I need to take the plunge to lipo
 

Somehow, over the last year, all 5 sets of my NiMh packs went bad. Not certain why, but I have a new superbrain charger which I had some difficulties getting set up correctly, and I have a new HV-4.5 system in my E-Maxx. I'm getting great performance for the first two minutes, but then it just pukes. I sent it back to Novak for testing, but it worked fine for them. So that puts me in a fix. Since I need to purchase batteries, I might as well start converting to Lipo.
I dont race - pure bashing. I have two Emaxx's and one revo. The Emaxx's are powered by HV-4.5's, and the Revo WILL have a MMM/Fiego 10L. The 4.5's limit me to a maximum of 4S, and 16.8V. What I dont know right now is, how much battery do I need, and should I go with 2 2S packs instead of a single 4S? Or should I be "safe" with the HV's and run only 3S???
I have a gift certificate to Tower, and so far have narrowed it down to: Flight Power Evo 25 3700 4S 14.8V
FlightPower Evo 25 3700 3S 11.1V
FlightPower Evo 25 5000 3S 11.1V
FlightPower Evo 30 4500 3S 11.1V
TrakPower 4900 2S 7.4V (seems to be very popular here)

Battery size isnt really an issue for me - I have to remake my battery trays anyway.

Thanks in advance for your knowledge!

i would go with 2 trakpower 4900mah 2cell. and just wire them up so you get 4 cells.


idk how your erevo is going to be setup. are you going to set it up so you have one big battery or you are going to have it like the new erevo where you use 2 batterys.

if its like the new erevo i would just go with the trakpower 2 cells cause it would fit perfectly on both trucks.

Before you spend big bux, check out Zippy Lipos on unitedhobbies.com

with your E maxxs the 4.5 is a really low turn motor with monster trucks its better to tun a higher turn motor they will run cooler but you could run dual 2s packs ( anything with Enerland cells would be great).... a pair of the Trakpowers run in series would be good and with your Revo run a XL size can...the L can will heat up faster due to the lack of torque...either a 4s with 9XL or 5s with 10XL

It currently has two aluminum battery trays that are sized for 6cell Nimh packs. So I have to rebuild those anyway - therefore, I'm open to anything regarding size.

With those trays you don't need trakpowers. The trays will obviously protect the lipos so might as well save the weight and get flightpower. Even check out the evo lite as they are a true 20c now in the higher mah. I have some and they are great lipos.

Trakpowers and Flightpower are the same cells I do like the 4mm connectors of the Trakpowers though

I love the Trakpower packs. Very durable and great cells. You can always get another later if you want to step up to 6s.

http://i21.photobucket.com/albums/b2...e/DSCF3334.jpg

If that is directed at me I am quite aware of that, I am referring to the weight savings of not having a metal case.

Nice ken!
how much do all those weigh together?

The cases are plastic. :mdr: I weighed 2 Trackpowers and 1 4s 4900mah Neu pack and they were very close with the Trackpowers a little heavier.

When I get home tonight I'll weigh them in both 4s and 6s configs.

At first I was concerned about being limited to 12 ga wire and 4mm bullets since Castle only rates them to 75 amps, but after running the 6s config on my MMM/1515 1y Savage, the wires and connectors were barely even warm.

If you don't care about size, have you considered a123s? Much cheaper and more durable. They're biggest drawback is size.

Just a thought anyway.

You know, I havent really considered them. Their ratings confuse me (not that Lipos are much better!), so I have never been sure what I could run, or need to run. I definitley would not be against going that route. How do I equate their ratings to NiMh packs?
Also, I'm not certain my superbrain 989 can charge them.

I don't think the 989 can.

The A123's sit right between liipo and NMHI. Weight and price IMHO. They have a huge advantage of durability and fast charging. So for bashing they get my vote. No reason at all to stay NMHI.

If you are racing LIPO's are the way to go for weight reasons.

