Another Fast Charging Option

[Evel_Knievel]

Just wanted to share another fast charging method I haven't seen posted.

As I have multiple wheels (NB1 E+, KS-16S) as well as a ninebot mini-pro and an ebike. I was looking for a method that would work for all of them. Decided to purchase a Cycle Satiator (yes it's expensive but very versatile: http://www.ebikes.ca/product-info/cycle-satiator.html) and programed multiple fast 100% and 80% charge profiles it for each toy. Voltage is listed the original chargers for each and you just have to decide what amperage you want to charge it at. (up to 5A for the one I bought). I bought a packet of Anderson Connectors (https://www.amazon.com/dp/B005P9CATU/ref=pe_861660_138883610_fxm_4_0_n_id) and inserted them on each of the original chargers as pictured below. That way the original charger still works and you don't have to find these odd connectors for each toy.

Not trying to plug the Cycle Satiator just figured you all might find the setup useful as another option to consider.

I've read up on fast charging, but some if it goes over my head pretty quick (and I still have a few questions) so if anyone sees any issues please let me know. 

Cheers,
A

 

 

 

 

 

[meepmeepmayer]

So it's essentially a programmable fast charger? Very cool! Didn't know these exist. (Not sure why it has such a strange name, sounds like something a James Bond villain tries to activate at the end of the movie)

[Evel_Knievel]

Yes, a programable charger. They have several available, but I bought the one that will charge 36-84V batteries from 0-5 amps. That covers all my toys.

[meepmeepmayer]

Is the 80% charge (for example) by current/voltage (values that you have to find out yourself) or does it somehow allow setting a percentage and it will automatically charge to that? Probably not, but that would be very neat.

A 5A charger + some charge doctors for every wheel type will be cheaper than the eye-watering price of this, but just selecting a setting instead of fidgeting around must be nice (and if you have many wheels, it gets closer and closer to price parity). I guess the best way to see this is as a universal charger for nearly everything (not just EUCs). And the more stuff you have, the more tempting it becomes

[Evel_Knievel]

3 hours ago, meepmeepmayer said:

Is the 80% charge (for example) by current/voltage (values that you have to find out yourself) or does it somehow allow setting a percentage and it will automatically charge to that? Probably not, but that would be very neat.

A 5A charger + some charge doctors for every wheel type will be cheaper than the eye-watering price of this, but just selecting a setting instead of fidgeting around must be nice (and if you have many wheels, it gets closer and closer to price parity). I guess the best way to see this is as a universal charger for nearly everything (not just EUCs). And the more stuff you have, the more tempting it becomes

80% is strictly what I named that profile. It's charging to a voltage which I calculated to be 80% charge (4.0 volts per cell).

Totally agree about the price. I wish it was cheaper, but it only hurt once and was pretty easy for someone like me to rig up. I had justified it to myself with the whole idea of 80% battery charging making the batteries last +/-3 times longer, and not wanting to find/buy 4 separate chargers for all my toys + future ones. Now that I have it, I'm not really sure I have to worry about the battery wearing out before I get tired of one of the toys/  I do charge slower when I don't need a fast charge which is most of the time. 

Again, not trying to talk anyone into it, just sharing.

[meepmeepmayer]

2 hours ago, Evel_Knievel said:

80% is strictly what I named that profile. It's charing to a voltage which I calculated to be 80% charge (4.0 volts per cell).

Wow I never realized cut off voltage may be easier to do than cut off current! Can you share how to do the computations? (We had a thread about how to compute cut off numbers for the charge doctor, and the result was nobody knew how/if that could be done).

2 hours ago, Evel_Knievel said:

Again, not trying to talk anyone into it, just sharing.

It was not meant as criticism! But if you only have one wheel, maybe not worth it. 3 or more different types, it starts making a lot of sense. One charging block + just a few adapter cables.

--

Does this thing just charge, or does the name somehow imply it charges in a special way to improve battery life?

