Is it OK to leave charger plugged in & on?

[Tinker]

Should the charger just be used to top back up to full power or is it advisable to leave 'plugged in' if the bike isn't going to be used for a couple of weeks.
The bike in question is my wife's iZip Trek Enlightened and my reason for asking is I have a disability scooter which advises being left connected.
Thanks

 

[flecc]

Not with your e-bike Tinker. The iZip Trek Enlightened uses lithium batteries which are best charged little and often but unplugged between charges.

These batteries use internal management which in theory cuts the charge when the cells are full and balanced, but for safety reasons that should not be depended upon. Large capacity batteries and especially lithium ones have at times been referred to as "household bombs" with good reason, so they should always be treated with care and respect.

Personally I won't even charge a lithium battery unless I'm at home and awake.
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[Tinker]

Thanks for the quick reply and valuable advice, little and often it shall be
Regards

 

[richard freeman]

charger for battery ..

Could anyone tell me if i need to buy a charger or it all comes with the bike ?

richard .

 

[Tinker]

If you are buying a half decent bike complete with battery I would expect there to be a charger with it.

 

[flecc]

Yes, there's always a charger with a new e-bike. If offered a second hand one ever which doesn't have a charger with it, it's reasonable to assume the bike is probably stolen, especially if any keys are missing too.
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[Sevenhills]

Hi

On my 24v charger there is a red light on the charger when the battery is very low, when plugged in its red, then flashing red/green and then green. Is it ok to leave the charger on for long periods? If it just needs an hours charge, can I plug it in on a morning and then will it be ok untill I get back after 5 o'clock.

S

 

[flecc]

I'm never in favour of leaving chargers unattended when on charge Sevenhills, as you'll see in the first post in this thread. If your batteries are lead acid (SLA), it is likely to be fairly safe, but if lithium I'd warn against it.

Leaving it on charge won't harm the battery, it's only on safety grounds that they are best not left unattended.
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[Synthman]

I'm with Flecc on this one. I don't feel safe leaving it unattended while charging, however I have put it to charge, and fallen asleep and nothing happened, and left it for short periods occasionally. If I can't keep an eye on it I tell my mum to unplug it once the green light comes on. If the charger and BMS are fine, then it should switch off when its fully charged. If you know roughly the exact charge time, you could use a plug timer, eg set it to stay on for 6 hours on an overnight charge. The mechanical ones are better. I would do this but I lost mine!

I'd say I'm more worried about how hot the charger gets than the battery exploding. If the charger were held for over 30 seconds, I reckon it would be enough to cause a burn eventually. Mine doesn't have a fan. Next charge I'm going to strap a thermometer to the charger and see what the temperature is.

 

[Tinker]

I would be concerned if the charger is getting hot. We charged the i Zip yesterday, took about 3 hrs. 'till the lights indicated fully charged and the fan switched off but it does its work and doesn't get hot at all.

 

[flecc]

Any risk is in the possibility of a short inside a battery cell. At one time this was far too common on large capacity lithium batteries but they have been much improved since then. However, metallic lithium is nasty stuff. When a lithium battery is in good condition there is no lithium in pure metallic form in it, but a fault condition can produce crystals of metallic lithium inside cells, which, growing in jagged formations can puncture insulation between poles, the resulting short circuit causing fire.

The risk with today's batteries is very small, but it does exist.

And as I remarked above in an earlier post, all high capacity batteries are potentially household bombs, capable of fire and explosion. Any fire brigade can tell you of the number of occasions when they attend cars burning out following a short circuit releasing the destructive battery potential to cause the fire.
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[Synthman]

Today I charged my battery and attached a thermometer to the charger. It went off the scale as it only goes up to 50°c nearly 60°c. I might have to try again with a higher range thermometer.

 

[flecc]

As yours isn't a fan cooled charger that doesn't surprise me Synthman, some I've known get very hot indeed. I prefer fan cooled chargers or those that charge at slower rates.
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