I run a E-maxx on 6s1p A123 packs. It moves quite nicely. Effectively the packs cost me 60.00 a piece.

Highflier

How much run time do you get with one pack?

It's hard to say the way I bash. when My wife and I go for a walk through the woods I get about 1.5 - 2.0 miles of walking in on the first pack or about 45 minutes it's rough terrain.

When I run in the back yard it is 10-15 minutes. Many others will tell you to run
6s2p packs. Then you will nearly double your run time and you will actually have better power. The voltage will hold better under hard load. However I found that the 6s1p pack puts out enough power to break Diff's, Clutches, and drive shafts. Now I have upgraded all of them and hopefully it will be realiable. I figure if it has enough power to break all of those items it has enough power :)

I don't mind a batter swap every 10-15 minutes. My motor needs cool down time anyways. When I get a higher quality motor. (should be here today) I will see if it can handle longer run time in summer heat. If so I may try a 2P pack. I just don't like the idea of adding that much weight to the truck.

Highflier

The 989 cannot charge them, but you can add a Dapter to the 989 for only $40 that will take care of that problem.

An a123 cell is 3.3V nominal and about 3.7 fully charged. One cell is 2300mAh, so running them in parallel gets you 4600mAh. My E-maxx works great with 5s2p a123. The great part is that you can charge them super fast and you don't need an LVC for them. You don't even need to balance them. They also last for 1000 cycles, compared to only 300 for lipos.

No doubt, you must make your own packs to get them at that price. I'm not all that fond of soldering, mostly because I've messed up so many electronics with my haphazard approach (if a little heat is good...more must be better!!)

So I've seen a recommendation for 5S2P, and 6S1P...if my math is correct, the HV has a limit of 16.8V, which means I should stick with the 5S, and I would likely want to run a 2P setup giving me 16.5V, 4600mah, right? But what about their limit of 4S for lipo - does that stand for A123's also?

Where is the best place to purchase premade packs? I seem to remember MaxAmps carrying them, but I'm sure there are places that sell them cheaper.
On edit....well those arent much cheaper....Maxamps has A123 5S1P for $145.....maybe I'd better look into making my own!

This place makes them.

https://www.tanicpacks.com/product_i...roducts_id=958

Got that off the CC site.

Don't know much about the novak but I would guess it would live with 5s A123

They would give you about 2 more volts..... HMMMM... not sure if that will work or not.

Highflier

Just buy the cells cheap and have someone on RC-M build the pack for you on the cheap.

I'd offer to build it, but you probably shouldn't trust the packs I build. I think lincpimp and BrianG both know how, and I'm sure there are several others that would be willing.

Just a thought.

I just purchased two 2S2P A123 packs (6.6V, 4600maH) off ebay for just under a 100, and I bought one of those 'Daptors....thanks kulangflow for the link. I'm going to send an email to MRC to see what they have to say about the 'Daptor, and how it might work.

2s2p for 100ish Ack...... that is 4 cells or more then 20 a cell. I will build a pack for you at that cost, I got the cells already.

No I am not trying to Rip you off I am trying to advice you to search for deals around 10 for cells or no more then 15.00 built up.


Highflier

He got two 2s2p packs, which is a total of 8 cells for $100. It's really not a bad deal at all considering they're built already and everything.

Yeah, it was 12.50 per cell.

But I'llyou up on that deal (15 per cell).......pm me if you are interested.

So now I have 4 of those 6.6V 4600's coming, and the 'Daptor. Now my question is has anyone had any experience with the 'Daptor? Can it charge two packs at the same time? I'm wondering if I may be better off selling my 989 to my brother in law (he's about to buy one), and just purchasing a pair of the A123 chargers and a power supply......I dont know anyone who has experience with either one....

I haven't actually used the Daptor, but I have a killer Hyperion a123 charger for sale if you're looking for one. It will charge both those packs at the same time at 10A.