MaxAmps comparison w/Zippys
 

Mods dont cringe seeing my name and Maxamps on the same page I'm merely showing some results of the 2 packs against each other.

I have 2 3s 5200mah MA packs that I aquired thru a deal a while ago and have ben useing them on and off the last few months in a 4wd Slash along with 3s 5000mah 30c Turnigys.

Anyway, this last Monday night I used them all during pratice,heats and mains in my 4x4 Slash Ashpault racer (Thread if interested)http://www.rc-monster.com/forum/showthread.php?t=28130
I raced the first and second heat with the MA packs about 55-57laps, and raced the Amain with one of my Turnigys and ran 59laps.

I was chargeing them all today and the 2 MA packs took 4770 and 4759mah where as the Amain Turnigy only took 2680mah ? The MA packs dont quite balance perfectly, the cells are a 3&4 tenths of a volt away from each other where as the 3 Turnigy packs are 4.20v across the board
The MA packs are "like new" still and have ben properly maintained and neither show signs of swelling(yet) The Turnigys were bought in Jan and have 70-75 cycles on each ! I can't help but wonder WTH is going on w/ these packs to use so much juice with exact same truck and set up ????
:neutral::whip:
(yes, I charged all the packs Monday afternoon)


I practiced with 2 other Turnigys but there was no controled run like the others, the power on tap didn't seem any different between any of 5 the packs I ran.

Whats the C rating on MA packs? Any noticeable difference in temps between the HK and MA lipos at the end of the runs?

I'd be inclined to do a little testing myself- discharge both packs down to 3.0-3.2v per cell or whatever your charge allows, note mah capacity removed if it displays that info, then do a normal 1c charge and compare the mah put back in again.

All things considered, it seems like the mah capacities are over and underrated perhaps?..

Underrated on the Turnigys and overrated on the MA, Sure I'd believe that :whistle:

The MA packs are 3490 "surge watts" :rofl: what ever the hell that means really ?

Temps, yes the MA packs were about 10*F higher than the Turnigys which were 95-97* after each run, even the pratice packs (Turnigy) which I ran roughly 100+ laps were only 95-97*F

With the Castle Blower fan, the motor was only 106* after the longest practice run. I had temps of 160* with this motor befor it was repaired so it obvisously had "issues" prior but def not now.

Keep nice - More likely the maxamps might have hit the lipo cutoff early...

Trying
OK, but why both packs ?
The Turnigys were run the same amount of laps and drew half the juice ??????

FYI, I dont have the ESC LVC on. Knowing I will not use the full capacity of the packs and wanting to win at any expense I elected to have it off.

Well I would say either the charger display is not accurate, the turnigies cut off early, or there was a large energy drain during use of the MA packs. (heat) A larger internal resistance may lead to heat produced while charging also, exaggerating the amt of E that was put back in.

IDK otherwise

how long was the race?

I probably should have waited till I had more info befor starting this thread, If I go race again next Monday I will make a serious effort to make more of a controled test. I will accurately note all findings and repost and hopefully have more to work with to try and make sense of this.
I honestly feel the MA packs just arent up to snuff due to getting warmer but to take 2k+ more E is awlfully excessive ? Since I did aquire them used maybe they are older and used much more than I was lead to believe, anything is possible I guess.

Till the next race ...........:neutral:

Yeah, def wierd. GLWTR.

Thanx....

It will be extremely difficult to provide exact testing parameters when they are being tested in a very loosely controlled environment. A logger would make results a little more useful since there would be hard data which would show relative current/voltage/runtime values. Without that, results are too objective.

Not saying your tests have no purpose Bondo, just that it will be your preceptions. So hope you don't take this post as bad. :smile:

I understand Brian, I dont have a logger and didn't plan on buying one so what results I'll be able to collect are going to have to be good enough.

