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.

Edited February 22, 20197 yr by Nealh

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.

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.

Edited February 22, 20197 yr by vfr400

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.

I have had to fast for 24-48hrs occasionally for medical reasons so not eating doesn't really have an effect on battery longevity.

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.

 

 

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.

 

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.

 

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.....

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?

All that is certain is balancing with dumb BMS only happens above 4.15v.

Only smart bms or pre- programmed dumb BMS are able to balance at lower voltage, the latter aren't common.

 

The LG BMS on the Swizzbee only allows charging to 4.15v so balance occurs at a lower voltage.

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%.

SInce #1 I have reduced charge voltage to 41v and although at first carried out a balance charge every couple of months which worked out about every 6th or 7th charge per battery as I alternate two batteries.

I haven't yet to balance the batteries to 42v this year and am not seeing any issues with cutting out or any unusual voltage sag.

I've just been pointed towards this interesting thread by Nealh. So far I've been charging to around 41.7/41.8V which is the standard output voltage of my Yose Power chargers (which I've just realised is SANS).

 

I've got this pack I've built, which I can test the individual bank voltages while in use. I plan to try charging to 41V and seeing if the banks go out of balance.

 

It is not for everyone as the battery can go a stray, one needs to understand the possible pitfalls should it go a bit pear shaped and have an understanding of how to notice or rectify a battery issue as they are not cheap to replace.

The forum is not just about Bosch or Mtb and which bike is best ( which there is no such thing), It is about a helpful interesting community with minds that sometimes think alike. The forum/ sub fora's are about progress, information and a playground for the buyers of OEM & tinkerer's

 

All the progress/tinkering threads are not for every one but those willing to try something a bit different must realise it is not a recommendation by any poster, it is about a technique or a slightly unusual process containing information that has been tried or is being used. Someone else might want to try or has been thinking/looking to try along the same lines, albeit on their heads if it doesn't work out.

No one wantonly posts dangerous techniques and those who do would be pulled up sharply by most on here.