My new 48v 30AH Chamrider Battery is shutting off at 50v

[carlosebermudez]

Hello!

I just finished my first e-bike build. I took an old mongoose MTB and bought a BBSHD and a 48v 30Ah battery from aliexpress.

After hooking everything up, and charging the battery to 100% for 7 hours. I noticed the 850c display showed only a 60% charge. I tested the output of the battery and it read 54.0 volts (AFAIK, it should be at least 54.5). So, I go for my first ride mixed PAS levels 1 thru 9 and it shuts off after 15km on PAS 2 (300w max). I recharged it, this time 12 hours and the display reads 62%, maybe it's balancing still, I thought. This time rode it harder, and it quit after only 10km. I took it for a ride a third time, charged it to 62% for 24 hours, this time I rode it very slowly on PAS 1,2, and 3, And only got 15Kms, again. The battery is shutting off at 50v, I rode it for a few minutes at around 49v but it quit as soon as I asked for a little bit more, it's reading 51v right now, but as soon as I take it out it quits after just 1 minute.

You can see four videos of it failing, I try to explain as best as I can with my crappy phone, but you'll get an idea.

I cannot return it, since shipping from my country will cost me the same as a new lower amp hour battery.

I'm sending these videos to Chamrider (aliexpress), they asked me for them, they are very slow to answer so that's why I'm posting on this forum. I think I'm gonna have to open it and take a look inside. Let's see what they say tonight after reviewing the videos.

In the meantime, if anyone has had an experience similar to this and is willing to help me out, I will very much appreciate that.

Thanks!

Here are some images of my display's readings when fully charged.

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IMG_20200908_211122734.jpg (234.14 KiB) Viewed 611 times

IMG_20200908_211135657.jpg (216.98 KiB) Viewed 611 times

IMG_20200908_211212297.jpg (201.84 KiB) Viewed 611 times

IMG_20200908_211217455.jpg (202.84 KiB) Viewed 611 times

This is a typical ride around my neighbourhood:

Screen Shot 2020-09-10 at 7.41.44 PM.png (30.78 KiB) Viewed 611 times

These are the videos i took:

[youtube]IQUwMAmJC0I[/youtube]
[youtube]9anJ4vQK1Yw[/youtube]
[youtube]wQrdu3DWuNY[/youtube]
[youtube]jX-z0HBig6E[/youtube]

[john61ct]

Test the battery for capacity

and the display for accuracy

separately from each other.

Most likely you got scammed on the battery, did you get a strong reco on that seller from trusted members?

What exact cells used? Could be counterfeit.

How many cell groups?

13S is nominal 47-48V, charge to 54V bit lower like 53V is better for longevity

[john61ct]

Get a cheap wattmeter for guesstimating SoC%

Very few devices do that well, best accuracy for dedicated battery monitors costing hundreds is usually only within 4-8%

cheap circuitry's guesses can be so far off might as well ignore

Tracking SoC via voltage is rough too but if DMM is accurate at three digits and you let the cells rest an hour can get a ballpark idea.

But really a capacity test using a CC load, from 4.2V down to 3V at say 0.2C is best way to benchmark deteriorating health (SoC)

[carlosebermudez]

I tested the battery and the display with a multimeter. They read 54v on the battery and 53.9v-54v on the display.

The supplier Chamrider has pretty good reputation in aliexpress.com, that's why bought from them.

The cells are 3400mah according to them.

The battery is 13s9p

[Teeman]

I had the same problem, It turned out to be a Bad charger. I hope it is that simple. Make sure the charger is set to Your voltage.

[carlosebermudez]

I tested the charger and it outputs 54.5v when the fan is off. Is that what it's supposed to measure?

[Teeman]

Do you have a switch on the back of the charger they can be set to 110 or 220 volt.

[carlosebermudez]

Nope, no switch.

The lable says.

Model DL-240W
AC Input: 100-120v
DC Output: 54.6v 4A

The longer I've ever left it on is 24 hours. I thought it would balance the cells, perhaps one bank was off and needed time to adjust. I've also left it siting with the Key On to see if it would balance and take a bigger charge, but it still only shows 54.0v and 60% capacity.

[john61ct]

The ~54V is just fine no need to go higher.

As I said the SoC% feature is very unlikely to work right anyway, ignore it even disable it.

If you can read the actual Ah / mAh drawn as I said maybe get a wattmeter,

cross-reference to voltage under load, with specific routes as you get familiar you will develop your intuition

try to leave 10-15% minimum in the pack when you stop for longevity, more the better really.

