Smallest battery for electronic deployment?

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dk54321

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I've been using the Hawk-eye optical apogee detector for deployment. It senses the difference in UV background of the the sky and the ground. It works great, and I'm curious how small a rocket I can use it in. Of course, the limiting factor is the battery. I've been using Xmas bulb initiators for my deployment charges. Two AAAs in series will set them off. The Hawk-eye will run on 8-12 VDC. The traditional 9 V alkaline works, but I want something lighter that will fit in a smaller diameter tube. An A23 puts out 12 V, but not enough current for the initiators. I thought about connecting a capacitor across the battery terminals—is there a rule of thumb for capacitance in this application? What other batteries weigh less than a 9 V, fit in a small body tube, put out 8-12 V at enough current to fire my charges, and are fairly inexpensive?
 
If you use different initiators (say Quest Q2G2's) one A23 should do the trick.
 
chadrog said:
If you use different initiators (say Quest Q2G2's) one A23 should do the trick.
Click to expand...
An A23 battery contains (8) LR932 10mm diameter by 2.5mm high alkaline button cells. These button cells will not source enough current to fire a Quest Q2G2 unless it is connected to an altimeter with a capacitive discharge circuit. A 1S LiPo cell will fire a Quest Q2G2 igniter which needs about 0.35 amps to activate. https://www.hobbyking.com/hobbycity...y=86&LiPoConfig=1&sortlist=W&CatSortOrder=asc is a list from Hobby King. A 130 mah cell weighs less than 4 g and will easily source several amps.
 
Bob,
You're right,,,
And I'm quite impressed with the G2G2's that's what I use exclusively,,,,,,,,
But I didn't know they would fire on a 1s lipo,,,,,,,,they're really great........

But he said he needs more voltage than that to run that piece of electronics.......

These are what I and a lot of others are using these days,,,,,,,, they're 2s 180mah,,,,,

https://hobbyking.com/hobbyking/store/__23135__Turnigy_nano_tech_180mah_2S_25_40C_Lipo_Pack.html

According to what he said, even this isn't enough voltage,,,,,,
he'd have to go with a very small 3s lipo for the volts he's asking for,,,,,,,,
I'm not familiar with the piece of electronics........

One thing's for sure,,,,,,
There's no way to match the energy density or the bang for the buck of lipo's...........

Teddy
 
bobkrech said:
An A23 battery contains (8) LR932 10mm diameter by 2.5mm high alkaline button cells. These button cells will not source enough current to fire a Quest Q2G2 unless it is connected to an altimeter with a capacitive discharge circuit. A 1S LiPo cell will fire a Quest Q2G2 igniter which needs about 0.35 amps to activate. https://www.hobbyking.com/hobbycity...y=86&LiPoConfig=1&sortlist=W&CatSortOrder=asc is a list from Hobby King. A 130 mah cell weighs less than 4 g and will easily source several amps.
Click to expand...

Anybody have a simple schematic of what a capacitive discharge circuit would look like?

Thanks
 
dk54321 said:
I've been using the Hawk-eye optical apogee detector for deployment. It senses the difference in UV background of the the sky and the ground. It works great, and I'm curious how small a rocket I can use it in. Of course, the limiting factor is the battery. I've been using Xmas bulb initiators for my deployment charges. Two AAAs in series will set them off. The Hawk-eye will run on 8-12 VDC. The traditional 9 V alkaline works, but I want something lighter that will fit in a smaller diameter tube. An A23 puts out 12 V, but not enough current for the initiators. I thought about connecting a capacitor across the battery terminals—is there a rule of thumb for capacitance in this application? What other batteries weigh less than a 9 V, fit in a small body tube, put out 8-12 V at enough current to fire my charges, and are fairly inexpensive?
Click to expand...
I think this 7 g battery will work for you. https://hobbyking.com/hobbyking/store/__10915__Turnigy_138mAh_2S_10C.html
 
kruland said:
Anybody have a simple schematic of what a capacitive discharge circuit would look like?
Click to expand...

