Battery charger

cyclenut1952

Esteemed Pedelecer
Nov 6, 2019
275
24
Leeds LS27
My charger has 2 red lights when switched on then 1 green 1 red is this the charged state?
Also should battery switch be on or off?
I realise fairly daft questions but I really don’t know.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,112
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West Sx RH
A green usually indicates charge completed though some times balancing is under way depends on what your manual tells you.
Battery switched on for charging.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,112
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West Sx RH
Final end /top cell voltage balancing doesn't occur until above 4.15v per cell or above, the charge light may go green but active balancing may be on going. The battery BMS will release higher cell group voltage to balance and then restart slow input charging until all cells are at an equal voltage this may be 4.15 to 4.2v per cell group and may vary from charge to charge, it will depend on the actual BMS programming how the balancing works. BMS use bleed resistors that open and close to adjust cell voltage top end cell voltage the manufacturer has set( but generally only work if voltages are quite close, they can't balance wide voltage discrepancies in one go. Some BMS will balance before 4.2v is achieved others after 4.2v up to 4.25v.
The charger can only charge if the battery BMS allows it to so when a battery develops a fault the BMS doesn't like, manual fault diagnosis comes in to play. This is fairly rare but does happen if the end user doesn't care for the battery.
 
Last edited:

vfr400

Esteemed Pedelecer
Jun 12, 2011
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Basildon
IIRC, one red light shows that the charger is switched on. The other behaves conventionally, i.e. off when disconnected, red when charging and green when charged.
 

cyclenut1952

Esteemed Pedelecer
Nov 6, 2019
275
24
Leeds LS27
Final end /top cell voltage balancing doesn't occur until above 4.15v per cell or above, the charge light may go green but active balancing may be on going. The battery BMS will release higher cell group voltage to balance and then restart slow input charging until all cells are at an equal voltage this may be 4.15 to 4.2v per cell group and may vary from charge to charge, it will depend on the actual BMS programming how the balancing works. BMS use bleed resistors that open and close to adjust cell voltage top end cell voltage the manufacturer has set( but generally only work if voltages are quite close, they can't balance wide voltage discrepancies in one go. Some BMS will balance before 4.2v is achieved others after 4.2v up to 4.25v.
The charger can only charge if the battery BMS allows it to, so when a battery develops a fault the BMS doesn't like manual fault diagnosis comes in to play. This is fairly rare but does happen if the end user doesn't care for the battery.
Hi Neath,
Thanks for battery info, it is a great help to me for your help.
Just got back from first 30 mile ride
What would be your advise as I charging battery,
Many thanks
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,112
8,219
60
West Sx RH
For long rides I only carry out a full balance charge before I need to use the bike again, typically about 12hrs before hand. If planning on using again within 7 days I leave the battery sitting at the finish voltage if it is above 36v, if not I carry out a top up charge to about 38v. If not riding for a few weeks I top up any charge to about 38v as a store charge , then simply fully charge a few hours before I need it again. On my commute/ town bike where the daily mileage is low <10 miles I only charge once or twice a week or when I have ridden about 30 miles.
Long term try not to leave the battery sitting at full charge for any long amount of time as it will aid some degredation of the cells over their life cycle.
 

cyclenut1952

Esteemed Pedelecer
Nov 6, 2019
275
24
Leeds LS27
For long rides I only carry out a full balance charge before I need to use the bike again, typically about 12hrs before hand. If planning on using again within 7 days I leave the battery sitting at the finish voltage if it is above 36v, if not I carry out a top up charge to about 38v. If not riding for a few weeks I top up any charge to about 38v as a store charge , then simply fully charge a few hours before I need it again. On my commute/ town bike where the daily mileage is low <10 miles I only charge once or twice a week or when I have ridden about 30 miles.
Long term try not to leave the battery sitting at full charge for any long amount of time as it will aid some degredation of the cells over their life cycle.
Hi, many thanks for your reply, both at 36.3 not sure when next ride.
So will take them to 38v.
Thanks again.
 

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