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Old 01-03-2006, 04:22 PM   #76
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More on the Scorpion 3200 mA-h Lipo vs the GP 3700

I have quite a few cycles on both of these batteries now. The last test I wanted to make was to equalize the weight in the car and run a back to back test. I added two battery sized sheets of lead under the LiPo pack to bring its weight up that of the GP 3700. Now the LiPo had more punch (more acceleration out of the corners), but only for about 4 - 5 laps. Then the two batteries felt pretty much equal in the car.

I have some new discharge numbers and data. The capacity of the GP3700 battery has dropped like a stone. It is only about 3100 mA-h now. This has improved the average voltage of a 20 A discharge to 7.26 V. So the numbers are now very similar to the Lipo pack in both voltage and capacity. The 3700 mA-h capacity of the GP 3700 seems to be only an illusion. I have made two attemps now to equalize the cells. They are equal so this is not limiting capacity.

I fast charged the LiPo at 9.5 amps with the Scorpion Charger. This only took 10 minutes off the full charge time which was now 1 hour and 20 minutes (normally 1 hour 30 minutes at 5.5 amps). The discharge voltage at 20 Amps was reduced to 7.12 Volts average. Down from 7.25 Volts at a more leisurely charge rate of 5.5 amps. I donít think there is much benefit to fast charging with this charger. I repeated a cycle at 5 amps and got my 7.24 Volts average back. This shows that the battery has not deteriorated, just does not like the fast charge. Capacity is 3127 mA-h, very close to what it had when new.

If you run this pack without a full charge then you are going to lose the advantage of a few faster laps as you will be running on a lower portion of the discharge curve.

Generally when a battery has more capacity you will get a faster run in a 5 minute race. This is because you run on the high voltage early part of the discharge curve. A 4,700 mA-h battery like the Orion cell will feel a bit better than this 3200 mA-h LiPo for 5 minutes. Scorpion does offer a 6400 mA-h LiPo, though. This is basically 2 of the LiPo batteries, that I have, stacked on top of each other. (Very expensive) Should be ballistic for 5 minutes. No ballast would need to be added. You would need a car with plenty of room above the battery so you could strap it in (not the JRXS).

My opinion at this point is that you would have to remain active in the hobby for a number of years before the benefit of longer life for the LiPo is of any benefit. At this point in time it raises the cost of racing because of the long charge time and high initial cost. You will need several of these packs and more than one charger to race.

More on Spektrum

The system worked really well during my battery test. No glitches. I have a new receiver on the way for the JRXS. I did a little test with the transmitter antenna horizontal. The system did not work as well this way. Keep it vertical. The antenna inside the car is really nice. There is an article in RC driver on how to locate the transmitter antenna to the stock location on the transmitter. This keeps it in a safer area of the radio during storage.

More on JRXS

These are tips from Tod Hodge. You can increase the clearance for the Losi Constant Velocity Drive Shrink Wrap, by beveling the outer edges of the drive axle hole in the caster block. He also reccomends sealing the edges of the chasssis with acoat of accelerater and then superglue to prevent delamination in the crashes.
Bevel Caster Block Link.
.http://www.teamlosi.com/jrxs-page/trick%20tip%20pg2.htm
Prepare chassis plates link.
http://www.teamlosi.com/jrxs-page/trick%20tip%20pg3.htm

Last edited by John Stranahan; 01-03-2006 at 04:54 PM.
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Old 01-03-2006, 04:34 PM   #77
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This is really interesting but please keep in mind the the cells in the FMA Scorpion packs are pretty old tech. The advertised ratings on those packs are pretty optimistic for the cells used in them. In the continuum of LiPo cell development the Scorpion LiPo's are about the same as Panasonics Blue NiMh's compared to other stuff available now.

As the market for LiPo cells cevelops its important to make this distinction. Your testing is completely valid and very well done but it only describes the characteristics of the particular cells you are testing....not all LiPo cells are the same.
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Old 01-03-2006, 04:47 PM   #78
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Well. And only 10 days ago they were high tech. Seems like Orion only started delivery on the 23'rd of December or so. Send me one of those puppies and a charger and I will be glad to test it.

The ratings of the Scorpion packs are right on specs unlike the GP3700's
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Old 01-03-2006, 07:04 PM   #79
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Knowing people at Orion dosen't mean I get anything from them...lol! I am getting mine from my LHS like everyone else.

You just made me look at my chargers. The Much more maxes out at one amp and my Triton maxes out at 2.5A . I guess its time to invest in that new Astro charger.
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Old 01-03-2006, 08:19 PM   #80
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Quote:
Originally Posted by John Stranahan
Spread Spectrum Road Test
[color=black]I did not need the auxilliary capacitor that Adrian mentioned for the Spread Spectrum receiver. This particular track does not have the best traction so you are never pulling the really big amps that might lower the Batterry Eliminator circuit's voltage to a level that the receiver would momentarily be weak.
It's entirely possible to put the Spektrum transiever into a low voltage induced shutdown by simply sawing away at the wheel with a digital servo....on the pit table. I would highly suggest using the capacitor. As one of the first people using the Spektrum system, I've lived through all of the little issues that cropped up in the beginning. Even though I ran without the capacitor using a standard servo, John Adams from Spektrum instructed me (easily so, by giving me a cap) to use the capacitor regardless of servo choice. Later testing showed the transiever to be awfully good at shutting the car down when voltage dropped too low, but it's awefully sensitive as well. If I were you, I'd stop finding other "causes" of the glitch and just install the capacitor. My 2 cents.
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Old 01-03-2006, 08:31 PM   #81
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Greg-Thanks for your report, but I don't have a glitch anymore. The Spektrum cured it completely. It's impossible for me to saw at my digital servo on this track without spinning out, so I don't do that. Gentle on throttle and steering is the key here. I'll order one of those capacitors at my next opportunity to have in the pit box. There is a newer track "Mike's" near New Caney Texas, 5 miles south of the K&M track. They have a track with more bite. Will probably test out there soon. I might need a capacitor there.

