ryan1685 said:
I don't have a shark pack I only have the on board battery that looks like this
https://radpowerbikes.ca/products/radmini-electric-folding-fat-bike?variant=5921615806496.
Looking to put a shark pack on the back rack and have it in parallel with my factory battery
that is basically a shark pack. they exist in a few versions and shapes but they are basically all the same.
looks fammiliar?
putting a fancy dress in a cheap ass chinese battery does not make it magically better, just more expensive.
you can replace the batteries you have right now with much higher performance ones. or just go for broke and have a second battery. that should help the pack from sagging under load as it does now. but you need better cells then the ones you have right now. having crappy cells is what is causing the sag in performance. the voltage drops but the controller keeps putting the same current (note: i dont say voltage!) so lowering the voltage but keep putting the same current means you get less power out of the pack. the controller is not smart enough to compensate for this so you get less and less power and top speed until the pack is dead.
the crappier the cells the harder they sag and cut out well before they are empty.
having high end cells designed for this kind of load reduces sag and usually also increases capacity.
good cells are expensive and hurt the bottom line, that is why they are raking in the money on selling spare batteries and i keep in business repairing those POS batteries when people are done paying 700 bucks for a new battery every 2 years *just* when the warranty has expired...
edit:
just for shitsngiggles i pulled a battery from the shelf and pulled it. i was just finished working on it:
looks fammiliar?
https://radpowerbikes.ca/collections/replacement-parts/products/radmini-battery-pack-2017
660 canadian dinars. and what do you get? 52 batteries worth 2 bucks a pop in a standard aliexpress battery holder...
i can smash 70 cells in that thing without even trying.
hers is a link to a chinese builder that makes them for 220 american roebels:
https://freeworld.en.made-in-china.com/product/QBSJIkXCnaYd/China-48V-E-Bike-Lithium-Battery-Panasonic-Shark-Pack-with-NCR18650PF-Cells-by-13s4p.html