Maxamps Thread...

[Arct1k]

Yes I had to remove yet another Maxamps thread... Suprise Suprise...

As has been stated many times personal attacks will NOT be tolerated...

If you want to raise concerns regarding the new design then feel free - I'm happy that Austin has logged in to comment.

For once why not have a similar technical dialogue that we have with Patrick rather than waste bytes of the usual comments on Maxamps pricing and C rating.

Maxamps pricing policy is there choice - I personally would prefer that they use a different C rating methodology for the NEWBs and would gladly have a dialogue with Austin on that if I actually could.

So PLEASE can we move on?

So I request no mentions of Austin, Jason, C rating or Price in any post...

Thank you

PS If you wish to complain about this please feel free to call Mike or Brian...

[Arct1k]

In relation to the design - The concept is interesting but my concerns are

- People mismatching old and new cells i.e. run a 2s pack 30 times and then adding a cell
- Charging complexity - swapping to 1S parrallel pack... Especially if you linked a charged and uncharged cell or just imbalanced cells
- Losses etc with all of those connections - There would be a lot going on in a 5s pack...

As i said interesting concept just worry about the practical realities...

[TexasSP]

Should it also be understood that vendors can not come here and make personal attacks themselves? Calling people bullies and such was an invitation for sure.

Reasonable dialogue has been attempted before but the vendor chooses to sling mud. This happened on a thread in which BrianG brought up ideas for C rating standards.

If this were Castle they would have offered to take care of us, possibly even offering for us to try out "new product A" to prove how well it performed.

You can't really compare the two because they really don't compare at all. PDC is an awesome statesman. He took care of me when his product failed with never a hint that I was to blame. He actually stands behind his product and follows through with his commitments. He also doesn't throw fits and send Joe Ford in to fight battles for him calling his detractors names and what not.

Plenty of CC bashing has been seen on this forum, and Patrick has taken it all in stride.

[lincpimp]

No prob Chris, I understand and apologize to you and Mike as i know I was part of the "problem".

I too worry about what will happen when mixing different age cells and charging them in parallel.

Interesting concept, but I do not see how it "fits" the way we currently use and maintain lipos.

[BrianG]

FWIW, I just PM'd Austin with my contact info if he wants to call me and discuss this in person.

[Finnster]

I didn't post up any tech concerns in the other thread, but in addition to what Chris said, there are a number of concerns that don't seem to be adequetely addressed in the current design.

Namely:

-Amp capability of the connectors. Given the "60C" rating, that would put over 300A through all those banana plugs, which look like 4mm plugs. Lots of places for losses, esp overtime as the connections are continually reconfigured. Lots of potential for failures.

-Overly complicated and potential for shorting batteries seem high

-Fragile construction. The connection plugs would be taking a lot of the impact forces that would normally be absorbed by doublesided tape/glue/heatshrink in a conventional pack. This is not where I want forces to be absorbed

-No specs or recommendations on balancing differentials. How far out of balance can these cells be before you plug them together?

-Large surge current potential between two out of balance cells. Normal balancers discharge slowly to achieve balance. Paralleling two cells with ea other will force a charge into the depleted pack. Completely different method. Given the (hopefully) low internal resistance of the setup, large current spikes are quite possible. How does this effect long term performance?

-Safety concerns if the recieving pack does not take the charge well. No internal mechanism to stop a runaway failure if it should occur upon connection

-Large amts of additional weight vs conventional design

-I think some price comparisons are valid, but I won't go into them. Ultimately this design has to answer is if, given the above design penalities and safety concerns, does this represent a significant value above purchasing dedicated conventional packs?

I don't see how.
Perhaps this design has some merit in some small scale/ slow speed applications, but for its intended purpose and application (high speed 1/10-1/8 cars) it seems far too much trouble for any convience benefits.

[rawfuls]

Oops, sorry for my thread =/

[_paralyzed_]

an edgy thread and I wasn't involved? somebody call a brotha....

I can't find any constructive criticism for MA's new "multi-cell" packs.

Did you guys watch the informative video? You have to play dominoes with your cells to charge them. What a pita. Were people really having that much hassle with balancers?

A 6s pack would be bigger than Bondo's belly.

Finn pretty much nailed the rest of the problems.