[Evel_Knievel]

6 hours ago, meepmeepmayer said:

Wow I never realized cut off voltage may be easier to do than cut off current! Can you share how to do the computations? (We had a thread about how to compute cut off numbers for the charge doctor, and the result was nobody knew how/if that could be done).

I'm not doing much calculating. You pretty much tell this charger

1) what current (amps) you want to start at, 0-5

2) what voltage you want to end at, 36-84V

It will then follow a constant current/constant voltage profile. A lot of detail on that here: http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries 

So all you really need to know is what voltage to charge to, which is conveniently on every charger you have. For example my KS-16S came with a 67.2 volt charger (1.6 amp which isn't too important). From what I can tell nearly everyone charges lipo cells to 4.2 volts per cell (100%) and 3.2 volts per cell (0%). Often times batteries will be labeled with a single nominal voltage which is often 3.7 volts per cell. So KS-16S I'm assuming is a 16 cell (67.2/4.2=16). If I want an 80% charge I'll charge it to 64v (16*4.0=64v).

And that there is stretching my understanding of lipos so please correct me if I'm doing something that is going to burn my house down. LOL 

6 hours ago, meepmeepmayer said:

It was not meant as criticism! But if you only have one wheel, maybe not worth it. 3 or more different types, it starts making a lot of sense. One charging block + just a few adapter cables.

Agreed. I have four different toys, if I'm able to keep from buying a single replacement battery because of this then it's close to worth it. Ebike battery is probably $500. It is nice having the ability to change the % and speed of the charge you need. Typically I'm only charging all my toys up to 80%. Will charge to 100% once a month or so just to balance cell voltage which KS has confirmed only happens once the battery is charged to 100%.

6 hours ago, meepmeepmayer said:

--

Does this thing just charge, or does the name somehow imply it charges in a special way to improve battery life?

Charging only. It gives the watt-hours and amp-hour details which is pretty useful if you want to nerd out on the battery health and range details, but the only thing that's affecting battery life is the voltage (and to some extent amps but from what I can tell 5 amps isn't hurting the larger batteries much).

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

So you could charge to 4.3 volts per cell and get some extra capacity out of your battery but it'll decrease the number of cycles you'll get out of the battery.

[abinder3]

This looks like a 'take-off' of the programmable chargers that have been available for several years in the R/C vehicle and plane/helicopter hobby. 

 

Allen

[esaj]

9 hours ago, Evel_Knievel said:

So you could charge to 4.3 volts per cell and get some extra capacity out of your battery but it'll decrease the number of cycles you'll get out of the battery.

Not an expert, but my understanding would be that charging to 4.3V won't give much if any meaningful extra charge, while it does stress the cells much more (most battery fires seem to be caused by overcharging, btw). If you look at the typical voltage curves of the discharge graphs, you see that usually the voltage drops very fast from the (around) 4.2V at beginning, and then drops far more linearly towards the end, where it again dives faster as the cell is becoming depleted, as an example:

That's 10A discharge, so the drop at the beginning is pretty much immediate, but it looks similar with lower discharge currents too. I doubt in terms of total amp hours / watthours, you'd get much if any more useable capacity with charging to 4.3V instead of 4.2V, while risking battery damage.

[meepmeepmayer]

13 hours ago, Evel_Knievel said:

So all you really need to know is what voltage to charge to, which is conveniently on every charger you have. For example my KS-16S came with a 67.2 volt charger (1.6 amp which isn't too important). From what I can tell nearly everyone charges lipo cells to 4.2 volts per cell (100%) and 3.2 volts per cell (0%). Often times batteries will be labeled with a single nominal voltage which is often 3.7 volts per cell. So KS-16S I'm assuming is a 16 cell (67.2/4.2=16). If I want an 80% charge I'll charge it to 64v (16*4.0=64v).

Thank you!It all makes sense once you know the 3.2V number the cells start at!

Was wondering if there is another way to find cut off voltage vs battery percentage than doing the experiment with the real wheel, and there it is. So simple, you need to know just the type of cells and their configuration!

