Lipo Lowdown From My POV.

[Paul Pachmayer]

Hi Joerg,

I got a 33" mono (Hopf Orca), I got a Neu 1527/1D, a Schulze 32.170 (just need to add water cooling) and enough LiPo's to make it a nice 4s2p P mono. I had planned to run it on 18-24 NiMH cells for SAWs and fun and I'd planned to use a different motor, but hey, why not? 4s2p will be ok too.

LOL, that's where we part company. I will be running Barracuda 125s in my 4S boats wether its 1P or 2P, either way makes no difference to me. If I get my ass handed to me because someone wants to run a boat as you outlined above I'm okay with that. You see I care about my equipment and don't need to push things to their limits.

If you got enough butt in your pants to run a S mono, why should you stop running the same mono with the same power, just because it's called P now and runs on half the voltage and double current? It's not more difficult than counting up to 3.

Come again? Not quite sure I understand what your saying there? If your comparing my T (open class) mono to a P mono that doesn't make sence to me. I find it very hard to belive a 33" 4S boat could even come close to competing with my 44 inch open boat which is running just shy of 70mph.

Paul, we'll see what happens during the year. Either me or you will be corrected. I bet a box of beer it's you.

I'll take that bet Joerg. I'm hoping for some "really good" German beer.

Paul.

 

[Darin Jordan]

I'm REALLY trying to understand how all of the sudden max voltage doesn't matter any longer?

Joerg's logic seems to be that an 8S1P (29.6V) setup would be at the same performance level as a 2S4P (7.4V) setup... or that likewise a 4S1P (14.8V) is the same performance level as a 2S2P (7.4V) setup...

Seems to me that even though the total power delievery might be the same, HOW that power is being delivered is going to matter as well... There is a reason why 24V hand drills are more powerful than 7.4V hand drills...

I've read everything here... but perhaps I need this particular issue explained a little further, because it seems very "theoretical" in nature and not really based on what is actually feasible to make happen...

 

[JfromJAGs]

Darin. Are you telling me you are just starting to understand? I mean I wrote my fingers sore for the last 2 months and you did'nt understand ??? How bad is that?

1. Electrical power = voltage x current. Both are equal in the equation, which is known for about the last 200 years (André Marie Ampère, Alessandro Volta if you want to read the history)

Example: 100A x 14V = 200A x 7V = 1400W

2. It is possible to construct 2 different electric motors that work identically well, one for 100A at 14V, the other at 200A and 7V. Physically both motors need to have the same size and weight. The 7V motor just needs to have half the turns compared to the corresponding 14V motor. So if you knew what to use for P hydro (12 NiMH of 4s1p LiPo), you can instantly select a motor that works similarly well for N2 now (2s2p). Same size, just half the turns. Half voltage, double KV and 1/4 IR.

Example: Let's say you ran a LMT "1940/6" for P in 2006. Now you will need a "1940/3" for N2 under the new rules and a 2s2p setup.

3. Why are 24V electric drills more powerfull than a 12V one? Because the 24V one uses 20 NiCd cells while the 12V ones just use half of that: 10 cells. They are all connected in series. So same current, but half voltage means only half the power. Clear?

=> The voltage rules does'nt limit the power, as it is only half of the power equation. (#93, I guess I need to count how often I repeat that sentence)

4. The bad thing about haveing electrical power mostly build from current is, that it is current which is responsible for the losses from resistance. And even worse, the current is squared in the power loss equation. That means double current means 4 times the losses. So to compensate that, all resistances (FET's in the controller) need to be 4 times lower - which makes it rather expensive.

=> So if you want to make electrical power cheap, you would want to gain power by voltage, not by current. So doubling the capacity and thus the current, is the wrong direction.

 

[JfromJAGs]

I'll take that bet Joerg. I'm hoping for some "really good" German beer.Paul.

Ok, booked. Can you get good german beer in the US?

Joerg

 

[Darin Jordan]

Darin. Are you telling me you are just starting to understand? I mean I wrote my fingers sore for the last 2 months and you did'nt understand ??? How bad is that?

Hey Joerg... "perhaps we could do without the wise-cracks"... We all know you're the smartest one here... no need to put everyone else down to prove it...

I understand the electrical theory... but there are PRACTICAL limits to this stuff... so voltage DOES STILL MATTER....

According to the way you see things going... we will be running 1/8th scale boats on 2S5P setups... just as soon as we have 500-amp capable motors and ESCs... :blink:

 

[brooks93]

can we get back to racing boats now?

Don call me or pm or email if you need anything.

Joerg can I tap into that case reserved for Paul when I come over the next time. Maybe I can lighten the load and save some shipping cost. LOL then I will return the favor the next time I am at Pauls house.

