Stock Trickle Charger Vs. Fast Charger 1 amp 100%

[LZMutant]

Hi everyone - 

Here's a first world question to chew on...

I have the Gotway stock trickle charger.  I also have ewheels' fast charger.  The stock charger and fast charger (1 amp, 100%) both take a long time to charge, which is fine by me.  I'm only in a hurry when I'm riding...

Ordinarly I run the wheel down to around 50%, then charge it back up to 100%.  Wash, rinse and repeat.

My question for you fine folks is, given that I don't need the wheel charged quickly in either case, which charger is safer?  

Thanks!

 

[erk1024]

There's a lot of discussion about this elsewhere on the forum already, so I'd search around and see if you can find it. I'll try to summarize it.

Lithium batteries don't like to be trickle charged, there is a certain optimal current to charge them, so slower is not necessarily better.

With the *huge* battery packs of the new wheels, the 4 or 5 amps of the eWheels fast charger is not coming close to stressing the batteries, and is not actually "fast" charging. The wheel can easily draw 10 to 20 amps continuous while you're riding it. So 5 amps is no big deal at all. This is doubly true with YOUR wheel, which has 8 parallel banks of 20 batteries (in series) each, so that 5 amps of charging is being divided between all those banks.

So charging with the stock charger at 1.5 amps is just a waste of time, and is also not helping the batteries in any way.

Your batteries will last longer if you don't leave them sitting around at 100%. If you charge to 100% all the time, then they could go as low as 70% of their original capacity after 500 charges. If instead you charge to 90%, you could double the life of the batteries, or charge to 80% and quadruple the life of them. Lithium Ion batteries like to be between 30% and 80%. And that's what's great about the eWheels charger because you can charge to 80% or 90% automatically.

BUT THERE IS ONE BIG CAUTION. The batteries need to be balanced once in a while. There was a guy on the forum who charged to 80% every day for *two years* and one of the cells in his packs got so unbalanced that the battery management system (BMS) cut the power because it noticed the voltage was too low on that one cell. In order to balance the cells, you have to allow it to charge to 100% and leave it there for a few hours or overnight, so it can rebalance the cells. The BMS' that we have only start balancing when you get close to 100% charge. Balancing the cells is slow. I charge my wheels to 100% once a month for that reason.

Now most people don't worry about this at all. They just charge to 100%. 500 charges means 500 rides. If you ride 20 miles on average per ride, thats 10,000 miles! If you get 10,000 miles out of a wheel, then you've gotten your value out of it, other components are probably getting worn out, and it's time to upgrade anyway! 

Edited October 20, 2019 by erk1024

[LZMutant]

Great reply - thanks a lot.  

Sorry I didn't take time to search.  Frankly the battery stuff has always been a little wonky to me...

Some folks have told me that as long as I ride all the time (I ride about 15 miles every day) charging to 100% is no big deal because the neurons are moving around...  That input was for my V10F, however.  With the Nicola Plus, you're probably right in that I should go to 90% instead.  The performance won't impact me at all, whereas the V10F really did perform better at 100% versus, say, 90%.

Recently I've read some scary feedback on fast chargers catching fire and whatnot.  Without raising a bunch of speculation I was just wondering if trickle chargers were safer.

Again - really appreciate your spelling it out for me.

[erk1024]

19 minutes ago, LZMutant said:

Recently I've read some scary feedback on fast chargers catching fire and whatnot.

I'd worry more about the cheap-as-possible chargers with no cooling fans that we seem to get from the manufacturers. The eWheels chargers look to have much better heat dissipation, and I haven't had any problems with the two I have. I always run them at max amps. But I've only been doing this hobby for a few months, so maybe others here have had failures? Dunno. There is always the possibility of getting a faulty unit, I guess.

If I charge from 50% back up to 80%, it's fast. I haven't measured it, but it seems like it only takes an hour or two, at which point you can unplug it and that removes the risk of a fire. If you want to charge to 100% and leave it on the charger, you could do it on a Saturday morning and then ride in the afternoon. That way somebody will notice if things are going sideways. But once you get to the balancing phase, the charger is drawing a fraction of an amp anyway.

All this info came from web sites or people on this forum, who (unlike me) know what they are talking about.  

[mrelwood]

I would like to take part in the conversation, but @erk1024 already said everything there is to say, and said it well and in an easily understandable form. So let me just raise my hat for his replies.  

[LZMutant]

Battery talk is as intimidating to me as Calculus...  I try to figure it out but eventually my eyes glaze over and my mind drifts back to simpler times of Ray-O-Vacs, AA or AAA.

Changing my mindset from a 980WH wheel to a 2100WH wheel has been a big adjustment.  If you haven't had an InMotion wheel before, understand that while they're really safe, they begin to throttle your top speed within about 5 minutes of your ride if you gun it.  My year has been spent charging up to 100% and enjoying 25mph for the 5 minutes or so I could sustain it.

