Originally Posted by Mike Mayberry

I guess it depends on how many 10 minute flights you want to get in. I'd go with at least 4000mah.

FYI: The 7940's just started shipped last week so they should be availble anytime now.

Mike.

Mike, it would be great if Hitec could create a list of specific battery options tried and proven by Hitec for 50cc, 100cc, and 150cc airplanes. ie.

For 150CC airplanes (2 7950's/aileron, 2 7955 or 7950/stab, 2-3 7950's rudder, 1 7940 for throtttle), the following batteries have been tested for acceptable performance:

- List Mfg, Chemistry (ie. LiIon or LiPoly), Part#, and Specs for common brands such as TP, Fromeco, Zippy, PowerBox/3W, etc.

As these new generation of high voltage servos have considerably more current draw, I'm willing to bet the many are concerned about too much amp draw and potentially killing a $5-$10K plane if the right batteries aren't utilized. I'd rather not try and find out by trial and error

Thanks

Greg

Originally Posted by gmilo

Mike, it would be great if Hitec could create a list of specific battery options tried and proven by Hitec for 50cc, 100cc, and 150cc airplanes. ie.

For 150CC airplanes (2 7950's/aileron, 2 7955 or 7950/stab, 2-3 7950's rudder, 1 7940 for throtttle), the following batteries have been tested for acceptable performance:

- List Mfg, Chemistry (ie. LiIon or LiPoly), Part#, and Specs for common brands such as TP, Fromeco, Zippy, PowerBox/3W, etc.

As these new generation of high voltage servos have considerably more current draw, I'm willing to bet the many are concerned about too much amp draw and potentially killing a $5-$10K plane if the right batteries aren't utilized. I'd rather not try and find out by trial and error

Thanks


Greg

I second that, I am going to use dual 922's in my plane with 8 7950's and 2 7940's.

GREAT POST gmilo

Well if you get the servo count down then the overall draw may be similar or even less. You should be able to get away with 2 per aileron, 1 per stab half and 2 on the the rudder which drops the count by 5 total servos compared to using the 7955's. Let's for the heck of it say that the 7955's draw 3A and the 7950's 4A (25% more w/heavy load) So... let's do the math: 3x14= 42A vs. 4x9= 31A. Hmmmm... 25% less overall current!

Even at 3 per aileron you're still less, or stick with 55's on the ailerons if you need the hard points.

FYI: Brandon has been using one per stab on his 42% AeroWorks Yak while still using a regulator, and Chris Hinson (Extreme Flight) has been flying his latest 40% with two on the rudder (unregulated)... both say they absolutely love em!

So... I'm really not sure if anything needs to change, powerwise, if the servo count is reduced.

Mike.

Originally Posted by Mike Mayberry

Well if you get the servo count down then the overall draw may be similar or even less. Youshould be able to get away with 2 per aileron, 1 per stab half and 2 on the the rudder which drops the count by 5 total servos compared to using the 7955's. Let's for the heck of it say that the 7955's draw 3A and the 7950's 4A (heavy load) So... let's do the math: 3x14= 42A vs. 4x9= 31A. Hmmmm!

Even at 3 per aileron you're still less, or stick with 55's on the ailerons if you need the hard points.

FYI: Brandon has been using one per stab on his 42% AeroWorks Yak while still using a regulator, and Chris Hinson has been flying his latest 40% with two on the rudder (unregulated)... both say they absolutely love em!

I'm really not sure if anything needs to change powerwise if the servo count is reduced.

Mike.

Thanks Mike. So, are my Fromeco 5200 LiIons sufficient If I go with 2 7950's per aileron, 1 7950 per stab and 2 7950's for rudder and a 7940 on throttle AND I would run unregulated through a Smartfly EQ10? I'm a little worried considering the 8amp rating on the Fromeco 5200's...

Well... if you were using an 8A regulator I'd say it wasn't enough. That's not even a 2C discharge rate?!?!? I really don't know.. What you don't want it a huge "sag" in the voltage if pushed hard. But, if these cells have already proven themselves in similar load situation then they should be fine.

I gotta say though that you guys are really the experts as you're in the trenches using this stuff all the time. What does everyone else think?

Mike.

If so, just run a regular lipo. a 10 dollar 2S 2000 lipo from HobbyCity has more than enough capacity to power these servos.

