Actions
Forum Thread Details
  • State Not Answered
  • Locked Locked
  • Replies 11 replies
  • Subscribers 336 subscribers
  • Views 217 views
  • Users 0 members are here
Related
See a helpful answer?

Be sure to click 'more' and select 'suggest as answer'!

If you're the thread creator, be sure to click 'more' then 'Verify as Answer'!

This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

18650 Li ion batteries question

dubbie

I have been gifted a (broken) child's electric tricycle toy. The main problem is that the 6V 4Ah lead acid battery is defective - a collapsed cell I assume. I would like to replace this battery with Li-Ion batteries, specifically the 18650 type. I am thinking of using two 18650 to get the 6V needed (it will be a bit more at 7.2V but that will just mean the tricycle goes faster - Yeah!). However, I am finding it difficult to find suitable 18650 batteries and associated charger. It is not clear what the capacity of these 18650 batteries is. Do they vary? What is the maximum capacity? I have seen 3300 mAh mentioned but I'm having trouble identifying these batteries. I could create a parallel series arrangement of batteries to get higher currents but then I do not seem to be able to find a charger. I'd like to have separate 18650 batteries so I can use them in other things such as mobile robots.

 

I thought of using a 7.2V battery pack as used in cordless drills, but I cannot find any at 7.2V (or is it 7.4V - but I cannot find any of them either), plus I'm reluctant to spend a fair bit of money without knowing if it would be suitable or not.

 

Any advice or sources of information would be welcome.

 

Dubbie

Parents
  • 0

    Hi Dubbie,

     

    Unless you are paying for a quality brand name battery do not expect to get the mAh that is printed on the battery. I have tested many different East Asian Brands with ratings of 2500 mAh, 4400 mAh, and others and they seldom actually produce more than 900 to 1000 mAh of usable energy. For charging it is good to charge at 1/2 C or about 500 mA for these batteries until they get close to Full charge and then allow the current to taper off. I usually charge them on my bench supply with the voltage set to 4.2 volts and the current limited to 500 mA. If you are going to charge them while in series it is best to have some sort of battery charge control circuit to equalize the charge on each battery.

     

    John

Reply
  • 0

    Hi Dubbie,

     

    Unless you are paying for a quality brand name battery do not expect to get the mAh that is printed on the battery. I have tested many different East Asian Brands with ratings of 2500 mAh, 4400 mAh, and others and they seldom actually produce more than 900 to 1000 mAh of usable energy. For charging it is good to charge at 1/2 C or about 500 mA for these batteries until they get close to Full charge and then allow the current to taper off. I usually charge them on my bench supply with the voltage set to 4.2 volts and the current limited to 500 mA. If you are going to charge them while in series it is best to have some sort of battery charge control circuit to equalize the charge on each battery.

     

    John

Children
No Data