They are generally built into the altimeter, I have not heard of someone retrofitting one to an older altimeter, but that is not to say that you can not do so. I know that the Raven and the RRC3 have capacitive discharge circuits, and I know several other competitive altimeters have them too.
 
I'm mostly curious how it works - and maybe incorporate into the Altiduo board I've been hacking on.

Cyril's Scribe said:
They are generally built into the altimeter, I have not heard of someone retrofitting one to an older altimeter, but that is not to say that you can not do so. I know that the Raven and the RRC3 have capacitive discharge circuits, and I know several other competitive altimeters have them too.
Click to expand...
 
onebadhawk said:
These are what I and a lot of others are using these days,,,,,,,, they're 2s 180mah,,,,,

https://hobbyking.com/hobbyking/store/__23135__Turnigy_nano_tech_180mah_2S_25_40C_Lipo_Pack.html

Teddy
Click to expand...

Hi Ted, Could you explain this battery a little bit to me? I am pretty close to buying it. I was inquiring about lipos for my RRC3 in another thread and obtained a lot of useful info. There seems to be two plugs on this battery. I am pretty sure one is for a charge balancer for recharging. What harness would I need for this lipo to hook into my altimeter? Do you hook one of the connectors (ie the red one) to the altimeter, or does the white one and red one need to be hooked up? Also, for recharging, do you hook both the white and red connectors into the charger? Sorry for the novice questions. I am pretty close to getting this battery and charger but can't quite visualize the plugs. I poked around on the hobbyking website for harnesses. I am just not quite 100% sure what I need from start to finish. Thanks.

Chris
 
Hi Chris,
I'm a big proponent of lipo's these days......
Especially since a 9V battery clip cost me an important rocket,,,,, altimeter browned out on launch........
Now I eliminate as many weak links as reasonably possible,,,,,,,
nice shiny solder joints and good connectors with something to fix them in place (tape is fine ).........

This battery in my humble opinion,,,, works better on Q2G2's then a 9V. because they are
just a touch lower in voltage,,,,, not quite as quick to burn the bridge wire........

https://hobbyking.com/hobbyking/store/__23135__Turnigy_nano_tech_180mah_2S_25_40C_Lipo_Pack.html

Also it will run your electronics for much longer then you'd be comfortable on 1 - 9V. and when it's time
you don't throw it away,,,,you just charge it......

The bang for the buck is massive.......

But,,, you have to buy a charger,,,,,,,

https://hobbyking.com/hobbyking/store/__6478__IMAX_B6_AC_Charger_Discharger_1_6_Cells_GENUINE_.html

My charger I've had for years,,, I love it,,,, I paid $125 for mine and $60 for a 12V. DC power supply
for my workbench to run my charger....... my charger will do from 2s thru 6s lipo and just about any other battery chemistry
lead acid motorcycle batts, ni cadmium, ni metal hydride......

This Imax B6 will charge any battery chemistry and it will do 1s thru 6s lipo's ,,, the 1s is good for circuit board batteries.....
and the B6 has a built in power supply,,,, you can use it on your workbench and take it with you to the field and use it off of your car battery.....
The B6 will also cycle batteries as well,,,, brings batteries not doing to well anymore back to life by cycling them...........
I wish I had this charger,,,,,,,,mine is almost as good,,,, I paid 5 times the money.....

Absolute,,,, most important with lipo's ,,,, the secondary white plug is for your charger,,,,,
the charger is a balance charger,,, or computer charger,,,,
the white plug on the battery will fit into a board that comes with your balance charger.
You balance charger will refuse to begin charging if it does dot see voltage from the white plug.......
The white plug allows the balance charger to charge each cell in your lipo pack individually,,,,, and balance them.....
We've all heard horror stories about lipo packs exploding when being charged.......
They don't explode,,,,, but violently ignite like a road flare....... those stories have some sustenance to them.......
If you don't charge a lipo properly ( with a balance charger ) the cells can become so out of balance that one is still calling for current and another overcharges.....
To better understand the white plug look at the pics of a 5s or 6s lipo,,, the balance plug is very wide with many conductors,,,
it gives the charger access to each cell individually......
I use to fly RC,,, I've charged lipo's for a very long time,,,,,do it right,,,,,,never a problem......

