Omnibook 300 battery cells


So I got an Omnibook 300 (hey, it was designed by the calculator division, so it's not completely off-topic), but the battery pack isn't in great shape. It will also run off AAs, but if you use NiMHs, it won't recharge them or display the battery level correctly. (And I'm not sure that off-the-shelf AA NiMHs have the same capacity as the cells that were originally used.) The original pack has 4 cells, and is rated for 4.8V, 1.5 AH.

I cracked open the battery pack, and the cells inside it aren't quite AA. These seem to be 17mm diameter, 41mm long. Because of the wide divider in the middle of the package, I can't simply stick AAs in there and pad the slack. Does this sound like a standard size? The cells have the following markings (inside the outer insulation):


I'm not getting any useful Google hits from those numbers.



You might try Panasonic HHR200A NiMH with tabs. They are 4/5 AA, 2000 mAh, 17mm x 43mm. Not sure if the 43mm includes the thickness of the tabs or not. It looks like they don't come standard with tabs, but NiCD Lady can add the tabs for you. There's also Sanyo HR4/5AU - same size as the Pansonic, but 2150 mAh.

New battery packs can be had from Interstate Batteries. They are 1600 mAh.

I personally use Everyready Lithium AA batteries. With a flash drive, they last a long time. If I'm doing anything heavy on it, like installing an operting system, or heavy use of com port, then I plug the computer in.


Edited: 14 Aug 2012, 12:14 p.m.


So it's a "4/5 A", huh? I think that'll give me enough to go on. I see a few sources for them with solder tabs.

On a side note, this machine is really impressive with regards to what they did for portability. Wish I could get OBMax to stop having fits, though.



I agree - the Omnibook series were fantastic computers. I know they were the workhorses for a lot of Journalists for many years.

OBMAX - While I have a copy of the OBMAX disc, I never really tried to use it - so can't help you with any problems you're having with it.

Now you need to collect the entire series - OB300, OB425, OB430, & OB530. The optimum one to have is the OB430 - last one that still ran on AA batteries and you can install other operating systems on it. I have installed Linux, Xenix, CPM/86. With Linux, you can use a large CF card or Micro Drive. I have installed Linux with 512 MB dos partition, and then the remainder linux on a 4GB MicroDrive.

Please let me know how you make out re-celling your battery packs. I might want to do the same to a couple of my dead packs.



Personally, I'd like to get ahold of a 425, or at the very least, an image of a 425 ROM card that I could write to a linear flash card and use in my 300 (apparently this can be done without problems). I like having the execute-in-place OS and programs, since it saves RAM in Windows, but the 300 won't use ATA compact flash cards, and it's extremely tight on conventional memory. So much so, that I can't really run CPACK200, especially if LLRA is active.

The OB300 1.1 ROM and 425 ROM both allegedly support ATA CF cards, and I think my OBMax problems stem from this being an English International model rather than a US model. Booting a US ROM might fix that.

If anybody knows where to find an OB425 ROM image, I would greatly appreciate it. It looks like it used to be available here, but the server isn't up any longer:

Or if somebody just has a dead OB300 with a US 1.1 ROM and wants to sell it cheap... :)


I checked the CD I made almost ten years ago after downloading many files from that site... unfortunately for you I only got the ones for my OB 800CT. Sorry.


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