Old Prather 46" Deep Vee electric conversion

[Bande1]

ironclad RC took me up on that challenge. he put a 11,800mah pack in the boat and went around at 40mph for 7 minutes. Then I said "now go race pace." he managed 52mph and blew the ESC from all the weight. Its about 90-120 seconds unless you putt-putt or something. the length of a race. plain boring old mathematics energy in-energy out.

[GeckoDragon]

its going to be an awesome 90-120 second run on batteries. wait an hour, run for another minute.

Or just use a parallel balancing board... I fly FPV freestyle multirotors, so I'm quite familiar with charging lots of batteries simultaneously and have the equipment for it.
@srislash, the boat ran very well previously (on flat water). Didn't get the front/rear balance dialed in, but that won't matter now since I'm changing the setup. I feel like 70km/h would be a good speed to aim for. I won't be doing any racing, just bashing around at the lake, and using it to introduce my young nephews to hobby-grade rc. Probably run a pair of 4s in series, 7.5-10Ah range. What C rating should I look for?
Loving the feedback, thanks y'all!

[srislash]

Or just use a parallel balancing board... I fly FPV freestyle multirotors, so I'm quite familiar with charging lots of batteries simultaneously and have the equipment for it.
@srislash, the boat ran very well previously (on flat water). Didn't get the front/rear balance dialed in, but that won't matter now since I'm changing the setup. I feel like 70km/h would be a good speed to aim for. I won't be doing any racing, just bashing around at the lake, and using it to introduce my young nephews to hobby-grade rc. Probably run a pair of 4s in series, 7.5-10Ah range. What C rating should I look for?
Loving the feedback, thanks y'all!

At least 40c. Actually I feel that is all there realistically is, lots of claims of higher but most testing that I have read proves otherwise. The hobbyking Panther grapheme packs are good, Dinogy always good, I believe CNHL is still good.

Shawn

[srislash]

Oh and here was my 45” Dumas conversion

[fweasel]

At least 40c. Actually I feel that is all there realistically is, lots of claims of higher but most testing that I have read proves otherwise. The hobbyking Panther grapheme packs are good, Dinogy always good, I believe CNHL is still good.

Shawn

FYI, the panthers are crap now, as are most of hobbyking's offerings. I was shocked when I saw their rating drop in the testing thread as they had always been one of my best performers. My 4yr old 6S packs are still performing like new.

[Peter A]

Or just use a parallel balancing board... I fly FPV freestyle multirotors, so I'm quite familiar with charging lots of batteries simultaneously and have the equipment for it.
@srislash, the boat ran very well previously (on flat water). Didn't get the front/rear balance dialed in, but that won't matter now since I'm changing the setup. I feel like 70km/h would be a good speed to aim for. I won't be doing any racing, just bashing around at the lake, and using it to introduce my young nephews to hobby-grade rc. Probably run a pair of 4s in series, 7.5-10Ah range. What C rating should I look for?
Loving the feedback, thanks y'all!

Ok so if 70 kph is your goal speed then I can set you in the right direction. I have previously built and run electric offshore endurance boats so have some experience here. 70 kph was the speed range I was running, and doing 20 minute races on 20,000 mah packs.
I would recommend changing the driveline to surface drive. Whether you use the existing strut and rudder or get a new stinger and rudder.

Props for the 70 kph range are X455-457, Prather 240-245. These will put you between 70-80 kph. You should be able to see an average current draw at around 70A, but don't skimp on the esc. A ZTW 200 or Castle for 8s, something bigger if you want the ability to go to 10s, but you don't really need to.
If you run 10,000 mah capacity then you should get runtimes as long as 7-8 minutes, but test and check. Set your esc lvc higher at 3.2v to reduce the risk of over discharge.

[LibertyMKiii]

Or just use a parallel balancing board... I fly FPV freestyle multirotors, so I'm quite familiar with charging lots of batteries simultaneously and have the equipment for it.
@srislash, the boat ran very well previously (on flat water). Didn't get the front/rear balance dialed in, but that won't matter now since I'm changing the setup. I feel like 70km/h would be a good speed to aim for. I won't be doing any racing, just bashing around at the lake, and using it to introduce my young nephews to hobby-grade rc. Probably run a pair of 4s in series, 7.5-10Ah range. What C rating should I look for?
Loving the feedback, thanks y'all!

C Ratings are completely bogus and made up values. There is no regulating body on the battery industry so they put a made up value in there to sell more products. One great example is CNHL and their 70c G+ lipo is their highest output lipo, but they also sell a 90c and 120c that output less power.

I would go with tried and true/trusted brands. The CNHL G+70c is a good pack that ranks high in the mid-grade list.
Or if you want to go top shelf go with something from SMC.
They happen to be running a great sale this week for thanksgiving/black Friday.

I'd also recommend going with any battery that has a minimum of 10awg or 8awg wire. QS8 battery connectors are also great for handling the heat these fast electric setups produce.

I'd go with the Castle XLX2 hydra for the ESC. It runs cool and has all the power handling you could want (better suited for a big heavy boat also)
Should you want to explore going faster it has data logs and you can get into the data for helping you make prop change decisions.

[GeckoDragon]

@Peter A - yep, I'd say it was in the 30-35mph range with the gas engine
@srislash - that's a 45"? Daaaaang. That kind of performance is badass, but I don't think I need mine to be quite that level...

Sounds like the Leopard 56110 w/ Castle XLX2 Hydra is a solid combination, so I think I'll go with that. As far as batteries, how do y'all feel about Tattu? They're pretty well regarded in the FPV community. Although we do prioritize low mass & high rate discharge (my favorite batteries [not Tattu] are 6s 1050mAh, and they handle 120A draw without breaking a sweat). CNHL doesn't have a bad rep, solidly midgrade, so I'll definitely look at those