3.1Vpc ~40V pack level is drop-dead danger zone, best to avoid getting anywhere near there excep for an occasional emergency, zombies chasing you or sumpin

[kcuf]

not sure how display acquires batt %

normal 48v system lvc occurs 42-44v


bms balance bleed off function perhaps

following bms equilibrium function

some chargers won’t resume bulk charging


badly out of balance packs

can take several days achieve equilibrium


leave charger plugged in for several days

note any activity

after 2 days power cycle charger

hopefully continue charging/balancing pack


yes to power meter altho

that leads to connector addiction/recovery

[carlosebermudez]

Thanks for all the coments!

The ~54V is just fine no need to go higher.

As I said the SoC% feature is very unlikely to work right anyway, ignore it even disable it.

If you can read the actual Ah / mAh drawn as I said maybe get a wattmeter.

3.1Vpc ~40V pack level is drop-dead danger zone, best to avoid getting anywhere near there excep for an occasional emergency, zombies chasing you or sumpin

I have no idea what SoC% is, or how to test it, and I don't have a wattmeter. .

I've been watching some youtube videos, and a couple of people had a similar problem, it turns out there's a way to bypass the LVC on the battery by soldering the ground wires and removing one of them. I can keep an eye on the voltmeter while riding if that came to be the case. I want to ride it until maybe 44v.

not sure how display acquires batt %

normal 48v system lvc occurs 42-44v


badly out of balance packs

can take several days achieve equilibrium


leave charger plugged in for several days

note any activity

after 2 days power cycle charger

hopefully continue charging/balancing pack

Have you had problems with unbalanced packs? I've left it for 12 hours and only gained 2%. After 24 hours didn't gained a thing. I could live it all weekend and see how it's doing on Monday. I haven't yet power cycled the charger, I can try that. Keep in mind this is not a smart battery with a communication cable or anything like that.

[E-HP]

can you provide a link to the battery?

[carlosebermudez]

can you provide a link to the battery?

https://es.aliexpress.com/item/32965186267.html

[john61ct]

YouTube is usually a horrible source for primary learning.

> Keep in mind this is not a smart battery with a communication cable or anything like that

That is not at all needed, only you need to be smart.

I have no idea what SoC% is

State of charge, what percent of energy capacity (Ah/mAh) is currently in the pack.

You really need to learn to google, read a bunch of past threads; you are not in kindergarten getting spoon fed.

Buy a coulomb-counting wattmeter, essential tool for troubleshooting your issues, and tracking your pack's health as it wears.

Learn to guesstimate SoC

ideally as accurately as possible

but at least roughly - completely ignore that data point from your display.

If you are relying on yourself judging when to stop riding, even more critical.

What other data points cause you to believe you have a problem?

What is your impression as to what problem(s) you have?

> I've left it for 12 hours and only gained 2%.

You are harming your pack doing that

>> ~54V is just fine no need to go higher.

Again, ignore that SoC% readout!

Aren't you able to **see** your cell/group level voltages?

[goatman]

on the screen with advanced settings and factory settings, can you get into those settings
can you see what the LVC setting is? and adjust it down to 42v or 39v?

or change the battery setting from 48v to 36v? to hack the lvc

[E-HP]

can you provide a link to the battery?

https://es.aliexpress.com/item/32965186267.html

There is no 48V 30Ah pack option in the link you provided. Can you point the the battery you have, in the specification table on the link page?

[carlosebermudez]

can you provide a link to the battery?

https://es.aliexpress.com/item/32965186267.html

There is no 48V 30Ah pack option in the link you provided. Can you point the the battery you have, in the specification table on the link page?

My bad! https://bit.ly/3hnc7mA this is the correct link.

[carlosebermudez]

Quick update.

Talked to the Manufacturer and he had me opening it and shooting some video of me testing the BMS. There's definitely a bad bank.

So... I understand that a 3.5v battery CAN be saved. And I want to prepare myself for what's coming, which is making it work by learning how this thing actually works.

Couple of questions:

1. By changing the BMS to a smart one make a difference? Is the Pinout ribbon connector standard for all Chinese BMS?
2. Can I charge just that one bank with an external charger? say from an old cell phone, the brick kind.
3. If there's just a couple of cells gone bad. Can I solder them back with a regular soldering iron? Or, do I absolutely need a spot welder?
4. What shouldn't I touch? I don't want to get shocked by 40amps

Here's the video

[youtube]eMuKguRO-hU[/youtube]

[E-HP]

can you provide a link to the battery?

https://es.aliexpress.com/item/32965186267.html

There is no 48V 30Ah pack option in the link you provided. Can you point the the battery you have, in the specification table on the link page?

My bad! https://bit.ly/3hnc7mA this is the correct link.

I see the BMS doesn't trip until the cells are down to 2.8V, or 36.4V for the pack. When you say the bike it cutting off at ~50V, is that a resting voltage? My guess is that at rest, the voltage appears good, because each group has working cells. Bet either due to bad connections, or bad cells in the groups, the voltage sags quickly and trips the BMS (I'm guessing at least 3 bad cell groups). You may not see that on the readout if it doesn't update quickly enough before tripping.
Do you have a throttle, so you can slowly increase the throttle so you have a way of seeing the voltage sagging before it trips?