I do have a E-Station Voltage and Watt Meter that I bought early this year but haven't even taken it out of the box, would it's results be viable or of any use for this ?
http://www.sussex-model-centre.co.uk...d.asp?id=25507

The watt-meter looks like it is good for only up to 100A. Unless you are running HV on a low kv, light/small setup, geared conservatively, you will be hitting peaks well above 100A.

You really think I'll be hitting over 100amps with my set up ?? I dont doubt you but it suprises me a little.

1509 2Y-1820kv running 3s, vehical weight is 6.4lbs w/battery & body geared 50/20

Differential Ratio: 2.8461538461538462
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 50
Pinion Tooth Count: 20
Total Voltage: 11.1
Motor KV: 1820
Tire Diameter (inches): 3.85
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0.018
Spur/Pinion Ratio: 2.5 : 1
Total Ratio: 7.11538 : 1
Tire Circumference (inches): 12.1 inches (307.22 mm)
Rollout: 1.70:1
Total Motor Speed: 20202 RPM
Vehicle Speed: 32.52 mph (52.24 km/h)
Effective KV Value: 1820
KT constant: 0.74 oz-in/A
Motor Torque: Amperage not specified...
Final Torque: Amperage not specified...
Final Power: Amperage not specified...

Have you played with the speed vs amp calc Bondo? If you can predict time taken to top speed and drag coefficient you will get a ball park figure.
http://www.scriptasylum.com/rc_speed/_speed_amp.html

Vehicle Weight (lbs): 6.4
Vehicle Width (in): 12.0
Vehicle Height (in): 6.0
Pinion Tooth Count: 20
Spur Tooth Count: 50
Transmission Ratio: 1
Differential Ratio: 2.8461538461538462
Other Ratio: 1
Tire Diameter (inches): 3.85
Tire Ballooning (in): 0
Drag Coefficient: 0.35
Total Voltage: 11.1
Electrical Efficiency: 85
Target Top Speed (mph): 32
Time to Get to Top Speed: 1.5
Usable Output Power: 425.15 watts (0.57 HP)
Input Power Required: 666.9 watts (0.89 HP)
Input Current Required: 60.08 amps
Motor Torque: 0.24 ft-lbs
Axle Torque: 1.68 ft-lbs
Average Acceleration: 9.54 inches/sec
Acceleration Force: 27.68 meters/sec^2
Acceleration Gs: 0.97 G
Required Motor RPM: 19879 rpm
Required Motor KV: 1791
KT constant: 0.76 oz-in/A

Bondo, I've logged over 140A on a CRT.5 (Medusa 36-50-3300 on 3s) geared for around 35mph. So, yeah, depending on how hard you nail the throttle, and ESC settings, I'm sure peaks over 100A are definitely possible.

BTW: That calc you are using is not factoring in burst currents. I'm sure your average current will be far less than 100A, but if you want to see all currents and respective voltages, you'll need something that can measure in excess of 150A (at the minimum) to give you any kind of true readings.

I'm hearing you Sir, I think I'll get some connectors and try testing this device anyway. It (may) work and be enough ? A few minutes invested may show some promise.
When racing I find that I roll on and off the throttle to be as smooth as possible and never grab a full pull except once in a blue moon trying to make up a little time or pass on a straight. When grabbing full throttle usually ends with bad results(spin or crash) so I try to rarely do it.

Honestly, I don't think that is all necc if you are just trying to get a relative comparison between the two batteries in terms of total energy consumption.

Lets assume you are running about the same number of laps and running very consistant lap times (ie no widely divergent driving styles.) Let's say also you are using a fully charged batt at the start of ea race. The veh should consume roughly the same amount of energy per race.

Take those batts, but them on the charger using the same charging program and a moderate to low charging rate, and measure that w/ your watt meter. You will get some variation due to the type of load you put on the batt, but the results should be similar across all the batts. You should not be having +/-100% variation. The more batts you test, the more confident you can be in your results.