Now?  On the Nicola I can begin at 70% and go faster than I want to.  I still find touching 25 is about the edge of my comfort zone, and I wind up cruising around 18 to 20.  The Plus can do that forever it seems.  Of course over time I'll should get more comfortable and my speeds should drift up, but only slightly.  I still don't consider myself a speed guy nor do I want to have that inevitable wipe out be at a high speed.

This has affected my charging routine and approach; and you've all been very gracious in helping me through my growing pains.

[Mono]

8 hours ago, erk1024 said:

Lithium batteries don't like to be trickle charged, there is a certain optimal current to charge them

That's new to me, do you have a source for this? I was in the believe that the charge current doesn't matter as long as it is under, say, 0.7 C or so (and/or, as long as the battery doesn't heat up under charging). You seem to say that a charge rate of, say, 0.05 C (20h until full) is bad for the battery? Getting hard data on battery degradation is very difficult in my experience, so I would be very interested to know the source.

Edited October 20, 2019 by Mono

[Mono]

3 hours ago, LZMutant said:

Recently I've read some scary feedback on fast chargers catching fire and whatnot.  Without raising a bunch of speculation I was just wondering if trickle chargers were safer.

I can see the argument why that would be the case, less current, less heat... On the other hand, charger safety really depends on so many things and in particular build quality, so I would think it is impossible to say this without observations. We only know how safe airplanes are because we officially count each time they come down and compare this number with their usage.

Edited October 20, 2019 by Mono

[Chriull]

43 minutes ago, LZMutant said:

Now?  On the Nicola I can begin at 70% and go faster than I want to.  I still find touching 25 is about the edge of my comfort zone, and I wind up cruising around 18 to 20.  The Plus can do that forever it seems.  

There is not only max speed affected but also the available safety margin.

43 minutes ago, LZMutant said:

nor do I want to have that inevitable wipe out be at a high speed.

Or even decrease wipe out chances at your "medium" speeds. 20-25 mph almost sound "nice" - but this 32-40km/h are already a "good" range for nasty accidents!

Don't really know the numbers for the nikola - but lets say lift cut off speed with really full batteries (84.2V - not the whole 100% range) is about 80km/h.

Then the maximum power output possible is at 80km/h / 2 = 40km/h.

Neither do i have any overlean logs to get limits data, but depending on the "severity" of ones acceleration/inclines overleans could be "possible/start" in the 50-60km/h range.

With 50% charge (assuming 99% is around 4.13V and 0% at 3.3V per cell -> 82.6V and 66V in total) would be around 74.3V.

That leads to a lift cut off speed of 80km/h/84.2V*74.3V~70 km/h.

So max power output possible at 35km/h - "overlean possible start range" very roughly around 45-55 km/h?

Down at 20% battery voltage is about 70V, lift cut off speed at ~66km/h, max power output at 33km/h - "overlean possible starting range" ~40-50?

All the numbers here are very roughly estimated, the power of the nikola is "huge" and mostly in your case more than enough safety margin available! This lower speeds for "overlean possible start range" should imho need real exzessive accelerations!

But, as life is hard and unforgiving if the going gets tough often everything "bad" tends to cone at once - one charged a bit less, drove a bit longer to lower charge, was going a little bit faster and than accelerated a bit faster than "normal/planned", was on a slight incline and some road eneveness.... and the first nasty faceplant arrived...

But with the wheel driving normally at the 20mph range, some peaks at 25mph, not too much acceleration in this range, some speed throtteling on inclines should give one more than enough safety margins!

 

[Chriull]

40 minutes ago, Mono said:

That's new to me, do you have a source for this? I was in the believe that the charge current doesn't matter as long as it is under, say, 0.7 C or so (and/or, as long as the battery doesn't heat up under charging).

With "older liions" 1C was specified fir charging and something around 0.5 (or this 0.7C) was (believable)"rumoured" to increase possible cycles.

"Newly" used cells (?sanyo/panasonic?) are specified for 0.5C charging.

Quote

You seem to say that a charge rate of, say, 0.05 (20h until full) is bad for the battery? Getting hard data on battery degradation is very difficult in my experience, so I would be very interested to know the source.

This "very low charge currents are bad for li ions" imho arose from a ?~two year? paper showing build up of dentrid like structures (in simulations) for LiFePo (or similar chemistries?) at these low currents. This structures could be reformated/went away again at "normal" charging currents?  Gotbvery quiet again after many newspapers mentioning this paper - or at leasr i did not hear/read anything in this direction anymore.

Has imho (about) nothing todo with our LiIon cells used.

5 hours ago, erk1024 said:

500 charges means 500 rides. If you ride 20 miles on average per ride, thats 10,000 miles!

