Can we get some feedback on the Nano Tech Lipos Please

[pinkpanda3310]

Is the mmmhv going to have logging built in like the ice range? If so (I hope it does) the logger you get will be redundant soon unless you have other smaller rc's. Plus going from 6s to 9s should be lowering the amp draw on the system anyway.

[Jahay]

well i believe it should have a data logger... i never really believed that i needed one just yet, untill i went up in voltage... I think the MMMHV will have data logger built in... maybe not the 8s version, but hopefully the 12s version should...

[pinkpanda3310]

The last I read Patrick say the 12s is further away than the 8s. Maybe it would be worth while getting a logger. Except that just draws out more time before you get more batteries. I don't have either battery your considering but I do have A123 which is similar to lifepo4. The high charge rate is a nice feature.

[Jahay]

i am quite happy the 12s isnt going to be available for a couple of months or so... i think the 8s is releasing very soon right?
i am a little low on cash for my rc side of things, so gives me time just to test my new current setup before putting 9s in it and potentially ripping the whole thing apart.

I will wait for the esc to release before buying the nano tech lipos... And i may actually see how they perform in 2 weeks time as a mate has a set and he may come to a meet. So i will compare them to my hyperions and get a vid of the comparison in performance.

i will also need to get a better charger so i can make use of the high charge rates... charging 6500mah at 5 amps takes nearly 1hr30mins! FOR ONE LIPO!

[brian015]

CC's 8s ICE aircraft esc's have data-logging already.



Edit:
I've logged current draw on my large scale build:
http://www.rc-monster.com/forum/show...t=26979&page=7

My max currents were 90-125Amps (depending on 10s or 8s setup). My 30c 3600mah batteries should have easily been able to provide this, but I saw a big difference in performance (punch) between them and the 40c 5000mah I was also testing (All Turnigies).

So either, even at 10 samples/second, its not registering the highest current spikes, or the batteries are not up to spec. That convinced me to stick with the 40c batteries when recently buying new ones, since the numbers say the 30c 3600mah should be OK, but they weren't as good.

I can't say anything, however, about the 40c vs. 45c nano's though.

[pinkpanda3310]

Originally Posted by brian015

So either, even at 10 samples/second, its not registering the highest current spikes, or the batteries are not up to spec.

I've read a number of people talk about the highest amp spikes being missed. I would have thought of all the people here with loggers someone would have logged one of those spikes by chance. Yet I rarely hear of anyone getting over 200a. I think that is because the batteries have there limits and the loggers are reading the spikes. If I were to draw 300a or 400a spikes wouldn't that drop the voltage excessively and be noticable on the logger?

[brian015]

Originally Posted by pinkpanda3310

I've read a number of people talk about the highest amp spikes being missed. I would have thought of all the people here with loggers someone would have logged one of those spikes by chance. Yet I rarely hear of anyone getting over 200a. I think that is because the batteries have there limits and the loggers are reading the spikes. If I were to draw 300a or 400a spikes wouldn't that drop the voltage excessively and be noticable on the logger?

I hear what you're saying.

The reason I suggest that the highest spikes are not being recorded is because I see minimal difference in the highest currents logged in my 30c 3600mah 10s vs. 40c 5000mah tests (92-99Amps - And part of that difference could be explained by slightly different gearing). Anyway, looking at the logger would indicated similar performance between the two sets of packs.

But, in fact, what I observed is that the 40c packs had much more punch when driving - clearly noticable differences in acceleration. The truck was easy to control under hard acceleration on the 30c packs - whereas with the 40c packs it had significantly more power (and therefore somewhat harder to control). This difference did not register in the logger, however. It simply may not have the sensitivity to detect very short, high spikes.

Those are my observations, anyway.

[pinkpanda3310]

Originally Posted by brian015

I hear what you're saying.

The reason I suggest that the highest spikes are not being recorded is because I see minimal difference in the highest currents logged in my 30c 3600mah 10s vs. 40c 5000mah tests (92-99Amps - And part of that difference could be explained by slightly different gearing). Anyway, looking at the logger would indicated similar performance between the two sets of packs.

