EX30 max charge current?

[Planemo]

With spring approaching in the UK I am getting geared up for using my server charger in anger on super long ride days. I have been looking around the webternet for answers as to how much current I can actually charge at but theres differing opinions.

I know theres a 15A fuse on the charge board so I guess thats the absolute max but I would like to know if it's possible to run up to that without problems. I ask this because from what I have seen, some say the max is 12A before the charge board cuts off. I read another comment that even with a charger set to 11.5A max the board cuts charge when the wheel gets to around 85%. I understand that charge current would likely decrease around this point but the poster stated that the wheel actually cut charging completely. It was also stated that to enable a proper charge to 100% the initial charge current had to be set to around 8A.

This would be a bit of a pain and make it a bit annoying. I don't want to have to keep an eye on the setup to see if charging has stopped, nor do I really want to run such a low charge as 8A.

If I can only get a max of 8A without having to keep checking whether charging has prematurely stopped it kinda makes it annoying that I splashed out on a server charger, not to mention the weight of the thing. However, if I can sustain a 12A charge I would be happy with that.

I appreciate that the Roger charge board bypass mod would remove these limitations but I'm really not keen on doing it.

Has anyone got any definitive info? I could do without having to learn about limitations on the day I am riding!

Cheers

[Bizra6ot]

2 hours ago, Planemo said:

..I read another comment that even with a charger set to 11.5A max the board cuts charge when the wheel gets to around 85%. I understand that charge current would likely decrease around this point but the poster stated that the wheel actually cut charging completely. It was also stated that to enable a proper charge to 100% the initial charge current had to be set to around 8A.

This would be a bit of a pain and make it a bit annoying. I don't want to have to keep an eye on the setup to see if charging has stopped, nor do I really want to run such a low charge as 8A.

If I can only get a max of 8A without having to keep checking whether charging has prematurely stopped it kinda makes it annoying that I splashed out on a server charger, not to mention the weight of the thing. However, if I can sustain a 12A charge I would be happy with that.

I don't remember where I read this fb or telegram, but some guys had this problem with the aliexpress charger (the cheapest one about $150 that was used by Roger at first) it didn't automatically ramp down the amps
After switching to the small one (i think it's the huawei 4830) they no longer had this problem

Edited February 14 by Bizra6ot

[Planemo]

Ah thats interesting. Yes, if the charger didn't automatically ramp down that would explain it. In that case I have no idea what my own charger will do, I did get it from Ali but it was sold as being for lithium batteries which would suggest (I would hope) it has automatic ramping. I haven't actually done a full charge on it so I don't know. And I don't really want to full charge with it until I'm out on a ride so...

Also, seems odd that there are so few cases of this 'non-ramping' being reported given so many people have bought and used server chargers. Personally I haven't seen any reports stating this but I'm grateful for your heads-up.

Aside from that, it would still be handy to know what I can actually commence charging at if anyone knows. I know 11.5A is OK as I have tried it but I would like to be able to use more if possible.

[Chriull]

2 hours ago, Planemo said:

Ah thats interesting. Yes, if the charger didn't automatically ramp down that would explain it. In that case I have no idea what my own charger will do, I did get it from Ali but it was sold as being for lithium batteries which would suggest (I would hope) it has automatic ramping. I haven't actually done a full charge on it so I don't know. And I don't really want to full charge with it until I'm out on a ride so...

Li Ion chargers do "automatically ramp down charging current" by design.

If charging current does not drop once about maximum charging voltage is reached either the charger is set to a higher/too high maximum charging voltage or something is seriously broken with the charger, bms or the li ion cells.

5 hours ago, Planemo said:

read another comment that even with a charger set to 11.5A max the board cuts charge when the wheel gets to around 85%

It makes no sense for a firmware to stop charging at 85% in because of high charging current. Either it should stop immediately or never at all!?

It's more likely that for example the bms stopped charging in because of single cell overvoltage (unbalanced battery) or this used euc had maybe a bms with temperature probes (litech?) sensing a too high cell temperature?

[Planemo]

18 minutes ago, Chriull said:

Li Ion chargers do "automatically ramp down charging current" by design.

