Rules thoughts

[Brushless55]

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

very true and I can clearly see why the rule

[blowNover]

I really like where this is going but I just want to bounce back to the nitro is not sitting on a charger therefore it's not a dangerous line of thought. Because you guys are leaving a little problem out of this. More house fires are caused each year by other types of hazmat kept inside peoples garages then just about any other household problem. If you look at the number of fired started by lipo and the number of fires started by some other hazmat lipo didn't seam so dangerouse. I think alot of people here are forgetting there is at least one pilot light in our garage always burning.

Now on the topic of being afraid to race against nimh I don't have an oval boat yet and am really ignorant of what those packs produce as far as power. My first "race" boat is going to be a saw boat. Would someone running similar nominal voltage in say t-cat using nimh stand a chance at winning?

[T.S.Davis]

The Nimh battle is starting to come back to me.

We pounded the Nimh cells just before a race with as many amps as we could get out of a charger to heat them up because they had a magic temperature that they were happiest. I've seen guys smoke Nimh packs right on the charger.
End to end soldering to eliminate the loss through the battery bars. Then you over heat one cell of a matched set and the it takes the whole pack with it. ugh At $15 per cell in some cases.
Anybody remember brushed motors and Nimh blowing hatches off boats?

I can't even remember how many cells I soldered up in the middle of the night after some catastrophe during a race. Got pretty good at it.

The Lipo are less finicky.

[sjslhill]

Yes, at the national level I guess NIMH was costly. I remember running 2400mah nicads though at Batavia against NIMH with Twaits and a guy from MI, can't recall the name. I was just a fast and it was an Astroflight motor too. Doug came over and said, "WOW" that motor must be fried! The com was shinny and new looking. At that point it was not all batteries, but I guess it's all dialed in to the max now. 8,000mah in a sprint race! Amazing!

I never ruined batteries when I raced, guess I was too slow.

I think I was the first to ever run NIMH, 2200 Green Meanies they called them, they were much higher voltage than the R/C 2400's during discharge. These cells were built like a nicad with sentered (welded not pasted) electrodes. The later NIMH cells turned into junk after time. I think GP3300's were the most durable, IB4200's the highest voltage. The cells out there today will just go bad sitting around above 4000mah

Don't recall $15 a cell, I would be retired.

[Brushless55]

I would love to see some Nimh packs run against some Lipos in a show down...
could be very interesting race for sure, and possibly turns some heads...

[sjslhill]

I think the guys name was David Newland, did he use to live in MI?

Brushless 55, I am ignoring you, no idea what your saying and I don't care. Your a know it all.

[Brushless55]

I would love to see some Nimh packs run against some Lipos in a show down...
could be very interesting race for sure, and possibly turns some heads...

I think the guys name was David Newland, did he use to live in MI?

Brushless 55, I am ignoring you, no idea what your saying and I don't care. Your a know it all.

wow big pants on today eh? and ignoring some interesting facts that have been posted that has kinda crunched your OP

and I really could care less!!!

[T.S.Davis]

I think the guys name was David Newland, did he use to live in MI?

Nope. Probably Dennis Whitt. That guy baked cells like nobody I have ever seen.

[Brushless55]

Nope. Probably Dennis Whitt. That guy baked cells like nobody I have ever seen.

not good!

[T.S.Davis]

.......aaaaand we're reduced to name calling. That took longer than I thought. All rules discussions end up there.

I'm a curmudgeon. Steve is a malcontent. There are plenty of know it alls. Anyone else need a label?

[Brushless55]

.......aaaaand we're reduced to name calling. That took longer than I thought. All rules discussions end up there.

I'm a curmudgeon. Steve is a malcontent. There are plenty of know it alls. Anyone else need a label?

LOL... I had to google those

[J.W. Pepper]

...The 1st commercial airline that goes down, it's history...
Hill...
Have you been following the news of late?? The new Boeing Dreamliner has LiPo's and depends upon them quite heavily for things that small jet engines called APU's (located in the tail end of the plane) used to take care of. That plane has been grounded several times as a result of "battery issues".

None have gone down "yet", but numerous flights have had to return to the origin airport. Your prediction is a whole lot closer to reality than you apparently realized.

I agree with you about NiMH's being safer, but I also agree with the others who mention the power density of LiPo's. My pede on 8.4v humps is fast, on 2S LiPo's it'll do wheelies all day long - no changes other than the ESC, cell count & cutoff voltage.

I was like you, held out forever & a day, but the time came when my needs dictated a move to LiPo's. Started with a Traxxas Blast converted to BL, 3000Kv motor on 4600mAh NiMH got bout 5~6 mins runtime before performance fell off. With 2700Kv motor on 2S boat is much faster (8.8oz LiPo vs 14.10oz NiMH) and runtimes are in the 10-minute range.

I am very careful during the charging process and only keep them bout 1/2 full if there going to be stored for a long time.

I've got quite a few NiMH packs (7.2v & 8.4v) that I no longer need, all are in perfect condition, be happy to put them in a USPS flat rate box and send them your way for a reasonable price.

Oh, I see now, chemistry is not list now in the NAMBA rules. Just a small tweak and NIMH could compete. But I can see 3 of you are dead set against it. Interesting.

I tell you what I think will happen. LiPoly will be banned someday, just a matter of time. (My 2 cents) It's not safe and it's shipped illegally all across America now. The 1st commercial airline that goes down, it's history.

I am not complaining, I understand why people want to run it, it has amazing energy. I just don't think it's safe and it's fragile also.

[J.W. Pepper]

I went to dictionary.com just yesterday for curmudgeon -

LOL... I had to google those

[sjslhill]

I just thought, anyone could show up with any battery type the way those rules are written

[Cooper]

Well isn't that the point of moving forward with technology? The way I see it (from this thread) is use of either "fuel" would be race allowed, wery similar voltages. And the rules state 17% give or take for voltage? (I forget, correct me if need be) but the choice is available. Now the technology advancement part, weight, lipo tec has cut the weight in half. Now to me that is a major issue in an extra pound or two when it comes to racing. Maybe more, how much difference would it be for say a 10s set up? Steve, it really is only a matter of time before our lipos become more hostile environment friendly. Military has lipos that can have a nail driven through them and they will still work, without heating up or blowing up. Chargers are riddled with safety features, at least the good ones. And the original common sense rules of charging any recharable battery still apply-use the right equipment, use the correct settings, use in the appropriate place, store and charge in appropriate locations, don't let your kids eat them or dog, its all the same stuff,,,, has anyone had a lipo battery just spontaneously burst into flames?? Not on a charger, not damaged, in a stored state, in the appropriate safe location and then cause a fire?? No.