Golden motor battery performance question

[Wolf krannich]

hello folks

I bought a Golden Motor kit 6 months ago. Magic Pie 4 heartless hub motor with 48v 10 ah battery.
Overall I am satisfied with the kit.
Usually I was able to do 20 plus km with almost no pedalling on one charge.
Since last week no more . I am now only able to reach 16 to 18 km.

The way it works there are 3 lights on the throttle: green, yello, red.

When green goes off you are still ok. When yellow goes off you almost dead etc.
Now the green light goes off almost immediately.

The battery used to charge up to 58.5 v. Now only up to 54.5 volt. And it deteriorates quickly.
I created a support ticket with the owner of Golden Motor Canada.

It's the weekend, so it's cool not to have an answer yet.

Anybody out there know what this might be? Any input on your experiences with this kind of thing?
Btw the battery/charger have a battery management system included, so it says.

Thank you kindly for your input

Wolfgang

 

[Wolf krannich]

Sorry about the typos! Its not a heartless hub (bloody auto correct feature). It is a gear less hub motor.

W

 

[George S.]

Seems like it might be a bad cell. You have cells in series (LiFePo) or series and parallel, for standard smaller cells. If something in the series goes bad, you can't get a full charge. No easy fix. The LiFePo cells are fairly easy to troubleshoot and swap, depending on the packaging. Could be poor balancing. Might help to leave it on the charger a long time, see if that brings the weak cell up. Or it could be something else. Might be a heartless battery pack. Sorry.

It's good to know what the 'normal' voltage was, and the large drop now. I hope it's all under warranty. Be interesting to know what GM does, given the problems with shipping batteries.

 

[Ann M.]

The battery is a good culprit; however, I'd also check the charger and the conditions where the battery is charged. Is it in the heat? Do you let the battery cool completely before charging; a warm to hot battery will not charge completely. Check the voltage output of the charger. Does that charger have an internal fan? If not, the charger may be overheating and cutting off too soon.

Just had a customer complain of a similar problem with a LiIon battery and his charger & battery were stored outdoors where both were warm. On top of that, he usually plugged in the charger right after a ride so the battery wasn't totally cool. I took his battery which was showing 'full' but not coming up to completely good voltage and brought it inside (in AC) and placed the charger (with no internal fan) slightly off the ground with better, cooler air circulation and that baby took a serious charge. Where he had only gotten about 30 minutes of ride time, I got over an hour and still not at the 'yellow' battery level. Let everything cool for another hour and again a real good charge.

So check out both the battery and the charger and charge conditions as possible issues.

 

[Wolf krannich]

The battery is a good culprit; however, I'd also check the charger and the conditions where the battery is charged. Is it in the heat? Do you let the battery cool completely before charging; a warm to hot battery will not charge completely. Check the voltage output of the charger. Does that charger have an internal fan? If not, the charger may be overheating and cutting off too soon.

Just had a customer complain of a similar problem with a LiIon battery and his charger & battery were stored outdoors where both were warm. On top of that, he usually plugged in the charger right after a ride so the battery wasn't totally cool. I took his battery which was showing 'full' but not coming up to completely good voltage and brought it inside (in AC) and placed the charger (with no internal fan) slightly off the ground with better, cooler air circulation and that baby took a serious charge. Where he had only gotten about 30 minutes of ride time, I got over an hour and still not at the 'yellow' battery level. Let everything cool for another hour and again a real good charge.

So check out both the battery and the charger and charge conditions as possible issues.

 

[Wolf krannich]

Thank you Ann.
Yes, I do not always let the battery cool off completely before charging. I always bring the battery in the house to charge it, especially now that temperatures are getting closer to freezing here in Canada.
I tried charging it several times today and the best charge it will take is 56.4 v which is less than what Gary Salo stated the optimum of 58.4v (I'll double check that number).
I'll check the output of the charger and post it as well.

Thanks for the tips!

Wolfgang

 

[Wolf krannich]

Seems like it might be a bad cell. You have cells in series (LiFePo) or series and parallel, for standard smaller cells. If something in the series goes bad, you can't get a full charge. No easy fix. The LiFePo cells are fairly easy to troubleshoot and swap, depending on the packaging. Could be poor balancing. Might help to leave it on the charger a long time, see if that brings the weak cell up. Or it could be something else. Might be a heartless battery pack. Sorry.

