Begode 134v Models (and possibly T4?) - Latest V4/C4 Charge Board drains battery packs for unknown reason

[Rawnei]

Bullet points gathered from the discussions:

• The V4/C4 charge board for Begode wheels drains the pack when fully charged
• It drains fast in the beginning but then slows considerably when nearing 131v (personal observation), expect to loose over 3v from a full charge if wheel is left untouched for a couple o days, possibly similar behaviour in the 100v T4 given similar charge board (not confirmed)
• Packs don't discharge by themselves only when connected to charge board, behaviour can not be explained by cell chemistry
• Discharge happens even when charge board is not connected to the motherboard so it's not a function on the motherboard that draws power
• Discharge did not happen on earlier version of charge board, my own reference is the V2/C2 charge board which did not have this behaviour
• Discharge happens even on perfectly balanced packs so it's not some active balancing function
• Kebye Gotway replied on a comment on Facebook regarding this issue but could not provide any clear answer why this happens

Original Post:

There are multiple versions of the charge board in the 134v Begode models, version 4 of the charge board I believe is the latest one at least I have not heard or seen of later revisions yet, it looks like this (distinguishing characteristic is that it has a cable to connect the motherboard instead of just a plug which makes it a bit easier to connect)

Background:

I have a Master V2 that originally came with the version 2 charge board, I had the same problem as everyone else that display and headlight stopped working in cold weather, I spoke to my AliExpress seller who spoke to Begode and who were going to send me the small driver board that you need to replace, to my surprise when the package arrived it also contained a new charge board, I asked my reseller why they also sent me a charge board and they simply said it was an optional spare and I only had to swap it if I wanted to, well huh how nice?

Skip to a couple of months later and there are rumors going around that Begode 134v charge boards had some sort of issue causing packs to become unbalanced and that resellers are advising and actively swapping charge boards out to the latest version 4, reading more and more about this I decided now was the time to swap mine as well, lucky thing they sent me one already!

Potential Problem:

My wheel charges to 134.4 just fine but I noticed several times that the day after charging and going out for a ride it had already dropped 1v or more sometimes which was very odd and concerning, after seeing this a bunch of times I decided to disassemble and start troubleshooting.

First I charged my wheel to full then I disconnected all the packs and measured them individually:

Left-Front: 67.3v
Left-Back: 67.2v
Right-Front: 67.3v
Right-Back: 66.3v

Ok one pack was lower, no need to panic, spoke with @supercurio who came over with his adjustable charger, we topped all the packs up so they we're pretty well balanced around 67.2v.

Second I left all the packs unplugged, I wanted to see if they would behave oddly on their own, if any pack was dropping voltage that would be very concerning but they didn't they kept their charge.

Third I connected all the 4 packs to the charge board but I did not connect the charge board to the motherboard, I wanted to leave them like this and see what happens, at this point the output from the charge board measured 134.3v.

Fast forward to around 24h later (give or take) and now the charge board only outputs 132.9v.. that's 1.4v lower just like that!

No point waiting even more, I am guessing it would just keep draining them more and more so again disconnect all the packs and measure them individually:

Left-Front: 66.4v
Left-Back: 66.4v
Right-Front: 66.5v
Right-Back: 66.4v

Ok so they are pretty decently balanced but for some reason the charge board is draining all of the packs, what's going on here? Is this a problem with the version 4 board in general or is there something wrong with mine?

What's Next?

I will again top up all the packs, this time more precisely balanced towards one another and see if the same thing happens.

I would like more people with the version 4 charge board installed to charge fully, leave the wheel overnight and then check voltage the next day, did the voltage drop significantly? Please report your findings in this thread!

Would also like to ask @Alien Rides @Kevin Graehl @Afeez Kay @eevees or any other reseller/service center that might read this if you guys have seen the same behaviour, please let us know. 🙏

Edited April 16, 2023 by Rawnei

[supercurio]

Let'e see:

Fully charged: 67.2V
4.2V per cell

After packs idling disconnected:
No drain

After connecting the packs to the charging board down to 66.4V:
4.15V per cell

Will it continue draining if remaining connected?

Edited February 23, 2023 by supercurio

[Rawnei]

10 minutes ago, supercurio said:

Let'e see:

Fully charged: 67.2V
4.2V per cell

After packs idling disconnected:
No drain

After connecting the packs to the charging board down to 66.4V:
4.15V per cell

Will it continue draining if remaining connected?

