HV 1/8 Truggy

Since I'm keeping my RC18T and getting a job at the end of the summer I want to plan my 1/8 Truggy build. I'm not set on any single truggy but the Hyper ST is at the top of my list because of it's amazing durability which is #1 to me. I want to do something different with the build and make it a HV set-up. From what I've seen Higher Voltage and Lower KV is the best way to go (Is this only true to a point?). So I decide to throw a quick list together...

Turnigy 2650mah 6S 30C Battery x2

Medusa 36-70mm 750kv Motor

Turnigy Sentilon100A HV 5-12S BESC

I'm pretty sure the Motor and Batteries are good but I'm not so sure about the ESC. I don't want to spend anything over the Price of a MMM just to keep the price in the ball park of your traditional conversion. Would one of Lutach's ESCs be better or is there something else out there that I should know about?

Also one disadvantage I do see is the weight... The Hyper ST is already heavy and with a HV set-up would that be too much?

[Metallover]

Your hv setup wont be any heavier then a regular 6s setup. If you parallel the batteries you have the average 6s setup. I guess the adapter does have an extra 6" of wire...

Would it be over powered? It would give me 33300 RPM so that seams like a great number.

[Metallover]

I think you'd want to be closer to 40,000rpm with a medusa, am I right? 30,000 is good for a chinese motor but a medusa is in another class.

I thought you wanted your RPM's around 35,000 since that is what a Nitro engine puts out on average.

[BP-Revo]

There is a lot of talk about peak RPM. Generally most agree that 35-40K is decent.

I usually aim for about 50K cause I love high-rev, but then again I have two-pole motors (Lehners) which love RPM.

With a 4-Pole motor it might be better to keep it a bit lower.

High voltage is definitely the way to go if you can, the problem with this is that it's usually harder to find a charger that will charge a 12S setup as quickly as a 6S setup. One idea is that you can wire the batteries to charge as a 6S pack but run them as 12S.

My plan for chargers was to have 2 Turnigy Accucel 8's. I need one soon to replace my IMAX B5 and then when I'm nearing the end of the conversion I could just buy a second charger. I did the speed calculator and it would give me 5HP and 3.5KW that is CRAZY!!!

[Metallover]

You have to make sure both packs are balanced as one. I don't know if two chargers would do that..

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[MetalMan]

Anything between 30-40,000 RPM will be fine.

Metallover makes a good point regarding balance between two batteries. However, if you set the LVC higher you might not have to worry about it.

So how high would I have to set my LVC? Wouldn't it not matter because the batteries are going to be charged on seperate chargers... or am I missing something bigger?

Because say I set my LVC to 3.0 volts that would cut each pack off at 18V. Then when I charge them they would both be balance charged up to 4.2 volts per cell. I don't see what the problem is with that. Some people use 1 charger for 2 batteries in E Revos so this is the same concept but with more cells right?

Like I said before I might be missing something...

[Jabe]

Im using those 2650mah 6S packs in parrel and have had toughts about running in series 12s, so any practical info would be great.
btw. im even using same truck.

Yea I saw your build and that is what gave me the idea. I like how it looks with 2 smaller batteries vs. 1 HUGE battery.

[MetalMan]

Originally Posted by Frozen72

So how high would I have to set my LVC? Wouldn't it not matter because the batteries are going to be charged on seperate chargers... or am I missing something bigger?

Because say I set my LVC to 3.0 volts that would cut each pack off at 18V. Then when I charge them they would both be balance charged up to 4.2 volts per cell. I don't see what the problem is with that. Some people use 1 charger for 2 batteries in E Revos so this is the same concept but with more cells right?

Like I said before I might be missing something...

Without having both batteries balanced by the same device there's no guarantee they will charge to the same level, but it will certainly be close. If you can set the LVC to something like 3.2-3.3V/cell it will not only be better for the batteries but it can also account for differences (charge level, actual capacity, etc.) between the two batteries.

[whitrzac]

Originally Posted by BP-Revo

There is a lot of talk about peak RPM. Generally most agree that 35-40K is decent.

I usually aim for about 50K cause I love high-rev, but then again I have two-pole motors (Lehners) which love RPM.

With a 4-Pole motor it might be better to keep it a bit lower.

High voltage is definitely the way to go if you can, the problem with this is that it's usually harder to find a charger that will charge a 12S setup as quickly as a 6S setup. One idea is that you can wire the batteries to charge as a 6S pack but run them as 12S.

nothin like a novak 4.5 reving to 74k RPM only 2nd to the sound of nitro

OK so setting my LVC higher would be the best way to make sure the batteries are always in sync right?

Should I get a 750kv or 880kv?

750kv on 44.4V = 33,300RPM
880kv on 44.4V = 39,072RPM

750kv seams like the way to go because if needed I could gear up and chances are everything would run cooler because it would also pull less amps and still give me 5HP.