Battery for pit bike engine

[Mid Wales welder]

Good evening all! Would someone be able to tell me if this battery will be ok for starting a pit bike engine? Thanks in advance.

 

[Maker]

That can supply 52 amps continuously (5.2Ah * 10c discharge rate), the peak discharge of a similar one on HobbyKing is 20c which means it can safely supply 100A for 10 seconds. I've got no idea how much current a starter draws or for how long though so I can't say yes or no but that might help.

 

[Mid Wales welder]

That can supply 52 amps continuously (5.2Ah * 10c discharge rate), the peak discharge of a similar one on HobbyKing is 20c which means it can safely supply 100A for 10 seconds. I've got no idea how much current a starter draws or for how long though so I can't say yes or no but that might help.

That’s good info thanks! I have no idea what the starter needs I don’t have a clue about anything to do with engines so it’s something I’m trying to learn.
If anyone knows how much a starter draws that would be great?

 

[Turbo]

I have a mini jump start pack I bought in Lidl that uses the same type of battery. I used it when the battery in my 306 diesel was failing & it provided enough power for starting the car 3 times before it needed charged again, which took several hours on a mains charger. But it was unable to start the car if the car battery was totally flat so it needed some other power source to help it.

So I don't think that the li-po battery would be suitable to regularly start an engine. What's normally fitted to bikes is a sealed lead acid battery & you will be able to buy a decent one for a lot less than £27. You need to size the battery according to how many amps the engine needs to start (cold cranking amps or cca) and how much current the alternator on the engine puts out so it can charge the battery back up to its capacity.

If anyone knows how much a starter draws that would be great?

It's all relative, depending on the size of the engine. You could try asking a bike dealer what size battery is normally fitted to those bikes.
Or you could attach the engine to a car battery & use a clamp meter on the battery cable to measure how much current it is drawing.

 

[knighty]

I don't know if it will start it or not, no idea how many amps you need, I think it probably will, 100 amps at 12v is 1.2kw and a lot of small cars don't have starters that big


but.. what's your plan for charging it ? you need some way to balance it when it's charging/charged
(there's 3 cells inside it, you need to make sure non of them are under or over charged)

 

[pod70]

I use a similar 3200mAh 4S as the battery on my CBR400 race bike (4 cylinder) and it starts it no problem and gives me about 20-25 minutes track time. I would say that you need a 4S (4 cells) which gives a maximum of 14.4V and drops down to 11.3V. I would say a 3S would soon drop to too low a voltage to turn the starter. If you do go this route then best to get an iMax B6 charger. these are better than most.

 

[pod70]

A much cheaper option and one that wouldn't need a balance type charger would this https://www.ebay.co.uk/itm/GT4L-BS-...300077&hash=item3f2f3bef21:g:yJ8AAOSwIJlZ7yD8 This is the sort of thing that was fitted to a Chinese monkey bike I had which also used a copy of the C90 engine

 

[Mid Wales welder]

I have a mini jump start pack I bought in Lidl that uses the same type of battery. I used it when the battery in my 306 diesel was failing & it provided enough power for starting the car 3 times before it needed charged again, which took several hours on a mains charger. But it was unable to start the car if the car battery was totally flat so it needed some other power source to help it.

So I don't think that the li-po battery would be suitable to regularly start an engine. What's normally fitted to bikes is a sealed lead acid battery & you will be able to buy a decent one for a lot less than £27. You need to size the battery according to how many amps the engine needs to start (cold cranking amps or cca) and how much current the alternator on the engine puts out so it can charge the battery back up to its capacity.



It's all relative, depending on the size of the engine. You could try asking a bike dealer what size battery is normally fitted to those bikes.
Or you could attach the engine to a car battery & use a clamp meter on the battery cable to measure how much current it is drawing.

The engine is 125cc with electric start, I will go into local bike shop and see what they say, thanks.

A much cheaper option and one that wouldn't need a balance type charger would this https://www.ebay.co.uk/itm/GT4L-BS-...300077&hash=item3f2f3bef21:g:yJ8AAOSwIJlZ7yD8 This is the sort of thing that was fitted to a Chinese monkey bike I had which also used a copy of the C90 engine

That’s a great alternative thanks, anything that makes it cheaper would be great as it’s just a little hobby project.