Odd charger behaviour

[AndyBike]

OK. This is the buzzbike i got from CRC in their sale.
Battery is 360wh i think, and from the advertised recharge time(5 hours, im guessing thats going to be 2A
The motor is Bafang
The odd behaviour is when i plug the charger in, the light on the charger is green, and when i plug that into the battery it changes to red.
It should after filling the battery automatically change to green, but it isnt.
I am guessing how much charge ive used and working out roughly how long i need to leave it running, which is about 1/2 full, so i leave it about 3 hours.

So I can after 3h look at the charger and the light is red, but if i unplug the charger from the battery then plug it back in, if it is full the light will go to green, but it isnt doing that automatically.

I'm never going to leave it unattended for longer than i think it needs, so I dont think thats going to be dangerous, but the fact is with the light staying red its a worrying issue.

Because its from crc and crc is now shut down(or at least the old crc) i have no way of buying a replacement charger
I have contacted buzzbike previously looking for a fork, that they(buzzbike) were buying their stock off crc too, and could offer no replacements

Thoughts ?
Or just keep an eye on it while charging and dont let it run too long.
Charger warms up to quite hot, but not so its really too hot to hold,and certainly no hotter than the bosch charger on my Emtb. The battery itself remains cold

Alternatively should the general consensus be thats not good and for the sake of safety get a replacement charger, I have no problem paying whatever it costs for the actual Bafang charger for this model

 

[Cisco-man]

First point, is that when you DON’T plug the battery onto the charger, then the charger light will be green, so you have the correct behaviour there. If you measure at the charger output without the battery, do you get 42v - if you do, then the charger is functioning ok.
If it struggles to get to a green indicator when charging the battery, then your battery cells probably are out of balance, so try leaving it on charge for an extended period (with all due cares of course).

 

[Ghost1951]

OK. This is the buzzbike i got from CRC in their sale.
Battery is 360wh i think, and from the advertised recharge time(5 hours, im guessing thats going to be 2A
The motor is Bafang
The odd behaviour is when i plug the charger in, the light on the charger is green, and when i plug that into the battery it changes to red.
It should after filling the battery automatically change to green, but it isnt.
I am guessing how much charge ive used and working out roughly how long i need to leave it running, which is about 1/2 full, so i leave it about 3 hours.

So I can after 3h look at the charger and the light is red, but if i unplug the charger from the battery then plug it back in, if it is full the light will go to green, but it isnt doing that automatically.

I'm never going to leave it unattended for longer than i think it needs, so I dont think thats going to be dangerous, but the fact is with the light staying red its a worrying issue.

Because its from crc and crc is now shut down(or at least the old crc) i have no way of buying a replacement charger
I have contacted buzzbike previously looking for a fork, that they(buzzbike) were buying their stock off crc too, and could offer no replacements

Thoughts ?
Or just keep an eye on it while charging and dont let it run too long.
Charger warms up to quite hot, but not so its really too hot to hold,and certainly no hotter than the bosch charger on my Emtb. The battery itself remains cold

Alternatively should the general consensus be thats not good and for the sake of safety get a replacement charger, I have no problem paying whatever it costs for the actual Bafang charger for this model

My guess is that you are not leaving the charger plugged in for long enough. You seem to have decided that three hours should be enough.

Reading what you say above it seems likely that you have estimated that the battery is about half charged and that 3 house ought to be enough.

One way to find out what is going on is to measure the voltage at the output of the battery when you are thinking the charge should have terminated. If it is a 36v battery the voltage at the end point of charging should be 42v or 41.9v. You have tested the charger at 42v I think.

If the charger is at 42V, I would just leave it for longer until the light goes green. This is necessary anyway for balancing to take place. I leave mine for an hour or two on a green light to balance the cells.

You are right of course to pay close supervision. Also, pass your hand over the battery case to see that it is not heating up. You can do the same with the charger to get a feel for how much energy is being put into the battery. At the early part of a charge the charger will be warm, but as the battery approaches full charge the charger will become much cooler. This just follows the pattern of how much energy is being passed into the battery at the different stages of charging - more at the beginning and much less as it comes towards full.

 

[saneagle]

Yhe only way to be sure what's going on is with a meter. You can put one of these in your charge cable, then nerd out on everything it tells you:

Pardon our interruption...

 

[matthewslack]

If you were sufficiently worried/curious, you could open up the battery and check balance.

I have the same symptom on a much smaller and simpler scale with GoPro batteries. The yellow led is sometimes reluctant to go green, but disconnect/reconnect and green it is.

 

[jarnold]

If you were sufficiently worried/curious, you could open up the battery and check balance.

I have the same symptom on a much smaller and simpler scale with GoPro batteries. The yellow led is sometimes reluctant to go green, but disconnect/reconnect and green it is.

