Yet another E-revo lipo question
 

Hey I've been reading post over many rc site trying to find the good setup for me. I need to be pretty sure of what I'm buying before doing so because I can't afford to make a mistake and waste 200$+ on battery and then realize I need to buy another pack!

About my setup:
I ordered the tekno neu 1515 1y squared I'm gonna use with the MMM I got some months ago (wish it will hold down it's V1) and never used.
I've upgraded to RPM a-arm
Using the L-travel shock with the original rocker
Gonna receive the Tekno Rc sway bar kit at the same time then the Neu.
New 32 pitch 18 tooth pinion that Impaktrc.com suggested to me for now. Might change that later as I see the results.


Now I'm looking for the right lipo to go with my kit. I've seen many and am pretty lost with all the post read. I'd like to be able to go bashing with em with some low gearing but also being able to do great speed run so I can waste my bro's nitro hitting 50 mph!

Here's the pack I saw and seemed interresting:

MA (yeah I know) 3s 5250Mah 30c x2 for 22.2v - about 350 they told me I could get 15% discount

Neu energy 3s 4900mah 25c x2 for 22.2v about the same price

A123 cell 4s 2300mah x2 in 4s2p setup with a 3rd pack of 3s2p for a total of 7s2p 23.1v 4600mah 30c. About 400$

I've been using home made a123 5s1p in my e-revo for some time and they miss a little punch, but that might be my soldering being pretty bad! ;) I heard well made pack have a lot of power.

Any of you have comments on my ideas, or other pack to recommend. Is the MA good even if they don't stand their claimed C rating or should I go with something else ? Some link would be appreciated too. Oh and btw I need to have them shipped to Canada:S

Thanks for your help!

Would 6s1p with lower MaH be good ? 6s1p 2500 mah x 2 or something close to this would give the sasme setup but with faster charge rate... Or are they all to big for the e-revo battery bay ?

Posting the same Q in several places is a no-no.

That said, to address your new questions:

MA = fail, just say no.

6s lipos will not fit, as even with the very low mah cells they are just too tall for the trays- the principle of usinf a couple lower mah packs in parallel is fine though.

Saddly, the traxxas monkies/engineers failed to take this into account really, so your bet bet for a 6s setup is a 5000mah 3s lipo in each side of the Erevo, just cant fit anything bigger really unless you hack the top off of each battery compartment.

A123 cells wont fit period, not without removing the doors, and even then you can only fit 5 in each side (side by side like a nimh pack), so that onyl nets you a 4s lipo equivalent setup.

Read my updated Erevo FAQ for more info and ideas, and a diagram of the battery compartment dimensions so that you know how much, or little, space you have to fit the lipos into.

http://www.robotwars.00server.com/erevofaq.html

http://www.hobbycity.com/hobbycity/s...0C_Lipoly_Pack

thats all you need. 2 packs for 120$

Thanks for your answer to both of you.

I don't want to get into a fight Suicideneil, but I must correct you by sasying that a123 does sfit tight in the e-revo. I've made a 4s1p pack == style that barely fit in but then transformed it into a 2s1p + 3s1p to get more voltage. I only have 7 working cell out of that salvaged dewalt battery I got from a friend. Still, I think lipo would be a better option, in that I agree with you. Think I'll stick with 5000 3s battery then. I only need to find one that put out enough amp.

Mikey, have you used the 5000mah 20c with a neu 1515 1y ? I'm affraid the voltage will drop when I try to push the motor to it's limits. I might be wrong, and would love it seeing the low price on those!

4s2p A123 fits, but thats only equal to 3s lipo, when what you want is something equal to 4s-5s lipo- thats 10-12 A123 cells...

Zippies perform pretty much to their advertised specs- voltage will drop under load, but with 6s lipo and a 2200kv motor you will naturally need to gear lower than normal (when running 4s lipo with a 2200kv motor for example), so the reduction in work load for the motor (lower gearing = more torque and less current draw) will help the batts somewhat. There are also 25-35c zippies that will work, and the newer versions of the zippies with a blue label on the blue heatshrink (especially for planes I believe), check the dimenions and specs as they might be better. You wouldnt be dissappointed either way for the price, or there are Mikes new lipos in the store that are performing very well (unbranded ones).