If charging current does not drop once about maximum charging voltage is reached either the charger is set to a higher/too high maximum charging voltage or something is seriously broken with the charger, bms or the li ion cells.

Thanks for the confirmation. That said, these are 'data server' chargers so to be quite honest I don't know really how they are meant to work by design. I am only going by the fact that the seller clearly listed it as a lithium charger and of course many people have used similar over the last couple of years on EUC's. It does surprise me that a power supply in a data centre (which I would assume runs at a constant output) would be designed to ramp down. Who knows, maybe the sellers are modifying them to suit a charge situation?! 

In light of your comments though I do think maybe something wasn't set up quite right with the wheel in question. As you say, maybe unbalanced packs, a charge voltage set too high or a combination of several factors. I'm not sure that the wheel had Litechs as it was an EX30 and I don't think they ever had those packs.

 

[Chriull]

9 minutes ago, Planemo said:

It does surprise me that a power supply in a data centre (which I would assume runs at a constant output) would be designed to ramp down.

Most switched mode power supplies have some current limitation to protect themselves (?as it's easy to implement?) and the load/wirings.

This can be made either by turning off the power supply and restarting until the overcurrent situation is gone. Or by lowering the voltage so that just exactly the maximum set current flows. In this second case one has a li ion charger. It should additionally have a constant enough output voltage - especially in regard to temperature drift and aging. 

16 minutes ago, Planemo said:

Who knows, maybe the sellers are modifying them to suit a charge situation?! 

Imho just the voltage adjustment is made easily accessible to adopt to the different needed voltages for the different wheels?

17 minutes ago, Planemo said:

As you say, maybe unbalanced packs, a charge voltage set too high or a combination of several factors

Charge voltage set to high is something not nice for the batteries, as they are then (over)charged until the first cell reaches the maximum single cell overvoltage threshold of ~4.25-4.3V and the bms shuts off.

... and then the cells are discharged by the balancing resistors to ~4.2V again...

[Planemo]

31 minutes ago, Chriull said:

Or by lowering the voltage so that just exactly the maximum set current flows.

It's the the other way around isn't it?!

[Chriull]

Just now, Planemo said:

It's the the other way around isn't it?!

While charging it looks like the other way round. But what's "really" happening is that the psu/charger with no load outputs the maximum voltage. Once one plugs the euc on the charger the current starts rising and would increase above the maximum set current. So charger voltage is reduced until just the maximum current flows. As the battery charges and cell voltage rises charge current decreases a bit so the charger increase the voltage a bit.

Until maximum voltage is reached and current decreases.

[null]

It seems there are a few people who have this issue with recent Begode / EB EUCs, I have seen it mentionned here and on the french forum (extreme, T4). The charge board, which is shared among several models, allready have a behavior where it bleeds the top charge by a couple of volts (really not practical to see if there si a dead cell). Could it have some some sort of protection against high current that could be over-sensitive in some cases?

In my case the EBCPs cuts charge as soon as current is a bit high when approchaing 80-90%, (or even before, it doesnt seem to like being close to 10A*) and I have to make a manual ramp off to get it to finish charge. An other thing is it seems the EUC cut charge quite early, while the charger still pulls 120W or so from the wall. I monitor every charge, and all my other EUCs make a nice curved voltage graph stabilising at the end, the EBCP stops while voltage is stil (slowly) climbing.

The limited charging speed is not practical and the early charge stop is a bit worrying for ballancing (could their BMSs ballance bleed to a correspondingly lower voltage?) It feels like (something) expects current in a certain envelope and will cut charge as soon it is outside of that.

*I haven't been able to frame what happens properly as its been raining close to every day since I got the thing.

Edited February 14 by null

[Planemo]

1 hour ago, Chriull said:

While charging it looks like the other way round.

Ah so I wasnt going mad then! But your explanation makes sense now, its kinda back to front.

[Planemo]

18 minutes ago, null said:

In my case the EBCPs cuts charge as soon as curret is a bit high when approchaing 80-90%, (or even before, it doesnt seem to like being close to 10A*)

Great info, thanks for that. So you are one of the people who I was first describing, where the system is shutting down prior to peak voltage.

