Lipo Battery Setup

Worth noting that current lipo practice in the RC world is to never discharge a lipo below 3.7 volts per cell. You still get most of the capacity. Newer high C lipos will typically have a shorter useful life and deliver less current over time if discharged to the "old" level of 3v per cell.

Have you considered 2032 coin cell batteries? Can get em for about $0.50. 3 volt 250 MaH. May can stack em to get 6 volts. I've never tried em so I don't know if they are a viable option. Buy a couple and ground test. If they don't work, you are out a dollar or two. I was looking at them as an option for my Quark, but it didn't make it through bench tests. Just a thought.

Mike

I remember hearing of a continuity tester that used coin cells purely for the fact that they couldn't deliver the current required to fire an igniter or e-match.
Worth checking the max discharge for any cells and ground testing your configuration to ensure it is up to the task.

Yeah possibly. I heard the same about the CR123A but I bench tested and got over 10 amps, and a lot of heat

I have been using Lipo's for years on many different projects, ROV's, Drones, Rocketry,Robotics. A good smart charger will take care of most overcharging concerns. I say most because there is always the possibility the charger itself has a failure which allows overcharging. I have run several Lipo's way below 3.7 volts per cell. The only issue I have had is the smart charger recognizes the voltage is too low and will not charge the battery so I throw it away. Be aware of the C rating for Lipo's. For most of our rocketry needs a 200-300mah Lipo with a C rating of 10-20 is more than enough. The main thing is to get the voltage right. 1S 3.7V, 2S 7.4v, 3S 11.1V. When when fully charged the voltage of a single cell is 4.2V so a fully charged 3S battery will actually deliver 12.6v. I like Lipo's lot's of power for very little weight.

tab28682 said:

Worth noting that current lipo practice in the RC world is to never discharge a lipo below 3.7 volts per cell. You still get most of the capacity. Newer high C lipos will typically have a shorter useful life and deliver less current over time if discharged to the "old" level of 3v per cell.

Click to expand...

Tom

What you are quoting is this article (or similar) with this plot. https://www.inspirepilots.com/threads/smart-batteries-not-so-smart.3612/



It's a bit more complicated than that and varies slightly with the battery construction and chemistry but most importantly, how long you wait to measure the battery voltage after you stop using the battery.

Most RC aircraft have a real-time fuel gauge that measures the battery capacity under load. The voltage values are very different. The plot below represents the voltage of the battery measured under load versus capacity. https://pixhawk.org/users/battery_config



The electronics in a battery protection pack when present, or in a smart charge, prevent each cell from being charged to over 4.2 volts per cell or being discharged below 3.0 volts per cell. These are the upper and lower voltage values that will cause unrecoverable loss of capacity to a LiPo cell caused by irreversible chemical reactions within the battery. If you have an advanced battery management in your RC vehicle, you can set the minimum voltage level for the battery low signal. The article recommends 3.35 volts which represent about 20% remaining battery capacity and is relatively independent of current draw. Setting the lower voltage level at this value will extend the life of the battery pack as well.

Bob

Anyone using tiny lipo batteries on RRC2+ or for firing deployment igniters? I have some as small as 40mah but I bet they are too small.