I've seen it when charging single Li Ion cells - no balancing involved. My hypothesis is that the charging algorithm is stuck in the CV topping off phase, and the battery doesn't quite make it to the desired terminal cut off current. It'd be interesting to see what the voltage and the current are doing.
When the charger is unplugged/plugged in again, it checks the voltage, and decides that the battery is as close to fully charged as makes no difference, and gives the green light.
As I say, I've seen this on single cells being charged by TP4056 circuits.

 

[thelarkbox]

Pretty sure one of my chargers behaves in a similar fashion if turned on prior to plugging into the battery.

But as soon as its plugged into the battery a second or so later it changes to red and charging ensues. and so far my rough hours needed and a suitable time set on the segment timer i use to kill charging regardless of my intervention, have been fairly spot on returning 1/2 an hour early to check on occasion finding it still charging and on other siilar occasions complete..

I dont recall ever disconnecting -reconnecting in any sequence tho..


Its probably due to a simple change in the logic applied perhaps the charger your used to displays green led when (If 'fully charged') while the new one may display red when measuring a bms voltage less than 42v??

The green led power floating until 'NOT-ed be the red condition. or other more oblique conditions to the same effect. -My best guess anyway..

Also the delay could be down to the testing cycle employed i doubt voltages are evaluated every rep of the logic loop perhaps every 1000 or 5000 loops?? so if not connected at the initial start up you may have to wait x seconds for the charger and bms to sync.

I know such devices 'should' be useable without any need to RTFM but is there a FM to RTF and cleaup how its expected to be used and operate? ?

 

[Cisco-man]

I've seen it when charging single Li Ion cells - no balancing involved. My hypothesis is that the charging algorithm is stuck in the CV topping off phase, and the battery doesn't quite make it to the desired terminal cut off current. It'd be interesting to see what the voltage and the current are doing.
When the charger is unplugged/plugged in again, it checks the voltage, and decides that the battery is as close to fully charged as makes no difference, and gives the green light.
As I say, I've seen this on single cells being charged by TP4056 circuits.

Interesting about the TP4056. I shall have a look at the ample documentation for it with interest. I see that it’s max current is 1A. Most chargers I’ve seen are 2A. Is there a 2A equivalent device?

 

[thelarkbox]

Interesting about the TP4056. I shall have a look at the ample documentation for it with interest. I see that it’s max current is 1A. Most chargers I’ve seen are 2A. Is there a 2A equivalent device?

tp4056 is good to charge a single cell or group of parallel cells only. 10x could charge a 10s battery quickly with a suitable 10a power supply behind them but would be a pita to wire up.. even if you can probably buy 10x for the price of 1 x amazon option on ebay/china

 

[sjpt]

Pretty sure one of my chargers behaves in a similar fashion if turned on prior to plugging into the battery.

I think that is not generally recommended, though it might depend on the charger.
I found it sparks on connection when I do that; I don't do it any more.
I'm pretty sure saneagle (much more reliable then me) has commented the same, pointing out that it can cause damage to the connection terminals.

 

[jarnold]

Interesting about the TP4056. I shall have a look at the ample documentation for it with interest. I see that it’s max current is 1A. Most chargers I’ve seen are 2A. Is there a 2A equivalent device?

I've only ever used it in products with a small single Lithium cell.

 

[Nealh]

Charger is generic dumb type so and leds changing colour is simply a function.
1. Green led no charge /no current = correct.
2. Red led when charging/ current flowing = correct.
3. The final changing of the led to green is dependant on the BMS swithcing off to stop the current .
No green usually means balancing still in process so red led will still show unless the process is disrupted.

Being 99% or more balanced, when the charger is disconnected and connected again the charger led will likely remain green (to indicate full charge). The BMS is asking for such little current (100ma or less ), there probably isn't enough current draw asked of the charger so the led doesn't change.

How long the final end of charge balance can take depends on the BMS balance specs, it may take 1/2hr or may take 1 - 2hours.

The BMS from PSWP that Sturmey linked to yesterday in another thread only had a 60ma balance rate , others can be lower at 40ma.

 

[matthewslack]

I've seen it when charging single Li Ion cells - no balancing involved. My hypothesis is that the charging algorithm is stuck in the CV topping off phase, and the battery doesn't quite make it to the desired terminal cut off current. It'd be interesting to see what the voltage and the current are doing.
When the charger is unplugged/plugged in again, it checks the voltage, and decides that the battery is as close to fully charged as makes no difference, and gives the green light.
As I say, I've seen this on single cells being charged by TP4056 circuits.

Might just be tolerances in a mass produced thing.

But always worth erring on the side of caution with a relatively complicated bunch of cells in an ebike battery.

 

[AndyBike]

I think I like the idea better that i just need to leave it a bit longer, to balance the cells

TBH electronics to me are like the cavemen trying to work out steam locomotion
And further It's not something i think i could get into. Too much to learn and im a bit long in the tooth to get into it, as i reckon its a deep rabbit hole.

