Fast Charging

Jam-jam

Finding my (electric) wheels
Oct 13, 2019
9
1
Hi guys.

I've got 2x 17.5 amp/h batteries 48v, and it takes a long time to charge it using standard 2amp charger therefore o got myself fast charger off aliexpress 48v (54.6v max) 10 amp. So in theory should be 5 times quicker fully charging my bike in less than 2h.

Is this safe? My wife is concerned that I'll burn down the house because it's 5x more powerful than regular charger.

Is any one of you using fast charge? Any experience issues with increased amp chargers?
 

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Nealh

Esteemed Pedelecer
Aug 7, 2014
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Your wife is rightly worried does/will the BMS accept the 10a charge ?
Are you happy to forgo cell life cycle and have a short battery life ?
There is a reason why most chargers are only 2 - 4a input.
Most cell can take a 2.5a and some 4a each but you will sacrifice life cycle .
 
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Jam-jam

Finding my (electric) wheels
Oct 13, 2019
9
1
Thanks for your reply Nealh.

I don't know much about batteries itself and assumed that if 5-8-10 amp chargers exist it's fine to use them, and small 2.5 amp ones are shipped together with batteries just bacause they are cheap.

Its bit odd that my phone charger output is 4.5 amp and massive ebike battery only 2.5.

I use my ebike for deliveries so on busy day I drain two 17.5 amp/h easily and have to stop for a day. Thought I can quick charge one battery while using other and have ultimately infinite power at my disposal.

Guess I need to consider third battery maybe.
 
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GLJoe

Esteemed Pedelecer
May 21, 2017
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UK
Its bit odd that my phone charger output is 4.5 amp and massive ebike battery only 2.5.
What voltage is your phone charger, and what voltage is your ebike battery?
Do you think this might make a difference?
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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The power draw form the phone is tiny compared to an ebike.
Cell phone will use a lipo battery these can pack a punch for it's size but lipo's are venerable to overheating and catching fire.

With ebike batteries folks want them to last for ever but most infrequent users will find after two years they are toast because they don't know/understand how to look after them. The worst you can do is either let the voltage drain by not keeping an eye on them every few months or leaving them at full charge.

Your cell phone is just simply plug in and charge and use it, it doesn't need to have mileage range to it, an ebike is a tool for A -B you will wan tit to get you home as well.

You can charge at 10a if you wish, just keep replacing the batteries every two years or so when they age and wear out. Better to be safe them sorry, charge them where the danger is least.
 

Jam-jam

Finding my (electric) wheels
Oct 13, 2019
9
1
Thanks again.
I cancelled that aliexpress order as it wasn't posted yet.

Replacing battery after 2 years wouldn't be bad, to be honest I never assumed they will last that log anyway as I fully charge it and discharge within couple of hours of my part time courier work, every other day. So I go through battery cycles way faster that average/recreational user.
But safety is a key here, live in a flat, bikes is in a living room, no garden, no shed.... Don't want to overheat it with some crazy 10a charger and cause fire that's crazy difficult to extinguish.

I'm looking into different lipo battery safe containers/bags now to keep them in there just in case. Any suggestions here?
 

Audio2

Pedelecer
Apr 5, 2015
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Try an army surplus ammunition box. 40 mm ammunition box on eBay should be ok for 17.5 size batteries.