N00b question... How do I know when my battery is about to die?

S

SmackHappy

Member
F450
Naza v2 + GPS
Dji 2212/920kv
Taranis x9d w/ x8r

Ok, I know this is probably a really rudimentary question... But, When flying, how do I know when my battery is about to die?


I've read more than one post on more than one forum that the Low-Voltage Alert for the Naza Flight Assist tool is unreliable and should not be used.

I often hear about basic arithmetic that needs to be done to find out how much of something you have left. (A * B = C cant do scratch math!)

I read somewhere that I need a volt meter alarm.
View attachment 18598
But I dont know how to use it... If its on the battery, how can I hear the alarm when im flying?

Basically, what Im doing now is I fly far and high for about 15 minutes, then I bring it in close and low until the battery is drained and comes down...


Silly questions I know. But how else am i to learn!

Thanks guys!
Chris.
 

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Motopreserve

Motopreserve

Drone Enthusiast
Are you saying that you fly it until the battery drains completely and the quad force-lands??? If so, that's very bad. There is a great sticky thread in the beginner section about batteries that would be helpful to read.

If you are using the Taranis, you can buy some sensors that will keep track of the current, consumption etc. I have been using them and they have been really helpful, and they're cheap. You can also just slap a cheap alarm like the one you posted. It plugs into the balance pet of your battery and they are usually pretty bright and loud. If you can't hear/see it from your flight position, the MR probably too far away for a beginner.

But to get you started: look up the 80% rule. It states that you don't want to deplete the batteries any more than 80% to maintain the health of the battery. Most chargers will charge each cell to 4.2V, So if you have a 3S battery, you don't want to run it down any lower than 3.36V/cell or 10V total under load. When at rest, the battery will come back up on its own a bit, and should probably be right around the rated voltage, or 11.1V. For 4S it would be 13.4V under load.

I personally play it safer and try to land when it's closer to 12.6 on my 4S. That's about 75% used.

Ideally you follow this rule, and use it to fly safe, but then calculate your usage (which will be more accurate than voltage). So keep track of the amount of mah put back into the battery (your charger should list this), and that should also line up with the 80% rule. So a 5000mah battery should only be depleted so that you need to put 4000mah back in. If you track the time you flew, and the mah replaced, you should be able to hone in on your safe flight times for your specific rig and have the taranis timer let you know when to land.

Make sense?
 

subsonic9

subsonic9

Member
I started using the battery alarm you have pictured. I is very loud! I am putting a osd on it now to show the mah used. All you do with the alarm is connect it to the balance plug and Velcro it somewhere.
 

S

SmackHappy

Member
Thanks for the responses guys, I just picked up an alarm off of amz prime for like $4 shipped as a stop gap.

Yes, I've been flying till drained. It's totally my beater battery... Frayed wires by getting caught in the props etc. I know I'm playing with fire literally,but it's stored safe when not in use. Once I understand batteries better I was going to pick up a few good ones to properly take care of...

Motopreserve said:
Are you saying that you fly it until the battery drains completely and the quad force-lands??? If so, that's very bad. .

If you are using the Taranis, you can buy some sensors that will keep track of the current, consumption etc. I have been using them and they have been really helpful, and they're cheap.
Click to expand...

What are these sensors you are talking about? I would love to have my taranis let me know when to come back by using more than just a timer or buzzer on the mc.

Thanks again!
Chris


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S

SmackHappy

Member
Heh...yah, well, that was actually shot last week...
See? Pool's still covered!


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Motopreserve

Motopreserve

Drone Enthusiast
SmackHappy said:
Heh...yah, well, that was actually shot last week...
See? Pool's still covered!
Sent from my iPhone using Tapatalk
Click to expand...

I know you probably already know this - but flying over a populated area with any battery, let alone a "beater" battery is a really bad idea. The chance of an MR falling straight down without some type of drift is not guaranteed.

The sensors are made by FrSky. The newer ones are called the Smart Port sensors, and plug directly to the X series RX (X8R). The older ones are for the D series RX - but can be used with the X8R if you have a Vario. I chose the older current/Anpere sensor since I wanted 100v capacity - which only comes in the older style. So I plug them together and connect them using the vario - which also gives you altitude etc.

you can find the sensors at Aloft Hobbies and several other places.

**SP-FLVS: like a battery checker, plugs into battery balance lead. Shows voltage per cell and total on a small screen - plugs into X8R for readout on the taranis. In my case it's plugged into vario.
**FAS100: current sensor - will show mah used on Taranis. Need to make a special harness from provided wires. Plugs into SP-FLVS.
**FVAS-02H: smart port vario that acts as hub between old and new sensors to X8R.
 

{}{steve}{}

{}{steve}{}

Member
SmackHappy said:
Thanks for the responses guys, I just picked up an alarm off of amz prime for like $4 shipped as a stop gap.

Yes, I've been flying till drained. It's totally my beater battery... Frayed wires by getting caught in the props etc. I know I'm playing with fire literally,but it's stored safe when not in use. Once I understand batteries better I was going to pick up a few good ones to properly take care of...



What are these sensors you are talking about? I would love to have my taranis let me know when to come back by using more than just a timer or buzzer on the mc.

Thanks again!
Chris


Sent from my iPhone using Tapatalk
Click to expand...