I can take apart machinery, and pretty much anything mechanical, but electrics are not my bag baby. I'd probably cause more harm than good.

But I'll take what I can from this thread from the folks that know this stuff and should be able to get on.
I'll also see what I can find on the 'buzzbike' website or if i can find other queries and reviews off people who hire out their bikes.

 

[guerney]

@AndyBike - just grab yourself a multimeter. You've seen what happens on Ghostbusters when they cross plasma gun streams, so avoid crossing probes and you'll be fine. Then hit the expert dudes up with a fully charged battery voltage measurement. Any cheapo will do, or push the boat out a little further for this, which my calibration board really likes...

I bought from here:

ANENG AN8008/AN8009 Mini Digital Multimeter rm 409b double fuse auto-range medidor eléctricoTrue-RMS Transistor Capacitor Teste - AliExpress 1420

Smarter Shopping, Better Living! Aliexpress.com

vi.aliexpress.com

Ebay:

https://www.ebay.co.uk/sch/i.html?kw=ANENG+AN8009&toolid=20004&LH_PrefLoc=1&LH_BIN=1&_sop=15

Thanks @thelarkbox for recommending this ANENG.

 

[AndyBike]

@AndyBike - just grab yourself a multimeter. You've seen what happens on Ghostbusters when they cross plasma gun streams, so avoid crossing probes and you'll be fine. Then hit the expert dudes up with a fully charged battery voltage measurement. Any cheapo will do, or push the boat out a little further for this, which my calibration board really likes...

I bought from here:

ANENG AN8008/AN8009 Mini Digital Multimeter rm 409b double fuse auto-range medidor eléctricoTrue-RMS Transistor Capacitor Teste - AliExpress 1420

Smarter Shopping, Better Living! Aliexpress.com

vi.aliexpress.com

Ebay:

https://www.ebay.co.uk/sch/i.html?kw=ANENG+AN8009&toolid=20004&LH_PrefLoc=1&LH_BIN=1&_sop=15

Thanks @thelarkbox for recommending this ANENG.

thanks for the recommendation, but that type of thing woould be lost on me given the slightly mad in the head person i am.

I'd need to fully understand the numbers, what exactly voltage means - in relation to this or anything else. the pluses and minuses, what resistors are, how this works or that works and also why this works or that works.

So for me to do anything electronic, i'd really look to do a one year course in basic electronics. Maybe even an HNC
For me its not just doing something, but understanding the where, whys and whats of the subject.

And as said currently my head is not- repeat not in the right place to get involved in anything new.
---
Bike needs charging again. just gone from green(full power) to yellow(20-40%) and as thats just happened, i would guess battery level is maybe 38% or thereabouts.
5 hours for 0%-100%(probably not zero, maybe 5% is the type of level they'd take as it really needing charged before using again) so guessing at 40%, that should be 3 hours.
So I'll leave it for 3 hours and then check for heat build up, then again at 3h15m, with the final finishing time calculating at 3h30m.
So if after 3h30m the light isnt green, I'll look to get a replacement charger from a Bafang dealer

 

[chris_n]

The charger has nothing to do with Bafang, they only make the motor. The charger is related to the battery but I wouldn't expect that they are ever calibrated together.

 

[AndyBike]

The charger has nothing to do with Bafang, they only make the motor. The charger is related to the battery but I wouldn't expect that they are ever calibrated together.

Thankx
Looked at the charger and its from Kunshan ST Electronics(China) And its a good system. This is the system a company uses to hire out to their customers for home use so I expect all parts are above board.
input is 90w, output is 36v 2A And Ive the model and part number so if i do need a replacement, shouldnt be hard to find.

E-bike Charger - Kunshan ST Electronics Co., Ltd.

All 36V 48V All Previous Next 36V Previous Next 48V St-Charger ST charger provides you with efficient and eco-friendly power support We are a family Compact & Lightweight，Pluggable, Good Value Your reliable safety guardain Innovation for better life Visible Charging Status Breathing LED...

www.stchargers.com

 

[AntonyC]

Sounds OK to me. Near to full the charging slows down so take a good estimate - your 3 hours - then add an hour or two to finish off, and if still red give it all day on this occasion to balance up. If you haven't noticed range fading a lot it's pretty certain all's well whatever the final colour (for the reasons given up-thread).

 

[AndyBike]

Sounds OK to me. Near to full the charging slows down so take a good estimate - your 3 hours - then add an hour or two to finish off, and if still red give it all day on this occasion to balance up. If you haven't noticed range fading a lot it's pretty certain all's well whatever the final colour (for the reasons given up-thread).

Pretty much whats just happened, though it appears to have only taken 3h15m for the light to go green. Which i am both happy with and somewhat relieved

Clearly I just wasnt leaving it long enough, but im my own defence, it was the worry of if something was faulty, the risks of leaving it i didnt want to deal with. But thanks to the above who know more about charging behaviour than me and meant i just had to put my faith in those experienced voices

Phew.