It's good to know what the 'normal' voltage was, and the large drop now. I hope it's all under warranty. Be interesting to know what GM does, given the problems with shipping batteries.

 

[Wolf krannich]

Thank you George.

I charged the battery several times today and the most it will take is 54.4 v.
I'll see if I make it to work tomorrow and what Gary Salo has to say.
Will post results here.
I'm starting to wish I had shelled out the 1200$ Canadian for a brand name battery.
Anyways, live and learn, right?

Wolfgang

 

[Wolf krannich]

Seems like it might be a bad cell. You have cells in series (LiFePo) or series and parallel, for standard smaller cells. If something in the series goes bad, you can't get a full charge. No easy fix. The LiFePo cells are fairly easy to troubleshoot and swap, depending on the packaging. Could be poor balancing. Might help to leave it on the charger a long time, see if that brings the weak cell up. Or it could be something else. Might be a heartless battery pack. Sorry.

It's good to know what the 'normal' voltage was, and the large drop now. I hope it's all under warranty. Be interesting to know what GM does, given the problems with shipping batteries.

 

[Wolf krannich]

By the way, no sign of life from Golden Motor Canada as yet. Logged a support ticket Saturday.

W.

 

[Ann M.]

I've used those Golden Motor systems to convert several trikes with the 48V battery from them and generally had no problems. Do remember that you have a warranty on the kit, so you should get some results from the company. They are much easier to work with than the parent company in China!

 

[Wolf krannich]

Thank you Ann. I have also been happy with the kit so far.
I logged a support ticket Saturday, so presumably Gary Salo will get in touch with me eventually.
I guess I'm just disappointed that my wife seems to be right (again): you buy cheap, you get cheap.
But then again, BIONX is more than twice the price and I guess their stuff breaks too . . .
I hope it'll get fixed without me having to spend too much money on shipping etc.

Cheers

Wolf

 

[JoePah]

@Wolf krannich I agree with George on this problem, but there are a couple of things you could try. I've charge LiMn cells in my hot Florida garage for the last 6 years, never worried or even thought about letting the battery cool down. Didn't seem to make a difference.

Golden Motors Canada has a terrific reputation and they've been around for a long time.. As long as youre still under warranty I'd bet they will make it right.

In the mean time, have you left the charger on the battery for 12 hours? Sometimes charging is halted because of cell imbalance. Maybe a longer soak time will equalize the voltage across the cells and will restore your fully charged voltage... That's what i do with my batteries once a month.

 

[J.R.]

Going into my second winter with my ebike I lose significant range/miles in the cold as compared to the warm summer. October in Pennsylvania with the mornings in the 40's F. and evenings in the 60's F. I lose about 5 miles per charge and come December I will have lost about 10 miles per charge. This of course has little to do with battery readings at full charge, but something to keep in mind. Also I do let my battery rest an hour or so indoors and charge at 68-78 degrees F. year round, I do believe it helps.

 

[Wolf krannich]

Yes

Going into my second winter with my ebike I lose significant range/miles in the cold as compared to the warm summer. October in Pennsylvania with the mornings in the 40's F. and evenings in the 60's F. I lose about 5 miles per charge and come December I will have lost about 10 miles per charge. This of course has little to do with battery readings at full charge, but something to keep in mind. Also I do let my battery rest an hour or so indoors and charge at 68-78 degrees F. year round, I do believe it helps.

thank you

 

[Wolf krannich]

Yes, Thank you JR.

I was wondering about this as well. In the last while it has been around 5 or 6 celsius (41 F) around 6 am when I need to leave for work, and that made a big difference.

Wolf

 

[Wolf krannich]

Seems like it might be a bad cell. You have cells in series (LiFePo) or series and parallel, for standard smaller cells. If something in the series goes bad, you can't get a full charge. No easy fix. The LiFePo cells are fairly easy to troubleshoot and swap, depending on the packaging. Could be poor balancing. Might help to leave it on the charger a long time, see if that brings the weak cell up. Or it could be something else. Might be a heartless battery pack. Sorry.

It's good to know what the 'normal' voltage was, and the large drop now. I hope it's all under warranty. Be interesting to know what GM does, given the problems with shipping batteries.

