Mah resitrictions

[Darin Jordan]

But there will all be some on saying ware does it all stop? 8000Mah packs and 2P or evan 3P???

Randy,

Just for the sake of clarifying... NAMBA already has UNLIMITED paralleling. In other words, there are NO restrictions on Paralleling in the present NAMBA rules. Only mAh limits.

[raptor347]

So, this has all the usual potential for becoming ugly and devisive. We really don't need it. NAMBA, IMPBA and NAVIGA all implemented Lipo rules at slightly different times in the evolution of the cells and with different levels of experience with the tech. At the time, NAMBA sticking with round cells for another season would have killed off most participation. The price, durability and reliability of the cells had made them very unattractive. I think the IMPBA rules show some lessons learned from out implementation and NAVIGA incorporated the experience of the FAI pilots in Europe.

I'll be happy to admit that the mah limit are not practical to measure, especially in a heat racing format. For record trials, it hasn't been an issue because most serious competitors are running 1P systems and the largest capacity cell that has any real performance potential is ~6000mah. The advent of the big twin cats and a few other projects I know about are going to make this a bit more challenging.

As far as huge horsepower applications not being practical. I agree that a 34" mono isn't going to handle a 6kW power system well, but that's the one hull type that doesn't lend itself to very high power. I can see where a sport hydro, rigger or possibly a cat could use the power. When you step up to the 40" limit for Q, there is all kinds of room to use up power. There are a few other subtle differences between NAMBA and IMPBA FE rules. NAMBA allows twins in P, IMPBA doesn't. IMPBA has a 60" length limit for all outrigger classes, NAMBA applies the same length limits across all hull types. Namba has a a timed 4 minute offshore endurance class, IMPBA doesn't. I guess what I'm saying is the batteries aren't the only difference in rule sets, so seamless transition from one to the other has other obstacles.

So here's what I learned from the latest 2-lap at Legg.
-A 6kW heat race P rigger is very possible, even within the 34" limit.
-Q boats have the potential of about 9kW in heat trim. That's sticking within the 10k mah limit.
-Is everyone going to show up with one, probably not.
-Am I going to try and build them, absolutely!
-Would I like a bigger fuel tank for these applications, maybe.
-Finally, do I think we need some limit to the size of the fuel tank, yes we do. We also need a good way to tech it.

That being said, this is something WE need to figure out. The 3.7 nominal wording can go, I think we all agree there.

[RandyatBBY]

I think if the Mah limit was lifted the 5000 Mah packs (and getting scarce) would not be so high priced and would open up the use of 5200Mah and 5600MAH packs that are cheaper. Old retired view of racing. But there will all be some on saying ware does it all stop? 8000Mah packs and 2P or evan 3P???

[T.S.Davis]

Well i guess its up to namba to change it.. Or for someone to propose it first

Yep.

I feel that the mah restrictions are silly as there is no practical way to verify it. Plus, if you go out and buy a Revo cell for instance but you never charge it to 4.35 or what ever it is.............is it still a 5800mah pack like the label says? Not really. If Revo guy charges to 4.2 instead of 4.35 and never gets to even 5000mah is he a cheater? Not by me he isn't.

I know I've said this before but the next gen batteries will require some careful timing to take the lid off them. We don't want to yank the proverbial rug out from under anyone's fleet.

John, that was awesome. Pretty accurate too. Although, a 2017 cup? Do I have too?

[rayzerdesigns]

Well i guess its up to namba to change it.. Or for someone to propose it first

[B Neal]

Hypotheticals really don't do this thread justice with all the good info stated here.

Facts are impba has no limits, namba is on the honor system, naviga is on the weight system.

Impba = path of least resistance no way to believe or assume a racer has an advantage

Namba = path with transistor, possible assumptions a racer is breaking a rule gaining advantage

Naviga = path of most resistance, from Paul's post, scary safety posibilities trying to reduce battery weight attempting to gain advantage.

With all that said if I could in some cases run more Mah I would.

Namba racers that are not honoring the rule / guideline / Mfg advertised Mah is just fooling themselves and wasting this earths air supply.

Either Namba goes no restriction, or weight limit to allow the heaviest of heaviest cells (wait for all mfg'ers to start producing HV cells for proper weight numbers) or leave it be.

My thoughts
Brian

[Doby]

Simple Solution:

At this years Mich Cup Race...prior to every heat....

#1) Racers charge up their packs.

#2) Terry runs around with a volt meter and checks all packs to be used in the heat.

#3) Terry then watches every racer discharge their packs on a certified charger (that either the club supplies each racer, or each racer has to provide) Documentation as to the accuracy of the certified chargers must be of course provided from a certified calibration facility, approved by NAMBA, but left open to IMPBA members personal choice.

#4) Terry then watches every racer charge their packs on the same charger as listed in #3.

#5) Terry then records the actual capacity of the racers packs.

#6) Terry then records the actual voltage of the racers packs.

#7) Terry then certifies the racers individual packs and quarantines them for use throughout the event by the racer.

