Battery charging 101

[Brian55]

How do I ensure my battery is fully charged ?
The instructions supplied with my new 48v battery tell me to charge the battery until all 5 bars on display are visible then stop charging.
The same set of instructions inform me that the 5 bars indicate a charge of 80-100 percent of the capacity.
So I am assuming that if I stop charging when the 5th bar shows I only have battery charged to the lower end of the range specified. This seems to be confirmed by the fifth bar only being visible for a couple of minutes use.
The 5 bars seem a very basic method of determining a complete charge is it possible to add a voltmeter to give a more accurate status?
My lack of understanding of things electric is legendary and if I am over thinking this then please let me know and I will go and l worry about something else

Toodlepip

Brian

 

[Nealh]

The charger led usually turns from Red to Green and then balancing can occur so some may need a half hour or so to balance, the best way of knowing is measure the end voltage it should be 54.6v for 48v nominal battery.

 

[Benjahmin]

Get yourself a digital volt meter. Cheap ones won't be 100% accurate but near enough for your purpose.
Measure the output voltage of your charger - careful not to short +ve and -ve.
When charger led goes green, disconnect and measure battery output voltage, should be within 0.1- 0.2v of charger output.
As Neal says, cell balancing only occurs at the top of a charge, so best to leave charger at green for half an hour or so every 5 or 6 charges. Don't leave it overnight.
Other than that, charge it, ride it, enjoy it, repeat.

 

[Brian55]

Thanks for the replies.

 

[Brian55]

Thanks for the replies.

This morning set of bright and early on my brand new BBS ET 48v 15 Ah full of enthusiasm and 4 bars on the meter.

After 10
Minutes I was down to 3 bars.

10 more minutes
I was down to 2 bars, at which point I headed for home.

Got home I was down to the little bar on the left.
A full charge got me less than 10 miles.
Very disappointed.

Would anyone like to hazard a guess as to what I am doing wrong,?

Any suggestions would be truly appreciated.

Brian.

 

[matthewslack]

This morning set of bright and early on my brand new BBS ET 48v 15 Ah full of enthusiasm and 4 bars on the meter.

After 10
Minutes I was down to 3 bars.

10 more minutes
I was down to 2 bars, at which point I headed for home.

Got home I was down to the little bar on the left.
A full charge got me less than 10 miles.
Very disappointed.

Would anyone like to hazard a guess as to what I am doing wrong,?

Any suggestions would be truly appreciated.

Brian.

Generic battery capacity indicators on the display are not 'calorie counters', like you get on Shimano/Bosch etc, but basically voltmeter and so non-linear. Very basic.

If your battery was fully charged, then all is not well, but given your earlier question I would recharge fully and ride again for a second impression.

Do not switch off as soon as 5th led is lit. Leave it maybe 3 more hours, then it has no excuse not to be full and balanced, unless defective. Don't leave on overnight.

Report back after another ride.

 

[cyclebuddy]

Post #1

...instructions inform me that the 5 bars indicate a charge of 80-100 percent

Post #5

set off... ...4 bars on the meter...

...A full charge got me less than 10 miles.

Does not compute! 4 bars is NOT a full charge!

As @matthewslack says, charge the battery until the LED on the charger turns green and then let it charge for a few hours more to allow it to fully balance, then test-ride again.

 

[Brian55]

Generic battery capacity indicators on the display are not 'calorie counters', like you get on Shimano/Bosch etc, but basically voltmeter and so non-linear. Very basic.

If your battery was fully charged, then all is not well, but given your earlier question I would recharge fully and ride again for a second impression.

Do not switch off as soon as 5th led is lit. Leave it maybe 3 more hours, then it has no excuse not to be full and balanced, unless defective. Don't leave on overnight.

Report back after another ride.

Thanks for the quick reply, it's nice to know I'm not alone, I really appreciate the help and advice.

I will try and give it a go tomorrow, but I am not promising. Lots of rain forecast but as soon as I can I will do as you suggest.

Toodlepip

Brian

 

[matthewslack]

Thanks for the quick reply, it's nice to know I'm not alone, I really appreciate the help and advice.

I will try and give it a go tomorrow, but I am not promising. Lots of rain forecast but as soon as I can I will do as you suggest.

Toodlepip

Brian

No rush! On the bright side, you have a tried and tested motor, so there will be an answer!

Edit:

Have a look at the label on the charger. Often they are only 2A, so expect 8 hours or so for a full charge from flat on your 15Ah battery.

 

[Nealh]

If your 48v battery is 15ah then that is 720wh of fuel to use, in my heyday of riding with a bbs01 I would get 52 miles from a 36v, 14.5 battery which is 522wh. My usage was though mainly using the lower PAS settings .
Can you link to the battery you are using , also one needs to buy a voltage meter to check the actual charge voltage when finished.

 

[Brian55]

If your 48v battery is 15ah then that is 720wh of fuel to use, in my heyday of riding with a bbs01 I would get 52 miles from a 36v, 14.5 battery which is 522wh. My usage was though mainly using the lower PAS settings .
Can you link to the battery you are using , also one needs to buy a voltage meter to check the actual charge voltage when finished.

Neal - link to battery as requested

Woosh Bikes - Online Shop

Online shopping for electric bikes and conversion kits. All models are in stock unless otherwise indicated on the web page and can be despatched on the same day or next business day. We will email you the tracking link as soon as the item has been despatched.

wooshbikes.co.uk

I do have a meter, but I have not seen it since the last last house move, I may have to buy another one if it does not surface on the next couple of days.