Does the Cycle Satiator allow cut off by current?

Even if it does not, IF there is an easy way to get cut off current vs battery percentage (just like with voltage), please don't hold back in telling us! [ This was the original question, because by default the charge doctor uses that. Nobody really knew how to (approximately) compute cut off currents. Turns out we should have wondered about voltages ]

(Voltage is better anyways, just out of interest)

13 hours ago, Evel_Knievel said:

And that there is stretching my understanding of lipos so please correct me if I'm doing something that is going to burn my house down. LOL

I certainly wouldn't know much about batteries...

13 hours ago, Evel_Knievel said:

So you could charge to 4.3 volts per cell and get some extra capacity out of your battery but it'll decrease the number of cycles you'll get out of the battery.

... except that this is a bad idea and will just ruin battery life. I think the "water baloon" analogy of batteries is quite apt. Push too much water into there, and the skin gets stretched and porous/brittle/susceptible, just like charging close to 100% (or even above) apparently stresses the cell membranes quite a lot. (and thanks to @esaj we know the details and that it would not even give more capacity)

[Evel_Knievel]

4 hours ago, esaj said:

Not an expert, but my understanding would be that charging to 4.3V won't give much if any meaningful extra charge, while it does stress the cells much more (most battery fires seem to be caused by overcharging, btw). If you look at the typical voltage curves of the discharge graphs, you see that usually the voltage drops very fast from the (around) 4.2V at beginning, and then drops far more linearly towards the end, where it again dives faster as the cell is becoming depleted, as an example:

That's 10A discharge, so the drop at the beginning is pretty much immediate, but it looks similar with lower discharge currents too. I doubt in terms of total amp hours / watthours, you'd get much if any more useable capacity with charging to 4.3V instead of 4.2V, while risking battery damage.

 

I'm not an expert either or arguing with you nor planning or recommending that anyone try it, but had just read the following on the previous link: 

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

I took that (right or wrong) to mean that 4.3 volts/cell would give extra capacity but definitely would stress the battery.

I will admit that it would be VERY easy for someone to make a BIG BIG mistake using the above charger as I have it setup..If I tell the charger to give my 13 cell ebike battery (54.6 volts at full capacity) a charge meant for my 14 cell ninebot mini pro (58.8 volts at full capacity), I will be giving the ebike battery a 4.5 volt per cell charge which will not end well! This would be as easy to do as making a mistake selecting the profile on the charger. In other words if you choose to do this, PLEASE BE VERY VERY CAREFUL!!!

 

[Bonzo]

Too bad it doesn't go to 84v for my ACM 1300.

Luckily my ebike charger is 84v @ 6A, so I just used that. Works great.

[meepmeepmayer]

@Bonzo There are different variants! One of them is up to 100V and 5A (which incidentally is exactly the usual limit people give for the Gotway 84V charge ports - 6A is pushing it, but if it works...). So you can use one of those for charging your ACM 1300. Check the site/pdf it's in there.

[Bonzo]

@meepmeepmayer thanks for the info on the higher voltage Satiator variants, I was unaware they existed and should really help in  getting a LOT more cycle life out of the 18650 batts, by limiting cutoff voltage, even though I am sure I will have to go to 100% occasionally, to balance due to the rudimentary BMS in Gotways. 

I have used Justin's cycle analyst for many years on my ebikes, so I know his products are worth the xtra $$. I have over 7000 miles on my current ebike. (52mph, 84v 26.1ah, 7500w, rear hub, dual suspension MTB)

Your comment led me to youtube to watch the 1:44min of Justin's place, Grin Tech, love the homegrown, honest,  70's feel of the place. Incidentally, my name is Justin as well  Thanks again.

 

[Lorents]

Thanks for the info on the Cycle Satiator guys! Just ordered the HV version

[meepmeepmayer]

@Bonzo They say you should charge to 100% every 10 times (cycles?) or so (maybe even have the charger plugged in a while after it is finished), and then give the BMS at least 20 minutes to balance.

