LiPos for my dual BL?
 

I am going to go LiPo for my dual 9L setup. I read on another post here Mike that you thought these LiPos were pretty good. Which one of the Scorpions would be recomended for my setup? I am currently running 28cells. If not these, then what else?
Thanks!

you would need about a 9s pack. you could run a 4s on one side and 5s on the other. i dont the the scorpions are your best option, way too $$. check out some polyquest packs, they are very good and a very good deal as well. or try maxamps.com.

You probably want something that can handle 80-100amps continuously (for both motors). 4s pack(s) should give the needed voltage. If you go with the Kokam 3200s, you may want to get 4 2s packs. On each side of the E-Maxx chassis, you could put 2 2s packs in series for 4s, so each side has a 4s pack.

I would agree with metalman's advice here. The 4S LiPo will be pretty close to the 14 cell ninhs you currently feed the dual 9Ls. You wouldn't need the 4s2p packs, though. 4s on each side will be fine and can handle the draw. You would cut your battery weight in half by going to this setup as well!

That's what I meant (guess it wasn't clear enough). But 2 2s packs per side, to make a 4s pack per side. And since there are 2 motors to handle the load, the individual work load should be lessened, therefore giving the Lipos a bit of a break. Also, the difference between the weight of 28 cells and 2 4s Lipo packs is just amazing! ~1750g for the NiMh's, and ~800g for the Lipos. Of course you have to pay though; $328 (without discounts) for the Lipos from Tower Hobbies, and ~$140 for 28 GP300 cells.

So, no go on the Scorpions Mike?
Can you get the 4s packs that you recomended or if not, then where would you recomend I buy them from (Tower like MetalMan sugested?)
Also I will obviously need a charger(s) as well, any recomendations there? Preferably something that is easy to operate and wont make my packs blow-up.
I am going in for spinal surgery tomorrow and will be on disability for about the next 6 months or so, so I am doing my home work now, while I can still sit in front of the computer for a while. :eek:
Thanks for the help.

Good Luck with the surgery. Hope you get well.

Yeah!

Succes with the surgery!

Those kokams are the thing for sure, it will fly, the weightsaving is huge.

Isn't it an idea of running one big lehner instead of dual? with these high voltages you can reach with 8 lipolys, it is getting more interesting to run one big motor, over two small ones. more efficient too,

The scorpions are the ticket, Johhny! I don't carry them yet, so Tower is a good source for them. I use the astroflight 109 charger for Lipoly duty. Works great and can handle up to 8 or 9 Lipo cells in series! It does need a power supply, though.
There are a few other Lipos that should work equally well, but I haven't tried them. Perhaps Lipomaxx will see and reply to this post, as Young has tried quite a few Lipo steups on his maxx.

Metalman: I just re-read your post regarding the Lipos(4s packs). You said it right in the first place! I basically repeated what you said.

Just a note regarding the Scorpion packs from FMA/Kokam: the first ones they are releasing are 2s only and are best charged with the Scorpion-specific charger. I'm sure they can be wired for 4s with a harness, but I haven't seen any specific information on if they can be charged with any lipo charger. I assume they can, but one can never be sure when a new, proprietary technology emerges.

Good point, Joe.

Anyone know if they are going to release a 4s?

I hope so!

I read a response from an FMA poster on a message board about a month ago that said something to the effect of 3s and 4s packs of the "Scorpion" type coming 2-3 months after the initial 2s release. These should, of course, be announced with their respective new chargers. Another thing to watch for is the "BalancePro" line at FMA. They are marketing them as the aircraft equivalent of the Scorpion. It looks like the only difference is that the BalancePro packs depend on the ESC for cutoff voltage where the Scorpion packs have the circuitry within the pack and a lead to the ESC.
The BalancePro pack description reads "The ESC must have corresponding cutoff voltage.", while the Scorpion pack decription reads "These LiPo packs drive both brushed and brushless motors, and work with any electronic speed control (ESC) that stops the motor on loss of signal. Built-in low voltage cutoff (LVC) prevents cell damage by disabling the signal between the receiver and ESC when a pack drops below 5.8 volts. Multiple restarts enable a driver to bring a car back to the pits when pack voltage gets low."

Hope that helps.

Sounds great.
Thank you all for all your help. Looks like I'll be getting the Scorpions.
Talk to you all in a couple of months.

Well I'm still wanting to go LiPo so I called FMA the other day. I talked to some guy over there and he pretty much said the same thing that MetalMan and Mike had said. I need to get 4 2s packs. The only other thing that he said that kinda confused me (very easy to do) was for me to use this.
I'm not sure if I need that or not, what do you guys think? I read the description on it and still cant quite figure why I would need it.
Thanks.

That is just a connector(series or parallel). No need to use this for your truck. You can make the same thing yourself with wire and solder. Thos ethings are a little bulky.

FMA Direct are releasing their SkyVolt system shortly.Now expected mid september i think.They use the same cell balancing circuitry and charger technology as the scorpion but without the LVC so like the balance pro but in 4s and 6s.The charger charges up to 6s.They'll be available in the 20c Kokam cells.YOu could use a pair of their 4s in series giving you only 2 packs to charge instead of 4.

This is what Greg Covey said on another forum:

" The 4-cell, 3.2AH Kokam packs are pre-wired to a special connector so that each cell can be monitored during charge and discharge for optimal safety, longevity, and investment security. The Skyvolt packs are used in conjunction with Protection Modules; one for charge and one for discharge. This new approach in Lithium cell safety and protection will be available soon from FMA Direct.

The Cell Pro 6s Discharge Protection Module (DPM) can monitor up to a 6s Skyvolt pack to provide a warning when the voltage gets low and use any ESC to pulse the throttle signal to the motor to alert the pilot that it is time to land. There are two dip switches on the DPM but Switch #1 currently has no function. The units will work out of the box without doing any setup, but they perform optimally when you tell the units which way low throttle is using Switch #2 and use the learning procedure mentioned in the manual.

Note that two DPMs can be daisy-chained for up to 12s configurations.

The Cell Pro Charge Protection Module (CPM) is used with any Lithium charger to monitor individual cell voltages and disconnect the charger when the first cell reaches 4.2v. This extends pack life by preventing overcharging. Note that this does not balance all the cells in the pack, only the Skyvolt Charger (not shown) provides true cell balancing during a charge."

Go herehttp://www.rcgroups.com/forums/forumdisplay.php?f=220 for discussion on skyvolt.

So does anybody know if the Scorpion charger plugs into your wall or is it 12v only.
Thanks.

The scorpion needs an 11-15volt power source for operation.

Uugghh.
Are all lipo chargers like this? Why do they do that?
Wouldnt be so bad, but I plan on running at least 2 at a time.
Thanks.

i woulda gotten a trition and duratrax ice chareger. both can charge nimh,nicd,lipo (triton can charge lead=acid). THey both are really good and can work on anything. Its worth the value. For a deceent lipo charger you gotta pay 50 bux.

Scorpion packs
 

Can (2) scorpion packs be placed in a series without loosing the LVC device. For example running (2) 2p2s packs in a series, if one falls below the 5.8V limit what happens, would it be unsafe to run with the other pack which is over the 5.8V limit? How do the packs work in a series. I have (3) 1p2s on order for 1/10 scale TC racing, but I am also in the works for a brushless 1/8 scale. I just need to find out what kind of battery set up to run.

You can run multiple scorpion packs in series no problem.You just daisy chain the LVC connectors.FMA direct have a standard response e-mail explaining the connections.

Scorpion 3200 R/C Car Pack
 

Is there a Thread about these packs, how other hobbiests are liking or disliking these new lipo batteries?