Help! Which is the correct charger

[phil_the]

Just bought second hand bike. They had two for sale but wasn't sure which charger went with which. They gave me both chargers to try but I need to return one of them , was wondering which is best to keep.


Battery says 36v 10.4 Ah.
One charger is 230-240v 140W / 36v 3A
Other is 100-240v 1.8A / 42v 2.0A

 

[phil_the]

 

[matthewslack]

Just bought second hand bike. They had two for sale but wasn't sure which charger went with which. They gave me both chargers to try but I need to return one of them , was wondering which is best to keep.


Battery says 36v 10.4 Ah.
One charger is 230-240v 140W / 36v 3A
Other is 100-240v 1.8A / 42v 2.0A

The 42V one is correct for a nominal 36V battery.

A charger labelled 36V is ambiguous. It might mean (a) 'I am a charger for a nominally 36V battery ', or (b) 'my maximum output is 36V '. You need (a).

If you post pictures of the labels on the chargers clear enough to read the small print, it might be possible to be definitive.

Aha, you just did!!!

So yes, the 42V one is what you need.

 

[Nealh]

The 3a one says +36v but one needs to plug it in the wall socket and see what the output actually reads, personally stick with the Sans 1.8a one.

 

[phil_the]

The 42V one is correct for a nominal 36V battery.

A charger labelled 36V is ambiguous. It might mean (a) 'I am a charger for a nominally 36V battery ', or (b) 'my maximum output is 36V '. You need (a).

If you post pictures of the labels on the chargers clear enough to read the small print, it might be possible to be definitive.

Aha, you just did!!!

So yes, the 42V one is what you need.

OK Thanks

 

[sjpt]

Odd. Presumably a real 36v charger (matthewslack's (b)) would be appropriate for a nominal 30v battery, but I don't think I've seen a 30v ebike.

 

[phil_the]

OK I dug out my old Avo. Both chargers are giving same output ~43v

 

[sjpt]

Hmmm, very poor labeling on the Kunshan one.

 

[Nealh]

It does say +36v so does imply voltage output is greater.

 

[sjpt]

Yes. I misread that as a polarity indication but I guess you're right.

 

[Bikes4two]

• Both chargers then, will charge the OP's battery - one at 3A max, the other at 2A max.
• So if you had to choose just one of them, which would you go for given that the 3A one will charge faster but on the other hand there is a generally held view that a slower charge rate will increase the total number of charge/discharge cycles you'll get from your battery (is this an urban myth or not?)
• I have both a 4A and a 2A charger so I'm interested to hear what you folks have to say on this point.

Cheers, B4two

 

[matthewslack]

• Both chargers then, will charge the OP's battery - one at 3A max, the other at 2A max.
• So if you had to choose just one of them, which would you go for given that the 3A one will charge faster but on the other hand there is a generally held view that a slower charge rate will increase the total number of charge/discharge cycles you'll get from your battery (is this an urban myth or not?)
• I have both a 4A and a 2A charger so I'm interested to hear what you folks have to say on this point.

Cheers, B4two

Whilst I would prefer 3A over 2A, I also prefer a label that says the actual output voltage rather than the nominal voltage of the battery. In this case I would pick the 42V 2A one as there is less room for error.

On charge rate, if you divide charger current in A by battery capacity in Ah you get the maximum 'C' rate the charger can put into the battery. So my 4.6A charger on 418Wh / 11.6Ah battery is 0.4C.

Anything under 0.5, I would have no worries about effect on battery life.

Fast charging on electric cars is up to 80% of battery in 30 minutes, which is 1.6 C. Normal ebike chargers are quite gentle compared to that, especially on larger batteries.

 

[Bikes4two]

...... Anything under 0.5, I would have no worries about effect on battery life.

Brill, thanks for that this graph here shows the truth of that