Batribike Breeze - cuts out after a few minutes

[Cancunia]

I've just bought a Batribike Breeeze, it came with a known problem that I hope someone here can help with. The drive cuts out after a few minutes & needs to be switched off, then back on to restart. The first cut out happens after 3 or 4 minutes of riding, after switching off & back on, the bike will run for 2 or 3 minutes before needing to be reset again.
The LED display shows a full battery when switching on, as does the charge display on the top of the battery, one thing that I noticed is that the battery charge indicator on top of the battery is dead after the drive cuts out, but shows full again after switching off and on.
After my initial tests which only latest a few restarts so about 10 mins riding, I recharged the battery, it only took a few minutes for the charger to show a full charge.

Any thoughts on what to test? I'm handy with a multimeter etc.

Thanks

 

[cyclebuddy]

Everything you say indicates a worn/knackered/life expired battery. The battery appears fully charged, but dies as soon as you put a load on it. The very short charge time confirms that. You can check that by fully charging it and measuring the voltage (it should be around 41-42 volts), riding the bike, and then as soon as it dies check the voltage again (likely around 30-32 volts).

Batribike claim to offer replacement batteries for every bike they make (click here), many commonly shaped/sized replacement e-bike batteries can be found on ebay, or you could consider having your existing one re-celled by someone like this specialist company (click here).

 

[Cancunia]

Thanks for the reply, the battery is suspect due to the bike's age. But what has me puzzled, is why does it then show a full charge at the LED display & also at the battery charge indicator after switching off & on again?

 

[cyclebuddy]

The battery has a Battery Management circuit (BMS) which cuts-off the power as soon as the cells sag too far to prevent the cells being damaged. Switching the battery off and on again resets it. By time you've done that, the cell voltage has recovered/bounced back somewhat. But that voltage is superficial - the cells have no "oomph" left in them.

Both your LED indicators are gauging surface voltage - not showing actual power remaining in the cells.

 

[vfr400]

The only way to be certain is to attach a voltmeter to the wires so that you can observe what happens to the volts when you take power. If it goes right down, then cuts off, it's a knackered battery. If it just goes off suddenly, probably a connection fault, faulty key switch or bad solder joint.

The key-switches often give exactly that problem. Either the switch itself fails or they have dry solder joints on the back. You can test by soldering a bridge across where the wires are attached to by-pass it.

 

[Cancunia]

I've taken the battery out of it's case to measure the cell voltages. My battery appears to have 10 rectangular LiPo cells approx 70x140mm, as opposed to cylindrical cells. I put a 240v 40w incandescent bulb across the terminals and after more than 3 hours the voltage has dropped approx 0.5 volt from 40.3 to 39.8v, the bulb is very dim so am guessing the current draw is not very high.
I appreciate what @cyclebuddy wrote above about the 'surface voltage' so am wondering if there's a way of increasing the test load.

 

[cyclebuddy]

I use 4 x 12v MR16 halogen lamps wired in series - the type used in domestic SELV kitchen/bathroom downlighters. The draw will be about 3.5-4A.

VFR's dry joint/faulty switch is a good point and continuity easy to test if the battery is now open.

 

[Nealh]

Test the battery statically on the bike, temporary rig up a volt meter you can see and lift the drive wheel off the ground. Whack it on a decent power level and apply the brake so the wheel doesn't quite stop, this will act as current loading and see what happens with the voltage. If it collapses then the cells have had it.

Knackered cells can still hold a full voltage charge but internally the cells can have internal high resistance which equates no ability to sustain or deliver any decent current loading.

 

[vfr400]

I use 4 x 12v MR16 halogen lamps wired in series - the type used in domestic SELV kitchen/bathroom downlighters. The draw will be about 3.5-4A.

VFR's dry joint/faulty switch is a good point and continuity easy to test if the battery is now open.

You won't find it with a continuity test because the contact only breaks down under high current.

 

[RoadieRoger]

Could be just a faulty BMS . I had similar on my 2 year old Pro Rider Flare . Jimmy diagnosed a BMS Fault and while it was being fixed I elected to increase my Battery Capacity from 10Ah to 14Ah with new Panasonics . Jimmy returned the 40 Samsungs to me and they were as good as new . I keep them charged up with a 10 station Power Bank after grinding off the tags . They fit Solar Lights amongst other things .

 

[Cancunia]

I use 4 x 12v MR16 halogen lamps wired in series - the type used in domestic SELV kitchen/bathroom downlighters. The draw will be about 3.5-4A.

By chance I have a few 12v halogen bulbs that I didn't get around to throwing away. I linked 4x 20W in series and the battery cut out after a few minutes. Cycling the power switch gave less & less time before the cut out. I rigged the meter so that it was permanently connected and it looks like the cut out occurs at about 32v but it may be a bit higher if the battery was discharging quicker than BMS reacted.
The battery is now back on charge and I'll see how long it lasts with the 4 bulbs from a full charge.
Assuming it's the battery, is there anywhere I can buy the 70*140mm 1000mAH LiPo cells or do I need to send off to a specialist refurb?

 

[Cancunia]

Could be just a faulty BMS . I had similar on my 2 year old Pro Rider Flare . Jimmy diagnosed a BMS Fault and while it was being fixed I elected to increase my Battery Capacity from 10Ah to 14Ah with new Panasonics . Jimmy returned the 40 Samsungs to me and they were as good as new . I keep them charged up with a 10 station Power Bank after grinding off the tags . They fit Solar Lights amongst other things .

