Dear,
Have a Sony PXW-X70 camcorder and charge the battery via the camcorder itself. Which external charger can I use best for my NP-FV70 battery, I think best to use an original Sony Charger? NOT the Sony double charger, far too expensive for me! And is it recommended to use the non-original battery's?
Thank you for your comments ...

I use this Watson charger....it has removable charge plates, you can charge anything on it, like one NPF light battery on one side, and an X70 camera battery on the other, at the same time. The plates are very cheap, $5-10 if I remember correctly? Check eBay for used ones cheaper.

Paul

https://www.bhphotovideo.com/c/product/836481-REG/watson_d_4203_duo_lcd_charger_for.html

I just looked: I've got 4 different wall chargers for my X70 that I bought or came (included) with different aftermarket batteries I have (1x MaximalPower, 1x Wasabi, 2x No-namers). I have a Sony battery but have been using aftermarket for years. I bought most of these from either Amazon or Ebay, like this:
https://www.amazon.com/MaximalPower-Charger-DCR-SR15-HDR-CX105-NEX-VG10/dp/B006OAKM9E/ref=sr_1_1?ie=UTF8&qid=1500563588&sr=8-1&keywords=np+fv70+battery+maximalpower

I use these small wall chargers about 95% of the time and they're the 'bomb' as far as I'm concerned if you shoot out and about, on the road, or in different countries. I haven't taken any chord chargers on the road for years ...too much bulk. I charge Sony and other aftermarket batteries interchangeably with them. I've got a whole box of these type of chargers with various names on them for DSLR's and other camcorders, cameras and LED lights I have or have had in the past. They have a small footprint, no cords, folding plug, lightweight, super handy for traveling, non-polarized plug-in (can attach to a socket any direction), work off just about any voltage and can charge with 12V too! The car charger capability has gotten me out of a bind more than a few times when yer in the middle of Tim-buck-too! The MaximalPower unit has a USB output which a lot of them don't have. It might help eliminate an extra USB charger from your packing list or get you out of a bind if you unexpectedly need to charge something USB like a Radian, GoPro or phone in central Wyoming or the Karst of Guilin ....and the only thing nearby is an old truck with a cigar lighter! You can charge the battery and use USB at the same time.

These chargers seem to perform the same in my experience regardless of what name or not is on them, I suspect they come off the same assembly line in China, who knows?? I always take 2 with me to charge multiple batteries and in case one craps out (which I've personally never experienced). I haven't noticed any unusual battery wear, and I generally leave them on overnight till I wake up (which I know I probably shouldn't do). The Watson charger that Paul A. linked to (above) seems nice in that it has a charge level LCD. The small wall units like the MaximalPower has a red light that becomes amber, then ultimately green when the battery is charged. A fully depleated fm70 size battery takes about somewhere like 3.5 hours +- to charge up (about like the camcorder charger). There's plenty of options out there for ya.

Hope it helps...