You're averaging 1410W and have a peak of 2742W? That 1515 motor of yours can take it I'm sure, but the Leopard 4082 doesn't seem so unrealistic anymore...
You're averaging 1410W and have a peak of 2742W? That 1515 motor of yours can take it I'm sure, but the Leopard 4082 doesn't seem so unrealistic anymore...
And OSE even has a custom 4082 in the same 2200 Kv, Y-wind motor like you have now. See, I'm helping you spend money
I bought a Leopard 4092 + free water cooler from OSE a few weeks ago & it was much cheaper than getting in the UK, i paid £94 in total inc shipping & didnt have to pay any customs. To get this in the UK was around £134, as it happens they didnt have the kv i wanted or the longer 68mm water cooler so i had no choice but to get from OSE. Glad i did in the end as its a fantastic service that Steven offers.
The 4082 - 2200kv my be a custom wind as Leopard dont list this motor the same as the 4082 - 1800kv that OSE sells.
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I dont have the box as i threw it away so dont know what it said, i was just pleased i didnt have to pay anything on it.
That would be my guess too, as the last three motors he lists say:
1800 Kv/rpm per volt. Custom wound for OffshoreElectrics
2000 Kv/rpm per volt. Custom wound for OffshoreElectrics
2200 Kv/rpm per volt. Custom wound for OffshoreElectrics
So martin, what do you think of that motor? I know we're getting off topic here on the LiPo batteries, but it gives us something to talk about while Drax is doing more research on his problem.
One more thing, although minor, is that you might get a little cooler run on your motor if you back the timing off a bit. The default on the SeaKing is 15 degrees; I run mine at 7.5 degrees. I have not measured it so I can't give an exact number. But most forums and Neu/CC themselves say the same thing; you don't need a big timing advance on those motors. Maybe you did this already.
Ive not run the motor yet.
Well, that would explain why 15 is the default then. In Drax's and my case (which is why I mentioned it), Neu recommends 15 degrees maximum on the Y and 10 degrees on the D. From the Neu web page FAQ with CC ESCs:
"For most uses the low advance setting is best—motors have better efficiency. “Y” wind motors can use medium advance for a little more power or speed. “D” wind motors should always use low advance as there is no improvement with higher advance settings."
If I can paste links in here from another forum's discussion, VintageMA has some really good points on why you don't need 15 degrees. At least on the 1515 motor anyway (I'd recommend reading the whole thread; it's not that long):
http://www.rc-monster.com/forum/showthread.php?t=14618
In reality, it'd be fun to have an Eagle Tree with temp sensor and GPS. Glue the temp sensor to the motor with Arctic Silver Adhesive; then try various timing settings to see if Neu is correct. That's too much work though, I'd rather be boating.
Last edited by Krusher; 05-15-2012 at 01:17 PM. Reason: Added recommendation to read whole linked thread.
I read the whole thing. Sadly there is plenty of poor info in that thread. Boats are not cars. Any motor needs a certain amount of timing advance depending on the physical characteristics of the motor and the load placed upon it. BL motors and brushed motors are the same in this regard. Because boat motors virtually always pull a higher load than cars or planes, their timing requirements are different. The higher the load, the more advance required to maximize efficiency.
Advancing timing can increase performance and efficiency, on Wye winds at least. Of course there is such a thing as too much, but within limits set by load and design you can do better with more timing. Last Fall at the LA SAWs I was running a 1515/1Y in my Q cat. By advancing the timing from 15* to 20* I gained almost 4 mph with no noticeable increase in amp draw. That tells me the motor was running more efficiently with the advanced timing. At speeds over 80 mph, an additional 4 mph is not a tiny increase in power either. Of course I was pulling over 200 amps, running 20* advance in a 100 amp setup would be a very BAD idea. Again, timing advance has to match the motor design and load. Try different advance settings and see which is right for your particular motor and load. Too little can be as bad as too much.
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I'll agree with you on that; I'm not saying every application is the same and we should try different things to see what happens. I couldn't tell any difference in speed or temp on my 1415 from 15 to 7.5, but all I had was my GPS and a non-calibrated finger lol. I do like the Castle comment from the president however. It just basically says to take it easy and that more is not better unless you have a reason for it.
So FWIW, backing off the timing on Drax's setup will likely only make a significant difference if he is already over 15 degrees. Once I get my charger back I can do some experimentation myself (on top speed anyway).
Yeah I'm at the standard on the SK180 which is 15 degrees. On another point..... I was looking at the Turnigys I bought for my latest DF41 build. I have used Turnigy in the past but I went away from them because of higher resistance and quality issues. Since then they have said that they have made a new formula for all of there batteries and it looks like it has been pretty effective. The resistance is very low. Will get some data up later of the readings.
Everything that has a beginning, has an End
My next set of batteries are going to be Gens Ace, their are more & more starting to use these with very good results for a mid price lipo. Ive also seen a number of test done with diff make lipos inc Gens Ace & the ir was very low on the Gens compared with Turnigy inc their Nanos.
It seems like more LiPo batteries are suddenly becoming "Nano" batteries. Makes you wonder what these manufacturers are defining as a Nano particle and whether they all hold the same standard. Probably not.
Either way, let us know Drax and martin how they work out for you. It would be nice to find something closer to the Maxamps batteries at a little less cost anyway. i.e. these 50C Winmax batteries look decent, but they aren't much heavier than my old 30C batteries (although they're a bit longer). It must be that new Nano technology. Yeah, that's it.
Measuring 4x 4s 5000mah 40-50c Turnigy Standard batteries.
