izzy-israel-73

I want to run one lipo for 5x15 min of flying without recharging, running 5, 21 kg hv servos, ignition for a DLE 30 what would be the right lipo for the job? I have a nano-tech 3000mah 7.4 receiver pack would this do the job?

kiwibob72

Just find out how many mill amp's the servo's and motor draw respectively, then its just a case of doing the math's - (someone correct me if I'm wrong), but my understanding is that if you have a system that draws say 1ma (hypothetically), a 3000 Mah (mill-amp-hours) battery will last 3000 hours, where a system drawing 5ma will last 600 hours (or 1/5 the total).
This video should help: http://www.youtube.com/watch?v=ZJHlJYDJohc

jetmech05

I have never been a fan of one battery on a gasser. Possibility of interference, or if ignition goes bad takes your aircraft battery with it and you have a re kit.
i would run the battery you have but you need to put on a voltage regulator. You'll be over 8 volts fully charged. I run LiIons they're 7.4 volts but all are through regulators

flyinwalenda

My Feedback: (5)

Receiver LiPo packs usually have a C rating of 5 or 10. A 10C 3000mah pack would provide 30amps of current safely.
As stated you would need to find out the specs for the servos to calculate the amp requirements and also the voltage limits. If they can handle around 9 volts then you won't need a regulator for them. Also to use a LiPo on an ignition you would need a regulator to drop it down to 4.8 or 6 volts.
I replaced failing Nixx packs with LiPo packs and regulators , Now I use LiFe and A123 packs as some servos and ignitions can handle the lower voltage from a LiFe pack without regulators.
On one of my 60 size planes with a gasser engine using standard servos, I run a seperate LiFe pack for the receiver and the ignition...2000 and 1500mah. I can fly (5) 30 minute flights before recharging.

BarracudaHockey

My Feedback: (11)

Been running single A123 battery pack setups feeding ignition and receiver on several planes for hundreds of flights, no issues

izzy-israel-73

I will be running a regulator for the ignition I have herd that the new ignitions on the DLE's you can run 7.4 threw them is this right?

flyinwalenda

My Feedback: (5)

Some of the newer ones can handle a LiFe or LiPo pack directly,

kiwibob72

It should tell you the voltage range on the CDI ignition module.

The 73" (gas powered) Sbach I'm putting together currently will run two separate 2 cell lipo or life batteries (ie 7.4 or 6.6 volts) through one of these: http://www.hobbyking.com/hobbyking/s...utor_RED_.html as I chose to run twin batteries for the electronics when I have a total of anything over 5 high draw servos (that has 7 including choke and throttle), and a separate 4.8 volt NiMh for my CDI ignition as I opt to keep the individual power systems (motor and electronics) separate. Like you, I'm running high voltage digital servos that can handle that voltage directly, so a voltage step down regulator is not needed.
The beauty of that power distributor aside from being a redundancy system, is that it includes an inbuilt remote controlled CDI optical ignition kill switch, which again I like, and if a company like Redwing RC can offer these same items as well (who I feel strive for supplying quality items), on top of what I have seen others gain from them elsewhere, then I feel safe using them (http://www.redwingrc.com/index.php?m...products_id=82)

BarracudaHockey

My Feedback: (11)

30cc with a power dist box?

It's your plane but you're wasting your money and making your setup heavier than needed.

If you're really determined to run two batteries, just run them to your receiver.

flyinwalenda

My Feedback: (5)

Ditto on the powerbox. I use an MPI Miracle Switch /Regulator with dual Lixx packs on large and giant scale planes. Maybe old-school but it works fine. . Powerboxes for 80-100cc+ planes with a lot of servos and higher amp requirements, receiver redundancy etc...

kiwibob72

It all comes down to personal preference - as at the end of the day there is nothing 'wrong' in running a twin battery redundancy system on the servos/receiver, just as there is nothing 'wrong' in using an remote optical kill switch to kill your motor over just relying on your throttle servo to be the only source of remotely killing a gas plane's motor (which it can easily be set up to do).
For me, it just comes down to piece of mind when looking at what really comes back to on-board safety systems, which is why I opt to use both a remote optical ignition kill and a backup power supply on my electronics on what is really a rather large and powerful model with a hell of a lot of momentum behind it at full speed (the fact mine is all in one unit is a bonus to me as it reduces unnecessary "links" in the system/chain - which is another bug bare of mine).
And while no single system is ever 100% perfect, I'll happily take a small weight penalty to get mine to where "I" am happy, as I'm more about sport/scale aerobatic flying over 3D where the scale tallies are much more important.

bjr_93tz

If you already have the battery, just plug it in fully charge it, run two flights, then fully charge it again. The charger will tell you how many mAh that it put back in and that's how much you used of two flights. If you're really worried fly one flight then measure how much you put back in. If you fly two flights and put 1000mAh back in then it's pretty safe you'll use 2000mAh for four flights. IF that were the case I'd consider four flights being safe and five (2500mAh out of an advertised 3000mAh pack) pushing your luck.

One plane I have 30cc with ignition and 6 brushless digitals, consumes about 250mAh per 12 minutes of airtime, at worst your's might consume 500mAh per 15 minutes??

jetmech05

Don't forget the voltage requirements of your receiver.

izzy-israel-73

Thanks Fellas I have a Pitts Python that I run 2, 2 cell 3000 mah lipos striate to a dual Miracle switch then runs to receiver then from receiver run a dual kill switch regulator to my ignition for the DLE 50cc the plane runs 8 HV servos, I really would like to run 1 lipo on my Extra so I can keep the wait down as above its running 6 hv servos so I really just want to know what lipo would do the job for 5x15min flights.

izzy-israel-73

jetmech05 how is this so not sure how it would?

speedracerntrixie

My Feedback: (29)

You should be just fine. My last 50cc airplane ran a 3000 mah lipo and an IBEC. I could easily knock down 4 30 min flights. It of course is always smart to check voltage with a esv that puts a load on the battery after 2 flights.

izzy-israel-73

Thanx bjr-93t that sounds like a safe and easy way I like that idea cheers

izzy-israel-73

jetmach im using a AR9020 receiver Spektrum with 3 sats

jetmech05

In any circuit voltage is the key too much and things burn up..too little things dont work. the weakest link is the component that is the most voltage sensitive. For example if your running HV servos it doesnt mean you can put 7.4 to the receiver.
as far as capacity goes electricity is lazy. it only gives you what it takes to do the job. i used to have a starter that I hooked up to a car jump starter, 300 amp of cranking power. now 300 amps would have done damage to me and the starter...but it only gives what the starter needed.
ok so if your airplane pulls 10mA on a 2000 mAh battery and you change nothing except the battery, go say 3000 mAh. you have more to pull from.
I hope I answered your question

izzy-israel-73

yes just a bigger fuel tank is what you are sayingand doesn't make a difference on power

jetmech05

That is correct.

chuckk2

Don't you mean single battery?

flyinwalenda

My Feedback: (5)

A single pack sized (mah) accordingly powering both the receiver and ignition.

BarracudaHockey

My Feedback: (11)

Yes, single A123 pack (2 cell) is what I meant, thanks!

izzy-israel-73

Going with the Ultra Ignition Battery Eliminator & Kill Switch and one nano-tech 2cell 3000mah lipo should be enough for a days flying