50 cycles sent the wrong charger ,is my battery ok???

[mr harris]

hi all i recently brought a charger from 50cycles for my 26v kalkhoff battery ,i posted a thread asking what charger would be best for my battery-as they do a fast charger and i was wondering if it would decrease the life of my battery in any way ect..

i finnaly made a decission to get the standard 26v charger,as the time it takes to charge is not an issue with me pluss i just wanted the maximum life i can get out of the battery.

ive contacted 50cycles and they say the charger i need is the fast charger- it doesnt help theres no real information on the site about any of their items ,but i must say they were realy helpfull over the phone today and they are going to send the new charger so thats good news but..............

the real question is i have had the battery on this charger for two periods of aound 7 hours, when i put it on the battery on the dock it seemed to acknowledge the battery as the power gauge lights on the battery lit up one by one but then just went off then ocassionally the first light on 0% would flash once every 5 mins or so.
i asked 50cycles if this could have damaged my battery in ANY WAY and they said no it will be fine.

i just want to know if this is true ,any information would be a great help

 

[flecc]

That's fine, the flash every five minutes or so won't indicate any harm. It's probably the battery's BMS attempting to start the charge every so often.

I can't understand how it could be the wrong charger though, since for a while it was the only charger for that unit's 26 volt batteries, until the introduction of the fast version.

Possibly it's just faulty, or perhaps the later batteries with larger 18650 cells need the fast charger due to a different BMS, in which case they should say so on the website.
.

 

[mr harris]

thats what i thought even more so they havnt even got a picture for the fast charger on the site yet-they realy do need to update it.

thats great news if the battery is fine, i quess i will find out monday fingers crossed, are you certain that charger could not have harmed the battery in any way (sorry to doubt just worried)i dont know any technical information about the battery yet but i have heard about cells becoming unballenced ect and now my battery has been dead for a number of weeks

where would be the best place to get some good information about the different batteries or differnt cell types kalkhoff realated if possible but anything will do just to get my head around it and save me asking silly questios

thanks again for your help flecc

 

[flecc]

thats what i thought even more so they havnt even got a picture for the fast charger on the site yet-they realy do need to update it.

thats great news if the battery is fine, i quess i will find out monday fingers crossed, are you certain that charger could not have harmed the battery in any way (sorry to doubt just worried)i dont know any technical information about the battery yet but i have heard about cells becoming unballenced ect and now my battery has been dead for a number of weeks

where would be the best place to get some good information about the different batteries or differnt cell types kalkhoff realated if possible but anything will do just to get my head around it and save me asking silly questios

thanks again for your help flecc

The battery should definitely be ok. The internal BMS* controls whether it charges or not and it's clear yours was refusing the charge, so no damage will have occurred.

Leaving it uncharged for several weeks is also normally not a problem, since both the Kalkhoff and Panasonic batteries for your unit have a sleep mode. After standing idle of about two weeks, the internal BMS is switched off to prevent the cells draining to levels which could damage them. Very few batteries have this. Starting the charge again switches the BMS back on.

Can you let me know what Ampere (Ah) rating your battery has? At various times the BMZ made ones were in 8, 12, 18 and 24 Ah.

* Battery Management System.
.

 

[mr harris]

ok its making sence now i didnt even know what bms was...
its the 18ah 25.2v which i was told was bassicly 26v
i have attached some pics

this exact one doesnt seem to be sold on 50cycles but it looks more like the the second battery in on 50cycles battery page -but with the branding like the others

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[mr harris]

 

[mr harris]

i dont know if they came out ok or if you can read the small print ,but the main info is ,,, 25.2v 453.6wh 18ah

 

[flecc]

Thanks for the information. Your Kalkhoff-BMZ battery uses 42 of the industry standard cylindrical 18650 cells. Nominally these are generally referred to as being 3.7 volts each, but I see from the 25.2 volts that BMZ rate them as 3.6 volts each. I would rate that battery as nominally 25.9 volts and so would most makers. It isn't important though, since in practice the cells are 4.2 volts fully charged and 3.1 volts at the low battery cutout point. This means your battery starts at just over 29 volts fully charged and about 22 volts when emptied on the bike.

The 42 cells internally are arranged as 7s 6p. The 7s means that there are banks of 7 cells in series (connected end to end), which means the voltage of them is additive, 7 times BMZ's 3.6 being the 25.2 volts.

The capacity of each cell is 3 Ah and the 6p means there are 6 of those 25.2 volt banks of cells in parallel (connected side by side). Therefore 6 of the 3 Ah banks totals your 18 Ah.

The cells are mounted in a plastic frame with the BMS circuit board on the side. I don't have a photo of the internals of your exact battery, but below you'll see a similar BMZ battery internal construction using 18650 cells. The one I'm illustrating is the one used for the Kalkhoff Impulse motor unit. Kalkhoff-BMZ typically use the best cells on the market, made by such as Samsung or Sony.

 

[Simon Rafferty]

As an aside, the best way to prolong the life of your battery packs is to limit the degree of discharge. Don't run the pack to zero (or until the BMS cuts them off).

If you only take (for example) 10% out of the battery, you may get thousands or even tens of thousands of cycles. At 50% this will drop to a few hundred - and drops of pretty rapidly after that.

I tend to use batteries with at least twice the capacity I need and never let them go below 50% (other than in an emergency).

Also best to store the batteries fully charged.

Si

 

[Deleted member 4366]

A fast charger can damage a battery, though you won't necessarily see it immediately. "Fast" doesn't mean anything. What's important is how many amps you charged with. As a general rule, you should charge at 0.2C, so an 18Ah battery should be charged at 0.2 x 18 amps = 3.6 amps. When you charge a little above the recommended level, no significant damage will be done, but the higher you go, the more the damage.

There may be a charge fuse, often 5 amps, so if you charged at say 8 amps, the fuse could blow, which for some batteries means a bit of dismantling.