Here a small correction: 500 hundred full (!100%) charges - two half xharges (50-100%) count as one charge cycle.

So if the range with one full charge is about 70 miles the number increases to 500*70~35.000miles!

... And then still about this 70-80% capacity is available.

[Mono]

On 10/20/2019 at 6:29 AM, LZMutant said:

Some folks have told me that as long as I ride all the time (I ride about 15 miles every day) charging to 100% is no big deal because the neurons are moving around...

Charging to 100% is in itself not a big deal, though charging always only to 85% doubles the life cycles of the battery (roughly from 500 to 1000 cycles). Keeping the battery at 100% charge in particular at higher temperature is what hurts the battery most. Keeping the battery always at 100% unless you ride, will degrade its capacity by 20% within one year, assuming ambient temperature of 25ºC. Keeping it at 40% will degrade its capacity only by 5% within one year. I haven't seen suggestions that it matters whether the "neurons" are moving in between. This may be a leftover from the good old days where chargeable batteries suffered from the memory effect.

Edited October 30, 2019 by Mono

[Ben Kim]

15 hours ago, erk1024 said:

There's a lot of discussion about this elsewhere on the forum already, so I'd search around and see if you can find it. I'll try to summarize it.

Lithium batteries don't like to be trickle charged, there is a certain optimal current to charge them, so slower is not necessarily better.

With the *huge* battery packs of the new wheels, the 4 or 5 amps of the eWheels fast charger is not coming close to stressing the batteries, and is not actually "fast" charging. The wheel can easily draw 10 to 20 amps continuous while you're riding it. So 5 amps is no big deal at all. This is doubly true with YOUR wheel, which has 8 parallel banks of 20 batteries (in series) each, so that 5 amps of charging is being divided between all those banks.

So charging with the stock charger at 1.5 amps is just a waste of time, and is also not helping the batteries in any way.

Your batteries will last longer if you don't leave them sitting around at 100%. If you charge to 100% all the time, then they could go as low as 70% of their original capacity after 500 charges. If instead you charge to 90%, you could double the life of the batteries, or charge to 80% and quadruple the life of them. Lithium Ion batteries like to be between 30% and 80%. And that's what's great about the eWheels charger because you can charge to 80% or 90% automatically.

BUT THERE IS ONE BIG CAUTION. The batteries need to be balanced once in a while. There was a guy on the forum who charged to 80% every day for *two years* and one of the cells in his packs got so unbalanced that the battery management system (BMS) cut the power because it noticed the voltage was too low on that one cell. In order to balance the cells, you have to allow it to charge to 100% and leave it there for a few hours or overnight, so it can rebalance the cells. The BMS' that we have only start balancing when you get close to 100% charge. Balancing the cells is slow. I charge my wheels to 100% once a month for that reason.

Now most people don't worry about this at all. They just charge to 100%. 500 charges means 500 rides. If you ride 20 miles on average per ride, thats 10,000 miles! If you get 10,000 miles out of a wheel, then you've gotten your value out of it, other components are probably getting worn out, and it's time to upgrade anyway! 

you missed one point, the batteries don’t magically die after 500 charges. They simply lose approximately 20% of their overall capacity after that many cycles. Consider a full cycle on Gotway Sanyo GA cells is 4.2v depleted down to 2.5V, considering Gotway wheels are considered dead at 3.33V, i think that 500 cycle number is also a bit conservative. I would say that pack would deliver a solid 20000 miles before the capacity loss becomes significant. 

Ive always said, the batteries in these EUCs will outlive the other components. 

Edited October 20, 2019 by Ben Kim

[ABEhrhardt]

I have an Airwheel S8+, supposedly built in early 2019.

I have four red LEDs to indicate charge state.

If I let it get down to 2 red dots, it charges to 4 red dots. I'm assuming that's a good system for not overcharging or letting it get too low.

The app mentions voltage, but has no battery power indicator.

Comments? Newbie, but engineer.

[ABEhrhardt]

15 minutes ago, Ben Kim said:

you missed one point, the batteries don’t magically die after 500 charges. They simply lose approximately 20% of their overall capacity after that many cycles. Consider a full cycle on Gotway Sanyo GA cells is 4.2v depleted down to 2.5V, considering Gotway wheels are considered dead at 3.33V, i think that 500 cycle number is also a bit conservative. I would say that pack would deliver a solid 20000 miles before the capacity loss becomes significant. 

Ive always said, the batteries in these EUCs will outlive the other components. 

Great to know. I intend to use this, mostly inside our huge sprawling building at the retirement community, on carpeted halls - sounds like I will not have to worry much about batteries for however many years I still have the ability to sit on a bicycle seat.