#8) Terry then repeats #2 through #7 for all packs used by all racers in all heats.

This results in:

#9) Terry, at the end of the 3 weeks of racing (#2 through #8 will not happen in a 3 day event) checks himself in to a local AA meeting for some much needed therapy.

#10) Terry's wife leaves him....her only reason given is "REALLY??" after he tries to explain the logic of all of this.

#11) Terry's club switches from NAMBA to IMPBA, his only reason given to his other club members is "REALLY??"

#12) No-one shows up to race at the 2017 Cup...only reason given is "REALLY??"

#13) Everyone sells their boats, buys airplanes and lives happily ever after...except for Terry....he's curled up in the fetal position, sucking his thumb, repeating "Really??", over and over...................all while hugging his favorite FE boat.....a puddle of drool on the floor gradually grows larger and larger after the days pass by...

[Doug Smock]

How would you confirm the capacity without fully discharging and re-charging?

The same way it's not being done now.

[Doby]

Premature? I don't thin so Lucy?

Are HV 5200s charged to 4.2 v/cell (capacity would be around 4680) in a 4s2p configuration legal to race in P class?

Thanks

How would you confirm the capacity without fully discharging and re-charging?

[Doug Smock]

Premature? I don't thin so Lucy?

Are HV 5200s charged to 4.2 v/cell (capacity would be around 4680) in a 4s2p configuration legal to race in P class?

Thanks

[T.S.Davis]

The length limits work. As far as I can tell at least. I can throw a ton of power in the water with a P mono but I can't finish with it to save my life. I've tried.

Jay, you keep coming back to an "advantage" a 12k offshore racer would have over a 10k racer. The discussion isn't about giving anyone an advantage. It's about potentially changing a rule for all. We would all have the same options. Right now it's 10k for Q and under. The bummer there is that very frequently the Q offshore boats run with the S/T offshore boats. So you're handicapped with a Q. If the limit was 12k we would all do that. If it's 100000000000000k then the length limits are THE limits. That's my thinking at least. A can build a 6000 watt P mono but it wont make it to the first turn with it only being 34" long.

This is kind of the premise under which IMPBA is currently operating. The results I've asked about a couple times seem to indicate that their rules not having capacity limits is of little relevance because they do have the length limits in place.

This whole discussion is likely premature. Sorry guys. The time to address it is likely during the next chem change that we are seeing more and more of. HV is likely the next gen and we'll revisit capacities then. I predict at least.

[Doug Smock]

Thanks for posting Paul.

[RaceMechaniX]

Good discussion Paul,

There are some twins being raced mostly in the hydro classes and the T classes. Although twins could double the power of a class, there are few classes for heat racing that could take full advantage. The boats are also prohibitively expensive to build and given the lack of popularity you only get to run them at larger events or in open class racing at the district level. Large singles tend to be the preferred setup for open racing although there are some big twin electric riggers being built by several guys across the country.

P mono is an excellent example of variety. The 34" length limits slows all out power wars. You will see the full spectrum of competitive power systems from a Castle 1515 1Y and T-180 ESC to Neu 1530 1D with Castle Hydra 240's or LMT 2260's with Schulzes. The standard and reliable power system is the Neu 1521 1.5D with 4S2P 10Ah total. Hull set-up and driving skills make this a very competitive class.

SAW's are the one exception where twin's are gaining popularity particularly in the Cat classes where the HPR, MHZ and similar hulls are being built for maximum speed. These are very high power set-ups which use every inch of the rules to their advantage. The top level guys are pushing 50kW+ with 10SP to 14S2P using old Schulzes and hot wind LMT 30 series motors.

Tyler

[NativePaul]

Oops.

[NativePaul]

OK a couple of people have asked me to explain my aversion to weight limits so here goes. Feel free to ignore me as I am not a NAMBA member and have no intention of becoming one in the foreseeable future. I have read the NAMBA rule book and seen a lot of race videos, but have never attended a NAMBA race, and the last time I spoke face to face with NAMBA racers and saw NAMBA boats we were all running NiCads, from what I gather it has affected us more than it will most of you, it should only affect 2p racers not 1p, and except the offshore runners they could mitigate all the problems just by running 8000mAh ish instead of 10000mAh+, so only offshore racers would feel the pain after the first year.

Firstly I should probably explain why we in Naviga have a limit. Almost all our classes are timed endurance races similar to your Offshore classes. With a set time and voltage, limiting the capacity of the pack will limit the average amp draw and wattage keeping racers on a level playing field and giving us close races.

Why didn't we just use a capacity limit? Realistically it can't be teched. The cell makers can't agree on a cutoff voltage for capacity measuring, and the capacity of any given pack will change depending on the discharge current and temperature, after much arguing it may be possible to come up with a set of lenient conditions for discharging that would be the same for all, but you would spend longer teching your cells than you do racing, and nobody wants that, I suspect that we would have very few racers left if that happened. Personally I would rather have an untechable limit, take it on trust that my fellow racers are playing by the rules and be beaten by the odd cheater, than have an easily techable weight limit, read on to find out why.

