As the title suggests I am trying to get an old board back to it’s former glory. I bought it back in September and have tried to convert it for a while (understatement) with not much success. I started by looking at the specs and it’s data sheet. The current setup is 2 12v lead acid batteries set up in series to make a 24 volt system. Each battery is 10 Ah (supposedly) but it feels like some short rides. On top of that each of them weigh about 5-6 pounds each. With the board it weighs about 50 pounds. 
The motor is brushed and is advertised as a 24 volt 400w system on E-glides website. https://e-glide.com/electric-skateboard-store/electric-skateboard-parts/motor-and-other-parts/motor-assembly-complete-detail
As for the motor controller it’s quite complicated so just look at the spec sheet, it has most of the info (too much imo since I don’t really get what’s useful or not). The main points are that the max current output is 60 amps as well as an operating range of 16 to 28 Volts DC and peak of 36 Volts (whatever that means). P.S. it’s called the s-drive S70 by PG Drives Technology http://www.cw-industrialgroup.com/Products/Mobility-Vehicle-Solutions/S-Drive.aspx https://e-glide.com/electric-skateboard-store/electric-skateboard-parts/electronics/s-drive-detail
I ordered 35 LG HG2 batteries from liionwholesale.com back in I think October. I don’t know if it’s a reliable source or not but it is what it is. I was planning to make a 7S5P pack with a vruzend kit but soon realized that it is not going to work out with the ampacity of the metal used in the kit is way to low for my use (3.5 amps nominal I believe). Looking back at the specs we see the controller is 60 amps max so if we do some calculations we see that we need something that supports 12 amps per series connection (60/5=12). so I need to find a solution to how to put a pack together that can handle that kind of amperage. I have looked into spot welding (Aulakiria’s) but that seems to have a lot of initial cost (about 105 cad) plus I don’t have any of the other parts to make it work like the lithium polymer batteries and chargers. However it might be worth investing in since I’m also building another board (and battery) from scratch. Shoutout to @Lionpuncher for helping me out with that. I have also looked into N.E.S.E. but found that its also quite expensive (approx. 125 cad without shipping and conversion fees).
So now I am turning to the forum for some advice for what the next best step is and help on taking the right one.
Thanks for reading (or not if you didn’t get this far). 
useful links to help understand further: https://e-glide.com/ http://18650.lt/ https://vruzend.com/