[Ben Kim]

44 minutes ago, ABEhrhardt said:

I have an Airwheel S8+, supposedly built in early 2019.

I have four red LEDs to indicate charge state.

If I let it get down to 2 red dots, it charges to 4 red dots. I'm assuming that's a good system for not overcharging or letting it get too low.

The app mentions voltage, but has no battery power indicator.

Comments? Newbie, but engineer.

all wheels contain a battery management system (BMS) which will prevent overcharging (and running the batteries too low). I wouldn’t worry too much about it 

[alcatraz]

The fires are most often from batteries that don't have a bms and are charged/discharged near their rated maximum.

While there are situations where the EUC batteries might have a problem, they are safer than some random hobby rc battery.

The fires in the smaller balance boards were due to extremely poor battery builds that no bms could ever manage. Many different kinds of used cells were mixed together.

The bigger the battery the higher the charge current it can take. The lower currents ~1.5A are normal (slow) charge for 300-500Ah. If you have a 1600Wh wheel 5A would be slow, and 10A "fast". I'm currently charging my 700Ah pack with 2.7A.

[Ben Kim]

30 minutes ago, alcatraz said:

The fires are most often from batteries that don't have a bms and are charged/discharged near their rated maximum.

While there are situations where the EUC batteries might have a problem, they are safer than some random hobby rc battery.

The fires in the smaller balance boards were due to extremely poor battery builds that no bms could ever manage. Many different kinds of used cells were mixed together.

The bigger the battery the higher the charge current it can take. The lower currents ~1.5A are normal (slow) charge for 300-500Ah. If you have a 1600Wh wheel 5A would be slow, and 10A "fast". I'm currently charging my 700Ah pack with 2.7A.

You mean Wh.   500Ah battery of any voltage would be bigger than a car lol 

[alcatraz]

1 hour ago, Ben Kim said:

You mean Wh.   500Ah battery of any voltage would be bigger than a car lol 

Yes, you're right. I've been studying 18650 datasheets and noone uses Wh there. Everything is Ah.

[mrelwood]

10 hours ago, Ben Kim said:

Ive always said, the batteries in these EUCs will outlive the other components. 

They should, but unfortunately that’s only in theory. Easily the most repairs I’ve had to do on my self-balancing vehicles has been replacing dead cells. Despite handling them using all the knowledge I’ve been able to gather from this forum and batteryuniversity.com, my 16S developed a dead battery cell at 5000km (100 cycles), and the other pack as well at around 9000km. And the Airwheel A3 battery was down to 30% of it’s original capacity at around 2500km (150 cycles).

Luckily all that also votes for not stressing out about batteries. Balance charge them every now and then and don’t leave at 100% or 0% for extended perioids of time. If they die, they die, and there has likely not been anything you could’ve done better.

[ABEhrhardt]

On 10/20/2019 at 11:23 PM, mrelwood said:

Balance charge them every now and then

Sorry. Newbie here. What does that mean? I've had my Airwheel S8 for over a month, and don't charge it unless it is down below half or I'm going to need a fuller charge for an outside trip (don't want it getting tired before I am). So it's usually not at 100% and I haven't let it get below 25%. How do I 'balance charge'?

Thanks.

[mrelwood]

1 hour ago, ABEhrhardt said:

How do I 'balance charge'?

Leave the charger plugged in for several hours after the LED on the charger turns green. That’s when the Battery Management System of the vehicle balances the voltages on the individual battery cells.

This is generally recommended to do after about every 10 full charge cycles. Once a month is probably good in most cases.

[ABEhrhardt]

Thanks. Once a month - will do.

[Aneta]

On 10/29/2019 at 8:21 PM, mrelwood said:

Leave the charger plugged in for several hours after the LED on the charger turns green. That’s when the Battery Management System of the vehicle balances the voltages on the individual battery cells.

This is generally recommended to do after about every 10 full charge cycles. Once a month is probably good in most cases.

Is there any actual evidence that the BMS in this wheel is a balancing BMS? It's very typical, at least in the world of e-scooters and e-bikes, that BMS's don't have a balancer. The advice to leave the charger plugged in to balance is common... then somebody opens their battery pack and, to everyone's shock, there's no balancer. I've seen this happen many times in e-scooters, what makes us think that all EUCs have balancing BMS?

[Chriull]

4 minutes ago, Aneta said:

what makes us think that all EUCs have balancing BMS?

The photos of the BMS boards.

[Aneta]

1 hour ago, Chriull said:

The photos of the BMS boards.

How does one determine by the photo if BMS has a balancer or not? What to look for? Apparently, there should be "bleeding resistors" for discharging higher-than-lowest-voltage cells. What do they look like? Here's a photo of the Gotway Tesla 84V BMS. Can someone point the bleed resistors here?

Edited November 1, 2019 by Aneta