homemade 24v 28ah battery

[dan1982]

Hi there I need some advice please. Ive made a battery for my electric bike and made it from used LG18650 2800mah li-ion cells. There are 60 of these cells in my battery pack and they are In parallel and series. The question I need to ask is do I need to fit a pcb protection board and do I need to fit balance leads? The charger ive got is Imax b6 is the good enough to charge a 24v 28ah battery? Any advice please

 

[pdarnett]

The Imax isn't up to doing the pack unless you're going to do each 3.7v cell group individually. A BMS board is a good idea if you want simple charging from a 24v power supply. You'd need to know the maximum current draw of your bike and the pack configuration.

 

[Deleted member 4366]

He's got a 6S battery, so the imax should be OK as long as he uses 6S balance leads. It'll charge and balance them.

The problem you'll have with a BMS is finding a 6S one and a 25.2v charger. The standard is 7S and 29.4v.

To run without a BMS, you need a lipo alarm of some sort to warn you of low cell voltage. You should set it to about 3.1v per cell. Once the alarm goes off, you have to switch off. You can use an extension lead to mount the alarm where you can see it, so that you know when the end is nigh.

http://www.ebay.co.uk/itm/RC-Lipo-Battery-Low-Voltage-Tester-1S-8S-Buzzer-Alarm-Checker-Test-LED-Indicator-/290761737693?hash=item43b2c005dd

http://www.ebay.co.uk/itm/10pcs-JST-XH-6S-Lipo-Balance-Wire-Extension-Lead-30cm-PF-/261621245343?hash=item3ce9d7659f

 

[dan1982]

thanks for the reply I've tried to charge the battery using the Imax b6 with balance leads and it won't take any charge? My other bike battery I made 24v 17ah 6s charges fine? Is there a charge limit on the b6 I don't, know. May look into getting a better charger.

 

[Deleted member 4366]

If it won't charge, something is wrong. Check that your balance leads are in the right sequence. Check that you have incremental voltages from the first pin to the last. What does your imax show for the six cell voltages? Anything less tgan 2.5v and it won't charge.

 

[dan1982]

Hi thanks again for your reply d8veh had the sequence wrong :-/ stupid me. Can I ask another question? Is it possible to use a hub motor that has hall sensors on a controller that is non- hall sensor?

 

[Deleted member 4366]

Yes, but not the other way round. Some motors, like the Q-series, don't run very well sensorless. Bafangs are normally OK.
Which motor is it?

 

[dan1982]

Am not sure I know it is an import and has no brand on it but I know it is à 24v 200w geared hub motor?

 

[dan1982]

Am a bit gutted as the rear hub I brought does not fit my bike it is to big 165mm and my drop out is 135mm can't believe I made that mistake lol. Do you know where I can get a electric mountain bike frame?

 

[Deleted member 4366]

Only certain electric bikes have the wide frame. It's bikes that have the band brake. You can always use the motor as a crank drive, but you need to know irs speed so that you can get the gearing right. I test them by holding one end of the axle in a vice, put a magnet on a spoke and hold a cycle computer sensor to it while I spin it up with the throttle.

 

[Alan Quay]

Am a bit gutted as the rear hub I brought does not fit my bike it is to big 165mm and my drop out is 135mm can't believe I made that mistake lol. Do you know where I can get a electric mountain bike frame?

I had one like that, I just cut the extra bit off with a hacksaw. Show us a picture....

 

[dan1982]

Hi guy's I've got a problem with my electric bike setup. My geared hub motor and controller get warm to touch? Battery is a 24v 28ah li-ion with a 24v 15a controller I brought from panda on the internet and a Chinese geared hub motor that is 24v 180a. will try and upload some picks soon any advice please