I too would agree with vfr400 & wheeliepete, good advice here. Going back to the OP of this thread, the charger Nealh was using to demonstrate his methodology is fairly generic, I have the same one with a different brand name. It seems the real key to achieving the 'perfect charge' is to know exactly what voltage your bike battery requires for optimum performance & longevity.
Basic Sans charger mods/adjustments.
- Thread starter Nealh
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I'm at total loss here. Everywhere I look, even on different eBike forums I see the tips that you shouldn't charge to 100% but rather 80%. Seems that everyone at least agrees that one shouldn't run it really low to often.
Have I gotten it right when I say, that for one cell there's definitely some truth to "80% 20%" charging method (numbers dependent on what cell). However, for unknown cells and unknown bms there are too many unknown variables that using that technique could actually make it worse and therefore it's better to just charge full to keep the cells well balanced?
Perhaps I need to open my battery to get a better sense on how the yose power china batteries work...
Have I gotten it right when I say, that for one cell there's definitely some truth to "80% 20%" charging method (numbers dependent on what cell). However, for unknown cells and unknown bms there are too many unknown variables that using that technique could actually make it worse and therefore it's better to just charge full to keep the cells well balanced?
Perhaps I need to open my battery to get a better sense on how the yose power china batteries work...
Don't do it, it will only add to your confusion
I bought a yose power battery a couple of months ago for a project which didn't go to plan, so ended up deconstructing it to use on another bike. Good quality LG cells, but with variable internal resistance between the cells and nickel plated steel connectors, which isn't ideal. Overall, well constructed with plastic cell holders and silicon wiring, but this provides no indication of how the rest of their batteries are built because they may well come from different suppliers, they are a reseller, not a manufacturer, which just adds another variable. "Charge it, use it or lose it" is the best advise, unless you want to enter the world of self-build battery packs.I understand your dispair. As I said before, people are reading what's on Battery University, which is about single cells and management system design and then trying to apply it to their batteries without changing anything. They then post on forums what they read, but they miss out salient facts, and so the myth gets propogated.
If you could change the management system in your battery to one that works at a lower voltage, then you could reduce the charge voltage and maybe increase the life of your battery. Some management systems are adjustable by cable or bluetooth, and some have manual balancing. If you have one of those, then by all means go ahead, but most others are fixed to charge at 42v for a 36v battery, so that's what you must charge to.
If you don't have a management system at all, like the guys who use lipos, then you can charge to whatever voltage you want below the maximum.
The full charge to 100% can be bad in wrong circumstances as has been mentioned many times now. Only do it if using the battery very soon after (I don't mean straight away) but certainly within 6-10hrs of charging. Leaving at full charge even short term(days/weeks) will age the cells life expectancy, set your stall out and keep to a process you are happy with and manage your battery. BMS will deal with discharge, if you ignore a full charge every few rides and only charge to 41 -41.5v then a full balance charge every few rides will keep things good.
I use hands on approach using either a DVM to check voltage status or a cheap £3-£4 battery meter wired with a male bullet to each wire and simply poke them in the discharge socket. Alternatively if you have the need to open a battery case simply get one of the cheapo battery meters and wire it permanently adhering the meter to the battery case, they have an on/off switch so no chance of battery drain.
https://www.aliexpress.com/item/JS-C33-10-100V-Universal-LCD-Car-Acid-Lead-Lithium-Battery-Capacity-Indicator-Digital-Voltmeter-Voltage/32843049709.html?spm=a2g0s.9042311.0.0.27424c4d60jBCp
I use hands on approach using either a DVM to check voltage status or a cheap £3-£4 battery meter wired with a male bullet to each wire and simply poke them in the discharge socket. Alternatively if you have the need to open a battery case simply get one of the cheapo battery meters and wire it permanently adhering the meter to the battery case, they have an on/off switch so no chance of battery drain.
https://www.aliexpress.com/item/JS-C33-10-100V-Universal-LCD-Car-Acid-Lead-Lithium-Battery-Capacity-Indicator-Digital-Voltmeter-Voltage/32843049709.html?spm=a2g0s.9042311.0.0.27424c4d60jBCp
If wanting to go down the 80-90% charge route then the need to fit a programmable BMS is surely the route to go, then you can set the parameters yourself and have up to date cell group info, with batteries though thee can get to OCD worrying about them so better to just use them and manage them with a simple routine.