Now,,,,,,,
The power plug on the battery your interested in is called a JST plug.............
I am using them everywhere I need a plug in my avionics bay,,,,,,,,
I like them,,,they seem solid,,,,,particularly with a piece of tape on the 2 plugs when you put them together,,,,,,just for piece of mind.........
and since they come on the batteries I like,,,,I don't have to cut them off of the battery to switch to another plug,,,,,,,,,,,,

so here ya go,,,,,,,,

https://hobbyking.com/hobbyking/store/__9683__Female_JST_battery_pigtail_12cm_length_10pcs_bag_.html

https://hobbyking.com/hobbyking/store/__9682__Male_JST_battery_pigtail_10cm_length_10pcs_bag_.html

Now your ordering from the other side of the planet,,,,,, your order isn't going to be here in 3 days,,,,,,,,
plus you'll need fill for the package weight,,,shipping cost is by weight,, right,,, ( your not going to like the cost of shipping )
but much of the stuff is not available in the USA warehouse,,,like the JST plugs.........

So here's some fill stuff for your package,,,,,,,

pick which size heat shrink you'd like,,, very handy,,,,,

https://hobbyking.com/hobbyking/store/__375__58__Hardware_accessories_-Shrink_Tube.html

super cool for your workbench,,,,,,,,

https://hobbyking.com/hobbyking/sto...tic_Tool_Stand_for_Hex_and_Screw_Drivers.html

Hey,,,,,how ya like me now,,,,,,,,

https://hobbyking.com/hobbyking/sto...f_Adhesive_Centre_of_Gravity_Marker_3pc_.html

This is how a lazy man installs shearpins,,,,,,,,,,

https://hobbyking.com/hobbyking/store/__24662__Hobbyking_Electric_Screwdriver.html

Weight fillers,,, but look for the knives with the metal inserts for a dime more,,,they are better,,,,,,,

https://hobbyking.com/hobbyking/store/__9335__Hobbyking_8_Point_snap_knife_5pcs_set_.html

Ok,,, Chris,,,,,, it's been a pleasure shopping for you,,,,,,lol,,,,,,,

but seriously,,,, you can find a cheaper charger,,,but how much cheaper do you need it to be,,,,,,,,,,
You will be very happy with these items,,,, I promise,,,,,,,,,,

Teddy
 
dk54321 said:
The Hawk-eye instructions say it requires 8-12 V. I'm not sure how sensitive it is to decreased voltage; I don't know if I could get away with 7.2 V. I think I'd need a 3-cell Li-Po. The lightest I found was: https://hobbyking.com/hobbyking/store/__23339__Turnigy_nano_tech_180mah_3S_25_40C_Lipo_Pack.html
It looks like it would fit in a BT-50, but not a BT-20. A slight improvement over a 9 V. It weighs 19 g. The Hawk-eye weighs only 6 g.
Click to expand...

bobkrech said:
I think this 7 g battery will work for you. https://hobbyking.com/hobbyking/store/__10915__Turnigy_138mAh_2S_10C.html
Click to expand...
Some advertising lists a 2S LiPo as 8.4 volts which is the full charge voltage. The average voltage is 7.4 volts and it's finished at 6.0 volts. (Lipo cells are fully charged at 4.2 volts, 3.7 volts is mid range and 3.0 volts is the lowest you should discharge them to without damage.) The battery I suggested costs $2.54 and easily fits in a BT-20. The altimeter you have is quite simple and you are simply amplifying the differential current from 2 photodiodes. The voltage that powers the amplifier IC shouldn't be very critical. I'd get one and try it.
 
Cyril's Scribe said:
They are generally built into the altimeter, I have not heard of someone retrofitting one to an older altimeter, but that is not to say that you can not do so. I know that the Raven and the RRC3 have capacitive discharge circuits, and I know several other competitive altimeters have them too.
Click to expand...

