[tonyzoc]

I've got a Pentax Motor MD and the batteries I use are either the AA battery grip M or the Battery Pack LX. I rebuilt the battery pack LX using 1.2v 1/3AA NiMH batteries with a capacity of 500 mAh. This is more than twice the capacity of the original NiCd batteries (226mAh I believe). I have another Battery Pack LX, and I have a set (of 12) NiMh batteries, but I also picked up a set of Li-ion AA sized 3.7v 800mAh batteries. I read that Li-ion batteries need a control IC chip...

"All lithium ion batteries have to be controlled with an integrated circuit to control input and output voltage. If the circuit is not present, the cell could have thermal runaway. I'm sure you've all heard of laptop batteries catching fire."

My concern is, do the batteries normally have a control chip built in? Or is it external to the battery cells?

I'd like to try the Li-ion because of the 800mAH capacity, but I'm not going to use them unless I can either confirm the have voltage control IC or some "how to" to add one inside the Battery Pack LX. I

do see on eBay someone doing the Li-ion rebuild for $180. I picked up the 4 AAs for $24.

[ProfessorBuzz]

LiOn and LiFePO4 batteries need a Battery Management System controller. For example an inexpensive charger:
Adafruit Micro-Lipo Charger for LiPo/LiIon Batt w/MicroUSB Jack [v1] : ID 1904 : $6.95 : Adafruit Industries, Unique & fun DIY electronics and kits
The output side is another story - low voltage cut-off needed to prevent battery damage from discharging too much, and regulation possibly, as the high voltage of the cells initially could be a problem for the LX hardware.

[tonyzoc]

LiOn and LiFePO4 batteries need a Battery Management System controller. For example an inexpensive charger:
Adafruit Micro-Lipo Charger for LiPo/LiIon Batt w/MicroUSB Jack [v1] : ID 1904 : $6.95 : Adafruit Industries, Unique & fun DIY electronics and kits
The output side is another story - low voltage cut-off needed to prevent battery damage from discharging too much, and regulation possibly, as the high voltage of the cells initially could be a problem for the LX hardware.

Thanks, I've been reading up on this and although I could probably find an appropriate controller pcb for a reasonable price, I don't have the electronics expertise to do this. While the Li-ion capacity would be nice...800 mAh vs 500 mAh, the NiMh is allot easier to deal with so I think I'll stick with that until I can be certain the controller I use will be safe.

[LesDMess]

Unless stated, standalone Lithium batteries don't come with circuitry. They don't need an active monitoring circuit to use as long as you don't draw higher then rated current and make sure the voltage doesn't go below a treshold - 2.8V or 3.2V, as defined by the manufacturer. They need to be charged properly and the circuitry in a proper charger will take care of that but even then they all say to monitor while charging. Lots of requirements to cover liability as they are extremely high density of energy.

BTW, there are many types of lithium based battery chemistry and their min and max usable ranges can vary widely.

[LesDMess]

Upon further review, it seems there are now available rechargeable 1.5V AA Li-ion batteries. See review of youtube vid

Youtu.be

Youtu.be

Seems you won't have to change anything in terms of form factor and most are more than quadruple the capacity you're used to per cell.

It would seem to me these have to have some control circuitry to convert a normal 3.7V to 1.5. Some have a USB port for charging so they must have charging circuitry. The way the video is shown, the batteries are run till fully "drained" which normally renders Lithium batteries unusable so internally it must have a cutoff. Looking at the most expensive battery tested - VAPCELL P1418A PROTECTED LITHIUM ION AA 1.5V BATTERY WITH USB PORT, it does state It has a chip inside that regulates the voltage to work with them.. However the site also shows a very long list of battery warnings typical of an unprotected lithium battery type.

[TwoUptons]

Upon further review, it seems there are now available rechargeable 1.5V AA Li-ion batteries. See review of youtube vid

https://youtu.be/CzZrB974Zro

Seems you won't have to change anything in terms of form factor and most are more than quadruple the capacity you're used to per cell.

It would seem to me these have to have some control circuitry to convert a normal 3.7V to 1.5. Some have a USB port for charging so they must have charging circuitry. The way the video is shown, the batteries are run till fully "drained" which normally renders Lithium batteries unusable so internally it must have a cutoff. Looking at the most expensive battery tested - VAPCELL P1418A PROTECTED LITHIUM ION AA 1.5V BATTERY WITH USB PORT, it does state It has a chip inside that regulates the voltage to work with them.. However the site also shows a very long list of battery warnings typical of an unprotected lithium battery type.

This is basically why I got rid of my lead acid battery pack and switched to lithium disposables in the 90s... energy density was so much better with the flash that I didn't need to lug some huge thing around...

I've used tiny lithium rechargeables and never had any issue with over-charging or over-discharging...

I have to wonder with some of these new battery technologies if the warnings are there because they aren't protected or if they're there because the battery manufacturers don't want to futz about with which warnings they need, so they put all of them.

-Eric