[kcuf]

"4. What shouldn't I touch? I don't want to get shocked by 40amps"

no offense

need book learning

basic electricity

[Tommm]

Quick update.

Talked to the Manufacturer and he had me opening it and shooting some video of me testing the BMS. There's definitely a bad bank.

So... I understand that a 3.5v battery CAN be saved. And I want to prepare myself for what's coming, which is making it work by learning how this thing actually works.

Couple of questions:

1. By changing the BMS to a smart one make a difference? Is the Pinout ribbon connector standard for all Chinese BMS?
2. Can I charge just that one bank with an external charger? say from an old cell phone, the brick kind.
3. If there's just a couple of cells gone bad. Can I solder them back with a regular soldering iron? Or, do I absolutely need a spot welder?
4. What shouldn't I touch? I don't want to get shocked by 40amps

Here's a link to the video: https://www.youtube.com/watch?v=eMuKguRO-hU

Unless there is something visible on the cells(rust, physical dent, nickel strip seperated) it is much more likely the BMS is crapped out. Changing it to smart bms would help yes.
Bypassing bms would just destroy the cells in that bank.

[john61ct]

Working without a BMS is no problem at all,

in fact much better and safer

for those with the gear and knowledge

[Davidcroatia]

I think bms is a last resort before disaster, and batteries shouldnt be ridden without it, im a noob but thats just my opinion, during shipping there is a lot of vibration so that could be the case, maybe its just some nickel strip missbehaving

[carlosebermudez]

Quick update.

Talked to the Manufacturer and he had me opening it and shooting some video of me testing the BMS. There's definitely a bad bank.

So... I understand that a 3.5v battery CAN be saved. And I want to prepare myself for what's coming, which is making it work by learning how this thing actually works.

Couple of questions:

1. By changing the BMS to a smart one make a difference? Is the Pinout ribbon connector standard for all Chinese BMS?
2. Can I charge just that one bank with an external charger? say from an old cell phone, the brick kind.
3. If there's just a couple of cells gone bad. Can I solder them back with a regular soldering iron? Or, do I absolutely need a spot welder?
4. What shouldn't I touch? I don't want to get shocked by 40amps

Here's a link to the video: https://www.youtube.com/watch?v=eMuKguRO-hU

Unless there is something visible on the cells(rust, physical dent, nickel strip seperated) it is much more likely the BMS is crapped out. Changing it to smart bms would help yes.
Bypassing bms would just destroy the cells in that bank.

The pack is brand new, I cannot return it cuz DHL charges me $300 to ship it. I'm pro changing the BMS to a smart one.

"4. What shouldn't I touch? I don't want to get shocked by 40amps"

no offense

need book learning

basic electricity

LOL I do have basi electricity knowledge, I have a hard time understanding complex cirquitry like what to test for on a BMS board, or how to bypass it to charge directly that one cell bank you saw on the video.

https://es.aliexpress.com/item/32965186267.html

There is no 48V 30Ah pack option in the link you provided. Can you point the the battery you have, in the specification table on the link page?

My bad! https://bit.ly/3hnc7mA this is the correct link.

I see the BMS doesn't trip until the cells are down to 2.8V, or 36.4V for the pack. When you say the bike it cutting off at ~50V, is that a resting voltage? My guess is that at rest, the voltage appears good, because each group has working cells. Bet either due to bad connections, or bad cells in the groups, the voltage sags quickly and trips the BMS (I'm guessing at least 3 bad cell groups). You may not see that on the readout if it doesn't update quickly enough before tripping.
Do you have a throttle, so you can slowly increase the throttle so you have a way of seeing the voltage sagging before it trips?

The BMS is tripping at ~50v after a full charge. It is not charging that one bank and is tripping when that bad bank reaches the minimum. That's my best guess.

The main question is, if I get my hands on a variable power supply, how can I charge just that one bank without having to take everything apart?. Or do I absolutely have to?

In the meantime, I want to leave it plugged in. The charger when its fan is off is outputting 54.5 volts. The pack charges to 54.0v. Does the remaining 0.5v is enough to slow charge the bad bank? I'm patient, if it takes two weeks I can live it. Have anyone had any experience charging like this?

Whats the general consensus on just buying a smart BMS and letting it do its thing?

[carlosebermudez]

on the screen with advanced settings and factory settings, can you get into those settings
can you see what the LVC setting is? and adjust it down to 42v or 39v?

or change the battery setting from 48v to 36v? to hack the lvc

Nope, can't change it on the 850c. Since I already know the problem I would like to fix it.