A Perspective On The B Type EESD - Robert Murray-Smith - Any issues?

[Nink]

MileHigh I am guessing you are basically saying in a round about way,  show me the independent test data. Maybe not as stringent as UL/CSA certification etc as it still in prototype but something from a recognized independent testing organization.

[PIH123]

MileHigh I am guessing you are basically saying in a round about way,  show me the independent test data. Maybe not as stringent as UL/CSA certification etc as it still in prototype but something from a recognized independent testing organization.

I believe he is saying that the test data is available right there in the video clip, but is misrepresented.



If I am right, looking at the graph shown from 17:36 onwards (I drew a more accurate version on my desktop) we can extrapolate that his EESd will be out of juice at about 290 seconds. RMS wanted a straight line graph, so that is what I used.


So wouldn't we have to apply the same criteria (out of juice at about 290 seconds) to the LiIon battery also.
1150 mAh / 290 * 60 * 60 / 26 (cells)
So the effect of each cell would be 549 mAh per cell that fully discharges in 290 seconds.

And at 0.455g per cell that would be 1206 Ah/Kg.

So he has misrepresented the competition by a factor of 12.
It would also COMPLETELY turn  claim around.

In conclusion, the competition Knocks the socks off his device. (his was 697 Ah/Kg)



Edited :

I am not liking the sound of that.
How can one out of 26 cell contain half the total capacity.

Please ignore the above calculation.
I will leave it there just to show what an Electronics novice comes up with when he is not a subject matter expert.

Sorry.
Pete

[Nink]

OK I hear what you are saying Pete.  His cell was burnt out in 290 seconds where the Li Ion cell will last 1 hour at 44mA.  At 5min 13 seconds the cell drops below 44mA so subtract the 3 minute charging time it really hit 44mA/h in just 2min and 13 seconds or 1/27th of an hour.   His EESD does drop fairly consistently example 4min 7 seconds it is at 94mA.    So lets assume straight line and for the 2m 13s it was running an average of 111mAh. 

I guess the basic assumption he is making is if we had charged it for 30 min and not 3  it would start at 1780mA not 178mA.   I am not sure this is the case. 
So do we need ~ 10 * the number of Graphene cells to Li Ion cells?

Edit:

That is if we are just looking at mAh but we really need to take into account volts as well.  We start at 2.7V but quickly drop to 1.5V and by 5:13 seconds we are at .5V  Now I am not sure what he said about the Li Ion Battery. I think he said it is a 1.5V 1150mAh battery at video time stamp 2m 35s and I assume they are all wired in parallel as he divided by 26 cells when he calculated amps / cell so each cell would be 1.5V. 

I guess we need to plot this all out in a spread sheet .....

[MileHigh]

Well thank you for trying to figure out the issue but nobody got it.

The problem with the clip is that RMS fails to calculate the equivalent ampere-hours in his test cell.  Ampere-hours is a nomenclature that is used to make comparisons between batteries of the same voltage.  Ampere-hours is a shorthand way of expressing the energy in a battery where you ignore the battery output voltage because it is implicit and understood to be the same.   It can be used when stating the battery energy capacity or when comparing the battery energy capacity between two batteries with the same output voltage.

So, suppose that you are comparing two batteries where one battery outputs 10 volts and the other battery outputs 5 volts and you are going to stick to using the term ampere-hours.  What do you have to do?

The answer is that you have to double the ampere-hours of the 5-volt battery to represent the equivalent amount of energy.

100 ampere-hours @10V = 200 ampere-hours @5V

The lithium-ion cell phone battery has a nominal output voltage of 3.8 volts.

When he starts the test his cell is outputting about 1.63 volts and when he finishes his test his cell is outputting about 0.36 volts.

When he starts his test his equivalent ampere-hour measurement is exaggerated by (3.8/1.63) = 230%
When he ends his test his equivalent ampere-hour measurement is exaggerated by (3.8/0.36) = 1055%

This is simply unacceptable for a man in his position.  He has made other glaring errors that I already mentioned.  So he is either ignorant or he knows what he is doing but he has other motivations.  That is an unknown and people can decide for themselves.

The clip is wrong wrong wrong and his data is pure junk and his smug conclusion at the end of his clip is pure junk.  It's a farce.

If I really cared about his project, which I don't, I would be extremely upset.

MileHigh

[MileHigh]

Edit:

That is if we are just looking at mAh but we really need to take into account volts as well.  We start at 2.7V but quickly drop to 1.5V and by 5:13 seconds we are at .5V  Now I am not sure what he said about the Li Ion Battery. I think he said it is a 1.5V 1150mAh battery at video time stamp 2m 35s and I assume they are all wired in parallel as he divided by 26 cells when he calculated amps / cell so each cell would be 1.5V. 

I guess we need to plot this all out in a spread sheet .....

Yes Nink, you are definitely on the right track here.  I believe that a lithium-ion battery has a nearly constant output voltage over its discharge cycle.  Ironically RMS even mentions this in his clip.  All that he really had to do was take voltage and current measurements say every 10 seconds over the 240 seconds of the test to get a handle on the energy capacity of his cell.  He could then convert it into equivalent ampere-hours @3.8V to make a fair comparison with the lithium-ion battery. 

But he didn't, and it's such a glaring and godawful mistake that my jaw dropped when I watched the clip.  And this is a guy that works in a "high capacity" technical position in a capacitor and battery company.

MileHigh