Battery no1 - 2 1 5 4 = 12
Battery no2 - 4 2 6 5 = 17
Battery no3 - 2 1 5 5 = 13
Battery no4- 1 1 5 4 = 11
These are used batteries which I bought off a member on here. The Resistance is lower than that of Hyperion and lower than the previous Turnigys I had a couple of year ago (They all measured in the 20s total resistance). Some of the cells are even showing a 1 which is extremely low resistance.
I have to wonder though. Is more resistance actually better for your battery? Like with the Hyperions and Winmax. The Hyperions with higher resistance held up better under extremely high draw not even puffing. The Winmax gave out a little.
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Well, internal resistance is like little resistors connecting your cells together right? So you'd want the smallest ones possible to generate the least amount of heat. But maybe there's something else involved in the cell construction that makes one less likely to puff than the other...like stronger plastic maybe :)
What do you mean by stronger plastic I think you might mean heat shrink well if so I mean this in a very nice way but I think that is way off I had cells that when puffed they split the hard case this is not there to keep from puffing it tis there to protect the pack puffing comes from stressing the pack past it's limits some packs have a better, stronger , more advanced chemistry to them this is why you pay double for hyperion there are some cheaper packs that may seem like they compare to them performance wise but in overall they don't this is why his hyperions did not show as much damage as the other cells so heat shrink even if doubled or tripled up is not intended to prevent swelling of packs. This is the simplest answer without going into great detail and filling up a whole page of info you can't only go off internal resistance
my youtube videos http://www.youtube.com/user/chris81983?feature=mhee
Wow that's a long sentence lol.
I think at this point we're just making some guesses. If you made the Lithium plates a little thinner and the plastic a little thicker, you'd have higher internal resistance and they'd puff less. So that's my vote.
EDIT: It could also be that Hyperion used smaller/longer wires on their balancing plugs so the resistance reads higher. When in fact it could be lower from cell-to-cell.
Hyperion uses different wire to any other battery I have. Not as bendy and IMO harder to solder. It springs out when you cut the silicon away.
Forgot to say.... I charged my batts up last night and all cells went back up to 4.20. The wandering cell problem I had on one of the Winmax batteries is now gone
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Ran the batteries yesterday. The run times are still shorter than they use to be and my top speed has gone down so I would say the motor is now only 80% efficient instead of the original 90%. Using this to work out the speeds I should be getting- http://www.offshoreelectrics.com/conversion.htm
Ran the Winmax batteries first.
Run time 5.30 mins
Top Speed 44.3MPH
Temp at the end of run 47c
Then the Hyperions
Run time 6 mins
Top Speed 42.3MPH
Temp at the end of run 47c
I timed these runs and brought the boat in 3 mins in between the runs on both sets. The voltage drop is pretty astounding although did not drop as fast as last time. The motor appears to be drawing a lot more amps than it was previously. I'm going to replace it at some point.
Last edited by Drax21; 05-20-2012 at 12:54 PM.
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Video added
Everything that has a beginning, has an End
Just had a check on Leaderhobby's website and the price of WinMax 4s 50-100c 5200mah LiPos has risen from $52 to $62 each. They must be selling a fair few. I can understand why with the results I have had. Last time I spoke to a Leaderhobby representative, she said that $52 for the above mentioned battery was a wholesale price. Interesting eh?
Everything that has a beginning, has an End
I have my Cellpro 10S back finally and had a chance to run my 3S, 4200mAh batteries twice.
Right after the cell resistance [mohm] popped up on my first charge, I had...
1=2.1, 2.1, 2.1, 3629 mAh
2=2.1, 2.2, 2.0, 3589 mAh
3=2.2, 2.3, 2.1, 3613 mAh
4=2.0, 2.1, 1.9, 3607 mAh
I used packs 1+2 paired with 3+4 paired.
Cell voltages after sitting overnight are:
1=4.19230, 4.19008, 4.19565 = 12.5778 at high current terminals
2=4.18589, 4.18554, 4.19069 = 12.5620 at high current terminals
3=4.17346, 4.18354, 4.19434 = 12.5512 at high current terminals
4=4.19025, 4.18565, 4.18948 = 12.5652 at high current terminals
I finally decided to get a nice bench meter so I'm not making those extra digits up. :)
Overall, the batteries seem like a good deal so far. My old batteries used to be the hottest running part of my setup; these batteries run warmer than my ESC but cooler than the motor.
I'm going to be away from my PC for a week; so if someone has a comment after tonight (Friday) I will get back to you later.
Everything has been working good and I have a chance to comment on some longer-term testing.
Overall, I seem to be averaging around 3.9 miles per set of batteries on my boat with a small (S215) prop. That's a mile less than when the batteries were brand new, but I believe that is due to me running the boat harder and not any loss in capacity. The batteries charge up to roughly the same capacity and always report 2.0 mohm internal resistance or less per cell after charging finishes. No cell puffing like I had earlier with my 30C's. I may get the same batteries again after a few seasons or something else on sale in the future. It would be fun to get a set of MaxAmps LiPo's for comparison purposes to these, but there are so many other goodies out there to spend $ on. These "C" ratings on batteries are misleading anway, i.e. my 4200 50C batteries can do 210A? Ya sure they can...have the fire extinguisher ready.
I also played with the timing a bit, going back and forth between 15 and 7.5 degrees of timing advance. Overall, I do get 1 MPH more on average with the 15 degree advance according to the GPS. I don't have a thermometer that I can put on the motor, but left it at 7.5 degrees since I'm not racing. With the bigger S225 prop, I'm consistently getting 41 MPH anyway. So, I just change props when I want more speed. But for everyone else, it pays to experiment.
Everything that has a beginning, has an End
That's a surprise and also valuable info. I will make a note of Gens Ace for the future.
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