smitty1001

My Feedback: (29)

To keep from hijacking another thread.......
If Iwanted an offboard "booster" battery for starts and cool downs to maximize flights between charge on my ECU batt could Isimply use a parallel "Y" and just be sure to have an insulated cap for the offboard plug in when not in use?

rcjetsaok

My Feedback: (7)

Jimmy,

I think a Y connection will work, but I think it's gonna pull on the on board as well. You need to be able to isolate or switch to the off-board battery so ground operations pull off the off-board only... I don't know this for sure but it sounds good to me, and I don't know anything about the traveling habits of those electrons running up and down that wire !!!! Try one if these out.. it will do just what you need !!!!


Danno

David Gladwin

Been using exactly that for a couple of years boosting the ECU battery with kero start JC P70 I use a Duralite Lithium Mang Y leaded into the normal batt. Get at least 6 starts etc and don't use it for cool down.

No need to isolate the normal batt.

Works perectly.

Regards, David Gladwin.

Dave Wilshere

The larger battery will supply if the smaller/weaker battery cannot deliver. As you say, you can also make a Y that allows you to disconnect the flight pack until the turbine is running, then reconnect and finally disconnect the ground battery.
Though the size and weight is reducing and C rating increasing so smaller packs can be used on board...if you like Li-Po's!

Dw

Vincent

My Feedback: (61)

Why play around with wire connections and isolation switches. Just install some A123 batts and while you are BS ing for 10mins just charge them up and go fly again and again!!
V..

bevar

My Feedback: (27)

I had one on my Lightning for a year. If you use a Multiplex connector on the Y side you use as a booster you do not have to worry about shorting it out.

It worked great for me.

Beave

Eagle Driver

I use a simple Y wire for exactly that in my B-ARF with the Booster 80+
No wories, still works perfekt ....

smitty1001

My Feedback: (29)

How much mah do you estimate a booster saving if connected on both startup and cool down? Iam currently using about 350 startup to shutdown.

swasey1982

here was what I made for boosting


Multiplex to (ECU)
Male Dean to (Onboard Batt)
Female Dean to (External Batt) with male to male adapter.

Cheers

DENTO

HEY SMITTY
Just do what swasey has done ,Do it all the time just attatch and detatch each flight .
REGARDS

Harley Condra

My Feedback: (4)

Smitty,
Why don't you make one of these? Save wear on your starter and save airborne battery voltage.

The photos are self explanatory.
Materials: Bilge blower (from the boat shop)
3" dryer hose
some old nicads, a charge jack,
a switch,
Project box from Radio Shack....

"The Super Sucker"

tothemax

Harley,
Do you blow air into the exhaust end of a hot engine,if so,do you disable the cool down cycle on the engine? (I have a JET CAT).
Thanks

causeitflies

Notice the name Harley gives, "Super Sucker". It doesn't blow, it sucks.
I'm resisting further comment

tothemax

Ok I get the S or B part. I guess "cool down cycle" could conjure up images of certain acts as well but my question still stands.

bcovish

My Feedback: (8)

Somebody please draw him a picture.

rcjetsaok

My Feedback: (7)

Make sure also that when you set it behind the engine to draw cool air through it, the engine is turned off !!!!![X(] That baby makes short order of those fan blades if you leave it running !!!!!

Danno

BaldEagel

If you have a JetCat get one of the replacement I/O boards shown below and just plug your booster battery into the charge socket.

Mike

Harley Condra

My Feedback: (4)

I use it on JetCats as well.....
When you shut the engine down, turn the blower on and position the free end of the dryer vent hose over the engine nozzle. It sucks ambient air through the airframe inlets, through the turbine, and through the blower.
The hot air gets cool in a couple of minutes. Use your hand to determine the temperature of the cooling airflow. When it feels just warm to the touch, the engine is cooled to below 100° C.

Refer to the last photograph on my original post....you can see the arrow indicating the direction of flow at the top of the photo. Assemble the dryer vent tubing on the upstream (opposite) side.
"Causeitflies" has it right. Don't use it for any other purpose.....

tothemax

Thanks Harley I see the answer to my first question now. Second question do you disable the automatic cool down cycle on the engine? I apologise if you have answered this too and I didn't catch it.

Harley Condra

My Feedback: (4)

The answer is NO!
Just shut the turbine down, turn the receiver battery switches and the Tx off, and start the "Super Sucker".
Pretty simple....there is no need to disturb any of the cooldown cycle settings in your ECU.

tothemax

Harley ,Thank You

i3dm

My Feedback: (51)

you guys using booster packs - are you using an identical pack to the ECU pack or something different ? how do you avoid the packs charging each other ?

BaldEagel

The pack I use as a booster is another three cell A123, its attached only during the start up sequence, so I think it drains both batteries at the same time, if one had a higher charge rate than the other, all I think would happen is they would eventually equalise, thinking about this, the starter and kero plug would draw power from the line of least resistance until they equalised, so I don't think one charging the other would be a problem unless the two where massivly out of ballance or of unequal capacity, just some thoughts.

Mike

i3dm

My Feedback: (51)

think about it this way - for lipo the ECU pack might easily be 7.5V while the booster pack can be 8.2V (just random numbers).

highhorse

My Feedback: (2)

That's a great question but basically a non issue.

If you use booster pack of same chemistry and # of cells it will not charge the on board unit because the voltage will be the same, or nearly so.

Even if there is a volt of difference, it won't matter during the start sequence because all of the juice will be going to the starter and not to another pack.