hi all, I've got a Teac R-3 DAB radio which has a rechargeable battery that no longer holds much of a charge. It used to manage about 3hrs at best but has taken some punishment as I use it for my site radio most days.

I could just replace the original battery pack quite easily but thought I'd see if I can beef up the run time with a bigger battery. What i'm not sure about is what I can get away with.

The original is a 7.2v 1600 mAh ni-mh and far as im aware I can use another 7.2v pack with a higher mAh and it should work as normal but last longer, although the charge will be slower. Does that sound about right? Would there be a limit to the mAh size of the new pack? Was thinking of using a 3800 mAh pack normally for RC cars, which should give roughly 2.5 times the run time. I've also got a 4400 mAh laptop battery I could use.

Alternatively I could use two of the 1600 packs in parallel for 3200 mAh.

I guess my main concern is if the radio will function ok and how well it would charge a larger battery.

any advice appreciated

 

Higher mA-hour ratings will give longer service between recharges, it's that simple. There's no limit. But you're right, a charger meant for a smaller battery will take longer to charge a big one.

I'd stay away from putting batteries in parallel if you can. Small mismatches can become larger and end up damaging one of them. It's common for manufacturers to do this, but they can start with matched sets.

 

Get the largest that will physically fit into the radio.

 

There are 2000 MA-HR NIMH cells in AA size available cheap because they used them in cameras. I used to see them in four packs for about $10.

What size are the cells?

 

I'll probably avoid running in parallel then since I've read a few people saying it can cause problems.

was looking at something like this

http://www.ebay.co.uk/itm/250727961...AX:IT&_trksid=p3984.m1423.l2649#ht_500wt_1202