making Li-ion battery pack

Thread Starter


Joined Dec 11, 2007
hy everyone ,

i want to make an Li-ion battery pack for my robotic applicaiton. I am to buy a
2*3.7 V 220mA-h Li-ion prism batteries. i will be buying a ready made charger for these so chargin is not an issue. But i am aware that onboard constraints of using Li-Ion.
So could someone direct me exactly how to go about it and the components i would require on board of my system to have adequate safety measures.
I am aware of IC's from MAX that may serve the purpose but not too sure !!!

Thread Starter


Joined Dec 11, 2007
the batteries i am buying are not datasheeted but available locally and loosely. The battery is guarenteed if used properly with safety precautions. i want to know how to make this onboard saftey precautions


Joined Jan 18, 2008
The battery is guarenteed if used properly...
Without knowing what you really have, how can we possibly advise on what is "proper."

You apparently got the batteries from an unauthorized retail source, maybe on the gray market. Do you know, for instance, if they really are Prism batteries and not counterfeit?

Can you post a picture? What type of termination tabs do they have? What's the open-circuit voltage? What are their dimensions? Etc.


Joined May 16, 2005
i want to know how to make this onboard saftey precautions
1) Make sure the lithium ion batteries do not overheat.
2) Make sure the lithium batteries do not have too much current drawn from them
3) Protect the lithium ion batteries from ESD
4) Do not attempt charging if ambient temperature or battery temperature is below 0C.
5) Never ever buy no-name Asian lithium ion batteries or Asian counterfeits of legitimately safe lithium ion batteries.
6) Do not, under any circumstances, allow the lithium ion batteries to be subject to physical damage.

If your "robot" is one of those silly remote-controlled "combat" drones, NiMH would be a smarter choice. If your robot is a robot, then you should be okay.


Joined Apr 29, 2008
It would probably be wise to purchase a pack that already has the safety circuit, li-ion battery packs can be pretty dangerous if they're used improperly.