It would probably keep draining, I'm topping packs up again now to make them even closer to each-other then will do connect them again and see.

[Rawnei]

Balance-charged all the packs again and connected both the charge board and main-board with the packs, same thing it again they start draining.

New observation:

Rode my wheel to bit under 50% charge today (119.2v), left the wheel uncharged for 6 hours and no drain happened, it remained at 119.2v even after 6 hours so at least we know that at some point it will stop draining, so question is what the threshold is and why, will observe this and see.

[Wheel Guy]

I just installed the new charge board since I previously had the Barbecue fire edition. Tested this out with mine as well.

My first observation was that my wheel used to overcharge a bit, usually to 134.6-134.8v. After charging overnight with the new board, it charged to 134.2, and dropped to 134.1 quickly after starting it. So not even "full" which was annoying. Maybe it can even start draining when the charger is done charging?

After letting it sit for 24 hours, it dropped to 133.3v. So it seems mine behaves the same as yours.

I would love to see some testimonials from people with older boards as well, as I'm not sure if my wheel did this or not with the old board as well. But like you're implying, it sure seems like the new boards are draining the batteries more than the old ones.

[Paradox]

The Master Pro boards were also upgraded at the same time.  I wonder if those with MP also experience this vampire drain.

[Cerbera]

Charged mine this morning. 134.0v. 2 hours later (machine powered off) 133.7. So yeah - where is it going ?!

[Cerbera]

Andy from Speedyfeet had this to say on the matter...

and then...

Quote

Another thing is being a high voltage wheel(as opposed to say 84v or similar) the voltage drop perceived by the observer is greater. Ie the voltage range of the packs could range between 134(4.2v per cell) down to around 89v(if they use say 2.8v per cell) discharged ( a 44v difference) vs  an 84v pack which would have a difference of only 28v between full and flat. 

Point of that is that the perceived voltage drop of a higher voltage pack is greater than a lower voltage pack thus leading people to be concerned when they see a volt drop off for example. Ie the "same voltage drop" would look like 0.3 of a volt on a 84v pack. 

 

But hey theres plenty of other reasons too. Be interesting to monitor it over a few weeks however.(maybe I should do that)

I am not sure if what he says holds true or not, but I don't ever remember the previous charge boards doing this, and certainly no wheel I have ever ridden before has ever lost voltage between charge and power-up a day or so later....

[Rawnei]

1 minute ago, Cerbera said:

Andy from Speedyfeet had this to say on the matter...

and then...

I am not sure if what he says holds true or not, but I don't ever remember the previous charge boards doing this, and certainly no wheel I have ever ridden before has ever lost voltage between charge and power-up a day or so later....

We know it's not because of imbalanced packs as I've topped my packs individually to the same voltage using adjustable charger calibrated with multi-meter, it will drain all the packs regardless how balanced they are.

Also with a voltage drop of ~1.4-1.5v which I observed (if I waited even more might have drained more) that means cells went from 4.2 per cell to 4.15 per cell which is quite a lot IMO.

Of course it's fully possible that they have implemented some sort of balancing mechanic here but if so it's a really dumb one that will drain to a certain voltage regardless of how balanced the packs here, another possibility is that there is a design flaw at work, both Kebye and Fei have not commented on the post I made in which I tagged them in 3 different Facebook groups where they are usually active.

[Cerbera]

22 hours ago, Rawnei said:

Kebye and Fei have not commented on the post I made in which I tagged them in 3 different Facebook groups where they are usually active.

They are probably both sighing to themselves that people are still whinging after version 4 of the charge board, the last of which they have already had to send a lot of people for free already... can't see them doing it again ! But I have still got the old charge board - maybe that should go back in the wheel ?!

[Rawnei]

Just now, Cerbera said:

They are probably both sighing to themselves that people are still whinging after version 4 of the charge board, the last of which they have already had to send a lot of people for free already... can't see them doing it again ! But I have still got the old charge board - maybe that should go back in the wheel ?!

Not if that one causes worse problems which was the indication and reason to swap.

[Wheel Guy]

22 hours ago, Rawnei said:

We know it's not because of imbalanced packs as I've topped my packs individually to the same voltage using adjustable charger calibrated with multi-meter, it will drain all the packs regardless how balanced they are.

Also with a voltage drop of ~1.4-1.5v which I observed (if I waited even more might have drained more) that means cells went from 4.2 per cell to 4.15 per cell which is quite a lot IMO.