I like the idea of those small meters that will allow you to keep an eye on what's going on. I have a fancy charging device for all of my camera batteries that has an LCD readout similar to those displays and it's really useful.
I'd be minded to build it straight into the charger case and hard wire it in, I'm not too fond of loose wires and plugs.
Incidentally I think I'm right in saying you can buy those meters in UK based stores, a bit dearer than direct from China of course but faster to arrive.
I'd be minded to build it straight into the charger case and hard wire it in, I'm not too fond of loose wires and plugs.
Incidentally I think I'm right in saying you can buy those meters in UK based stores, a bit dearer than direct from China of course but faster to arrive.
Batteries with cells charged to 4.15v need a BMS that balances to that voltage. There are no commercial e-bike batteries that have on, you have to use a Speedict or other smart, programable BMS to get that feature. Sorry I should have made that clear in my other post.
This is not me trying to be rude but you have urged me to charge until 41.5v rather than just 40.0v. Is it correct that your advice only is sound if paried with a siutable BMS? ie, not in my case?
I actually did some googling yesterday and aimed for what manufacturers of eBikes themself say about charging rather than forum threads. From what I gather, the tips in this thread are very similliar to what the manufacturers recommend. Ie, charge to 100%, no problem in topping up (even better according to Bosch who counts 1 charge cycle as one complete charge and not just one for each top up), and 50-60% charge for longterm storage. Some say full charge and recharge every month for storage which is the opposite of what we're saying here. I did not find anything about a problem leaving your bike fully charged for a couple of days. Perhaps that's beacuse the general eBiker would then be as confused as I am
4.15v isn't enough. It has yo be 4.2v. Balancing doesn’t happen in an instant. It takes some time and only happens above 4.15v. For the same reason, it's a very bad idea to do a balancing charge every fifth charge or whatever. It needs to be done every charge to keep your battery healthy. You could do a much longer fifth charge to balance, but that would undo what you gained by charging to a lower voltage because you'd be holding the cells at the maximum for longer.
My dolphin 29E's I used to fully charge every time but now only charge to 4.12-4.14v per cell with the odd occasional full balance charge, in the one or two cases where I have opened the battery all groups have been remained perfectly balanced to 4.14v even now in there 5th year.
I only charge before use otherwise they are left sitting at the voltage they are at following last use, but always leave them above 37v and if needed give them a .1/2hr -1hr top up
The best advice though is to follow the manufacturers/dealers user manual and fully charge each time unless you are happy with another regime .
What be do need though is all packs to have user settable smart BMS's though would push prices up.
I only charge before use otherwise they are left sitting at the voltage they are at following last use, but always leave them above 37v and if needed give them a .1/2hr -1hr top up
The best advice though is to follow the manufacturers/dealers user manual and fully charge each time unless you are happy with another regime .
What be do need though is all packs to have user settable smart BMS's though would push prices up.
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Did you eat evey day in those 4 years because I ate every day in the last 6 years since I bought my battery, which is also still working well. If you did eat on all those days, that supports the theory that the eating is what prolongs the battery life, since everyone that achieved long battery life ate every day.
I went out for a 23 mile ride yesterday, and I didn’t lose a single segment on the display. During the 6 years I've owed the battery, I always charged to the max and left the charger on for more than 24 hours many times, so it can't be the charging routine that has helped.
This is what I mentioned before. Until someone does an objective double blind test, we might as well claim that aliens are determining our battery life from their space ships.
Are you sure that your voltmeter is properly calibrated to show the correct voltage in that range?
