A lot of fakes in/from China, a Bafang hubfor £20 in bulk hmmmm.

How about alink so we can see for ourselves.

@ vfr400.. Well I wasn't talking about BMS itself, as you say that's built into all e-bike batteries we would hope.

I'm thinking more of Nealh and his excellent advice on controlling battery charge voltage, I believe it's sound and correct.

I've been using similar methods of voltage/current control on lithium camera batteries for many years, and I believe it's because of that I'm still using batteries that are in some cases as much as 10 years old.

Their ability to hold a charge has diminished over the years somewhat of course but still plenty of life left in them.

Incidentally, I have some Sanyo Ni-Cads that are over twenty years old and still going strong !

 

[mention=9614]Nealh[/mention]...Ah the Chinese, been doing business with them for years. Ali-x, DH, Bangood know em all. Used to buy Fit Bit clones for a fiver each and sell them for 35 quid on flea bay, happy days...

You have to remember £1 here is worth a lot more in China but as you say watch out for fakes. The problem is you have to buy in large quantities to get items so cheap, then you end up paying import duties so bang goes your profit. There are ways around that of course but perhaps I'd better leave that subject for another thread.

Even more expensive now due to Bosch and the EU consortiums resorting to closing out any competition.

The Swizzbee is a good 13 years old now ( was 2.5 - 3k euros) and the electronics are LG made by Dreifels Ag, the pair will have extensively done the numbers game and the BMS is set for 41.5v per cell for max balance. With thoughts on cell longevity without compromise on range as range is what the buyer wants the most.

The original li -poly was scrapped two years ago.

Edited February 20, 20197 yr by Nealh

Swizzbee...that name reminds me of a fizzy lollipop I used to suck on as a kid. Nice bikes though, neat is the word I would use to describe them. Everything's there but tucked away...early stealth nice.

I've been using similar methods of voltage/current control on lithium camera batteries for many years, and I believe it's because of that I'm still using batteries that are in some cases as much as 10 years old.

Their ability to hold a charge has diminished over the years somewhat of course but still plenty of life left in them.

I have a Sony Handycam that I bought in 1999, so 20 years old. It too uses lithium batteries and they still work. I only used the standard charger and charging procedure but during that time, I always wore the same Casio watch on my wrist, so if you want to extend the life of your batteries further, you could think of trying the same.

 

Let's try and make this clear. There's cause and effect. Two statements can be true, but it doesn't mean that they're related. Only by doing tests according to scientific principles can you draw conclusions.

 

Do you remember at school when you did experiments and you had to make two headings "experiment" and "control", then you did two experiments, one to show that the liquid turned blue when you added the chemical and another to show that it stayed clear when you didn’t so you could draw the logical conclusion that the chemical turned the liquid blue. Without the experiment where you didn’t add the chemical, you would never know if the liquid was going to turn blue on its own.

 

Coming back to the point. We have some guys on this forum who's batteries have lasred a very long time using the standard charger and charging procedure and others who's batteries expired very quickly, so we can reasonably deduce that there are factors that affect battery life, though we don't know how many factors there are and how significant they are. For data from anybody that tried non-standard charging procedures, all we have are a few anecdotes. Not a single one has taken their battery to the end of it's life nor compared a battery's decline with a similar one that had standard charging under the same usage conditions.

 

If anyone is interested, there's some good reading here on how to draw conclusions from statistics.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://uca.edu/psychology/files/2013/08/Ch10-Experimental-Design_Statistical-Analysis-of-Data.pdf&ved=2ahUKEwium4nKncrgAhVDRxUIHZ7ZDeQQFjAAegQIAxAB&usg=AOvVaw15gZHKd6ciwZkIzuwkXTZH&cshid=1550663255779

 

I'm not disagreeing with the data and tests done by the Battery University, though I have many questions about which cells they tested and whether they were the lastest much improved ones that we have in our batteries now. Their test were done on cells that didn’t have a typical ebike management system. To draw any conclusion, they'd have to redo the tests that included them, then look at all the outcomes and failure modes.

