What Lipo For 1940/6?

[Papa]

Greetings

I'll be running a Lehner 1940/6 9918,combo in a SuperGMaxx, singlespeed, don't know the weight yet. This unit will be used only at the local track. Speed runs are not on the agenda. Well maybe once or twice.I must buy batteries either NIMH or Lipo. I am leaning towards lipo, for weight and runtime reasons. With Lipo I will need charger, power supply and packs. Keep it safe.

Thanks in advance for your advice ,recomendations, and links? :P:

[Papa]

Heres a pic.

[RC-Monster Mike]

4s Lipo would be my choice. I use the Kokam 3200 cells. If you only race for 5 minutes, these work quite well. I don't use any type of voltage cutoff device, but I only run for 5 minutes also. These are available at Tower hobbies, along with the astroflight lithium charger. They also make packs with a cutoff built in, along with the ability to quick charge. For longer runtime and safe running, a pair of the 6400 mah 2s scorpion packs in series would be pretty sweet. This is slightly heavier than 12 cells, but with 6400 mah of power and 120 continuous amp draw capabilities, the performace would be very nice(better than 14 nimh cells).
Sweet truck, by the way! I have a similar truck, but I use the towerless vbs and a custom rear skid to use the extension on the chassis(no wing on my truck, either).

Mike

[Papa]

Mike

Our qualifiers are 5min, mains 10min, I'll be in the same class as the nitro boys. These packsbalance pro intrigue me. I am concerned about both cutoff and cell balance. Mike I'd like to use the G Maxx extension but have not figured out the skid thing. How did you do it? Are the packs with the cutoff built in the scorpion packs? Have you got a link to the Astro flight? Is this it?Astro flight

Thanks

[RC-Monster Mike]

I used the g-maxx front skidplate, a stock rear skidplate and the UE rear skidplate to make the custom skid(used these to line up the chassis braces with the ext. length and get the hole locations for the rear bulkless). I basically drilled the UE mount holes into the g-maxx skid and cut away the excess material on the outside.

The scorpion packs have the voltage cutoff built in. The scorpion charger allows quick charging as well(astroflight doesn't). That is indeed the astroflight charger I use.
The 6400mah packs will get you through the 10 minute mains. You should lap the nitro guys if you can drive well enough.

[Papa]

How would you wire the scorpion packs? Looks like a few more wires than I am used to? Will I be able to get 6v to the servo's?
Would the balance pro packs work with a voltage cutoff wired in line?:C: With the skids I imagine you had to counter sink the new mounting holes? Would a bench grinder/dremel work for removing the extra material? Yeah some driving skill would be helpful I am sure!:L:

[RC-Monster Mike]

The balance pro packs would work as well, but the advantage of the scorpion system is the fast charge and built in balancing/charge/discharge cutoff. I would use a series connector from the controller(as described in the "how to program your BK controller" post stuck at the top of the brushless forum.
I did have to countersink the new mounting holes. And a bench grinder/dremel would work fine(this is what I used, as I did not have the mill when I did it).

[Papa]

You are the man!;)

[coolhandcountry]

Originally posted by Papa
Mike I'd like to use the G Maxx extension but have not figured out the skid thing.

I thought the gmaxx extension came with the bottom skid. Or am I missing something.

[Papa]

It does come with the skid. Unfortunately, the Gmaxx skid does not match up with the UE VBS.

[coolhandcountry]

OKay. I understand now thanks papa. I was confused for a second. I thought I messed something. Sure enough I did. By the way. I like the looks of you ride so far. Keep up the good work.

[Batfish]

Just an FYI - if you have a speed controller with lipo cutoff or a seperate device for LVC, you should get the BalancePro packs. They are cheaper by about $10-$20 per pack and they are the same technology as the Scorpions, minus the LVC.
I use the BalancePro 2s 6400 in my Brushless Jato and rely on the cutoff from the MGM controller. Considering I haven't been in a race longer than 5 minutes, it hasn't been a problem at all.
I do plan on running two of these packs in series to power either my 1/8th buggy or my MGT.

[Papa]

I like the sound of a LVC, the 9918 does not have one. I thought there might be a way to wire one in. However scorpion packs may be simpler.

[crazyjr]

Hey Mike. On the scorpion packs. Do you use a y-connector between the esc and batteries and a y-conn to the reciever? Or. Do you use only one batteryto determine cut off? Hey Batfish. Do you use the kokam fast charger? If so, how do you like it?

[Batfish]

You can get FMA's LVC device that will work with up to 4-cells of lipo: https://www.fmadirect.com/site/detai...989&section=35

Yes, I use the BalancePro fast charger (it's the only one approved for use with the batteries) and I think it works just great. I can't charge my pack at the full 3C that they're capable of since it's a 6400 pack and the charger won't go to 19 Amps :) . It does, however charge the pack to over 80% in about 20-25 minutes, although I can't completely verify that since I haven't run it down to 6v yet either.

The new SkyVolt system from FMA looks great for high-voltage applications, but I don't have a need for high-voltage in racing. You can, however, get a 6s3p 9600 for only about $1,000 ;)