From what Chriull says, it seems this shouldn't happen. This issue is kinda what prompted me to start the thread, along with questioning what the peak charge current can be on the EX30.

[null]

36 minutes ago, Planemo said:

Great info, thanks for that. So you are one of the people who I was first describing, where the system is shutting down prior to peak voltage.

From what Chriull says, it seems this shouldn't happen. This issue is kinda what prompted me to start the thread, along with questioning what the peak charge current can be on the EX30.

Ah yes, thanks for the thread, I was considering making one for the same.

Indeed, whatever the reason it touches some people and not others. Chriull mentionned dead cell it looks like there are a bit many cases for it to be that, and also my EUC seems to hold the charge, save the bleed of the board. Beside, shouldnt the "difference between batteries" alarm (If it exists on Begode) warn us about that? I really wish GW/EB EUCs where easier to monitor while charging, currently it is a hassle (lay down EUC, power will time out, chunky voltage reading..)

As soon as I can I will try to frame the issue better, but for that I need to be able to ride it so I can charge it.

edit: a thread on the french forum in case that can get us somewhere..

Edited February 14 by null

[onewheelkoregro]

9 hours ago, null said:

It seems there are a few people who have this issue with recent Begode / EB EUCs, I have seen it mentionned here and on the french forum (extreme, T4). The charge board, which is shared among several models, allready have a behavior where it bleeds the top charge by a couple of volts (really not practical to see if there si a dead cell). Could it have some some sort of protection against high current that could be over-sensitive in some cases?

In my case the EBCPs cuts charge as soon as current is a bit high when approchaing 80-90%, (or even before, it doesnt seem to like being close to 10A*) and I have to make a manual ramp off to get it to finish charge. An other thing is it seems the EUC cut charge quite early, while the charger still pulls 120W or so from the wall. I monitor every charge, and all my other EUCs make a nice curved voltage graph stabilising at the end, the EBCP stops while voltage is stil (slowly) climbing.

The limited charging speed is not practical and the early charge stop is a bit worrying for ballancing (could their BMSs ballance bleed to a correspondingly lower voltage?) It feels like (something) expects current in a certain envelope and will cut charge as soon it is outside of that.

*I haven't been able to frame what happens properly as its been raining close to every day since I got the thing.

What version EBCP do you have? I was thinking about picking one up and I thought Begode resolved the issue of the 134.4 volt wheels not charging to 134.4

[Mrd777]

Super pain fast charging at 10-11 amps on my Ali fast charger on the ex30. It stops charging at 75%, and if you try to continue and turn down the amps it just won’t let you proceed . I have to then finish with the stock 3 amp charger. This charger works on a dozen wheels but not the ex30, and yes it ramps down to balance on every other wheel except the Ex30 at 95%. This behavior prevents the ex30 being my range long distance wheel if I need to charge on long trips.

[Planemo]

On 2/15/2024 at 3:50 AM, Mrd777 said:

Super pain fast charging at 10-11 amps on my Ali fast charger on the ex30. It stops charging at 75%, and if you try to continue and turn down the amps it just won’t let you proceed .

This is a disaster, totally not what I wanted to hear but I was kinda worried might be the case. What Ali fast charger are you using? One of the data server ones? This is the one I have:

Teswatts V4 Charger 4 Preset Voltage  90v 120v 0- 20A 15A 140v 126v 134v Quick Switch Adjust Power Supply XT60 GX16 V3 roger
https://a.aliexpress.com/_EJDY38V

On 2/15/2024 at 3:50 AM, Mrd777 said:

I have to then finish with the stock 3 amp charger.

This is weird because I can definitely charge from empty to full, including a balance, with my Ali 'no name' 8A charger which actually outputs 5.2A (tested), which is obviously still more than 3A but still far less than I could really do with.

On 2/15/2024 at 3:50 AM, Mrd777 said:

and yes it ramps down to balance on every other wheel except the Ex30 at 95%

Sorry I'm a bit confused about this...you said it would only go to 75% previously? *CORRECTION* sorry I misread, it ramps correctly at 95% with other wheels, not the EX30.