20c 5000mah is plenty enough for the 1515 1Y. Of course it also depends on the brand/cells of the battery.

zippys
 

Neil thanks for the update on the latest zippies. i have been a MA guy but today was the last straw. sons and i were running the emaxx and erevo - both have MMM/s and 8XLs. towards the end of the run BOTH of the 8000 25C HV's puffed AND one of the 8000HV's in the erevo got hot, melted the battery container and puffed. 3 batteries in 20mins. sadly the one 8000HV which has the 3 year warrantyl didnt puff!!!

I am ordering a pair of the zippies now to see if they can at least last through a race without puffing.

Go with the NeuEnergy batteries! A 4900mah 3s will fiy, it's tight but they fit and stay cool. I run a 2s on the motor side and 3s on the esc side in series for 5s. Motor is a Tekno neu 1515 2.5d. I couldn't ask for more power or better temps. I have run the same motor esc on 4s MA packs with low gearing, didn't puff or over heat the packs, got a bit hot at 127* a few times but they went way out of balance!!! about .5 volts off within a pack. sent them in under warranty. I tried 6s but it was insane. 5s is controllable and plenty of speed, looking forward to racing this season.

Thanks again all for your answer!

With everything that has been said, I'll try to check the price between the neu 3s 4900 mah pack and the zippy to see if it's worth or not going with top cell. If the price isn't that bad I'll go with neu, else I'll go with the zippy one.

I really appreciate all your comments and experience! Saved me the trouble of going with MA! I was about to order 'em yesterday!

If we only save one person from buying Maxamps it is all worth it!:lol:

In all honesty there are better packs for the price. Zippys and truerc are cheaper than maxamps and just as good. And neu lipos are really good and very well priced for what you get. They are generally the cheapest enerland cell based packs.

How old are your 8000hv packs? How many cycles old?

Do you know with those 3 packs alone, you're talking $570 bucks?

I can't understand what went wrong though. :whistle::oops:

According to the website, they should be more than enough.

http://www.maxamps.com/proddetail.ph...O-Pair&cat=172

20C Constant(160 amps)
30C Sustained(240 amps)
50C Burst(400 amps)

Maybe you were drawing more than 160 amps constant! No, wait a second, the MMM is rated for 120 amps constant.

Maybe your Amp Bursts were more than 400 amps. No, wait a second, the MMM is rated for 300 amps Burst.

Oh Oh, it must be your charger! You should have bought a MA charger!

At the bottom of the page you can get a new fresh pair of Lipos and a charger for just $660 bucks. :oops: :yipi:

All kidding aside, I think if you go with zippy's you will see true "C" rating performance. :yes:

If you want GREAT performance go for some Enerland based cells! I didn't think there would be such a difference but there is! Going from MA to NeuEnergy is like going from NiMh to MA Lipos!

frankly we were racing on my track in my backyard. ( it was loads of fun emaxx erevo both with MMM and a slash with a sidewinder and 5700) we were about 20 minutes in when the emaxz with the 25C 8000HV's started to slow down a bit. we stopped and the MMM fan wasnt on and wasnt warm. motor hot to be expected and packs were warm but not hot. Lipo cuttofs on ESC hadnt kicked in

i then looked at the erevo and on one side the 8000 ("20C") pack was hot and puffed so much it deformed the battery tray right under my MMM. the batt had reached 140. of course this wasnt the one with the warranty. I have been using MA for 3 years and think Austin is a great guy but all of the discussion about overrated packs has cost me a fortune. i will relegate my remaining MA packs to slash and my 1/18th scale where they seem to do fine.

I ordered a pair of the zippys 11.1 5000 for the erevo and am going to try the Neu's or SMC's in the emaxx. might stay at 7.4 packs on the emaxx as the thought of my sons driving 50Mph around the 2 year old is scary....:gasp::gasp:

what tires and wheels are those in the erevonut revo pic??
 

what tires are those on your erevo erevonut?

They are Maximizer Beadlock 17mm rims and Proline Badlands MT tires. Good combination as long as you tape the inside of the tires.