Just repeating what I read here somewhere, no expert!

[Lorents]

Its a good idea to let the BMS balance the cells every now and then. How often you should do it depends on the state of your battery pack. It may take months and maybe years before a new pack whith healthy cells gets out of balance, but unfortunatelyyou never know what state your battery is in before you tap in and measure each cell individually

If you plan on taking a longer ride it may be a good idea to charge to 100% and let the BMS do some balancing before you take off. Just dont let the wheel stay 100% charged for days or weeks.

[Evel_Knievel]

You guys are correct about needing to balance (every once in a while). Exactly what that means I'm not sure. I'm planning on doing it once every 2 months on the riding toys. I do know it's important to balance every flight on my drone but it has got to be a lot harder on batteries (faster drain - those batts get really hot!)  The more I read on it the less important I think it may be since we rarely suck EUC batteries down past 20% and drain is pretty slow compared to the battery size.

Another interesting thread is 

Found it last night, but apparently ninebot's chargers in north america may be charging to 80% only. Seems to make sense so I may need to adjust my satiator profiles. As many of you all know, BMS's can balance continually or once max voltage is reached. I've confirmed with KingSong engineers that they only balance at max voltage. Kinda wonder about ninebot. I haven't heard of anyone having battery issues so either my NB1 E+ and NB Mini Pro balance continuously or it's really a nonissue. Anyone have an idea?   

[meepmeepmayer]

Balance = the BMSes well... balance (optimize?) the last tiny voltage differences between the individual cells. Given that everyone says you should regularly charge to 100% and then wait a little, seems like that happens only at full batteries (higher voltage differences fix themselves anyways, as the cells are connected) and not always.

No expert!

[Evel_Knievel]

2 hours ago, meepmeepmayer said:

Balance = the BMSes well... balance (optimize?) the last tiny voltage differences between the individual cells. Given that everyone says you should regularly charge to 100% and then wait a little, seems like that happens only at full batteries (higher voltage differences fix themselves anyways, as the cells are connected) and not always.

No expert!

I'm no expert either LOL I read this here:

http://www.ebikes.ca/tools/charge-simulator.html

Partial Charge and Cell Balancing

One of the only downsides to partial charging is that many inexpensive battery management system (BMS) circuits will only do active bleed balancing of the cells when they are at or near the full charge voltage of 4.2 V/cell. This means that with partial charge profiles that don’t reach that voltage, the BMS circuit will never be able to rebalance cells if they are drifting apart. Over time you may have less available capacity from the pack as certain cells will hit the low voltage cutoff on discharge well before others.

If this is an issue it can be easily remedied by occasionally (like once every month or two) leaving the pack connected to a 100% charge cycle overnight.

Good quality programmable BMS circuits will usually attempt to balance the cells whenever they see more than a certain voltage spread between the highest and lowest cell in the group, and in that case there is no problem with partial charges. Similarly, good quality cells rarely drift out of balance in a series string, and can easily handle 100 or more cycles and maintain a perfect voltage matching even if the BMS circuit doesn’t do any active balancing. But if you aren’t sure of the makeup of your battery pack, then the protocol of occasionally giving a 100% top-up is a good bet to ensure both a long cycle life and evenly matched cell voltages.

_______________________

I asked KingSong and they said they only balance at 100%. I haven't been able to find out about my ebike. Since reading that the NB1 E+ and NB MiniPro are both 15 cell batteries but come with 61 volt (NB1 E+) and 59.5 volt (NB MiniPro) chargers. From the other threads it seems everyone outside North America is sent a 63 volt charger for the NB MiniPro (as well as many replacement chargers). I called Ninebot today and was told that even a 63 volt charger will work on the minipro because the BMS will only allow the battery to charge to 59.5 volts (you can't overcharge it and will get the same range regardless of the charger). Seems like the ninebot products may be charging and probably balancing at 80% rather than 100% and might even be doing it continuously. Pure speculations on my part.