The Raven has a hold-up capacitor; it's not used for firing.
 
CarVac said:
The Raven has a hold-up capacitor; it's not used for firing.
Click to expand...

Wow,,,,
I always heard the Raven had a cap,,,,
maybe it was me,,,,,,
just assumed it was for firing the charges........

Teddy
 
onebadhawk said:
Hi Chris,
I'm a big proponent of lipo's these days......
Especially since a 9V battery clip cost me an important rocket,,,,, altimeter browned out on launch........
Now I eliminate as many weak links as reasonably possible,,,,,,,
nice shiny solder joints and good connectors with something to fix them in place (tape is fine ).........

This battery in my humble opinion,,,, works better on Q2G2's then a 9V. because they are
just a touch lower in voltage,,,,, not quite as quick to burn the bridge wire........

https://hobbyking.com/hobbyking/store/__23135__Turnigy_nano_tech_180mah_2S_25_40C_Lipo_Pack.html

Also it will run your electronics for much longer then you'd be comfortable on 1 - 9V. and when it's time
you don't throw it away,,,,you just charge it......

The bang for the buck is massive.......

But,,, you have to buy a charger,,,,,,,

https://hobbyking.com/hobbyking/store/__6478__IMAX_B6_AC_Charger_Discharger_1_6_Cells_GENUINE_.html

My charger I've had for years,,, I love it,,,, I paid $125 for mine and $60 for a 12V. DC power supply
for my workbench to run my charger....... my charger will do from 2s thru 6s lipo and just about any other battery chemistry
lead acid motorcycle batts, ni cadmium, ni metal hydride......

This Imax B6 will charge any battery chemistry and it will do 1s thru 6s lipo's ,,, the 1s is good for circuit board batteries.....
and the B6 has a built in power supply,,,, you can use it on your workbench and take it with you to the field and use it off of your car battery.....
The B6 will also cycle batteries as well,,,, brings batteries not doing to well anymore back to life by cycling them...........
I wish I had this charger,,,,,,,,mine is almost as good,,,, I paid 5 times the money.....

Absolute,,,, most important with lipo's ,,,, the secondary white plug is for your charger,,,,,
the charger is a balance charger,,, or computer charger,,,,
the white plug on the battery will fit into a board that comes with your balance charger.
You balance charger will refuse to begin charging if it does dot see voltage from the white plug.......
The white plug allows the balance charger to charge each cell in your lipo pack individually,,,,, and balance them.....
We've all heard horror stories about lipo packs exploding when being charged.......
They don't explode,,,,, but violently ignite like a road flare....... those stories have some sustenance to them.......
If you don't charge a lipo properly ( with a balance charger ) the cells can become so out of balance that one is still calling for current and another overcharges.....
To better understand the white plug look at the pics of a 5s or 6s lipo,,, the balance plug is very wide with many conductors,,,
it gives the charger access to each cell individually......
I use to fly RC,,, I've charged lipo's for a very long time,,,,,do it right,,,,,,never a problem......

Now,,,,,,,
The power plug on the battery your interested in is called a JST plug.............
I am using them everywhere I need a plug in my avionics bay,,,,,,,,
I like them,,,they seem solid,,,,,particularly with a piece of tape on the 2 plugs when you put them together,,,,,,just for piece of mind.........
and since they come on the batteries I like,,,,I don't have to cut them off of the battery to switch to another plug,,,,,,,,,,,,

so here ya go,,,,,,,,

https://hobbyking.com/hobbyking/store/__9683__Female_JST_battery_pigtail_12cm_length_10pcs_bag_.html

https://hobbyking.com/hobbyking/store/__9682__Male_JST_battery_pigtail_10cm_length_10pcs_bag_.html

Now your ordering from the other side of the planet,,,,,, your order isn't going to be here in 3 days,,,,,,,,
plus you'll need fill for the package weight,,,shipping cost is by weight,, right,,, ( your not going to like the cost of shipping )
but much of the stuff is not available in the USA warehouse,,,like the JST plugs.........