If you confirm you initial results, then I would move on to a more detailed analysis of the race conditions to nail down the source of the energy drain should you care to do so.

You can also just set up a simple discharge/recharge cycle to eliminate many variables for a more controlled experiment, but what fun is that?

I know why your maxamps packs took so much more mah back during the charge.

But I am not going to tell you why, cause i am a Dick. Not a Richard, just an a-hole who knows something and will not share cause he was an only child and sharing is for sissies that cannot man up and beat the snot out of other little kids who want their stuff.

Ok, all of that is true but...I guess I can tell you. Just don't go posting this on a public forum and let everyone know that i am a nice guy who cares.

Your maxamps packs took so much more juice due to ... Balancing!!!!

Yeah (lots of clapping and screaming) we have a winner.

Keep in mind that as the charge puts the juice back in the pack it does so as a complete pack. The balancer places a draw on the higher voltage cells in order to bring them down to the level of the lower voltage (in maxamps case, improperly matched or weak cells) cells, just like our public school system.

So if you have a few cells way out of balance the charge just keeps charging and the balancer circuit sucks it back out. The charger keeps track of the total MAH put in, but does not factor for the losses generated bu the balancer.

So I can imagine your maxamps packs were way out of balance, due to the 20 amp load you unrealistically asked them to produce (Jeff, you are a douche for this, Jason at MA will never cuddle with you again).

I have had this issue. I had some maxamps 10000mah packs back when it was cool to own maxamps. I used a 3s pack on a emaxx with a 9l and 35mph gearing and it took 22hrs and god knows how much charging to get the pack back in balance. If I had owned the cheap hobby city 4 channel charger back then i could have done a 2amp charge for 5hrs or so and got the pack back in balance easily, but all I had was a ICE and a hyperion charge thru balancer. Ah the old days.

I hope you enjoy your cuddle-free weekends now, I bet jason is curled up in a ball crying cause of what you did to his packs. You really are a heartless bastid...

Speaking of maxamps.....i got an email from them the other day and it said that all of their packs are now cheaper by like 30%. So the obvious is happening....people are getting wise and realizing MA is just a bunch BS. Which kinda sucks because they are within walking distance of me. If they had good stuff (which doesnt seem to the case) and low prices (which they dont) i would buy from them just because it would be convenient. I guess ill just keep ordering the blue packs from japan.

James, You may be a weiner, I mean winner !

I don't remember specific times but the MA packs did take considerably longer to charge due to the Hyperion trying desperately to get the POS's balanced.

I'll bet your absolutely correct.
Good call James, You are wise and homely.

@ Finn; Unless I'm "exaggerating the amt of E that was put back in" cough cough U dickface. :whistle:

Not as homely as yo mama.

Now that I have resorted to calling your mother names, well I guess we can go make fun of frostybuns...

I wonder when he will start a thread asking how many licks it takes to get to the center of a tootsie pop?

A cheap yo mamma is the best you can do ?
I'm terribly dissapointed, I expected more from you. I guess you lost your touch since you ben so busy with preparing for the youngling and keeping Mrs.Pimp happy.

However busting Freezys balls is always warranted since he's such a tempermental/mental little feller. I hope he gets the help he needs, being a penis w/feet must be tiresome ?

I would have used my A list material, but to be perfectly honest, you are not worth it.

And I only mention your mother as Freeze did comment to me that she is a virtual shut in since he has been going over to her house and offering her his "services". Rubbing her feet, watering the plants, having huge debate style arguments on whether Equal is better than Sweet and Low...

If I'm not worthy of A list material thats understandable, I respectfully bow out

But your right, Not only the great conversations my Moms is super happy about Freezy takeing care of the corns via his teeth and supple lips. Moms really appreciate's him handwashing her bloomers and takeing the time to paint their toe nails together, She calls it "Ladys Day".

HAHAHA, I can just see him with some toes in his mouth...

Nah Jeff, you will always be worthy of my A list material, even if you do not understand it.