Edited February 20, 20197 yr by vfr400

For the most part I would agree you but would take issue with you on one thing. I'd suggest we do know how many factors affect battery life and their significance.

I haven't read every thread that exists on these forums, but I can take you word for it that know one has carried out a full and scientific test on their batteries over an extended period of time. But there again they wouldn't have to, it's already been done many times before by the manufacturers that's what they release spec sheets for.

Of course you can always do what one poster said earlier in this thread, namely buy a battery use it and when it's done get another !

For the most part I would agree you but would take issue with you on one thing. I'd suggest we do know how many factors affect battery life and their significance.

I haven't read every thread that exists on these forums, but I can take you word for it that know one has carried out a full and scientific test on their batteries over an extended period of time. But there again they wouldn't have to, it's already been done many times before by the manufacturers that's what they release spec sheets for.

Of course you can always do what one poster said earlier in this thread, namely buy a battery use it and when it's done get another !

That's right, but we only see manufacturers tests on individual cells and under specific conditions. I've never seen any life cycle tests done on compete batteries, where there are a large number of extra failure modes, and operating conditions are cosiderably more variable.

Tesla charges cells to 4.15v, they might know a thing or two? That would be for Sanyo NCR/Panasonic cells which they make.

Tesla charges cells to 4.15v, they might know a thing or two? That would be for Sanyo NCR/Panasonic cells which they make.

 

And I even recall this tweet from Elon Musk who have joined this discussion numerous times:

 

One should mention that he in another tweet states that going below 80% isn't worth it even though some research indicates 70% is best of the best and even 90% is "still fine" as he puts it.

What happens in a Tesla car has very little relevance to a typical electric bike because they have completely different management systems and operating characteristics.

 

This is thec big problem, that people take things from one context and apply them to a different one and expect them to work the same. We're talking about batteries here, not cells.

As I see it there are several problems with battery tests. As you say test are usually carried out on individual cells only and not as a complete rechargeable power unit. Then there's manufacturers brand, who makes what for whom?

I have a Panasonic battery in my bike, well it's supposed to be that brand only I happen to know the cells inside are LG's. So that poses the question who makes LG battery cells, the company themselves or are they outsourced.

Manufacturer's advice is of no use if the cells inside a battery are made by someone else.

I am also of the belief that whoever claims to build a particular battery the cells inside are more often than not mass produced in China.

That's not to say they will explode or degrade any quicker for it, it's just we should all bear in mind because an item carries a well known brand name does not mean they manufactured it themselves.

You can wear a t-shirt with 'CocaCola' printed on it, that doesn't make you a can of fizzy pop!

So to summarize, what would be the best method to charge your eBike battery ?

So to summarize, what would be the best method to charge your eBike battery ?

That's the million dollar question. The advice I would give if you haven't opened up your battery and know which sort of management system it has and how it works, is as follows.

 

1. Use the charger supplied with the bike and always charge it to full.

2. Don't leave the charger on for hours after it's gone green.

3. Don't keep topping up your battery when you don't go far.

4. Don't run your battery to minimum unless you need to.

5. Don't leave the battery uncharged for very long when it's run right down.

Had to agree with all vfr's suggestions on battery care and here's a couple more for consideration.

6. keep your battery in cool storage conditions, but charge at room temperature.

7. Don't charge your battery to full and leave it unused for long periods of time.

You may also want to check the following.

1. Make sure the material connecting the cells in your battery are pure nickel and not nickel plated steel and of equal length to ensure even current flow and reduce power loss through heat.

2. Ensure the main power take off wires on the pack are connected to all of the last group of cells and not just one, so as to keep the load even and not put unnecessary strain on one cell leading to premuture ageing and failure.

I am only adding these to show that any charging regime you may adopt will be futile if your battery is poorly constructed.

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.

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...

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 confusiono_OI 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'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...

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

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.

What happens in a Tesla car has very little relevance to a typical electric bike because they have completely different management systems and operating characteristics.

 

This is thec big problem, that people take things from one context and apply them to a different one and expect them to work the same. We're talking about batteries here, not cells.

 

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.

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.