I can live with it if it does indeed go to 95%, but 75% would be a nightmare to work with.

Thanks for the feedback though despite it being rather depressing

Edited February 16 by Planemo
To correct response to Mrd777

[Planemo]

5 hours ago, onewheelkoregro said:

What version EBCP do you have? I was thinking about picking one up and I thought Begode resolved the issue of the 134.4 volt wheels not charging to 134.4

Just bear in mind that the issues being raised in this thread are not necessarily related to the problem you mention above. For clarity the main issues on this thread are:

1. What is the absolute max charge current for the EX30
2. What is the max charge current the EX30 can take and still complete a full charge

The issue you raise is separate as it was experienced even on the stock charger. Marty had this on his EX30 and he resolved it by fitting a Master charge board but as you say Begode may have modified the EX30/CP boards since. In any event the issue is independent of the 2 points above as even on Martys wheel the voltage still went to near max. Just wanted to clarify.

[Bizra6ot]

It's probably this guy who was talking about it on telegram or guys who were talking about him idk, try to contact him to find out more 
3. They auto ramp down. No need to manually ramp down the amps like my AliExpress charger.
https://www.facebook.com/groups/ElectricUnicycle/posts/7125107744253794/

[Planemo]

No I read about the 80%-ish charge cut off problem when over 8A from someone months ago. I'm just surprised that if this issue was widespread we would have heard more about it - I'm not sure I've ever actually seen it mentioned on this forum. In any event, whats causing it?! Assuming a wheel is fine with one 12A charger but another (eg server) charger cant go past 80%, why is that?! Any ideas @Chriull??

@Marty Backe, you have huge experience with Rogers server chargers on EX30/CP, did you ever have issues with them/the wheel shutting down far earlier than they should do? (assuming non modified charge boards)

[Tom384]

Hello, I have a theory about this phenomenon. When Begode started selling 134V wheels, they fundamentally changed the balancing of the battery pack. The 100V wheels had passive balancing, but for the 134V ones, they adopted a variation of an active balancing scheme. The difference can be observed in this picture:

https://www.researchgate.net/figure/Exemplary-passive-left-and-active-right-balancing-circuit-topologies_fig3_274655455

The advantage of the old method of balancing was its simplicity, but it is slow, and it dissipated a lot of energy as heat. Consequently, the charging power in balancing mode was strongly limited, and balancing was only possible at the end of the charging cycle.

Active balancing has the advantage of being applicable at any voltage level. It is much more efficient, eliminating the need for extensive thermal management of the Battery Management System (BMS). However, the implementation by Begode also has some disadvantages. It seems that the charging process follows this sequence:

When you connect battery the charger, the battery pack begins to charge until one of the cells reaches its maximal voltage. Balancing is provided at the start of charging. When one of the cells in the battery pack reaches 4.2V, the charging stops, but balancing continues until all cells have the same voltage.

If this is true, then it would explain the early stop of charging when one cell reaches its maximum voltage, especially at high currents. Additionally, it would explain why Begode's 134V systems often do not reach 134.4V. Finally, it would explain why the voltage of the battery decreases relatively quickly after charging stops, as balancing is still in progress.

Edited February 15 by Tom384

[Marty Backe]

7 hours ago, Planemo said:

No I read about the 80%-ish charge cut off problem when over 8A from someone months ago. I'm just surprised that if this issue was widespread we would have heard more about it - I'm not sure I've ever actually seen it mentioned on this forum. In any event, whats causing it?! Assuming a wheel is fine with one 12A charger but another (eg server) charger cant go past 80%, why is that?! Any ideas @Chriull??

@Marty Backe, you have huge experience with Rogers server chargers on EX30/CP, did you ever have issues with them/the wheel shutting down far earlier than they should do? (assuming non modified charge boards)

Yes, I and other have experienced this. You start charging at a very high current (~12-amps) which works fine and then when you return later you discover that the charging has stopped. So you decrease the current (let's say 8-amps) and the charging is able to continue.

I don't see this as a problem with the charger but with the distribution board.

