Lipo discharge q

[fastbaja5b]

Originally Posted by suicideneil

Define "full charge amp burst"- you didnt list the current draw so the *true* C rating can not be determined...

Wouldnt mind seeing some eagle tree graphes of Zippies though, there must be some around somewhere.

Not sure what you're wanting, I charged the 5000mah pack at 1C on my balance charger, then hooked it up to the logger and another identical pack (no logger) on the otherside of the Savage Flux

Powered it up took it for a bash

Downloaded graph as above.

Was hoping some of you lipo gurus would have answers!

I am thinking maybe we need to set the LVC at 3.5v a cell to avoid these below 6v drops near the end of the cycle but before a 3.2v / cell cut off kicks in. Because as I said before, LVC did not kick in.

[zeropointbug]

Maybe their Coulombic efficiency is not very high? I am still wondering if this efficiency is converted into heat, or if I am off base with this..?

I have seen one video on youtube where they test a flightmax 20/30C 2200mah pack and the voltage drops to 3.05v/cell @ 26C, which I guess isn't too bad, and might actually be on target for a 20C rating... but I would like to see the same kind of test for the 30C packs. Cuz don't get me wrong, I am very interested in these packs, I just have not seen any data showing they deliver as advertised.

Where as I did a bit of research on the Hyperion G3 35C packs I bought, and on RCGroups, and helifreak forums they did some good tests and they really do deliver amazing power, and just a touch off the 'ultimate pack' Thunderpower 40C batteries, but for almost 1/2 the cost of the TP.

Like you said Sike, these G3's are delivering the power right up until the end, much like A123's in fact. From the few tests I did of my own, I found they would deliver around 3.35v/cell at 35C discharge, maybe higher. The one temp reading I ever took was at the track, someone else's gun (lost mine), the temps were only ever 5F above ambient temps... that's impressive.

I suspect Flightpower is using the same cells in their EON X30 packs, as they state VERY similar benefits for their 'new' packs over their old ones. Neu I think might be using these cells as well, along with CTech batteries.

[sikeston34m]

Originally Posted by fastbaja5b

Not sure what you're wanting, I charged the 5000mah pack at 1C on my balance charger, then hooked it up to the logger and another identical pack (no logger) on the otherside of the Savage Flux

Powered it up took it for a bash

Downloaded graph as above.

Was hoping some of you lipo gurus would have answers!

I am thinking maybe we need to set the LVC at 3.5v a cell to avoid these below 6v drops near the end of the cycle but before a 3.2v / cell cut off kicks in. Because as I said before, LVC did not kick in.

If I were you, I would double check everything. Make sure you have the latest firmware version uploaded to your ESC. I remember issues with the lvc on previous versions.

Looking at your graph, the run really started at about the 3 minute mark. The pack wasn't doing too bad until about the 15 minute mark. (12 minutes into the run).
It was at this point, it really began struggling to keep up with the load. Only 3400mah spent at this point.

Based soley on this graph, IMO, this isn't a 30C pack and it probably isn't a full 5000mah pack either.

What is this pack's size? Dimensions? What does it weigh?

[zeropointbug]

Maybe your eagletree logger is not calibrated/inaccurate?

[fastbaja5b]

Pack measures 137mm by 46mm by 25mm

Weight 320 grams

ESC is running V1.21 (Beta) firmware and has been for weeks.

[Patrick]

Originally Posted by zeropointbug

Yikes, those Harris packs are way overpriced

It's an Australian site (I'm pretty sure), so stuff like that is a bit more expensive here usually, but manly it's in AUS$, which got up to 97US cents around this time last year, but is down to a bit under 80US cents now.

I wonder what types of cells the 30C packs use. I remember hearing a while ago that some of the 30C packs didn't hold voltage quite as well as the older 25C cells of the same brand.

[suicideneil]

Originally Posted by fastbaja5b

Not sure what you're wanting, I charged the 5000mah pack at 1C on my balance charger, then hooked it up to the logger and another identical pack (no logger) on the otherside of the Savage Flux

Powered it up took it for a bash

Downloaded graph as above.

Was hoping some of you lipo gurus would have answers!

I am thinking maybe we need to set the LVC at 3.5v a cell to avoid these below 6v drops near the end of the cycle but before a 3.2v / cell cut off kicks in. Because as I said before, LVC did not kick in.

You said you did another run with the Reedy pack hooked up and produced a voltage of 5.89 under load, but you didnt post the graph for use to look at & determine the C rating, nor did you say what the load was that produced that voltage drop, thats what I was wanting. If you posted the graph elsewhere, then a link would be handy (my psychic powers arent what they used to be....).