Intermittent Power in a GNG 450W Mid-Drive, why?

[shapebuster]

Hello there,

I have installed a GNG 450w Mid-Drive Brusheless kit, and made a 48v battery from 4 12v UPS batteries.

The problem is when i conect the battery, and accelarate, the engine runs...and stops...and runs...and stops...in a intermittent way.

The first time i run it didn't happen.

By battery is measuring 0.20A 46,5V

4.80AP 9W

WHo can help me?

Regards from Portugal

 

[wesnewell]

Sla batteries sag a lot. At 46.5V your battery pack is very close to empty. You need to charge them back up. What's happening is that the controllers LVC (Low Voltage Cutoff) is set to 42V to keep you from ruining your batteries. Under load the voltage is dropping below LVC and the controller shuts you down as it should. You can't expect much mileage from an sla pack. I think the best I could get out of a 48V 7ah pack was about 8 miles using a 48V 500W motor. SLA batteries sulphate fast too, so you need to recharge them immediately, if not sooner, after every ride or you will kill them in a matter of weeks if not sooner. A fresh 48V sla pack should charge to ~53V.

 

[shapebuster]

Sla batteries sag a lot. At 46.5V your battery pack is very close to empty. You need to charge them back up. What's happening is that the controllers LVC (Low Voltage Cutoff) is set to 42V to keep you from ruining your batteries. Under load the voltage is dropping below LVC and the controller shuts you down as it should. You can't expect much mileage from an sla pack. I think the best I could get out of a 48V 7ah pack was about 8 miles using a 48V 500W motor. SLA batteries sulphate fast too, so you need to recharge them immediately, if not sooner, after every ride or you will kill them in a matter of weeks if not sooner. A fresh 48V sla pack should charge to ~53V.

Thank you for your answer, here is my built:

And the battery i have build to transport in my backpack:

I dont know why, but suddenly the charger, started charging the battery, it as two lights, and the darker light is now on, as well as the fan.

Anyway i will do like you say, and buy a new battery pack. I dont need many miles, i live in Lisbon, and in the worst case cenario, i will do 6 to 8 miles a day.

What do you think about this battery+charger pack?
http://www.bmsbattery.com/48v/496-48v-10ah-lithium-ion-electric-bicycle-battery-pack.html

Thank you for all the help.

Regards from Portugal

 

[d8veh]

This one will be better because it has a higher discharge rate that you need:
http://www.bmsbattery.com/packs/559-48v-10ah-38120-lifepo4-battery-16-cells-ebike-battery-pack.html

 

[shapebuster]

This one will be better because it has a higher discharge rate that you need:
http://www.bmsbattery.com/packs/559-48v-10ah-38120-lifepo4-battery-16-cells-ebike-battery-pack.html

Thank you!

Wich one? There are three options, 15-30A, 30-60A or 50-100A?

What charger do you recommend? Here in Portugal we have 220v.
Regards

 

[wesnewell]

Just one concern when buying a battery pack. It must be able to output the max amps the controller will draw. If your controller is 30A max, then the battery must be capable of 30A. I'd want a 30A continuous output with a 30A controller. There's all kinds of options in lithium batteries you can use. Personally I use nothing but rc lipo without a bms so I don't have to worry about that. a 20C 5ah lipo pack is rated for 100A and will handle 50A easily. A 12s pack can be put together in seconds for $75.

 

[d8veh]

This one will be better because it has a higher discharge rate that you need:
http://www.bmsbattery.com/packs/559-48v-10ah-38120-lifepo4-battery-16-cells-ebike-battery-pack.html

Thank you!

Wich one? There are three options, 15-30A, 30-60A or 50-100A?

What charger do you recommend? Here in Portugal we have 220v.
Regards

I'd get the 30-60 amp BMS
Theie chargers are not so bad now. They seem to be a bit more reliable, but I'm in two minds whether to advise you to get two because they're cheap when you buy them with a battery. As it's only 9aH, I'd get two of these:
http://www.bmsbattery.com/alloy-shell/24-alloy-shell-120w-lifepo4li-ionlead-acid-battery-ebike-charger.html

 

[shapebuster]

[/quote]
I'd get the 30-60 amp BMS
Theie chargers are not so bad now. They seem to be a bit more reliable, but I'm in two minds whether to advise you to get two because they're cheap when you buy them with a battery. As it's only 9aH, I'd get two of these:
http://www.bmsbattery.com/alloy-shell/24-alloy-shell-120w-lifepo4li-ionlead-acid-battery-ebike-charger.html[/quote]

Im going to buy three of these,

I just dont know if my actual "ebay from china 48v charger" its apropriate for them, is it?

 

[justlooking]

Im going to buy three of these,

I just dont know if my actual "ebay from china 48v charger" its apropriate for them, is it?

what voltage are those batteries ??

and that charger looks like one for sla batteries, if it is dont use it with those batteries, get a proper one for the batteries that you will be useing

 

[1KW]

bump, any updates to this cool bike?