Don't get me wrong. I'm not saying that what you're doing isn't right. It's just that we don't have proof between cause and effect. What I know is that less than 100% charging definitely doesn't work for one because I had to fix his battery.
On another note, I noticed from all there pairs I've done, something like 98% of them were brought in by guys or women wearing trousers, so if you don't want your bike to go wrong, wear a skirt.
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I have had to fast for 24-48hrs occasionally for medical reasons so not eating doesn't really have an effect on battery longevity.
As you mentioned there doesn't appear to be any side by side testing of identical batteries using a different charge approach.
Likely hood is most of us will not even get near 500 complete charge/discharges and and cell age degradation will likely occur before we even half the charge discharge cycles.
As you mentioned there doesn't appear to be any side by side testing of identical batteries using a different charge approach.
Likely hood is most of us will not even get near 500 complete charge/discharges and and cell age degradation will likely occur before we even half the charge discharge cycles.
Blast! You've just destroyed my thesis and 6 years of research. I'll have to start again now. I'm thinking about checking whether wearing your underpants outside your trousers extends battery life. I tried it for a day and my battery didn’t expire or show any signs of deterioration, so I'm optimistic about my new theory.
Half the time you don't even switch on your bike or it's inside your van when your doing your out riding.
Maybe wearing kilts is an alternative …..
Looks like a kilt could be the answer then.
But what about when the wind blows high.....
Just smile
.OK, sorry to go about this in circles but this is the way I see it from reading all of your insightful responses here:
There's no hard evidence that eBike batteries would benefit from "80-20" charging method and there's also some concern about the balancing. The balancing seems to come down to the BMS system for one particular battery and going from NealH experiences there are some indications that charging to 100% just once in a while could be enough to keep cells balanced.
However, there is no research that indicates that "80-20" charging for eBike batteries are bad either. There's also knowledge about how individual cells would benefit from "80-20" charging method. So a reasonable hypothesis would therefore be that "80-20" charging method could indeed be beneficiary for eBike batteries but we just don't know for sure.
So until there's some side by side comparison we just don't know and therefore can go in either direction regarding charging method?
There's no hard evidence that eBike batteries would benefit from "80-20" charging method and there's also some concern about the balancing. The balancing seems to come down to the BMS system for one particular battery and going from NealH experiences there are some indications that charging to 100% just once in a while could be enough to keep cells balanced.
However, there is no research that indicates that "80-20" charging for eBike batteries are bad either. There's also knowledge about how individual cells would benefit from "80-20" charging method. So a reasonable hypothesis would therefore be that "80-20" charging method could indeed be beneficiary for eBike batteries but we just don't know for sure.
So until there's some side by side comparison we just don't know and therefore can go in either direction regarding charging method?
The balancing is quite a slow process through 100 Ohm resistors. The maximum current that could flow would be 4.2/100 amps or 40 miliamps. That's about a tenth of the charge rate of a USB charger, and anybody that's used one to balance a battery knows how long it takes to get any significant charge into a cell group.
The system is designed on the little and often principle, so balancing once in five charges most likely won't be enough. It would be no problem if your cells are nicely matched and stay in balance by themselves. The only way you'd know is to measure the voltage of your charger and compare it with the voltage of the battery immediately after disconecting the charger. If there's any difference, you have balance issues.
You could then do the next four charges to 80%, but you must check the voltage on the 5th full charge one. If you find that you have to leave the 5th charge on a long time to bring the battery back into balance, you'll probably lose e erything you gained by charging to 80%.
The system is designed on the little and often principle, so balancing once in five charges most likely won't be enough. It would be no problem if your cells are nicely matched and stay in balance by themselves. The only way you'd know is to measure the voltage of your charger and compare it with the voltage of the battery immediately after disconecting the charger. If there's any difference, you have balance issues.
You could then do the next four charges to 80%, but you must check the voltage on the 5th full charge one. If you find that you have to leave the 5th charge on a long time to bring the battery back into balance, you'll probably lose e erything you gained by charging to 80%.