Apologies for my newbie question, who is 'Jimmy'?

Thanks

 

[sjpt]

Jimmy at Insat: https://ebikebatteries.co.uk/
You'll find lots of warm references to him on this forum, often people assume you know him!

 

[Nealh]

Lipo cells are last years lithium for ebikes and in recent years decent safer cylindrical cells are the best option.

 

[Cancunia]

Many thanks to all that replied and for the help towards understanding the problem with the battery. I think I've now got to the point where I understand what's going on and why I get the confusing results.
There is one cell in the battery that only charges up to 3.5v while the others charge to 4.1v or thereabouts. The BMS shuts off the battery under load when the low cell gets to a certain point, while the rest are still relatively well charged, this results in an overall battery voltage at shutoff of about 38v and explains why the charge indicators show a full battery when restarting via the on/off switch.
I've written to Jimmy about a re-cell and have read some other posts on here about reputable replacement 'Silverfish' batteries, namely 'Yosa' from @RoadieRoger >here< If anyone else has recommendations for 'low' cost Silverfish batteries with a good rep, please can you let me know?
Also, as I'm a dabbler, I'm keen to see if I can squeeze a few miles out of the existing LiPo pouch battery. Does anyone know where to purchase LiPo pouch cells?

 

[Deleted member 16246]

Many thanks to all that replied and for the help towards understanding the problem with the battery. I think I've now got to the point where I understand what's going on and why I get the confusing results.
There is one cell in the battery that only charges up to 3.5v while the others charge to 4.1v or thereabouts. The BMS shuts off the battery under load when the low cell gets to a certain point, while the rest are still relatively well charged, this results in an overall battery voltage at shutoff of about 38v and explains why the charge indicators show a full battery when restarting via the on/off switch.
I've written to Jimmy about a re-cell and have read some other posts on here about reputable replacement 'Silverfish' batteries, namely 'Yosa' from @RoadieRoger >here< If anyone else has recommendations for 'low' cost Silverfish batteries with a good rep, please can you let me know?
Also, as I'm a dabbler, I'm keen to see if I can squeeze a few miles out of the existing LiPo pouch battery. Does anyone know where to purchase LiPo pouch cells?

I wonder if the low cell is just well out of balance with the rest, so that as the pack charges, the fuller cells reach the high voltage cut off well before the low one and stop the charging process. This leaves you with the low cell crippling the battery's capacity.

If you have access to the individual cells, with care, you could try discharging the stronger cells to the same voltage point as the low one, using your home made 'load'. Then give a full recharge and measure the cell voltages again. Connect your load to the positive and negative terminals on each of the strong cells in turn. If I was doing it, I think I would make a connection by rigging my multimeter leads to the wires from the load, so that I could monitor the voltage as I was discharging the cells. This would also provide nice probes to make the contact with the cell tabs. Be careful not to cause a short while doing this.

If you are not confident in what you re doing, don't do it.

 

[Cancunia]

I wonder if the low cell is just well out of balance with the rest, so that as the pack charges, the fuller cells reach the high voltage cut off well before the low one and stop the charging process. This leaves you with the low cell crippling the battery's capacity.

If you have access to the individual cells, with care, you could try discharging the stronger cells to the same voltage point as the low one, using your home made 'load'. Then give a full recharge and measure the cell voltages again. Connect your load to the positive and negative terminals on each of the strong cells in turn. If I was doing it, I think I would make a connection by rigging my multimeter leads to the wires from the load, so that I could monitor the voltage as I was discharging the cells. This would also provide nice probes to make the contact with the cell tabs. Be careful not to cause a short while doing this.

If you are not confident in what you re doing, don't do it.

That's an interesting thought and well worth investigating, the low cell has held it's charge perfectly overnight. However, does the BMS not charge the cells individually?
I have good access to the individual cells as the pouches are connected via flaps. Do I understand correctly, the idea is to leave the cells interconnected but discharge them one at a time? It should be fairly easy to rig the load in parallel with the meter leads, but as each cell is only 4v maybe a smaller load would be better.

 

[Nealh]

0.6v is a large difference voltage wise, either the BMS balance looking after it is faulty or the cell is faulty.
Its not really viable to buy just one lipo cell if you can find one of similar capacity or size, AliExpress is usually the place to buy from.

 

[Nealh]

That's an interesting thought and well worth investigating, the low cell has held it's charge perfectly overnight. However, does the BMS not charge the cells individually?
I have good access to the individual cells as the pouches are connected via flaps. Do I understand correctly, the idea is to leave the cells interconnected but discharge them one at a time? It should be fairly easy to rig the load in parallel with the meter leads, but as each cell is only 4v maybe a smaller load would be better.

It is simpler to try and manually charge the one low cell up to or near the level of the others then to discharge multiple cells singularly.
Manually charge the single cell and then watch to see what happens to it once left to rest for 24/48hrs, once charged leave it somewhere where it can't burn your house down should an issue occur.
If the battery has a BMS then it is often better to disconnect the balance connector and charge the cell through the balance lead with a < 500ma single cell voltage.
I use an old phone charger 5v and monitor the voltage every 10 -15mins to start with then keep an careful eye on the voltage as it nears the target figure.

 

[Cancunia]

I've rigged up a single 12v bulb to discharge the cells one by one and will see if the re-charge brings the low cells back up. I thought that the BMS would try to bring the low cells up, but this test will give an indication. If this fails, I'll look into charging the low cells individually via a usb charger.