Why did we choose the LiPo weight limit if it is such a bad idea? Pack weights limit capacity and thus power to keep racing close and is easy quick and cheap to tech, anyone can use a digital scale with little training, you can tech a pack quicker than you can sign and fit a tamperproof sticker, and you can get accurate digital scales for just a few pounds/dollars/euros/yuan. The only other semi viable alternative was a F5B/F5D style electronic power limiter, and at the time they were still in there infancy, would need to be altered to our use, were an additional expense we would have had to make on our already expensive hobby, and quite frankly I dont think anyone invisioned that weight limits would become problematic. The limits we chose were 110g for Mini classes 280g for 2 cell classes and 560g for 4 cell classes, which with the then current technology gave us about the same capacity of the top NiMh cells which were 7cell 1600mAh for minis and 7/12 cell 5000mAh for the full size classes which allowed rough parity for the changeover season. Looking back I could probably have bought 2 power limiters for every boat in my fleet and still had money left over.

What is wrong with using LiPo weight limits? You don't always know what you are getting, I must have spent hundreds of pounds over the years on LiPos that were overweight and never saw the inside of a boat, some advertised weight are off, some advertise the weight of the cells as the pack weight, I have had legal weight packs from one batch then on the next order of the same packs had them overweight, I have taken my scales into an LHS and found a 15% variance between a basket of the same packs so some would have been legal and some not.
Tyler mentioned TP "lite" cells which brought our <110g Mini's capacity up from 1600-2100mAh and they are a few years old now, the current state of affairs gives us 2650mAh for the same 110g and 7200mAh under 280/560g, while not as high as a "high C" pack the voltage is pretty good so there is a healthy advantage to be had from running them, but there is no such thing as a free lunch and the cells are not as robust so while they cost the same you will need top replace them more and spend much more over time on the high capacity cells. The newcomer can't always tell what they are getting either, take these 65C-130C Aspec 6600mAh cells, you might think that they were robust "high C" cells, but there is no way in hell, check the weight i know they have short leads, but they are 30g heavier than the same brand's 65-130C 5000mAh that are not marketed towards boaters, in fact they have a remarkably similar shape, size, weight and discharge curve as cells sold by another make as 20C.
The cost of progress, battery technology increases year on year but with a capacity limit the improvement is only voltage under load and is a relatively small difference each year not being worth an upgrade, but with weight we are getting big capacity improvements which directly relate to power so even if the cells weren't fragile and lasted forever, you would probably want new cells every year or two anyway, this year packs have gone from 6800-7200 a 6% capacity boost last year it was 6600-6800 so 9% capacity in two years plus voltage under load improvements, so probably around 10% extra power over someone with 2 year old technology.
Brian mentioned pushing the rules and this has happened with batteries the rules say the cells must be covered in heat shrink, but a few years down the line the silver cell casing is heat shrink, wires are either nominal or connectors are soldered directly onto tabs, balance wires are tiny or sometimes holes are drilled into tabs for separate balance leads to be inserted when charging, there is little in the way of strain relief, so tab and balance wire failures are not uncommon, and you can kiss goodbye to the ease of mounting cells with velcro. Tenshock are amongst the best cells we have available so I won't knock them, but check out the instructions for their packs to see what we are dealing with, I am not keen on it myself and it is certainly not a way to get youngsters into the sport.
If you live near the sea and want to silicone up your cells you have to either take the disadvantage of running less capacity to allow for the extra weight, or not do it and risk your cells. On the subject of water, you can put legal cells in your boat, develop a leak for one reason or another and now your wet cells are overweight and illegal.
Last but not least is availability, there are 3 competitive cells for each class that I know of and none of which are available anywhere in my country, and all need to be imported.

What are we doing about it? we are trying to get away from it as fast as we can. On a club level most clubs in the UK are already offering an alternative to the weight system where you can chose to go by capacity if you prefer as long as the shrink and label are unadulterated from the distributer. On a national level it has been proposed that we adopt a 2 tier system where if you are trying to qualify for the Naviga worlds you have to go by the naviga weight rules, but those not interested in racing abroad can chose weight or capacity as they prefer. At an international level Naviga are looking at F5B/F5D electronic power limiters again, as everyone now knows it isn't really an added expense as we originally thought it would be, and I believe some prototypes are being made as I type. (off topic so PM me if you want, but Brian I would like to know your views on this as I think you come from an F5D background.)






As an aside from my experience with weight limits, I have long thought of your 10000/12000 limit or no capacity limit for sprint races was unlimited power, just because it is so much more power than we have available with our 6 minute races, whereas it has of course been limited by the availability of reliable high current ESCs. With the discussion of twins in this thread I take it that twins have started appearing effectively doubling power availability, are you worried at all by the new MGM 400A and 800A ESCs that would allow leagues more power from singles, and that the first one to go there might cause a cascade reaction meaning next year you would all have empty wallets and MGMs with 2220/1Ds in your P boats, or is your current power pushing your hull lengths to their limits already?