Should be fairly easy.. check the voltage first, take a few pictures... than all you need to do is de-solder it.' order the batteries.. which I'm not sure the size but you can get them from 18650 batteries, they carry all sizes and always buy brand names and not the junk from Amazon or ebay.
Putting it back together just reconstruct, I would say the only thing inside would be the li-ions and a BMS.
Post some pics as you go, I can guide you along if needed. I've done several Li-ion packs over the last 8 years for metal detector and everything else that uses a battery. I found it way cheaper, Fisher wants 200 for the stock batteries for the AQ, I found I could make them for about 100 each, and mine last 11 hours to their 3.5 hours.
Also Be careful and not short out any connections breaking down the pack than making, they are like little nukes.. very dangerous if shorted. And you will need a Good Solder gun..
Couple TDI Pro batteries I did for a friend this past week.. One Stock battery they want 189.00... I did two batteries for him, cost me 120. and cost him 175.oo w/chargers. And I only do work for the guys I hunt with now.. retired from all of that stuff but will give advice.
