Do it!! 36V on a 2019 Phoenix 20Xp with ultrex. I'm hard on TM batteries. No matter what I get or do, they last me 1.5 years max. Just switched to Ionic 100 AH. Took it to the river and put them to test. There's a good hole that I normally have to keep the TM on speed 6 just to stay in one spot. Normally I can only fish there 2 hours max. Not a problem with the ones I got. 50AH probably would have been sufficient but I'm tired of buying batteries and went overkill. I burned the bank, up current throwing a whopper plopper 8 hours. When I got home, I still had 81% battery life per their bluetooth app.. What I really enjoy is, the speed is always the same on the dial setting. No more 4 in the morning and 6 an hour later to maintain same speed. Since I got the bigger batteries, I only lost 81 pounds. Holeshot is ridiculous with the 4 stroke 250.. I did notice the transom floats an inch higher... Anyway, I'm not sponsored or associated to Ionic anyway. Just thought anyone who is on the fence, should do it! In fact, they should come standard in new bass boats.