Thats just the kinda of friend I am. LOL

 

[AlanN]

Joerg...are you trying to say that if you have a 100 amp overall pull out of a 2P that each P gets 100 amps pulled from it?

No, not exactly.

I'm saying, if you found that 100A is safe for a single battery pack for 60s, then 2 packs in parallel are safe to provide 200A together for 60s. That's 100A from each pack, but the overall power output is now 200A. Now you need to find a motor and controller that can handle 200A instead of 100A (bigger!) and you are fine with running at 200A. You just doubled the power output with paralleling 2 packs, but it will stay 100A from each pack.

This is exactly what happens right now. People are building P monos with Neu 1527/1D motors - a size that was common for 24 cells last year, just as 2D with 24cells. These motors are perfect for 180-200A continous. All you need is an appropriate controller - which would be a Schulze 40.160 with water cooling.

I mean you can stick to your 100A motor setup and draw only 50A from each pack if you use 2 in parallel. But there are people who understand that they will be faster running at 200A and they know what it takes...

Paul has pretty much cleared up the "why" as to my own operating theories.

I will still try to keep my setups running as previously stated.

 

[Darin Jordan]

can we get back to racing boats now?

Would love to Kelly... Season doesn't fire up until April though!

Another couple weeks of building, however, and I will have some to test!

 

[topfuel443]

Illl take that bet Joerg. I'm hoping for some "really good" German beer.
Paul.

Paul, I dont know if you'll win that bet with Joerg, I dont even know what its about, but if you come to the National Outboard Tunnel Championships, Ill have the best German beer there is. Its called Franzinskaner Hefe Weisen (sp?). The best there is period, dont care what Joerg says, its the best period. What do ya say? Never mind everyone else in the nitro tunnel club, im calling you out Paul. Beat me with your own stuff dude!! ("FE newbie" tunnel guy against a FE guy "tunnel newbie"(yeah im calling you a tunnel newbie))???? Q tunnel is where its at!!

Please: show me how to drive a tunnel. (since we are talking about racing here, not SAW......)

~James " I dont know what i'm talking about" Clegg

 

[Kris Flynn]

Yeah what that Clegg guy said LOL

NOW Andrew, I dont remember any of your boats finishing races (maybe the 10S Mono) so to me those values of mAh are wrong.

Oh yeah, James I hear Yankie beer is just flavoured water, so it wouldnt be hard to find a beer better than that ;-)

Kris

 

[topfuel443]

Yes Kris. You are correect!

~James

 

[Paul Pachmayer]

Hi Guys,

Joerg's logic seems to be that an 8S1P (29.6V) setup would be at the same performance level as a 2S4P (7.4V) setup... or that likewise a 4S1P (14.8V) is the same performance level as a 2S2P (7.4V) setup...

Darin, Joergs theory is correct on paper. Someone "could" do exactly what he states, the problem is it's simply not practical. Also racing style and boat size will play a huge factor in what "can" be done. Over the last couple of years we've been running lipos I think I was the only one who actually "pushed" things with that Q-Cat. I'll be the first to admit it wasn't practical but it was a really fun experiment.

Ok, booked. Can you get good german beer in the US?

Nope, but we do have Samuel Adams which I see the Germans saying "das good beer" on the commercials. lol

Never mind everyone else in the nitro tunnel club, im calling you out Paul. Beat me with your own stuff dude!!

LOL, you think I would beat you with someone else's stuff?

NOW Andrew, I dont remember any of your boats finishing races (maybe the 10S Mono) so to me those values of mAh are wrong.

LMFAO!!!!! That is just rich, best laugh I've had in along time.

Paul.

 

[Andrewg]

Paul, I dont understand why Kris has posted incorrect information.

The event records for at BoB 2007 show:

* the 10S1P Falcon had 2 heat wins 2 DNFS (flipped). I also had the benefit of practice and development data.

* the 6S1P H&M NS4 mono was lent. It had 3*4 lap races before the esc thermalled (I had not reset the esc timing after using it in another boat). In each race the boat was fast and led by such a large margin I thought it was just the effect of a new hul and 100+F ambient temps. When the timing was reprogrammed it won in blustery conditions and set fastest electric mono time.

* the 6S1P rigger had a heat win and 2nd place + full length practice runs. In the first two races it was overpowered for water conditions set by heavy monos and flukey wind. After reprogramming it recorded the fastest electric time of the meeting running at part throttle and well below the pace of which it is capable.

* The 10S1P H&M T-Plus had 2 x 6 laps practice runs without problems. This boat was also lent and mixing my DSM receiver & 2 other racers DSM handsets resulted in an unraceable radio range - se la vie. The original reciver handset combination resolved those issues. Pity it was being used on my baot suring racing and not availabel for the 1/8.

