I recently purchased a used FS-5 to begin acquiring digital files on my Canon XL-H1 Camera. The unit works with the wall charger but the battery does not hold a charge. I can't find a replacement battery on the internet. Does anyone know where I can buy a couple of these batteries for this unit? Or a work around to make this unit portable?

The battery number P/N Batt 0012-01 and AVT 900607.

I found a site out of china(sunpow) but they have not responded to my inquiries.
Thank you in advance.

Santiago, just to be clear, is this the FS-5 you're referring to?

https://www.bhphotovideo.com/c/product/680956-REG/Focus_Enhancements_ASYF_1442_01LF_FS_5_120GB_Portable_DTE.html/BI/2855/KBID/3801

If so, then this is the battery?

https://www.bhphotovideo.com/c/product/567889-REG/Focus_Enhancements_ASYF_1323_01LF_ASYF_1323_01LF_1950mAh_Li_ion_Battery.html/BI/2855/KBID/3801

And this is probably the Chinese company you found:

Focus FS-H200 Pro DTE Recorder Battery AVT-900607 for sale ? Professional Camcorder Battery manufacturer from china (102605019). (http://sunpowcn.sell.everychina.com/p-102605019-focus-fs-h200-pro-dte-recorder-battery-avt-900607.html)

I found this source, which is a legitimate company, but the price seems high to me.

Contact them regarding availability.

Vitec ASYF 1323 01LF Battery for FS 5 Standard 3 Hour | Full Compass (http://www.fullcompass.com/prod/154401-Vitec-ASYF-1323-01LF)