1DS battery option question

Hi all. I recently bought a 1ds with 2 almost useless batteries. I can get a third party one on ebay. Has anyone done a DIY job on one of these with more modern batteries. I was hoping to make one up that would last a bit longer or is a proper one my only option. Thanks

Go for a Lenmar or Pearstone batteries for your 3rd party options...anything else is HORRIBLE IMHO..
of course YMMV..
I would rather have 2-3 Lenmars(my preference over ANY 3rd party, even the higher power(IIRC ~2000mAh)Pearstone) than one Canon brand.
Sure the Canon OEM is gonna work better for longer...most likely...

Typically, EVERY other model EOS I would never recommend 3rd Party over the OEM battery, but for some reason the NP-E2/3 model batteries are made very well...
With my 60D/5D2/7D/etc that all take LP-E6's, I would never bother wasting my $ on anything but the Canon LP-E6..nothing else lasts as long, gets as many clicks, or doesnt become defective after a few discharge/recharge cycles, like so many 3rd party LP-E6's I have have owned have...

But for the 1D2n and 1DsII I have, I will only be buying Lenmar replacements..

Hope this helps some..
good luck!

Thanks HyperCams