Track temp was 100 F today. Air temp was 80F. Thought it was the middle of winter. My mistake.


Adrian- It just sounds like you are somewhere in the supply chain. A fellow asked on another thread specifically about a Scorpion battery and you tell him they charge in 30- 40 minutes. Well that's just is not true. I answered him specifically about Scorpion equipment. You can do a partial charge in that amount of time. The Scorpion pack is not likely to be the first generation of LiPo's. The aircraft guys have been using them for quite a while. I might get my hands on some of the Orion LiPo's eventually. I'll see.
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Old 01-03-2006, 09:23 PM   #82
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I am the sales manager for Schumacher USA so I am in a supply chain but just not for Orion product.
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Old 01-03-2006, 10:22 PM   #83
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Default John how are the LVDs holding...

up? I wonder if Losi will make them for other cars like it had been mentioned.
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Old 01-04-2006, 08:42 AM   #84
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Quote:
Originally Posted by RCknight
up? I wonder if Losi will make them for other cars like it had been mentioned.
I don't know. I'll bump this back up. Does anyone know if Losi will make LCD's for other cars.
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Old 01-04-2006, 10:04 AM   #85
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They have them listed on the Losi site for XX4/XXX4 in the new products section.It would be nice if they would make them for the xxxs as well.
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Old 01-04-2006, 04:03 PM   #86
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Default John what's your opinion on them...

and how are they wearing? I have been told they wear worse than the reg. cvds, is this ture?
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Old 01-04-2006, 06:12 PM   #87
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RCknight-check out these posts #5,#6,#12, and #68 in this thread. Realize that the wear of the drive axles will be best with a standard diff, worse with a one-way, and worst of all with a locked diff.

DrOlds-Thanks.
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Old 01-06-2006, 06:14 PM   #88
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Went to Mikes-hobbyshop.com and Gulfcoast Track in Porter Texas 281-577-8250 which is just north of Houston. This is one fabulous facility. Full line hobby shop. Concrete parking lot. Steel framed covered drivers stand (14 feet up or so) and an enclosed announcer Room along with a big covered balcony with shaded pit space above and below. The assphalt track was bump free and smooth. It was 250 feet by 50-60 feet in size. Way too big for my stock motor. There is a cutoff on the straight to shorten the course about 50 feet for electrics. I ended up running a 28 tooth pinion for an overall ratio of 6.4. Motor not too hot 190 F. Lots of run time. The corner material was a fiberglass and foam sandwitch which is very light and forgiving on impact. I did not test it with the car. I'll get some more detail later as this is very nice stuff for the corners. A 4 inch white painted stripe marks the inner bounds of the course. The boards are 1-2 feet from this and the fiberglass about 8" , so if you have a good line, you are on the stripe at the apexes. The course is perfect for mod 4wd-touring and of course the 1/8 and 1/10 gas have enough room as well. First electric race will be next Saturday. Plan to run the JRXS with the GTB 6.5 which is allowed in their mod class (10 turn limit, rubber tires). Perfect. Traction is much better than M&M.

Spektrum.
No Glitches. Great range. The receiver antenna is still inside car body. Capacitor in pit box still. Will install it to run mod.

Proper Tire Wear
Track temp was 59 F, 15 C. I used HPI 20R tires with two different traction compounds. I used citrus oil first and got pretty good grip and a great wear patern on the tread. Ripples lined up with the circumference. You can feel these ripple with your finger accross the tire and can see them clearly if you have good light. I tried some TQ MOD traction compound which they had on sale at the shop. The tires felt OK on the track , but not much better. The tread was worn smooth with tiny rubber marbles felt by the finger (too soft). Probably would have to go up a tire rating to use this. The tires that were in stock at the shop were Sorex 36 and Sorex 40 for running mod.

Last edited by John Stranahan; 01-30-2006 at 02:03 PM.
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Old 01-06-2006, 09:54 PM   #89
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Default bac to the prginal topic...

the other day i answerd the phone while driving my xxx-s and it iterferd with the signal and BOOM! i nailed the right front and my LCD was one of the only things not bent, i had to replace everything but the turn buckel


im a basher/drifter but i thing the satisifaction (if ur bashing) that for a extra 3-4grams a LCD wont break unless ur running like 30 or up head on with a dead hit

but will the mip's break b4 the lcds or the other way around?

btw i nailed the right side at about 27mph ish in cold weather (high 30 F)
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Old 01-06-2006, 10:16 PM   #90
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thedudeaturdoor-Thanks for the post.
The MIP CVD's that come with the JRXS have an Aluminum cup with a pin through it. The Losi LCD is all steel. just the material change increases the strength and wear resistance of the steel part. I have had some steel MIP CVD's for the TC3 that also held up better in the crashes and wore better than Aluminum. I used the steel part for Mod, where weight is not as much a concern as is finishing four heats without breaking.
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