[redshift]

I had to chime in over there. You guys ever see a modular V8? Well I just invented one. I'm wondering if anyone has a spare minute to help me remove 3 cylinders? I'm thinking I want a V5 this week, mileage was killing me with the V8!

[Arct1k]

Originally Posted by redshift

I had to chime in over there. You guys ever see a modular V8? Well I just invented one. I'm wondering if anyone has a spare minute to help me remove 3 cylinders? I'm thinking I want a V5 this week, mileage was killing me with the V8!

Actually that is almost a common setup - some of the v8's etc do actually shut down a bank for fuel efficiency...

I worry abut the safety aspect - Even in the video jason was about to plug things in the wrong way around a couple of times and had to correct himself.

I know this setup is only intended at advanced users whilst I do think that it is very innovative my safety concerns for Newbs would personally mean I not recommend it. I would rather get 2 x 2s and a 3s pack with traditional connections and be able to make : 2S, 3S, 4S, 5S, 7S.


Another thought - Chargers I don;t think will like the 20 amps 3,7v setup as they are going to have to do a lot of voltage reduction... vs a 5amp 14.8v charge

[_paralyzed_]

Originally Posted by Arct1k

Another thought - Chargers I don;t think will like the 20 amps 3,7v setup as they are going to have to do a lot of voltage reduction... vs a 5amp 14.8v charge

and only the best chargers will even do 20 amps. It's noobs that buy MA, not "experienced hobbyists". They will have dynamite chargers (like freezebyte wants) and not have the discipline to always assure correct polarity.

I can foresee esc and motor failures happening as people try "one more cell" and exceed specs.

I think this is bad for the lipo industry in general. Bad joojoo comrades.

[Arct1k]

Originally Posted by _paralyzed_

and only the best chargers will even do 20 amps. It's noobs that buy MA, not "experienced hobbyists". They will have dynamite chargers (like freezebyte wants) and not have the discipline to always assure correct polarity.

Agree in that a lot of chargers are 5amp 50w - with a 3,7v cell you'd be only using maybe 20W of your 50W capacity charging at 5amp

Originally Posted by _paralyzed_

I can foresee esc and motor failures happening as people try "one more cell" and exceed specs.

Don't agree as that can happen with any setup to a degree

Originally Posted by _paralyzed_

I think this is bad for the lipo industry in general. Bad joojoo comrades.

Not into joojoo - i'm a touch more positive I actually LIKE that they are trying something new and thinking out of the box - There is a good idea in here; its just not quite right now IMHO.

[_paralyzed_]

Originally Posted by Arct1k

Not into joojoo - i'm a touch more positive I actually LIKE that they are trying something new and thinking out of the box - There is a good idea in here; its just not quite right now IMHO.

Ha! I'm not really into joojoo either. Like has been stated there is a lot of room for error, and I would just hate to see lipo accidents cause stricter regulations.

What do you guys think the shrinkwrap + hardcase on every cell will do to lipo temps? Negligible? It can't be good...

[nitrostarter]

I understand they are the first to sell individual Lipo cells to stack like this but people have be doing "multiple voltage" lipos since forever. Its called a multiple packs and plugging them in series. For example, look at Chris's post below...

Originally Posted by Arct1k

I know this setup is only intended at advanced users whilst I do think that it is very innovative my safety concerns for Newbs would personally mean I not recommend it. I would rather get 2 x 2s and a 3s pack with traditional connections and be able to make : 2S, 3S, 4S, 5S, 7S.

Also, a guy said it best on rcgroups.com:

Originally Posted by gulio

Please make sure that all cells are at the same SOD before using them together. This is the worst part of this I can see. It's not a new concept as I have seen something like this before (on most of my models). Many of us use powerpole connectors to series connect cells and packs at will.

Powerpoles are very user friendly for wanting to make series or parallel connections. This is just a spin-off of this.

[suicideneil]

Money making spin off even?

Companies like Thunderpower, Neu, Hyperion have very clear generations of cells & innovate with new technology & chemistry to offer people the lastest and greatest ( even hobbyking have the nanotech cells that Im sure we're all eager to hear testing results for ). Maxamps innovated by selling cells seperately and have the customer work out the correct assembly prodecure; no fewer than 7 connections with a 6s pack, and 12 male + 12 female connections, made with tiny ~4mm bullets. That isnt progress, thats a health hazard. ¬_¬