MMM 2200 on 6S with 3905 Emaxx and zippy 5000mah 20C cells

[hemiblas]

I just thought I would post some numbers with my emaxx 3905 geared with the green Castle 18t pinion on the stock 68T spur. With some zippy 20C flightmax 3S lipos in series to get 22.2V. I know there is a lot of zippy bashing out there but I was pretty impressed. According to the Brian G's calculator I'm geared for about 50mph which should be a nice top end. With my basic wattmeter I got 80A peak with 11.11V on the volt dip. This was done after 3 or 4 passes. Again, this was just some informal testing. The cells were probably 80-90 percent charged when I tested them. If you guys have any questions shoot away, but this seems like a nice 6S alternative for the emaxx and the cells will fit if you loosen the screws on the battery hold downs as they are 51mm or so in width.

[lincpimp]

I would like to see some temp readings after a full run, and runtime with fully charged packs to a 3.2v/cell lvc. Zippys are a superb deal, no question there.

I think you see some zippy bashing because people who sell the lipos that cost three times more are concerned they cant compete. I have run them now in the e-revo, emaxx 3905 and slash and see no real performance issues vs Neuenergy and maxamps in real world racing and bashing. The neuenergy's are the ones that get pretty warm where the zippys and newer maxamps dont. the neuenergys wires were cut from the case opening where they come through - ie no reinforcement, the cases open - have to seal them shut etc.
I am not that impressed. they may hold their voltage longer but in real world ie - not trying to break speed records in front of your house the zippys seem to be no better or worse than other batteries i am using and we push the models pretty hard.
the reality is that if you misuse lipos- dont use LVC's and or let them discharge they are going to fail. if you charge them at the right C and keep them balanced the zippys are just fine for most use cases

[V0RT3X]

Nice, I have the same 20c version, I mainly bought them because they were in stock and I'm saving them for my flux.

And they rip in the Slash.

i ordered some Zippies a month ago on backorder, puffed an older maxamp cell and emailed the company to ask when the Zippy batteries will be shipping out.... They told me July... so they look like a great value, but I have to wait 3 months to get said value. Lucky for Mike his C-Tech batteries seem to be well liked, $300 later.... I will be checking out Mikes batteries while waiting for my value batteries.

Sorry for the rant, I know it is sorta off topic, I guess I just want to warn anyone interested in a Zippy (from hobbycity/hobbyking) to not order a battery not currently in stock.

[ZippyBasher]

Yeah but when they are in stock, I received mine in 4 days from time of purchase to my doorstep.

EDIT: On Several Orders...

Originally Posted by ZippyBasher

Yeah but when they are in stock, I received mine in 4 days from time of purchase to my doorstep.

EDIT: On Several Orders...

I am sure that they ship fast when product is in stock (or else they wouldn't be popular). But when I placed the order (in mid to late April) it was out of stock but the page said they would be receiving more in mid-late April. When May came around they updated to Mid-Late May. When I emailed them Friday they told me July.

yes - the shipping is surprisingly fast WHEN they are in stock. You can sign up for email notification but need to pull the trigger when you get an email or they will be gone.

[hemiblas]

Ok, I got some data for you guys. I fully charged the lipos to 12.6V. I ran up and down my street going basically all out, speeding up to max speed, then slowing down and a quick turn and doing the same thing back and forth. All asphault. It was 88 degrees outside and the sun was shining. My MMM was 114(this was the warmest I could measure pointing inside the case, outside case temps were even cooler) at the end of the run. The batteries were between 105 and 110 degrees. The motor was at 175 degrees. This is with just the stock emaxx 3905 and no cutouts for airflow. Just the standard lid. The batteries settled to 11.38 after the run and I couldnt get a full run but I'm pretty sure I was close. I could tell the power dropping off after a bit towards the end but the lvc didnt cut off. My batteries on my radio started to run short so I had to stop the run. I hope this helps. I'm sure there is still at least 20 percent left in the battery pack given the final voltage vs start voltage.

I'm not sure what final speed I am getting out of this setup, but its just scary fast at WOT. I may gear down a bit which would probably help on the motor temps. Keep in mind too, this was all asphault. Offroad the motor would have gotton even hotter, even though I dont think you could keep it going as fast off road.