So here's some fill stuff for your package,,,,,,,

pick which size heat shrink you'd like,,, very handy,,,,,

https://hobbyking.com/hobbyking/store/__375__58__Hardware_accessories_-Shrink_Tube.html

super cool for your workbench,,,,,,,,

https://hobbyking.com/hobbyking/sto...tic_Tool_Stand_for_Hex_and_Screw_Drivers.html

Hey,,,,,how ya like me now,,,,,,,,

https://hobbyking.com/hobbyking/sto...f_Adhesive_Centre_of_Gravity_Marker_3pc_.html

This is how a lazy man installs shearpins,,,,,,,,,,

https://hobbyking.com/hobbyking/store/__24662__Hobbyking_Electric_Screwdriver.html

Weight fillers,,, but look for the knives with the metal inserts for a dime more,,,they are better,,,,,,,

https://hobbyking.com/hobbyking/store/__9335__Hobbyking_8_Point_snap_knife_5pcs_set_.html

Ok,,, Chris,,,,,, it's been a pleasure shopping for you,,,,,,lol,,,,,,,

but seriously,,,, you can find a cheaper charger,,,but how much cheaper do you need it to be,,,,,,,,,,
You will be very happy with these items,,,, I promise,,,,,,,,,,

Teddy
Click to expand...

Thanks Ted. And thanks to Bob also, you helped me in my previous thread. This is enough info. for me to push me over and try lipos. None of this stuff is that expensive, but it adds up, especially if I was not sure if I would use it or not. I will try this in my current project. Thanks again.

Chris
 
Chris,
I order from them rather infrequently,,,,,,,
the shipping from the other side of the planet is very expensive.......
because of that it pays to go to the trouble of understanding and using the column on their shopping cart page that shows shipping weight,,,,
and jiving out what is in the USA warehouse and what's not......
So when I do order,,,,, I don't hold back,,,,, lots of inexpensive super useful goodies,,,,,,,,,
If you'll place an order for ,,say,, $100 with the charger,, when you finally get the package you'll feel like a kid on Xmas morning........

Teddy
 
If the shipping cost from a non-US warehouse is excessive, you can make your own batteries from single cells. https://www.hobbyking.com/hobbyking/store/__23309__turnigy_nano_tech_80mah_1s_15c_round_lipo.html weighs 2 gm. https://www.hobbyking.com/hobbyking/store/__23310__turnigy_nano_tech_90mah_1s_15c_round_lipo_.html weighs 3 gm. https://www.hobbyking.com/hobbyking/store/__23311__turnigy_nano_tech_130mah_1s_15c_round_lipo.html weighs 3 gm. https://www.hobbyking.com/hobbyking/store/__23314___turnigy_nano_tech_180mah_15c_round_lipo.html weighs 4 gm. https://www.hobbyking.com/hobbyking/store/__23313__turnigy_nano_tech_200mah_1s_15c_round_lipo_.html weighs 5 gm. https://www.hobbyking.com/hobbyking/store/__23315__turnigy_nano_tech_270mah_1s_15c_round_lipo_.html weighs 6 gm. All will deliver more than 1 amp, are $1.20 a piece, and can be taped together to make 2S and 3S battery packs. Lengths are different, but all will fit inside a 24 mm airframe.
 
I will load up a cart and see what the above shipping comes to. I have a 9 v solution for my own project, so don't have to go lipo. Another option might be to use Tenergy lipos in series that Adrian at Featherweight sells. These are single cell lipos. Fruity chutes also sells the Tenergy Lipos, a wall charger, and USB charger. I would just need a JST series harness. I doubt if shipping from Featherweight or Fruity Chutes is exhorbitant. That is a possible option.

Chris
 
Chris,
You should open a tab in your browser with the USA warehouse.........
Put everything you can in that cart.......... Don't check out yet............
Open a tab in the global warehouse,,,,,,,,,,
find everything you want that you can't get from the USA warehouse...........
That will keep the shipping down,,,,,,,, a bit.....................

