I'm just now re-entering this hobby, and as such I'd never used LiPo's before. Knowing from my old timer's experience how important it is to have good batteries, I spent well over $100 on a Reedy 5000mAh 35C battery...works fine.

Then, I needed a couple more for bashing with my son and practice, and since I've been buying all sorts of stuff in a short time, I didn't have much budget, so I bought 2 Zippy Flightmax 5000mAh 30C batteries from a reseller here in the states for about $42 each, shipped.

BOTH of the Zippy batteries are better than the Reedy in every way. They take more charge, are both at slightly higher voltage (8.42 v. 8.39), they both came, and stay, better balanced by a good margin, and the Reedy gets really warm after a run, while both Zippy's are barely warmer than ambient.

I am aware that 3 batteries is hardly a representative sample, but until I see a reason to spend almost 300% more on the expensive stuff, I , well, won't.

Funny, I did it exactly backwards from you, but still came to the same conclusion. I bought the HK lipos first, then thought, WOW, if this is this good, imagine a 200-300% better product. Yeah, I ended up with about 5 lipos that cost close to $100 each and none of them did any better in any situation I could produce.

It sounds like you may have received a bad reedy. Your batteries shouldn't get much above room temperature, even after running for 20+ minutes with a good mod driving aggressively. Mine don't, ever. The warmest my most abused reedy got was "Hey, this thing isn't ice cold this time" -- I would have to estimate it was around 75F in a room that was 70F ambient, and most of that heat probably came from the speedo and motor right next to the battery.

I run only reedy batteries and mine really never get out of balance, but then again, I balance charge them every time. You shouldn't be charging over 8.4 volts as charging over 4.2 per cell will start converting lithium ions into lithium metal on the electrodes inside -- basically a cumulative ticking time bomb. There is tolerance built into that 4.2 volts per cell number, but please be careful!

What you are paying for with a higher priced battery is more quality control and certification. There are only a few actual cell makers, so they all come from the same places, much like nimh/nicd did, so you're really paying for the hard case certification, craftsmanship, warranty, and quality control. Every manufacturer makes a dud once in a while -- if your cells are getting way out of balance and the batteries are getting hot, you really need to talk to reedy honestly because that's not normal.

One more thing, depending on how/where your lipo cutoff is set, you may be damaging your cells, which will greatly skew your results.

Wayne

I think the point your probably missing, is that a Lipo that is 5000 mAh and 35C can in theory pull 175 amps continuously. Now, almost NO rc cars are really going to do that. a 13.5 is more like 40 amps or so, and a 5.5 mod may get up to about 70 amps. So, in low power applications, the batteries aren't really working hard most of the time, and you won't notice a lot of difference..
You say they take more charge and have higher voltage. Firstly, taking more charge is subjective to a point, as every time you use your car, it will draw more or less power from it, it's impossible to use the exact same amount of capacity, so how do you know they can draw more charge?
Secondly, great news if you got good Zippy's, fantastic stuff for the price. When they work. I have heard stories on both sides of the fence about great ones and bad ones. It's probably worth the chance considering their low price.
One last comment though. Reedy support the industry and lots of race meets and racers. They also put a lot of time into product research and development, that the Chinese companies later reverse engineer for little cost. Ask yourself where the RC industry would be if companies like Reedy packed-up shop.....

While I can't speak for the original poster, I do have plenty of experience with my Reedy Lipos and my Zippy Lipos, among others. I have cars that I strictly race with and I have cars that I bash with, running everything from 13.5 to 7700s. I never had any problems with most of my more expensive packs, but the performance increases and durability factor have not proven themselves great enough in any circumstance to justify the cost. Considering that companies like Reedy support this great hobby the way that they do, I do not worry they will be hurt by a company like Zippy. Reedy will continue to win races, and people will continue to buy their products because of it. But someone like myself, I do not need a sponsored racer to tell me I can win local track races with a cheaper product.

When a lipo is getting warm from running, its prob that its having some kind of prob generating the current thats being called for. That implies these are no where near the 35C that you paid for.


I'd be talking to Reedy about why this is happening.

When you charge 3x as much you can afford to support race meetings & sponser racers I would rather keep my money & pay for, sponser, my own racing

Back on topic, i have 6 zippy packs & all have been great. Leigh

Wayne - OP uses a Dynamite Passport Ultra charger, so he is not tweaking the charged lipo voltage - thats just the voltage he is seeing coming off the charger.

WOW! I usually temp my lipo's around 120 after a good run. And those are the Trak Power high dollar ones...now the ACE 5300 only about 110...I am running a MMM 2650kv...in the Slash I run some Intellect 4000 and they top out around 100 in temp after 15 minutes...

All lipos I have ever used (all 16 of them) get hot when discharged, but never hot when charged and I balance charge all of them.

The most a 2s lipo is worth should be about $60 each. I don't know how EPIC and REEDY can slap a box and sticker and MAYBE resolder a pack and add $160.....

Could a bad or poor solder joint on the connectors cause resistance that would contribute to heat?

ben

Not in the body of the lipo itself - the heat would be where the resistance was - in/at the connection.

Cool, asking because my soldering skills are lacking to say the least -- especially with thicker gauge wires.

My Lipos never seem to get above about 85 degrees. I'm wondering if that will still be true when peak ambient temps out side are 110 degree, and surface temps on the ground are even higher.

Right now, both of my CC MMM setups are running nice and cool. Motors never higher than 110 degrees. Loving that.

ben

In the words of the very wise Jules from Pulp Fiction...Well, allow me to retort!

1. I'm not missing that at all. I wasn't complaining that the 35C battery wasn't delivering expected superior performance because it was 35C...I understand that both batteries are providing tremendous head room vs. what I'm actually drawing. My point was that for 300% more, I expect superior overall performance, not inferior. By performance I mean that the cell should stay better balanced, take more of a charge...something besides a sticker that says "Reedy."

2. Taking more charge is definitely not a subjective point. When I discharge the Reedy to 3.2VDC, and then charge it, it takes roughly 300mAh less than either of the HK jobbers do (310 less than one and 300-303 less than the other). I"ve done this multiple times on all of the batteries, and the results are consistent.

3. re: cutoff voltage: I'm using a Passport Ultra set up to cut off at 8.4VDC. The charger apparently floats that number a bit, as both of the HK batteries go to 8.42 when they charge, and the Reedy goes to 8.39. Again, I understand that this is not a meaningful difference, but the point is that the thing is 300% more expensive...it shouldn't be 'worse' even if 'worse' in this case isn't very important.

4. I doubt seriously that Reedy has significantly contributed to the R&D of Lithium Polymer battery technology...in this case they're just re-badging imported batteries, just like anyone else (except for the small number of companies...Thunder Power for example, who assemble here).

That said, I am 100% with you that Reedy supports the sport. That isn't a reason to sell a $35 (w/o the shipping) battery for $120. If they want to support the sport, they should sell the batteries at a price that represents a solid value. If they were assembles in the US, that adds some value for me. If they have great CS, that adds value.

So, if the $35 HK battery was $55 or so from Reedy, I'd buy a bag full, I promise. But $35 v. $120 is just ridiculous. In my opinion, selling these batteries (and Reedy isn't alone btw) at these outrageous prices it taking advantage of people's trust that if it says 'Reedy' on it, it's worth extra. In this case, it isn't.

Check out Hobbyking...

Great customer service, great prices for Lipo and LiFE and great shipping...and a cool Tshirt...

Ya that's where Zippy Flightmax batteries come from. There are domestic resellers though.