClintBX]

A quick update on my experience. The vendor for one of the packs sent me a replacement. This was the pack that started sparking up and burning a hole through its bag. I've been riding with it for only 20 days and already, it just started to not get a full charge. It stops charging at 53v, whereas it normally charges fully to 54.6. I've even been extra careful to avoid draining it right down to the bottom this time.

[Tommm]

A quick update on my experience. The vendor for one of the packs sent me a replacement. This was the pack that started sparking up and burning a hole through its bag. I've been riding with it for only 20 days and already, it just started to not get a full charge. It stops charging at 53v, whereas it normally charges fully to 54.6. I've even been extra careful to avoid draining it right down to the bottom this time.

Bank out of balance and shiit bms not doing its job, just the regular.

[powrtrip]

Just email them.. they'll send a new one out.... I've had 6 packs from them all awesome...

[tomjasz]

UPP sucks. Very poor quality builds, using nickel-coated steel connections rather than pure nickel. And low ball cheap featureless BMS.