Sudden loss of range - charger or battery?

[Timo]

I've been delighted with the range on my Cannondale Synapse Neo (see threads in the Cannondale section). I'm not posting there as the problem that has suddenly occurred is not specifically about the Cannondale marque. It's Bosch equipped with a 500 watt battery. Suddenly, my range has plummeted from circa 100 to the late 60s. In addition, I bought a Bosch Fast charger last year (6 amp). And it has been fast but the last few charges have taken 6 hours before the lights go off - and that was with 2 bars left when I started charging. My wife and I came back from a ride the other day and she has a 2 amp Bosch charger. Her battery showed full a couple of hours before mine.

Anybody have any thoughts about this? Is it the charger or the battery? I remember reading about some folks who had done some incredible trip from China to the UK (something like that). They thought they had a problem with one of the batteries when it started losing range. They subsequently discovered it was the charger and not the battery. I thought I would pass it by you knowledgeable people in case you have any experience of this. Many thanks in advance.

 

[6zfshdb]

A good place to start is to check the battery voltage after fast charging with a good quality meter. This chart will give you the % charge. If it isn't at or near 100%, try using the old 2A charger and see if it brings up the voltage. If it does, I would suspect the 6A charger.

Fast charging can shorten the life of some batteries but the degradation should happen over time, not all at once. It is also possible you have one or more bad cells.

 

[AHicks]

A long charge time like that COULD mean that the charger is timing out for safety reasons, because it's trying, but not able to equalize all of the cells. That would indicate a potential for at least 1 bad cell.

I would start with a good volt meter and battery pack in hand......

 

[rich c]

A simple trip to a dealer will quickly give you the answer. A quick computer diagnostic will tell you battery and charger health. Otherwise it’s purely guesswork. You’ll get dramatic loss of range in cold weather, and you can really damage a battery if you are charging it when it’s cold.

 

[fooferdoggie]

plus plug the battery into the other charger and see what happens.

 

[AHicks]

A simple trip to a dealer will quickly give you the answer. A quick computer diagnostic will tell you battery and charger health. Otherwise it’s purely guesswork. You’ll get dramatic loss of range in cold weather, and you can really damage a battery if you are charging it when it’s cold.

Identifying a bad cell is hardly guess work....

 

[Johnny]

I've been delighted with the range on my Cannondale Synapse Neo (see threads in the Cannondale section). I'm not posting there as the problem that has suddenly occurred is not specifically about the Cannondale marque. It's Bosch equipped with a 500 watt battery. Suddenly, my range has plummeted from circa 100 to the late 60s. In addition, I bought a Bosch Fast charger last year (6 amp). And it has been fast but the last few charges have taken 6 hours before the lights go off - and that was with 2 bars left when I started charging. My wife and I came back from a ride the other day and she has a 2 amp Bosch charger. Her battery showed full a couple of hours before mine.

Anybody have any thoughts about this? Is it the charger or the battery? I remember reading about some folks who had done some incredible trip from China to the UK (something like that). They thought they had a problem with one of the batteries when it started losing range. They subsequently discovered it was the charger and not the battery. I thought I would pass it by you knowledgeable people in case you have any experience of this. Many thanks in advance.

First charge your battery with your wife's charger and wife's battery on your 6amp one. That should tell you if the problem is with your battery or the charger.


Once that is sorted out it would be good if you update us and people can point you to the right direction.


How many full cycles do you have on your battery? Also check the minor things like tire pressure, temperature etc, they can make a difference in your range.

 

[rich c]

Identifying a bad cell is hardly guess work....

What I meant is that it's guesswork for us to figure out what the problem could be with such limited information from the OP. We don't know any voltages, don't know the age, don't know how he charged the battery except for fast, how many miles or charge cycles, etc.....we only know the range has dropped. Also no guesswork if he just goes to the dealer and has a diagnostic done.

 

[AHicks]

I think Johnny's plan above makes great sense. That should point at what's going on pretty easily....