I also have data from all the lipo boats developed here to date and the several sanctioned events at which they have been raced. So I have both our proposed Lipo classes and for some others covered across mono, sport hydro and rigger. I am happy to share that information.

To todays racing @ HVMMC - 29.5C/85F at midday-3pm (seemed hotter)

Falcon mono 48" TP Extreme 10S1P - Neu 2215 2y - 17.5lbs - over 7 laps consumed 2400 mah driving a P235. In the final heat handling issues had been overcome and a run with a P240 showed it as quick as any gas mono I raced today. However I would like to run with the benchmark Seaducer at HVMMC. I have a way to go before I get the amps up to where I would like them. I have not done a discharge or recharge to ascertain the energy used (last run of the day).

H&M T-Plus TP Extreme 10S1P -Neu 2215 1.5Y 15.5lbs 7 laps used 2700 mah with X447/3. Pack heat was moderate - felt like 55C did in a higher ambient temperature. Swapping to a faster P235 (2 blade), 7 very wide laps around dead boats resulted in noticeably reduced pack heat and a race win. Again as this was the last run of the day I will check capacity used tomorrow.

Each boat used a designated 25C Thunder Power eXtreme 5000 mah 10SX pack in the three heats each boat ran between 10am and 4pm. ie each pack was charged three times today.

On the hydro I have found the shaft was jamming in the last heat yesterday. Today the pack recharged to 4.2AH. So tomorrow it gets a new stuffing tube and a further test. Mark Ferriera was right these things have torque to burn! Given the change in tube colour I am guessing a lot of the energy became heat in the stuff tube. More results soon

 

[Pagemaster]

Joerg I totally see where your coming from and agree.

But the rules are written and we need to start getting ready to race.

I have decided to go the cheap route. 1p and a Feigao in my monos and offshore. I may get spanked

but I will try to build a reliable and well handling boat. I will let the cards fall from there.

I would have loved to run a neu motor and Schultz but with 2 boys pulling at my pants to run this year, its just not in the cards.

Steven

 

[Darin Jordan]

I have decided to go the cheap route. 1p and a Feigao in my monos and offshore. I may get spankedbut I will try to build a reliable and well handling boat. I will let the cards fall from there.

I would have loved to run a neu motor and Schultz but with 2 boys pulling at my pants to run this year, its just not in the cards.

Steven

You'll be money ahead for next year Steven... by then, 1P will be all that's needed and you'll already have a fleet balanced and set-up to deal with it... That's exactly what I'm doing as well... it's going to take a season for everyone to figure out how to set this stuff up and used it anyhow... all but the elite ones, that is... They'd be "spanking" us regardless of the rules anyhow, so I don't let that concern me...

I'm finding that getting a Sport Hydro balanced properely is going to be a challenge... especially if it's a pickle-fork... 1P isn't heavy enough to use traditional motor mounting... I know some are running 2P just for the additional weight, but they are leaving all else the same...

It's going to be interesting...

 

[Kris Flynn]

Andrew,

Dont get your knickers in a twist mate! I was just going on what I had observed. See that word 'remember' it doesnt mean 'fact'.

'Venting here'

Guess I am peeved that you didnt even run in our CURRENT LEAGAL classes which we are pushing. Hey, OPEN class is great cause i got to run my tunnel...BUT well.................... h34r:

Anyways, Sorry for taking this off topic slightly gents I will be on the sideline again till I see the need LOL

 

[Jeff]

Is a leagal some kind of spec class?

Jeff

 

[AlanN]

I think it's a cross between a lawyer and a beagle. :blink:

 

[jfruge]

Just so I am on the same page I have some questions. I have been thinking for the past 6 mounts that 1P or 2P ment that say for p sport hydro you can use 4 cells (1P) of say the TP EX 5000 type. If they say its ok for 2P and it (passed) ((looks like it did) now I can run 2 x the cell count in this class. 4s2p pack of 5000 cell can be used (8 cells total)?

Same thing for say 1/8th scale. What used to be 32 round cells can now be 10 TP EX 5000 cells or if I wanted to go 2P it can be 20 cells... AKA 10S2P of the 5000 type cells.

Is that correct?

Thanks,

John Fruge

 

[Andrewg]

Alan

BTW when do you guys start racing - just trying to get you a video of whats going on over here and will look forward to hearing how you guys are doing. Its going to be interesting to see how it all pans out. The good thing was at the last sanctioned meeting we had the "open" class ie Lipo legal was the largest class - It was the lipo baots which grabbed peoples attention. All good for the future