9 volt alkaline vs lithium

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
The cold temperature characteristics of an alkaline cell will not show up unless it's under load. Open voltage (or the light load of the altimeter electronics only) will not show the voltage when firing a charge. So, the "beeped out" voltage of the Perfectflite will not show the whole story. Below 40F (cold soaked into the battery, not just ambient) is when the voltage vs temperature tanks for alkalines. Non-rechargeable Lithium-ion cells do much better down to -20F. They also have more capacity in the same 9V size. But all are not created equal, so look at the manufacturer's specs and verify by testing.

Considering the overall cost of the rocket, electronics, and motor, there's no reason to skimp on the battery, or make any assumptions. Duracell alkaline are great for most circumstances (that's what I use). For projects that are going to be outside <50F for a while, I use the 9V Lithiums... and never the Lipo rechargeables in the cold.

Here's the link to Duracell Coppertop 9V data sheet https://d2ei442zrkqy2u.cloudfront.net/wp-content/uploads/2016/03/MN1604_US_CT1.pdf
The operation temp. range of -4 F to 130 F.

Again, I use these for altimeters which are low load and ematches which are also low draw. Even cold soaked, I've never had an issue in the last 10 years.
 
The cold temperature characteristics of an alkaline cell will not show up unless it's under load. Open voltage (or the light load of the altimeter electronics only) will not show the voltage when firing a charge. So, the "beeped out" voltage of the Perfectflite will not show the whole story. Below 40F (cold soaked into the battery, not just ambient) is when the voltage vs temperature tanks for alkalines. Non-rechargeable Lithium-ion cells do much better down to -20F. They also have more capacity in the same 9V size. But all are not created equal, so look at the manufacturer's specs and verify by testing.

Considering the overall cost of the rocket, electronics, and motor, there's no reason to skimp on the battery, or make any assumptions. Duracell alkaline are great for most circumstances (that's what I use). For projects that are going to be outside <50F for a while, I use the 9V Lithiums... and never the Lipo rechargeables in the cold.

CJ has suggested chemical hand warmers around the batteries in the past if one has the room. I had a few in the past. Boil 'em, and when you want to use, you snap a metal disk inside the "magic gel". Boil 'em up again and reuseable. Kurt
 
Here's the link to Duracell Coppertop 9V data sheet https://d2ei442zrkqy2u.cloudfront.net/wp-content/uploads/2016/03/MN1604_US_CT1.pdf
The operation temp. range of -4 F to 130 F.

Again, I use these for altimeters which are low load and ematches which are also low draw. Even cold soaked, I've never had an issue in the last 10 years.

If you look at the graph, it says 50mA at 0C is 8V after an hour. This is not representative of a cold use case with an altimeter load + two ematches in parallel. Load is 250mA plus. The output at 0C (32F) will be about 5V. The altimeter may reset itself at apogee.

You may not have seen problems like this, but I have. Just trying to let people know about the technical details and choices. (I've done a lot of battery analysis and thermal-vac testing for payloads I've designed for NASA in the past. Lots more I could pass along, but not pertinent to HPR).
 
Back
Top