Teddy
 
onebadhawk said:
Chris,
You should open a tab in your browser with the USA warehouse.........
Put everything you can in that cart.......... Don't check out yet............
Open a tab in the global warehouse,,,,,,,,,,
find everything you want that you can't get from the USA warehouse...........
That will keep the shipping down,,,,,,,, a bit.....................

Teddy
Click to expand...

Okay I am in. I ordered 2 batteries, a charger, and a cigarette lighter from the USA warehouse. I also ordered the male and female jst pigtails from the international warehouse. Shipping was pretty low as I limited the weight of the order. We will see what happens. I like learning new things so am excited about the whole lipo thing for my current project. Thanks again for everyone's help.

Chris
 
Got my batteries, charger, and cigarette lighter adapter yesterday. Still waiting for the jst plug / pigtails. I knew from the measurements that the batteries were small, but seeing them is something else! They are small. I put them into my small av bay application, and no problemo! I am glad I got these.

Chris
 
They're amazing right,,,,,,,,
The energy density of todays lipo's is unreal,,,,,,,,,,
When I was flying I got 3s 11.1v lipo's for a plane......
They came with the wrong plug,,,,,,
so I had to solder on the plugs I was using......
I was using my big bench vise to hold the plug while i soldered it.......
I slipped..........
If you ever made a ---I slipped--- with a wrench on a car battery,,,
thats what this did,,,,,,,
This little lipo blew a chunk of steel out of my bench vise.......
I was astounded.........

Teddy
 
CarVac said:
The Raven has a hold-up capacitor; it's not used for firing.
Click to expand...

That's correct. The Raven's aerogel capacitor will keep the electronics up and running for several seconds after power is removed or during a short. The Raven's electronics work on a 1S lipo, which is how the Featherweight av-bays can be so small. A 1-series, 130mAhr lipo (smaller that the HK examples discussed in this thread) will also ignite just about any igniter or ematch.

With lipos, the most common problem I'm aware of is people burning out output switches by using a lipo that's too big.
 
Adrian A said:
That's correct. The Raven's aerogel capacitor will keep the electronics up and running for several seconds after power is removed or during a short. The Raven's electronics work on a 1S lipo, which is how the Featherweight av-bays can be so small. A 1-series, 130mAhr lipo (smaller that the HK examples discussed in this thread) will also ignite just about any igniter or ematch.

With lipos, the most common problem I'm aware of is people burning out output switches by using a lipo that's too big.
Click to expand...

I was so impressed with Perfect flights tech dept..........
That is exactly what they explained to me............
If theres a problem,,,,,, and you inadvertently short one of the outputs when it's "made"
a 9v is not capable of putting out enough current to damage the altimeters output transistor..........
A 2s 180mah 40c lipo IS capable of putting out much more then enough to fry them.........
That is the reason Perfect flight will not advocate using these batteries,,,,,,,,,

Makes sense to me..........

I didn't know a 1s would fire a Q2G2,,,,,,,,,,,,, very interesting.............

Teddy
 
I tried an A10. Enough current to light an Xmas bulb, but not when connected to the Hawk-eye.

I decided to try Li-Po. I ordered three of these cells: https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=36942 Advertised weight it 3 g, but my scale says 2.5 g ea, and 7.5 g for all three. They will fit end-to-end in a BT-5 or even a BT-3. For a shorter package, I can fit three of them in a triangular cluster in a BT-20.

Being new to Li-Po, I'm unfamiliar with the different types of connectors. These cells have small tabs of thin sheet metal / thick foil at each end for terminals. I need reliable, quick-change connectors to hook the cells up in various combinations for testing, and connectors that will let me charge them with this charger, if possible: https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=41163

HobbyKing has a wide selection of connectors, but I'm having a hard time figuring out what fits with what. Can someone point me in the right direction?
 
The charger I have has a JST connector on it so that's what I soldered on to the batteries.

m7DWB-4M8HYz71PeI1N3udQ.jpg

The batteries I have are different than yours but you should be able to solder to the tabs. I noticed that a lot of the batteries now come with a smaller size JST connector. You should be able to get either kind from All Electroncis.
 

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