But, in fact, what I observed is that the 40c packs had much more punch when driving - clearly noticable differences in acceleration. The truck was easy to control under hard acceleration on the 30c packs - whereas with the 40c packs it had significantly more power (and therefore somewhat harder to control). This difference did not register in the logger, however. It simply may not have the sensitivity to detect very short, high spikes.

Those are my observations, anyway.

I don't doubt your obs at all. In fact they re-instate higher c ratings perform better. If your gearing were to remain the same for both setups it might look like this...
Battery(s) 1 = 10s 3600mah 30c
30c*3.6ah=108amps (continuous)
37v (10s) *108amps=3996w max continuous
Your setup as indicated- 37v * 92amps=3404w peak

Battery(s) 2 = 10s 5000mah 40c
40c*5ah=200amps max continuous
37v*200amps=7400w max continuous
Your setup- 37v*99amps=3663w peak

259w is a bit of difference but I'm sure the 40c battery holds it's voltage better when under load so the difference in real life will be greater and therefore a noticable difference when driving. Even larger than that difference is the capabilities of the different batteries. The logger doesn't show that much difference because the system is not drawing any more than it needs. At those amp rates the solder joints are less of a problem.

As for the spikes, I am still not convinced a system will shoot off enormous 'invisible' spikes that the logger can't detect (given perfect timing for the sample). The spark when the batteries are plugged in would be a good spike and fast too. I reckon I'll even test that theory, my logger will start recording when a set amp# has been exceeded. But when the system is in action all lines are full of electicity and produce resistance. I don't fully understand voltage ripple but it seems more plausable than huge amp spikes.

[Jahay]

Brian - Thanks for that.. .i did follow that thread closely and was very impressed with your extended truck!

Panda
1. The hyperions are great, i just believe for the money spent, that the solder job from factory should have been of a higher quality...

2. i know i have contradicted myself a little with C ratings.... but i am also accounting for price of the lipos as well.
Nano tech 3s lipos are $75 5000mah... the hyperions i sourced were $110+...

3. hopefully by the time the ESC is available, i will have enough cash for the esc, lipos, and charger... Looking at the hyperion duo, but there are a few great chargers out there for less... i think i will also need a powersupply which can hack it, or i may just remove my 400watt power supply from my desktop.?

[nitrostarter]

I think the problem with the spikes mentioned above is that they happen for such a small fraction of the second that it is not noticeable anywhere, or that the voltage drop associated with the spike is so minimal as well.

[pinkpanda3310]

Originally Posted by nitrostarter

I think the problem with the spikes mentioned above is that they happen for such a small fraction of the second that it is not noticeable anywhere, or that the voltage drop associated with the spike is so minimal as well.

I used to think that but the max draw on the system is for example landing a jump which lasts longer than 0.2 seconds. If a system is set up to rev out at 30k then the rotor spins 50 times each time the logger samples. That's at full revs! Spikes happen at lower revs (or the sudden drop in revs). So my pickled brain is having a hard time understanding why it doesn't have a lasting enough effect to be logged (even by accident). I don't really know how loggers work TBO. Do they sample for 0.2 seconds and average it out? Even at 10k revs the samples are taken every 33 revolutions. I would have thought somthing would be more noticable.

[pinkpanda3310]

I understand where your coming from Jahay. Everyone wants bang for buck. Good luck deciding.

[Jahay]

cheers buddy.... once the esc is available, i am probably going to need a little help understanding the results... so i will call on you soon enough... it may be quite interesting to see if the nano techs allow for a more detailed graph capturing the spikes??? we will see in due time...

[Jahay]

oh right, i am starting to get a better understanding of how it records its data, but im still completely flabbergasted by it all

[pinkpanda3310]

Don't be flabbergastered Jahay. You have a good understanding of brushless and I've had lotsa beer :)