Newbie, 48V battery pack not charging

[waratte]

It seems my battery isn't charging anymore, it still discharges fine from its last charging when it could charge.

The charger stays green when I connect it to the battery, only when it turns red is when the battery is actually charging, right?

I noticed this after I left it on the charger for about 6 or so hours at about 50% capacity. It didn't charge at all.

This is a pretty new battery, I've only charged it once.

What can I do to determine if it's the charger or battery? I'd like not to buy a new battery.

My battery: http://www.aliexpress.com/snapshot/6907042153.html

 

[999zip999]

Do you have a multimeter put it on the right DC setting above 60volts and probe the charger, post voltage.
Check fuse.

 

[waratte]

I'm guessing I just plug the charger in the wall and test the end terminals? I get 54v, does that mean the charger is good?

 

[dogman dan]

One reason a charger acts this way is it's unplugged. So look for broken wires at the plug. The connection fault could be on the battery side, but 54v on the charger side does indicate the problem is not on the charger side.

But the charger could actually be broken.

 

[waratte]

So how would I check my battery?

 

[dogman dan]

No voltage at all on the battery side of the charge plug would mean the problem is in the plug, the wires, or the bms of that battery.

If you find voltage at the plug, the problem, whatever it is, is the charger.

If you find voltage at both the charger and the battery plug, it's getting likely the charger will not turn on for some reason. One reason a charger will refuse to turn on is the battery is too discharged to charge safely.

How sure are you, that the pack is only half empty?

I found out really quick, that having spare chargers around is worth it's weight in gold. If nothing else, it allows you to go, OK, it works with the other charger, or doesn't.

 

[waratte]

Ah, I see, I got some voltage from my the battery side, 32ish Volts, so that means the battery is fine, right?

I do get voltage from the charger's side also, so I would need to get a new charger? Where could I find one at?

Well, I'm going by my bike's LCD, right now my battery is close to being completely out, I hope I didn't run it out too much, I've only had it for a couple miles.

 

[waratte]

Well, my battery is nearly drained, shouldn't that be expected? I haven't been really measuring my battery in any detail before now, but the first time I charged it the battery charged fine. I charged it fully, and my battery read around 50V and that voltage decreased as I used it, which is normal right?

Riding it I didn't go very fast, I had an average speed of about 20MPH and traveled about 35 miles before I started having these problems. Weight, I weigh about 180 lbs and my bike, I'm not sure but I could easily accelerate to nearly 30MPH on a flat road, but not enough power to climb steep hills.

Though, that 32V is what it reads out the charging port out of the battery, not the plug where it discharges at, it is right now discharging at 43V-44V. Is this bad?

I would really love to know where to get a new charger though.

 

[KarlJ]

Though, that 32V is what it reads out the charging port out of the battery, not the plug where it discharges at, it is right now discharging at 43V-44V. Is this bad?

Yes a 48V battery should rarely if ever go below 45V work on 3.5Vpc x13= 45.5V (which is ~5% of capacity remaining! and AVOID!)

 

[waratte]

Wow, what should I do then?

 

[Ykick]

Obviously verify connections and attempt to determine reason for BMS cutoff and perhaps why it won’t charge?

Someone comfortable with DVM and a little Ohm’s law can probably be guided to troubleshoot further but I’m not getting the impression the OP is ready for that sorta exchange.

At this point shotgun troubleshooting might cause more problems than it solves. Most likely need somebody with battery pack knowledge/skill to sort this out first person. You might find someone willing to step up and help if you narrowed down your location a bit?

 

[Voltron]

Though, that 32V is what it reads out the charging port out of the battery, not the plug where it discharges at, it is right now discharging at 43V-44V. Is this bad?

I would really love to know where to get a new charger though.

Yes.. getting different voltages between the charger port and the main output sounds bad. Usually with a popped fuse on the charger port (which is sometimes inside the case and has to be opened up to be gotten at) there would be no voltage there at all. Total guess, but maybe a balance wire got detached from the BMS, so the charger doesn't want to start up thinking the pack is way too low?
Sucks that you're having problems with a new battery... some pictures might help of course...

And getting a new charger is usually a matter of finding one with the right plug for the battery, or being ready to hack on a matching plug... unless you have some special battery like a Bionx, and or a Prodeco that charges to a weird in between voltage, any 48v lithium charger should work.

 

[waratte]

Obviously verify connections and attempt to determine reason for BMS cutoff and perhaps why it won’t charge?

Someone comfortable with DVM and a little Ohm’s law can probably be guided to troubleshoot further but I’m not getting the impression the OP is ready for that sorta exchange.

