Battery charge lights MP3

[Bwizz]

Just noticed that after a full charge . I set of and as usul I have the 3 lights but after only a short distance I loose the green light
I don't remamber this happening before ,Is it sign of a failing battery , any way I can check? Its a 48 volt.Software is set to 24 Volt

[Bikemad]

If you have a voltmeter, you can check the battery voltage at the charging socket (the centre terminal is positive).

Check the voltage before you start your ride with the battery fully charged (and make a note of it) and then check the voltage when the Green LED goes out (and make a note of it too).
Then let us know what the two readings are.

The voltage setting in the controller will not affect the operation of the battery LEDs on the throttle.

Alan
 

[Bwizz]

Ok thanks, Alan, Why didn't I think of that. Will do tomorrow then report back.
Brian W Cornwall

[Bwizz]

Hi weird happenings . I bought this bike as an abandoned project with seized motor. It was advertised  48v battery etc I fitted new GM 26"complete package
Ive never noticed before but the charger is rated as 58volts. After this mornings ride of 12miles I came back with the green light out. checked the voltage  read 56volt . straight after a 3 hr charge approx 57volt light on.  checked again after an hour "bike not used" green light still on, 54volt. My voltmeter is usually consistant, not sure what this is telling me

[Bikemad]

Have you tried taking any more readings since, to see if they are more consitent?

Alan
 

[Bwizz]

No I'm using the bike tomorrow , so I'll check with and without green light.
I suppose my battery must be a nominal 60volts ?, should the software still be at 12volt for best performance.
Thanks for interest Alan

[Bikemad]

Although it's commonly referred to as a 48V battery, the LiFePO4 battery has 16 cells with a nominal voltage of 3.3V/cell which means the battery is actually a 52.8V battery. The charge voltage is usually 3.65/cell which means the maximum charger output should be ~58.4V.

If the software setting of 24V (there is no 12V setting) gives improved torque then it hopefully won't be a problem with the 48V (52.8V) battery. If there is no noticeable difference, you might as well run it on the correct voltage setting (48V) just to play safe.

My MPIII is set at 24V to allow the use of different voltage battery packs without having to reprogram it each time, but on the later MP4 controllers, you have to enter the correct battery voltage for the regen to operate correctly.

Alan
 

[Bwizz]

Hi Alan thanks for explanation, before setting of yesterday with a fully charged battery "green light on"
the voltage was 54 volt. covered approx 15 miles , came back with light out .voltage the same.

[Bikemad]

Brian, try the same test again but measure the voltage at the power output terminals instead of the charger socket and see if it is any different. Both ports connect to the battery through the BMS board rather than being a direct connection, so it might make a difference.

If the before and after readings are still the same, I would say your voltmeter may be suspect as the battery wouldn't be able to power the bike for 15 miles without the voltage dropping at least a couple of volts. Unless you are not using the throttle at all and the regen is keeping the battery voltage topped up. 

Alan
 

[Bwizz]

Hi Alan again thanks for support, my voltmeter is usually consistent , I regularly check my cars charging rate, it reads as expected. . I'll try as suggested, i've not charged it since yesterdays ride
, If I turn the bike on at the mo, the green light comes on , then without even moving, it goes of as I'm watching it. On the other hand the bike does not lose its settings now. I wonder why David suddenly took an interest. He did not reply when I mentioned that the hole centre of the output cable
had moved in the replacement.
Brian W

[Bwizz]

Seem to have lost yesterdays post . Set of yesterdaywith full charge. Within less than a mile I lost "both yellow and green light"
Also notice a vibration and slight braking effect when I first engage the motor. This used to happen previously then stopped of its own occord. I covered my usual 15 miles or so uneventfully with minimal motor and lost of pedal assistance. "being worried about a total battery failure"! Got back and checked the voltage. 52 volts with just the one light. Tried running the motor with bike on the stand and checked the voltage, still around 52 volts. After overnight charge . I  altered the settings in the software
setting the voltage to 48v.  I noticed that the battery icon in the software showed about two thirds charge?
After a trip of less than a mile I again lost two lights . came back rechecked voltage 52 volts. Is this pointing to an imminent battery failure?. I seem to have lost two volts since last weeks checks.

[Bikemad]

Seem to have lost yesterdays post.

I think you'll find it was a personal message you sent yesterday instead of a post on the forum, and I have only just read it.

I noticed that the battery icon in the software showed about two thirds charge?

Brian, that battery icon is not a functional gauge, it is purely there to indicate that the voltage settings directly below it relate to the battery.

Measure the battery voltage at the battery power outlet at the end of an overnight charge while the charger is still connected and turned on with the green light illuminated and it should be ~58V if the correct charging target voltage has been achieved.
With a good battery, this voltage will typically drop to around 57V within 5~10 minutes of disconnecting the charger (with the bike's power plug still unplugged).

If the maximum charging voltage is not reaching 58V I suggest you check the output of the charger by measuring the voltage at the charging plug with the charger turned on but not plugged in. 
Cut a half inch length of plastic drinking straw and slide it over the centre pin to prevent the possibility of shorting out the plug contacts with the meter probes. One simply goes inside the straw and the other goes outside.

Poor switch contacts or plug contacts can cause a lower voltage at the power plug compared with the charging socket, so it might be worth sliding the rubber cover back on the power plug and measuring the voltage on the harness side of the plug as well while the bike is turned on.

Do you have any idea as to how old the battery is and how much use it might have had?

Please let us know the results of your voltage measurements.

Alan
 

[Bwizz]

Hi Alan, Not done the last bit re charger test. But I was getting 57v+ last week at the charging socket.  Seems the battery or charger has weakened since I checked the voltage last week.. Just done a full  charge after a short ride , The voltage at output pins charger connected or not
and charger socket are the same at 52 volts max. Cleaned the connection pins at both ends
no difference. the green light won't come on at all now. Don't know how old the battery is for sure,
According to the chap I got it from ,Said he had regular use for around 8 months. I have had the bike/battery for two years , and used no more than once a week on average.
If it is a failing battery , am I likely to get a sudden failure , or progressive weakening..
In the event of it being the battery , can I identify a failed cell. and replace individually.
Just checked voltage at the charge socket after being stood overnight, Its risen to 56V and the green light is back

[Bikemad]

Hi Brian,

I don't understand how the battery can go from 52V to 56V after being stood overnight unless it was also on charge throughout this period.

If one or more of the cells is faulty it's possible that the charging may take much longer for it to reach the correct fully charged voltage.

If it is just one cell that has failed, you might be able to find it by measuring the cell voltages with the battery under load to see which cell is low. But this would involve dismantling the battery and connecting it to a high load (e.g. a 3kw radiant bar fire or electric cooker hob etc. but not a hair-drier or fan heater)

Alan
 

[Bwizz]

Hi Alan, This is very strange I checked voltage this morning 56v After ,last trip of only a couple of miles yesterday.
 I set of for a short ride of 4 miles, Within a mile I am down to one light.!
Stopped for around 11/2 hrs , and rode back along the same route ,involving a fairly steep climb" no regen,"of 1 mile .The yellow light stayed on most of the way back. recheck voltage at charge socket
56/57 volt .After 10 mins rest the green light is back.
Only consistent thing is the lights corresponding with the measured voltage.
Think I'm going to find a circuit to ride to see how far the bike will actually go with a full charge,
otherwise I have no confidence in setting of on a longish trip