Eggtimer/Altimeter sled battery placement

The Rocketry Forum

Help Support The Rocketry Forum:

Mr G

Well-Known Member
Joined
Feb 10, 2013
Messages
431
Reaction score
37
It appears that the Eggtimer needs at least two batteries function.

Both Eggtimers I have are set up for a 9v battery for deployment leaving a 3.7v battery (Lipo, I presume) for everything else. If so, where do people put the second battery on an Adaptive Aerospace 54mm altimeter sled?

There is dedicated space for a 9v but it is not clear where another battery would fit? Any photos of how you did this would be very helpful.
 

Keisling

Licensed Practical Rocket Surgeon
Joined
Jan 22, 2017
Messages
197
Reaction score
87
Location
Florida
I don't think the Eggtimer "needs" two batteries. You can use two but most people wire it with only one.
 

timbucktoo

Well-Known Member
Staff member
Global Mod
Joined
Jun 13, 2014
Messages
7,090
Reaction score
881
Location
Cocoa Beach
Are you referring to the Eggtimer TRS or the Eggtimer?
I use 2 batteries with the TRS, one for pyro charges and one for GPS. I believe that Cris recommends that set-up and there are 2 connections for such.
But like Keisling says, the Eggtimer itself only requires 1 battery.
 

ksaves2

Lifetime Supporter
TRF Lifetime Supporter
Joined
Nov 25, 2009
Messages
5,795
Reaction score
210
The early version egg-timer deployment altimeters needed a 3.7 volt lipo to power the electronics and a separate pyro battery. I think a later version there was an option to have it operate off of One battery. Kurt
 

cerving

Owner, Eggtimer Rocketry
TRF Sponsor
TRF Supporter
Joined
Feb 3, 2012
Messages
3,596
Reaction score
836
You can use the same power for deployment power as the altimeter power, the second battery option prevents high-current igniters from causing a brownout that resets the altimeter. Typical ematches don't draw enough current to cause this to happen, so going with one battery is fine. Note that we generally do not recommend using 9V batteries... a 2S LiPo (or a 1S if you wire the Eggtimer Classic for it) puts out a lot more current, and they're very reliable. Whatever battery you end up using, ground test it thoroughly before you fly it.
 

Mr G

Well-Known Member
Joined
Feb 10, 2013
Messages
431
Reaction score
37
The two Eggtimers I have are both version D's and set up for 9v. What I can't find are good photos showing how to use only one 9v battery for everything. For those of us that are total neophytes in electronics and only wanting to start out with basic dual deployment, descriptions of so many options is very confusing.

Can anyone provide up-close photos of and instructions on how to use just one 9v battery given that there are 4-pin locking headers? And how do you hook up one battery between the two deployment channels plus one for the processer?

"If you are using both Channel A (Main) and Channel B, and they are OK on the same battery (i.e. they’re both either servos or both igniters), then you can jumper the BATA and BATB terminals together: + to +, and – to - ."

What does a jumper look like? Where and how does it attach to a locking header? It would be really helpful to have some simple instructions, diagrams and photos to show how this all goes together.
 

rharshberger

Well-Known Member
Joined
Oct 13, 2014
Messages
9,277
Reaction score
1,380
Location
Pasco, WA
Pictured just above the red wire and below the screw on the altimeter is a jumper, it is simply a U-shaped wire inserted into the two holes and soldered in place.

MiniFrenzyXLdd19.jpg
 

SierraDrinker

Member
Joined
Jun 17, 2017
Messages
19
Reaction score
3
Location
Okotoks, Alberta
You can use the same power for deployment power as the altimeter power, the second battery option prevents high-current igniters from causing a brownout that resets the altimeter. Typical ematches don't draw enough current to cause this to happen, so going with one battery is fine. Note that we generally do not recommend using 9V batteries... a 2S LiPo (or a 1S if you wire the Eggtimer Classic for it) puts out a lot more current, and they're very reliable. Whatever battery you end up using, ground test it thoroughly before you fly it.
Hi Cris,

Do you have a recommendation for the number of mah I need for a 1S to run an eggtimer classic off one battery? I was using a 9v, but want to go with a smaller, lighter option.

Thanks,

Jason
 

cerving

Owner, Eggtimer Rocketry
TRF Sponsor
TRF Supporter
Joined
Feb 3, 2012
Messages
3,596
Reaction score
836
A 300 mAH 1S should be fine. You can probably go down to 120 mAH, maybe smaller... it depends on your ematches. The Classic itself only uses about 8 mA.
 
Top