Could there be a problem?

cogs

Pedelecer
Sep 3, 2008
90
0
I have recently replaced my battery. What I've noticed is that the charge up time on this new one seems to take much longer than I remember the old one taking.

Today, following an 18 mile run, it was plugged in for a charge at 3.30 pm. I've just checked it, and the red charging status light is still on, some seven hours later..

As far as I know the battery is identical to the one it has replaced (an Alien 36v 10ah), so I assume I can still use the original charger, which is about 18 months old.

Question is, is there a battery fault (it seems to perform reasonably, but there is a slight concern that it may be a little less powerful than the old one), or, alternatively, is it possible that the charger has become less effective in some way?

Could anyone please suggest how I might proceed on this one? Is it possible to check the charger, and is it possible to check the battery?

I suppose its possible that there isn't an issue at all, but surely a seven hour charge period is excessive (and the lights still not green) ?

Any advice would be appreciated.
 

NRG

Esteemed Pedelecer
Oct 6, 2009
2,593
10
This is the new Alien battery Cogs? What is your charger rated for? The one I have is 41.9v @ 1.8amp but I have the internal BMS on my battery....
 

cogs

Pedelecer
Sep 3, 2008
90
0
Yes it is the new Alien battery, and the charger is rated at 41.9 (1.8amps) NRG.

If there is a mismatch between charger and battery will it cause damage?
 
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NRG

Esteemed Pedelecer
Oct 6, 2009
2,593
10
Don't think so, it seems its the same battery and charger combo as I have. I wonder if there is some cell balancing going on which is causing the prolonged charge time.

I'd leave it longer and see what happens.
 

cogs

Pedelecer
Sep 3, 2008
90
0
The green 'charge complete' light was on this morning, indicating that the charge was eventually accepted. I'm off out for a run later, and I'll try and monitor the charge time after that.

Thanks for the advice.

Its all mystery and imagination this lark init?;)
 

cogs

Pedelecer
Sep 3, 2008
90
0
I have given the battery several charges now, some from it being almost completely exhausted (about 20 miles), and some from it being partially discharged. The time taken for complete re-charge is still much longer than I remember it being with my first Alien battery.

I wonder if anyone has experienced similar disparity of charge time (using the same charger) between two apparently identical batteries.

I'm really not certain whether I should worry about this, after all, the battery does eventually charge up, and seems to function ok.

Any battery boffins out there who might advise?
 

flecc

Member
Oct 25, 2006
46,532
23,366
Increased cell content density (a good thing, more effective capacity) increases charge time due to increased resistance. Alien did have a lot of battery failures and had to change a number, so the later batteries may have an improved specification to overcome those problems. All manufacturers have been continuously improving lithium batteries over the last four years.

I can't say for certain that's the answer, but it would account for this. If you've kept an eye on the range you get from a full charge in the past, that may give you a clue. If thr range on the new battery is a bit better than it was on the earlier one, it would indicate this is likely to be the answer.
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