I'd rather get some type of references from either Hitec and/or a battery mfg for a 150CC aircraft in common configurations (ie. regulated/unregulated and common number of servos). I don't want to do a trial and maybe error with my tricked out and pricy 3W Yaks and 3W Votecs......

The cheapest batt now is at least rated for 15C. That's 30A. With two of them, you're looking at 60A. They sure as heck are able to handle whatever meager load we put them through with our high-powered servos.

Originally Posted by BoneDoc

The cheapest batt now is at least rated for 15C. That's 30A. With two of them, you're looking at 60A. They sure as heck are able to handle whatever meager load we put them through with our high-powered servos.

Okay, so why can't Hitec, JR or battery mfg state this? Both Hitec and JR state LiPo 7.4V as the only spec. Yet, fully charged LiPo's/LiIons are cranking out 8.4V. Will running unregulated at fully charged 8.4V cause an issue or do we need to regulate to 7.4V maximum? And the amp draw normal and under extreme load in 3D for typical configurations and hence recommend battery specs would be much appreciated. I'd just like more detailed information from the mfg's.....maybe its just me

They dont because they dont have to. They will only list specs of an individual servo because of the liability of setting up a plane. If they say 2 servos should be able to handle a certain load...and your 2 servos are binding which creates a great load on the battery, they become liable. I would count on seeing any servo manufacturer recommend what servos to use, and how to power them...other than one server at a time.

Just as the common ratings of 4.8v and 6V are nominal, so is the 7.4v rating... fully charge batteries are fine.

A lot depends on the number of servos used... I would personally go with a pack that gave me some headroom. With the Aurora we can see the real time RX voltage and it's clear as day that the voltage drops as you work the servos hard, if a pack can't handle this then you risk a brownout situation. (Although not with the Hitec system if you use the Suplimental Power connection though ) Just as using a low "C" power battery causes the BEC in an ESC to shut down a high load motor as it thinks the battery is dumping due to the voltage sag.

Mike.

Originally Posted by pepatrick

They dont because they dont have to. They will only list specs of an individual servo because of the liability of setting up a plane. If they say 2 servos should be able to handle a certain load...and your 2 servos are binding which creates a great load on the battery, they become liable. I would count on seeing any servo manufacturer recommend what servos to use, and how to power them...other than one server at a time.

They may not have to, but the specs they do provide are not helpful for a 150cc airplane where at least 2 servos will be required for some flight surfaces (ie. rudder and aileron).

I guess I'll just keep my 7950's in their pretty boxes until I see some battery spec data from 150cc pilots running unregulated and performing. Seems like none of the servo or battery mfg's are viewing this as an opportunity to step up and clarify rather sit back due to potential legal liability. Heck if we take what specs are being published, we will need to regulate down to 7.4V considering a fully charged LiIon or LiPoly is producing 8.4V.

Originally Posted by Mike Mayberry

Just as the common ratings of 4.8v and 6V are nominal, so is the 7.4v rating... fully charge batteries are fine.

A lot depends on the number of servos used... I would personally go with a pack that gave me some headroom. With the Aurora we can see the real time RX voltage and it's clear as day that the voltage drops as you work the servos hard, if a pack can't handle this then you risk a brownout situation. (Not with the Hitec system if you use the Suplimental Power connection though) Just as using a low "C" power battery causes the BEC in an ESC to shut down a high load motor as it thinks the battery is dumping due to the voltage sag.

Mike.

Thanks Mike, you've clarified my concern, but your still speaking in generalities.....I'm just looking for a specific battery recommendation or a list of batteries that will work per my prior post...Sorry for being a PIA, but the electrical aspects of these systems does not come naturally to me...

Originally Posted by gmilo

Thanks Mike, you've clarified my concern, but your still speaking in generalities.....I'm just looking for a specific battery recommendation or a list of batteries that will work per my prior post...Sorry for being a PIA, but the electrical aspects of these systems does not come naturally to me...

I heard that, I agree. I lost my brand dalton to a brown out. my rx locked out twice. I still don't what caused it. I was running 9 7955's unregulated. I too need to know before I go putting 7950's and 7940's in my 42% Dalton.

Any 20C Lipo of 2100 and above would have no issues... ANY!

I know that's general but seriously... even the cheapest stuff would work so get a quality brand with sufficiant capacity and be done.

Again... the Fromco's may work but I would be warry of a battery only rated for 8A... even the old AAA NiHh's could handle that! I'd talk to them.

There is also the argument for A123's. I've heard nothing but good things with them at a slightly lower voltage.

Mike.