Rules thoughts

[Cooper]

What do the nitro guys do? Nitro is pretty danged volatile too. Do they ship that crap ground? I know they aren't storing it in a bomb shelter. I'm so ignorant where nitro is concerned.

Now we are comparing something that is acceptable, (good). Just like when three wheelers came out, people were getting hurt a lot, government stepped in and banned three wheelers now allowing four wheelers saying three were too unsafe. Now the truth, not manu people could get hurt on a motorcycle-if you couldn't drive one you couldn't go anywhere to get hurt. Once the three wheelers came out this opened the door for those unskilled and foolish people to have no skill and go get hurt. So government said they were too dangerous and solution was adding a wheel, four wheelers were accepted. Now the initial shock of someone hurting themselves on a recreational vehicle was over and there had to be something so that's what we ended up with! Just like lipos, technology is advancing only as fast as we can accept it to the masses.

[TheShaughnessy]

I would talk to the cd at the race you wana go to. nAMBA rules don't limit cell type just voltage. Boats are speced after you win a race not before hand. I'm almost positive you'd be under 15 v by the end of a heat. My fully charged 4s lipo reads 16.8 . You would probably be around .9 v per cell after a heat. And if you aren't winning nobody is gonna care what batteries you are using.

[sjslhill]

Rules are based on what the nominal voltage is. 1.2V for NIMH and 3.7 for Lipoly

[fas]

The rules read

2S 7.4 nominal
4S 14.8 nominal

nominal being the key word the nominal voltage on 7 NIMH is 8.4

I have not used NIMH in 5 years when I first switched over the reason was lighter and holds voltage
today weight is not so much the problem voltage drop would be I would be intrusted in seeing a test done 2s lipo to 7 NIMH same boat and run time just different fuel

good Stuff

[sjslhill]

Very well stated! I think 8.4V NIMH vs. 7.4 LiPoly would be a good comparison. 7.2V NIMH is what one would need to run with today's rules, no chance of competing.

energy density would be the best rules, but that would be too complicated for the sport. LiPoly has tons more energy per weight as others.

The rules read

2S 7.4 nominal
4S 14.8 nominal

nominal being the key word the nominal voltage on 7 NIMH is 8.4

I have not used NIMH in 5 years when I first switched over the reason was lighter and holds voltage
today weight is not so much the problem voltage drop would be I would be intrusted in seeing a test done 2s lipo to 7 NIMH same boat and run time just different fuel

good Stuff

[T.S.Davis]

Steve's right. You don't plug your nitro supply into a charger and wait for the results. It's complacency that could bite us on the butt. We keep having no problems and we'll take our eyes off the ball then WHAM right in the face. We have to keep respecting these or they will become very dangerous. With nitro you KNOW it's a volatile liquid and treat it accordingly. With LiPo it's easy to forget they're fuel too.

What capacity is available in Nimh these days? I suppose you could parallel packs the same way we do with LiPo. A pair of (13) 4200's gives you 8400mah at say 150 amps without making the cells too angry. That's maybe 2100 useable watts with the voltage drop. It could work. I'm not saying it would win. Power to weight and all that rot.

It's still crazy Steve but the idea has merit. Good thread.

[T.S.Davis]

Not to get off on a tangent but you guys all know it's cheaper to race P limited mono than it is to race N2 mono right? N2 is big amps with big amp equipment.

[sjslhill]

Woops, your point just killed the thread....I forgot your running 10,000mah, NIMH is never going to work and would be too heavy. Oh well, it was an exercise in brain usage anyway.

[NativePaul]

In the UK (and many other countries worldwide that run Naviga rules) we run 7x subC, 3s2p 4600 A123 LiFePo4 or 280g LiPo 2s/3s, for Hydro1 and Mono1 and Eco, NiMh were still at a disadvantage from day one, we run 5-6 minute endurance races, and with the sprint racing that you run I would think that the disadvantage would be bigger as LiPo drop less voltage under heavy loads.

I don't think that adding cells is the answer as with NiMh you are adding a fair bit or weight too so the ideal boat for it gets bigger and heavier and takes more power to drive and you need more cells again etc for ever, I am pretty sure that my old 12cell hydro2 would get beaten pretty badly by my LiPo Hydro1.

[fas]

I would not kill it so fast we may carry 10k but in my book I only use 80% so that would be 8k if I remember right we used to take NIMH all the way down I can remember putting 4300 back into 4200 cells so you would only need 8k at that point

don't get me wrong I love lipos I am not going to switch until something better comes out. just nice to kick the start the brain

great stuff again

[sjslhill]

thanks! I see your point the weight is double LiPoly is an amazing lite weight power source. In fact, really good LiPoly cells will just totally destroy themselves trying to put out max. power.

In the UK (and many other countries worldwide that run Naviga rules) we run 7x subC, 3s2p 4600 A123 LiFePo4 or 280g LiPo 2s/3s, for Hydro1 and Mono1 and Eco, NiMh were still at a disadvantage from day one, we run 5-6 minute endurance races, and with the sprint racing that you run I would think that the disadvantage would be bigger as LiPo drop less voltage under heavy loads.

I don't think that adding cells is the answer as with NiMh you are adding a fair bit or weight too so the ideal boat for it gets bigger and heavier and takes more power to drive and you need more cells again etc for ever, I am pretty sure that my old 12cell hydro2 would get beaten pretty badly by my LiPo Hydro1.

[sjslhill]

Love the eco class, I have a tenshock and rapido

[sjslhill]

using 8,000mah for a sprint race is just amazing! WOW!

[Doby]

Anyone remember trying to slow charge Sub C cells to try and "Balance" them.....

Would add a lot more time between heats on race day...

[Brushless55]

Doug,
The sport has went way beyond my experience.

The thing that shocks me in this thread is I guess people are afraid that NIMH would beat LiPoly if it had a slight beginning voltage advantage. I don't expect any rules to change but I thought I'd bring up the idea. The way the rules are written, LiPoly is the only batteries that could win.
.

Not one person I see with comments to this thread ever stated they are afraid to run Lipos against Nimh batteries...
very strange comment

In the UK (and many other countries worldwide that run Naviga rules) we run 7x subC, 3s2p 4600 A123 LiFePo4 or 280g LiPo 2s/3s, for Hydro1 and Mono1 and Eco, NiMh were still at a disadvantage from day one, we run 5-6 minute endurance races, and with the sprint racing that you run I would think that the disadvantage would be bigger as LiPo drop less voltage under heavy loads.

I don't think that adding cells is the answer as with NiMh you are adding a fair bit or weight too so the ideal boat for it gets bigger and heavier and takes more power to drive and you need more cells again etc for ever, I am pretty sure that my old 12cell hydro2 would get beaten pretty badly by my LiPo Hydro1.

very well said Paul