Good Battery for altus metrum easy mini

[chipotle mg]

Hello,

Can I get some recommendations for a good battery for the EasyMini and a link to the suppliers website so I know where to buy it if you can? Thank you in advance.

 

[Off Grid Gecko]

I'm just using a 9V with mine. Though I have a ton of little lipos from my midget CP helicopters. Just make sure you get the polarity right. I would pass on the connector and plug whatever battery you get straight into the terminal block to be safe.

 

[Josh Anderson]

Wildman, Chris’s, and a bunch of the rocketry suppliers sell the 1S Lipo’s Bdale recommends with his products. It’s all I’ve ever used, and I think they work great!

https://wildmanrocketry.com/collections/parts
https://csrocketry.com/electronics/altus-metrum.html

 

[chipotle mg]

Wildman, Chris’s, and a bunch of the rocketry suppliers sell the 1S Lipo’s Bdale recommends with his products. It’s all I’ve ever used, and I think they work great!

https://wildmanrocketry.com/collections/parts
https://csrocketry.com/electronics/altus-metrum.html

Josh, thank you for your response. One thing that bothers me is that the directions for the easy mini specifically say 4-12 volts but the 1S Lipos are 3.7v. which amps do you use for your set up? Is seems there are 120, 160, 400, 850 mAh choices with each having proportionally bigger weight. I will be using this battery for dual deployment so I need enough to ignite a deployment charge. I also Do not want it to be so heavy. A 9v is ~33 grams.

 

[Josh Anderson]

I think I generally use the 400 mAh, but I can’t quite remember for sure. That rating is the capacity rating and will just change how long the computer can stay on for, so picking something that will fit inside your AV bay easiest is generally the best choice. All of them will fire the E-Match just fine. The main thing that’s important is those specific batteries don’t contain an overcurrent protection circuit. This is unlike most other Lipo’s on the market, and is specific to Altus Metrum products.

As far as the voltage goes, the 3.7 is just a nominal rating, with the charger (that you should be able to purchase for a few bucks on the same web pages) it generally charges to somewhere around 4.1 V.

I hope that helped clarify some things up. Good luck with the DD! And let me know if you have any other questions.

 

[waltr]

If input Voltage can be 4-12V then why not a 2S Lipo. These are 8.4V Full change down to 7.4V.

I use 300mA-Hr 2s on my Eggtimer altimeters. Work great to reliably fire Ematches and even 40ga DIY motor igniters for Airstart.
A 300mA-Hr 2s weights 22gram and are about same volumn as a 9V, just longer and narrower.

 

[Voyager1]

I just use a 1S 350-400 mAh LiPo on each of my EasyMinis. I generally get them from HobbyKing.

https://hobbyking.com/en_us/turnigy...D=30693&indexName=hbk_live_products_analytics

 

[RocketDestroyer]

From the EasyMini web site... Designed to use a battery supplying 3.7V-12V.

I used 400 mA Lipo batteries for my L3 flight and they worked great. I get mine from the Altus Metrum store. I see no reason that you couldn't use a 200 mA battery, as mentioned above the difference is how long the altimeter runs after the rocket has landed.

 

[RocketDestroyer]

So, just for fun I measured the current draw for my EasyMini. It draws around 6 to 7 mA sitting on the pad. It likely draws a bit more current in flight when it is writing data to the memory. So even a 120mAh battery should last for many hours, more than enough for several flights.

 

[SolarYellow]

All of them will fire the E-Match just fine. The main thing that’s important is those specific batteries don’t contain an overcurrent protection circuit. This is unlike most other Lipo’s on the market, and is specific to Altus Metrum products.

So if I go buy a generic lipo that looks like those from any of many sources, will it not supply enough current to light an e-match?

 

[waltr]

So if I go buy a generic lipo that looks like those from any of many sources, will it not supply enough current to light an e-match?

Look at the batteries C Rating. Typical is 30C which means peak output current is 30 times the capacity rating. Therefore a 300mA-Hr LiPo with a 30C rating can output 9Amps.

If the Generic battery does NOT have a high C rating then it probably has a current limiting circuit which you do NOT want.

 

[SolarYellow]

Good to note, I hadn't thought of that, but going back and looking, I see it on some of the generic sourcing sites when they are advertising them for small digital electronics. Stuff advertised for drones/planes/etc. may or may not have a C rating in the listing, but doesn't appear to have the little circuit board attached.

 

[waltr]

Typically the batteries for electric motor powered aircraft do not have the limiting circuit since these require many Amps of current.
Last step after getting a battery and wiring is to TEST to ensure it will fire the deployment igniter.

 

[troj]

One thing to be aware of, and it's mentioned somewhere in the Altus Metrum documentation, is that not all LiPos use the polarity on the plug.

I buy my batteries from AltusMetrum (or one of their dealers) so that I know I'm getting a battery that I know will work with the board.

Bdale and Keith (the two guys behind Altus Metrum) fly the LiPos that they sell.

 

[Chad]

One thing to be aware of, and it's mentioned somewhere in the Altus Metrum documentation, is that not all LiPos use the polarity on the plug.

I buy my batteries from AltusMetrum (or one of their dealers) so that I know I'm getting a battery that I know will work with the board.

Bdale and Keith (the two guys behind Altus Metrum) fly the LiPos that they sell.

yep, that's why i do as well. i just get batteries from them so i don't have to worry about it. Their prices are pretty inline with other places too.