[null]

Sounds interesting @Tom384, I would be glad for a more active ballancing. I'm afraid this would have been noticed from people inspecting the BMSes though.. Anyone?

Else: This is the adjustable charger I use. I never could reach 10A, maybe because the charge level wasn't low enough, not been able to test enough.
Until now all chargers I have bought from ali (no PSU chargers) have ramped down the current toward the end, some more gracefully than others but they always did. 

It would be great if this was confirmed to be linked to the distribution board as Marty suggests.

Edited February 15 by null

[Bizra6ot]

I had a chat with the guy from my link above, the problem with the Ali charger is the 1500W power vs 2500W for the 4830, so depending on the amperage it cuts off the charge at a certain voltage level because it just can't handle it

[null]

1 hour ago, Bizra6ot said:

I had a chat with the guy from my link above, the problem with the Ali charger is the 1500W power vs 2500W for the 4830, so depending on the amperage it cuts off the charge at a certain voltage level because it just can't handle it

Thanks for checking with the guy and getting back to us. I am not certain his conclusion is right though.
It should not matter how much readroom the charger has, li-ion chargers should not use more than max V*A, so in this case 134V*10A*=1340W (+loss) (*or whatever A it is). They should also not provide more Amps than they are set for, thus, the headroom is just there.
All chargers I have seen will lower their amperage when reaching the upper voltage.
Power supplies however do not modulate their A at the end in this manner AFAIK. It is the main difference between a PSU and a charger as far as I've understood. The modded server PSUs ought to follow the "constant current - constant voltage" stages, but who knows of course.

Edited February 15 by null

[Bizra6ot]

Feel free to talk to him about it i'm just reporting our chat, he rides the commander pro(which can be seen on the video that guli has posted on his home page) https://guli66.com/
with his Ali charger the charge cut off ~125V 12A then with the 4830 he now charges straight to 100% "As for the auto ramp down, it does go down on amps when the reading on the charger gets near 100%"

Watch the 2nd video with the close-up on the display
https://cdn.shopify.com/videos/c/vp/cdc5adec0e0a4577bca71f5ffeb20a73/cdc5adec0e0a4577bca71f5ffeb20a73.HD-1080p-2.5Mbps-24138445.mp4

Edited February 16 by Bizra6ot

[Planemo]

12 hours ago, Tom384 said:

but for the 134V ones, they adopted a variation of an active balancing scheme. The difference can be observed in this picture:

Interesting theory, and I never knew that the 134v had a version of active balancing, I thought they were the same as previous 100v wheels. Do you mind sharing where you heard this information?

10 hours ago, Marty Backe said:

Yes, I and other have experienced this. You start charging at a very high current (~12-amps) which works fine and then when you return later you discover that the charging has stopped. So you decrease the current (let's say 8-amps) and the charging is able to continue.

Thanks for the clarification. Thats a shame though, I could really do without having to keep an eye on the charge process to check whether it has stopped or not. What a pain, especially when my charge points (car outlets) are often away from where we are actually sitting  Interesting to hear that you were able to continue at around 8A though, after @Mrd777's comment that he has to drop right down to 3A.

10 hours ago, Marty Backe said:

I don't see this as a problem with the charger but with the distribution board.

I guess the answer to that is if the same charger at the same amp output goes to full charge on other wheels or Begodes with modded distribution boards it has to be the distribution board no?! 

10 hours ago, null said:

Else: This is the adjustable charger I use. I never could reach 10A

I can't get that link to work, would you be able to check please? FWIW, my server goes to 11.5A happily, and doesn't 'seem' to be struggling at that which would suggest that it could indeed go to 15A @ 134v if required.

9 hours ago, Bizra6ot said:

I had a chat with the guy from my link above, the problem with the Ali charger is the 1500W power vs 2500W for the 4830, so depending on the amperage it cuts off the charge at a certain voltage level because it just can't handle it

When you refer to the 'Ali' charger we really need to know which one you are referring to. From what I can work out, the 'data server' chargers all seem to be around 2500w output, I have even seen some quoted at 3000w. So they should be absolutely fine at 12A/134v (1600w). In short, I don't think this is a case of the charger not being man enough but of course I'm open to the suggestion.