Of course it's fully possible that they have implemented some sort of balancing mechanic here but if so it's a really dumb one that will drain to a certain voltage regardless of how balanced the packs here, another possibility is that there is a design flaw at work, both Kebye and Fei have not commented on the post I made in which I tagged them in 3 different Facebook groups where they are usually active.

I may be over-analyzing, but I feel like it has a noticeable effect on range/voltage sag. I rode 35km after being off the charger for a day, arrived with 35%. Rode the same way and distance home after charging and arrived with 45%. Could be other factors, but I also felt that the sag at the start of the way there was more than usual. EUC World reported 65% battery after like 5 mins of 40km/h riding, that would normally be around 85-90% with the old board. 

[Cerbera]

10 minutes ago, loofv said:

I may be over-analyzing, but I feel like it has a noticeable effect on range/voltage sag. I rode 35km after being off the charger for a day, arrived with 35%. Rode the same way and distance home after charging and arrived with 45%. Could be other factors, but I also felt that the sag at the start of the way there was more than usual. EUC World reported 65% battery after like 5 mins of 40km/h riding, that would normally be around 85-90% with the old board. 

No I think we are right to over analyse this until it becomes clear what is going on and why, if it matters, and what we can do about it ! I have also noticed a similar drop in range, but I don't tend to accelerate or break very hard so haven't noticed it much in available ride power...

Edited February 26, 2023 by Cerbera

[Cerbera]

8 minutes ago, Rawnei said:

Not if that one causes worse problems which was the indication and reason to swap.

Yeah we kinda need to know for sure what the reason for the swap was. It's all been rather nebulous from Begode so far, as is their way...

[Rawnei]

1 minute ago, Cerbera said:

Yeah we kinda need to know for sure what the reason for the swap was. It's all been rather nebulous from Begode so far, as is their way...

Maybe Ian has some insight regarding the swap?

[Cerbera]

1 minute ago, Rawnei said:

Maybe Ian has some insight regarding the swap?

You'd think he would have told his technician ! But Andrew muttered something under his breath about better balancing / less fires and moved swiftly on when I asked him about it. I didn't press him, presuming he knew best, and pleased to get an updated part voluntarily replaced...

[Rawnei]

Mine stops draining at 133.0v it seems, that's 4.156v per cell.

[Wheel Guy]

6 hours ago, Cerbera said:

No I think we are right to over analyse this until it becomes clear what is going on and why, if it matters, and what we can do about it ! I have also noticed a similar drop in range, but I don't tend to accelerate or break very hard so haven't noticed it much in available ride power...

Good point. Yeah, it's not like it was beeping at me but hearing 65% when 5 mins into a 35km ride was kind of concerning, was worried I wouldn't make it :X 
 

 

3 minutes ago, Rawnei said:

Mine stops draining at 133.0v it seems, that's 4.156v per cell.

Interesting, after how long? I've had mine sit for half a day now, might give it a few more days and see where it is. 

[Rawnei]

8 minutes ago, loofv said:

Good point. Yeah, it's not like it was beeping at me but hearing 65% when 5 mins into a 35km ride was kind of concerning, was worried I wouldn't make it :X 
 

 

Interesting, after how long? I've had mine sit for half a day now, might give it a few more days and see where it is. 

I just let it be for like 2 days, checked this morning was at 133v in EUC World quickly went to 132.9v when turning on so must have been right there at the edge of what the sensor is calibrated too then checked many hours later still at 132.9v.

[Cerbera]

OK, if it doesn't drop past 133v that's not too dreadful. Mine hasn't gone down further than that either. I have taken to doing its main charge the night before a ride, and then I top it off an hour before I go to take it back up to 134 again. Not a massive drag I suppose...

[Rawnei]

I spoke too soon, it keeps draining just much slower, checked this morning 132.6v.

[Cerbera]

8 minutes ago, Rawnei said:

I spoke too soon, it keeps draining just much slower, checked this morning 132.6v.

Well...dammit

[Wheel Guy]

1 hour ago, Rawnei said:

I spoke too soon, it keeps draining just much slower, checked this morning 132.6v.

What the fuck... Is it too much to ask for Begode to ride their wheels at least a few times before they consider a part revision to be working?

[supercurio]

@Rawnei well then let's find where this energy is going with the help of the thermal camera!

[mrelwood]

19 hours ago, loofv said:

What the fuck... Is it too much to ask for Begode to ride their wheels at least a few times before they consider a part revision to be working?

Yes.