At this point shotgun troubleshooting might cause more problems than it solves. Most likely need somebody with battery pack knowledge/skill to sort this out first person. You might find someone willing to step up and help if you narrowed down your location a bit?

Yeah, I'm all new to this, would it be worth it to figure out the problem vs buying a new battery?

The bike still runs with the battery, it's just slower now since the voltage is lower. It never just cut off on me or anything.

 

[Ykick]

So not cutting off? And you continue to push it? Okay…

No doubt, it’s always better to figure out what’s wrong or else you will likely run into the same situation.

The fact that it never cuts off is suspect but with unfamiliar description terms and not even picture, how’s somebody supposed to offer help?

To dig down to this problem a person needs minimal electrical skills and ability to communicate with some knowledge of electrical terms.

 

[999zip999]

So where do you live ? As we might suggest support for you with MM or charger.

 

[Golyo]

Info about the battery, from the link in the OP:
Battery Model
48V 20Ah
Nominal Capacity (AH)
20ah
Nominal Voltage (V)
48V
Source Resistance (mΩ
about 40
Cell Specification
3.7V 2.3AH 18650
Cell Combination
9-parallel
13-series
Cell Quantity (parallel*series)
117
Discharge Cutoff Voltage (V)
41 +/- 1V
Charge Cutoff Voltage (V)
54.6V
Rated Discharge Current (A)
30A
Instantaneous Maximum Discharge Current (A)
130A
Maximum Continuous Discharge Current (A)
30A
Maximum Continuous Charge Current (A)
5A
Charge Mode
CC/CV
Standard Charge Current (A)
2A
Charge Time under Standard Charge Current
10
Fast Charge Current (A)
5A
Charge Time under Fast Charge Current
2.5
Charge Temperature Range
-20 - 60
Discharge Temperature Range
-20 - 60
Battery Size
70*170*260mm

Chargeing Cycles
>1000times
Recommender for Moto
Less than 1440W
Battery Net Weight
5.5kgs
Battery Gross Weight
7kgs

 

[waratte]

So not cutting off? And you continue to push it? Okay…

No doubt, it’s always better to figure out what’s wrong or else you will likely run into the same situation.

The fact that it never cuts off is suspect but with unfamiliar description terms and not even picture, how’s somebody supposed to offer help?

To dig down to this problem a person needs minimal electrical skills and ability to communicate with some knowledge of electrical terms.

I'm not sure what else I could show you honestly :s I'm new to all of this.

So where do you live ? As we might suggest support for you with MM or charger.

Near cincinnati, if that helps any.

 

[docw009]

Well, the good thing is you report the output of the battery is still around 43 volts. The internal circuitry should shut the battery off before it can go below the low voltage cutoff (LVC). For your battery, LVC should be around 41 volts.

Just to run thru the numbers, your battery has 13 groups in series. IF nominal voltage of one battery is 4.7, then 13x3.7 is 48.1 volts. Lithium cells are generally charged to 4.1 vols, so 13x4.1 is 53.3 volts. Most designers set the LVC at around 3.2 volts, so the lowest output is 41.6 volts. You will probably have an LVC both in the battery and the controller. The specs on the battery says it has one. However, quit using the battery.

If you overcharge a battery or run it lower than the over voltage and low voltage limits, it leads to deposits forming in the electrolyte. These can/will cause short circuits, which lead to over heating and possibly fires. That's why people were alert when you first reported 33 volts.

Now you have to figure out why it is not charging. Unless you know the seller will take the battery back, if it has a warranty, your next steps generally involve opening the battery and voiding any warranty.

I have no further input, as I don't have direct debug experience on battery BMS. Good luck, if you decide to dleve deeper.

 

[Ykick]

It can be irritating when folks ignore providing general location and just dump a link for us to click on and do the legwork and burn bandwidth of loading specs, images, tracking cookies, etc. More courteous IMO to at least read posting suggestions/guidelines and provide as much image/text detail in a “seeking help” post as possible.

Plus, off-site links often die and then there’s not much value remaining for someone in similar situation who comes across this forum post looking for help with similar problem. Many of us are motivated to help around here so that it's a "knowledge base" for all to use if/when the need arises.

“Feelings” aside, if you’re not able to use a DVM/DMM on the charger/battery output(s) I’m afraid myself and others won’t really be able to help you accurately determine where the failure’s occurring?

I’m not unsympathetic but if you don’t have the knowledge to use a DVM/DMM then you probably bought from the wrong seller.

Alibaba/Aliexpress is best for folks who understand that they’re gonna be the service technician if/when something as complicated and expensive as large eBike battery pack and/or charger needs attention.

I don’t recall someone doing service in the Cincinnati area but it may be worth a try to post in the “wanted” marketplace section.

Good luck…