 

[Wolf krannich]

Hello George
Thought you might like to have an update:
Gary Salo got back to me after the weekend and a couple of days. Then a bit more time to log a proper support ticket. All in all he thinks it's the weather.
The current drop in temperature here in good old Canada, from 20 to 30 Celsius a few weeks ago to 5 to 15 Celsius now is supposed to be the culprit.
What I don't get is that the battery is kept in the house. I plug it in and ride. And the power loss is kind of apparent after a few hundred meters or so.
When I get to work the bike goes into the building with me, same deal, warm and cozy.
Also, no reply to why a 48 volt charger with an output of 58 volt will only charge the battery to about 56 volt, and only after several charge attempts, which then drops to about 52 volts very quickly.
I installed the watts up meter a few weeks ago to get an idea of the voltage and aH . The power loss occurred at least 2 weeks after the installation. Did you experience anything like that after you installed the watts up meter?
I appreciate your thoughts, or anyone else's for that matter. So it's normal to lose about 10-20% power when it gets colder? Also the bike cuts out when it hits about 48 volt power and according to Watts up meter, the most aH I ever get are about 8 to 9 , which equals power consumption after riding about 18 to 20 km, what I have is a 10 aH battery..

Just wondering..

Thank you for looking at this.

Cheers

Wolf

Ps I paid more attention to my spelling...

 

[JoePah]

@Wolf krannich All this discussion about the impact of cooler weather on charging voltage seems like a casual way of ignoring your problem.

Is there any way you can determine the age of your battery pack or when it was assembled? Cause a new pack that degrades quickly reeks of an old new pack that was lying around.

Also it seems a bit off that the low voltage cutoff for your 48v battery is 48v. Maybe ask GMC what should be the LVC. My 36v battery charges to 42V and cuts off around 34v.

IN the long run it's better not to charge your battery to 100%, so 56v is not bad. It's the LVC that is robbing your range, imo

 

[George S.]

@Wolf krannich

This is why electrical problems are not much fun! What Joe is saying makes sense, and it is only one piece of the puzzle, the LVC in the controller.

For the good news, if you can get 8-9 ah out of a 10 ah battery, that's fine. You want the LVC to stop pulling out of the battery at around that point. The key, right now, is how to get that 85% discharge. You should be able to just plug the charger into the 'empty' battery and get a full charge, without multiple cycles on the charger.

The Watts Up doesn't draw much. You can see what is happening if you turn on the battery system, on the bike, with no power being drawn from the motor. The circuitry will have a small draw. Any bad connection can leak power or prevent current from flowing. I solder everything, and use good connectors.

I agree with you on the temperatures. It would need to be colder for any real impacts, and batteries get warm when you draw them down.

There are a lot of things that change in the first six months. New riders get used to using the motor, they tend to go faster. This kills the range. Most battery packs that are run down completely will start to show some aging after 100 cycles. We always suggest to people going as 'big' as possible, to start. People generally go farther as they get used to riding. That means they are using the last half of the battery. That means you are drawing from a 'smaller' battery, a 5 ah battery, because that is what is left. You won't get as much current, generally, especially toward the end of the battery.

I monitor what is drawn from the battery, with the Watts Up, and what goes in, with a Kill a Watt meter that goes in the AC plug. What you want is to see is a steady watt draw when the charger is plugged into the bike battery. It might be 100 watts or 150 watts, but it should stay there for a while. It might drop toward the end. But if you have a 48 volt system and you draw it down 8 ah, a 2 amp charger will need 4 hours, more or less, to recharge. You want to see that happening.

Most people are not going to get into the details, but it's fairly simple. It becomes a routine. You know what you draw out of the battery, so you know what you have to put back in. For me, I generally draw down about 8 amp hours, and I know my 2 amp charger will need 4 hours to recharge. I know where the final voltage will be, about 41.4 volts.

You should be able to figure out if you are 1) getting a consistent 8.5 amp hours out of the battery 2) whether the charger is putting that back (hours to charge will work) 3) what watts you draw as you ride, which means what speed.
4) whether there is a consistent voltage where the LVC is cutting out (low voltage cuttoff).

There does seem to be a drop in voltage when you start out on a fresh battery. Some of that is normal, and it could be a slight 'overcharge'.

Not sure what the battery chemistry is, or the exact nominal voltage. It would be different if you have a 48 volt versus a 52 volt, Lion or LiFePo. My LiFePo pack has a very tight range on the voltage, from 41.4 fully charged. That drops a volt immediately. It's rated 36 volts but that would be just about dead.