Toodlepip

Brian

 

[Bikes4two]

@Brian55 - you haven't actually said much about how you are using the BBS01 (ET with Extra Torque) and in your avatar you are on a tandem.

• Is the motor fitted in a tandem and was your test ride with two riders?
• and what motor power assist level are you using?
• and flat or hilly terrain?

Having said all of that and has been posted by others, you really need to find that volt meter so that after having had the battery on charge for a good 8 hrs, unplug the charger and measure the battery voltage at the output terminals.

 

[Nealh]

As the Woosh page mentions 70 odd miles should be possible and is what I would expect also from the battery and BBS combo, albeit with low PAS usage .
It is hard to say any more unless the actual fully charged battery voltage is truly known, as mentioned siply going by Red or Green charger LED's is of little use.

Voltage readings can give an indication of a possible fault , where as LED's can't .
Both the charger output and battery need t be checked.
The charger should show 54.6v +/- 0.1v to allow for meter reading inaccuracy, again the battery should read similar when fully charged though anything below 54v would need investigating.

 

[Brian55]

@Brian55 - you haven't actually said much about how you are using the BBS01 (ET with Extra Torque) and in your avatar you are on a tandem.

• Is the motor fitted in a tandem and was your test ride with two riders?
• and what motor power assist level are you using?
• and flat or hilly terrain?

Having said all of that and has been posted by others, you really need to find that volt meter so that after having had the battery on charge for a good 8 hrs, unplug the charger and measure the battery voltage at the output terminals.

We bought the tandem when we were working in Dubai about 15 years ago. It was a Korean knock-off of a Chinese copy. A great bike, bought it new for about £100 and sold it for £300. So no the motor is not for the tandem, the picture just seemed nice for an avatar

I am still building the bike it has only done 10 miles most of which were on power level 1 or 2. I never tried it on a hill I ran out of battery before I got there.

I appreciate the need for a meter and will get one as soon as I can.

Toodlepip

Brian

 

[Nealh]

Something is very wrong then if the usage is in low PAS mode, that may be and could be a battery issue .
Woosh are pretty good but before contacting them one needs to see what the battery is telling you when you have a meter.

 

[Woosh]

Thanks for the quick reply, it's nice to know I'm not alone, I really appreciate the help and advice.

I will try and give it a go tomorrow, but I am not promising. Lots of rain forecast but as soon as I can I will do as you suggest.

Toodlepip

Brian

Hello Brian,
The battery is full when the LED on charger switches from red (charging) to green (not charging). It is best to fully charge the battery at least once or twice a year and charge only when at least one bar out of 5 on the battery meter has gone. I usaully recommend 2 bars gone.
The charger that is supplied with the kit is from SANS, 54V 2A, one hour of charge gives you about 8 miles riding on motor. The 8 mile figure is an average, less if you ride fast on throttle, more if you pedal a lot. A full charge gives an average 50-60 miles. When you ride on the last two bars, the battery sag may cut out the motor, you will need to reduce your speed a bit to avoid voltage sag and get the most out of your battery.

 

[Brian55]

Thanks for all your help.

Sorry but I have had a few mental blocks.

1) I used the row of LEDs on the battery to define when the battery is full. I now know this is not the case and the only indicater to use is the red / green light on the charger.

2) I have been very conscious about over charging the battery. I am safely assured that the battery cannot in fact be overcharged. The green light on the charger indicating that the charger is no longer charging and the battery is fully charged.

Armed with these two bits of knowledge and an £8 voltmeter from Screwfix I started again. I charged the battery until all the lights on the battery were green, then kept on charging for another 4.1/2 hours.

I am now confident that the battery is fully charged and will respond as it should do. I will give it a run over the weekend just to prove it.

Please feel free to say ,"I told you so"

Toodlepip

Brian.

 

[Brian55]

Sorry before I could finish yesterday,s post I was called away.

The battery voltage when the indicater changed to green was 53.7 v.
But the best indication was the built in tail light which started flashing rapidly, it's bright enough that I can see it from the house. It looks like I have Xmas lights in the shed.

I am a happy bunny.

Toodlepip

Brian

 

[Nealh]

53.7v is a bit too low, it needs a bit more balance time on the charger. It may need a few more discharge /balance cycles to right it correctly, no reason it shouldn't read a lot nearer to 54.6v. At the moment it is 0.9v out of balance which is a lot in voltage terms .

When the charger LED turns Green next time leave it like it for another 30 or 40 mins to allow balancing to occur.
If you don't see a dramatic rise in range /mileage then there is likely a severe balance issue that needs sorting out. One should get at least 50 miles with low PAS use.

The minimum voltage one should see is 54v but better if higher up to 54.6v, to most 0.9v seems trivial but it isn't and may mean a bad cell group that fails to charge correctly and could be woefully low. Hence the poor range /mileage in use.

Any battery with a low cell group voltage is only as good as that low cell group, so once a BMS senses that low cell group has hit the minimum voltage or LVC threshold it will cut out. The BMS senses each of the 13 cell groups as an individual entity and not as one where LVC is concerned.

 

[Nealh]

With my batteries I expect to see any full charge to be within 0.1v of the opitmal charge anything wider then this then I investigate for the cause as it can mean an imbalance.