SMC 4000/25C/3.7V single cell Hardcase pack.

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11-17-2008, 06:21 PM

#31

Fred_B

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Having the pack go soft isn't really an issue as long as everyone has it. When the speedo's start to get updated to run on low voltage it might be an issue for a bit but it's not that big of a deal.

Having a speedo that can download updated firmware is going to be a good thing with the lower voltage packs.

11-17-2008, 06:28 PM

#32

Matt Howard

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Quote:

Originally Posted by Fred_B

Having a speedo that can download updated firmware is going to be a good thing with the lower voltage packs.

Losi already has downloadable firmware updates for their esc

11-17-2008, 07:37 PM

#33

Danny/SMC

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I think the issue as that most speed controls have a cutoff that is set around 3.3 volts that when the voltage dips under that it cuts power back to the motor to save it for the reciever. I think this is more a hardware issue than a firmware issue.

Donny Lia has been testing the Novak booster circuit and he told me it works very well.

11-17-2008, 08:26 PM

#34

Cain

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posted on the tekin thread:

Code:

Using the Hotwire there is a custom voltage profile.
You can adjust it down to 3.0v which would be perfect for the 1/12 lipo.

Dayton

11-17-2008, 08:30 PM

#35

Danny/SMC

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I'm sure this will help but I think it's not low enough. The problem is under hard acceleration the voltage will drop under 3 volts for a fraction of a second and the speed control may cut the power when it sees this.

11-17-2008, 08:33 PM

#36

Cain

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if its a software thing, maybe they can go lower?

11-17-2008, 08:42 PM

#37

byron.s

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Danny,
how low should it be 2.5??

11-17-2008, 08:45 PM

#38

Danny/SMC

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I'm not sure how low it needs to be set at. At the moment I think the reciever priority circuits are set at 3.30 volts so I'm not sure how much lower it needs to be set at. I know Novak should have a prototype real soon and from what I was told the new KO can go down to 2.1 volts.

11-17-2008, 11:19 PM

#39

Ike

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Quote:

Originally Posted by Danny/SMC

Any chance you can confirm that the KO and possibly the new Orion which is based on the KO will work?

11-18-2008, 05:34 AM

#40

andrewdoherty

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Is it a problem for the lipo to be discharged below 3 volts? I thought the reason for the cutoff was to keep the lipo from over discharging. 3 volts per cell is the limit, right?

11-18-2008, 07:03 AM

#41

buffalobill989

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danny you have email

11-18-2008, 07:19 AM

#42

Danny/SMC

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Quote:

Originally Posted by Ike

Any chance you can confirm that the KO and possibly the new Orion which is based on the KO will work?

I will send a pack to Josh Cyrul as he has one of the new KO units and see what he figures out. If the current speed controls have a 3.3 or so cutoff I'm pretty sure 2.1 should be fine.

11-18-2008, 07:21 AM

#43

Danny/SMC

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Quote:

Originally Posted by andrewdoherty

Is it a problem for the lipo to be discharged below 3 volts? I thought the reason for the cutoff was to keep the lipo from over discharging. 3 volts per cell is the limit, right?

Actually Lipos can be discharged down to 2.8 volts per cell. The voltage will drop a bit lower only under acceleration so it's not a constantly under 3 volts.

11-18-2008, 08:40 AM

#44

Mutabarucka

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I have a quick Q I bought a 5000 lipo with 7.39 volts and IR 6.2 and after about 4 runs the volts went down to 7.2 volts and the IR up to 7.2 I ran the pack back to back 3 qualifing and the main and then store the pack at 7.8 volts for a week I then did 1 cycle and the number was change from what was first on the pack, why is this?

11-18-2008, 08:48 AM

#45

Danny/SMC

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Where are you attaching the voltage sensing leads ?

Also storing the pack with 7.8 volts is to high. As were getting use to Lipos in high end racing I have noticed that storage charge seems to affect the packs performance. So the key is to use very little storage charge as Lipos don't selfdischarge real fast. I have left packs discharged at 35 amps down to 6 volts and then they sit for 6 weeks and the voltage really hasn't dropped. In one of my tests I kept a pack fully charged for one week and that packs dropped 10 seconds in runtime and the IR went up a bit. So we still are learning as to what keeps the pack in top condition.

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