Seriously please do some research on LiPo batteries and please don't put your MR back up in the air until you understand what you are doing. This isn't meant as a jab, I just don't want you to ruin your gear or hurt yourself or anyone else. Running a battery too low can easily cause it to puff and ruin it. Frayed wires? If those short together your battery will swell and then will burst into flames. Thank about what would happen if your battery lit up, while in the air, and your whole setup fell into one of those boats in your video...or worse yet, onto someone's house.
 

S

SmackHappy

Member
Motopreserve said:
The sensors are made by FrSky.
you can find the sensors at Aloft Hobbies and several other places.

**SP-FLVS: like a battery checker, plugs into battery balance lead. Shows voltage per cell and total on a small screen - plugs into X8R for readout on the taranis. In my case it's plugged into vario.
**FAS100: current sensor - will show mah used on Taranis. Need to make a special harness from provided wires. Plugs into SP-FLVS.
**FVAS-02H: smart port vario that acts as hub between old and new sensors to X8R.
Click to expand...

Fantastic.
I'll definitely pick up at least the sp-flvs...
Thanks again!




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M

min0nim

Member
Now you've got the voltage sensor, Have you worked out how to program your Taranis to show and speak the lowest cell voltage, and set off an alarm when one drops too low?

Let me know if not and I'll write a simple how-to tonight.
 

Motopreserve

Motopreserve

Drone Enthusiast
min0nim said:
Now you've got the voltage sensor, Have you worked out how to program your Taranis to show and speak the lowest cell voltage, and set off an alarm when one drops too low?

Let me know if not and I'll write a simple how-to tonight.
Click to expand...

I think you should go put that in the Taranis/FrSky sensor thread. It will be helpful for others as well.
 

M

min0nim

Member
Motopreserve said:
I think you should go put that in the Taranis/FrSky sensor thread. It will be helpful for others as well.
Click to expand...

Ok! So maybe someone can re-direct me for this - I've had a great night so far! No flying for me!

The Smart Port Lipo Sensor FLVSS will read each cell in your lipo. It will display these on its screen, but can also transmit the readings to your TX, so you can monitor the state of your batteries during flights.

How to read the FLVSS from your Taranis:

1. Enter your model setup. Press 'Menu' once to select your model on the Tarnis. Press the 'ENT' key to select.
2. Press the 'Page' button to enter the model selection screens. Keep pressing 'Page' until you reach the "Custom Switch" screen.
3. Press "Ent" to access the first custom switch. This is probably CS1 unless you've already programmed something into the Taranis. If CS1 is already set, pressing "-" will take you to the CS2 setting - pressing it again will take you to the CS3 setting...you get the idea.
4. Assuming this is the first custom switch you are programming...
5. Press "Ent". You will have highlighted the column to the right of CS1. Press "Ent" again to select this parameter for editing.
6. The column next to CS1 will be flashing - press "+" until you get to the reading "a<x". Press "Ent". We're making a 'switch' that will turn on when a value gets bigger than 'x'. We want that value to be the lowest voltage reading of an individual cell from your battery.
7. Press "-" to get to the next row to the right. Press "Ent" to select the parameter.
8. Press "+" until you get to the parameter "Cell". Press "Ent" to continue. This will now read the lowest cell voltage reported by the FLVSS - sweet! It's too easy :)
9. Press "+" to get to the next row to the right. You should be getting the routine now. This time you are going to set the voltage warning trigger level. I suggest 3.6v for the lowest cell.
10. Press "Ent" to select the parameter.
11. Press "+" to get to 3.60v (my recommendation for a multi rotor. You could go as low as 3.0v if you really pushed it - but only do this if you know the power curve of your battery - you WILL kill it otherwise, and also risk a sudden shutdown...copter rain). I have a second warning set at 3.4v. I know I should be on the ground by then.
12. Press "Ent" to accept.
13. Press "Exit" to get out of the custom switch page.
14. Press " Page" to get to the next screen - "Custom Functions".
15. Press "Ent" to access the first unused Custom Function - CF1 probably.
16. If the first custom switch you set above was CS1, press "Ent", and then press "+" or "-" until you find CS1. You set a custom 'switch' above, now here you're telling the Taranis what to do when that switch is triggered.
17. Press "Ent" and "-" to get to the next column.
18. Press "Ent" to edit the setting, then "+" to find "Play Sound". We want the Taranis to play an alert when cell voltage gets low. Press "Ent"
19. Press "-" then "Ent" to access the next column. Press "+" or "-" to find "Siren". Press "Ent" to select this sound.
20. Then press "-" to get to the next column, "Ent" to edit it, and "+" until you reach the value "10". This will then play the siren every 10 seconds once one of your Lipo cells has reached the lowest voltage of 3.6v - set from the logic above. Press "Ent" again to accept the setting - the cursor will stop flashing.
21. Select "CF2", then "SC-", "Play Value", then "Cell", then "15". This will read the lowest LiPo cell voltage to you every 15 seconds when you set your Taranis switch "SC" to the middle position. You can choose any switch you want instead of "SC". The Taranis will literally "read" the voltage of the lowest cell to you, in English.

This should give you an idea how to program the Taranis. You can set up secondary alarms, and warnings the same way. This is great, because you don't have to rely on an average reading of the lipo, but can monitor the status of your weakest cell. You can also fly your copter well away from you, and not have to worry about hearing a battery motor alarm - the Taranis will tell you what you need to know. This is one of the best things about the Frsky system, in my opinion.

Let me know if this needs any more filling out with steps or info.

Cheers,
a..
 
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Motopreserve

Motopreserve

Drone Enthusiast
Great stuff. I have this working but stumbled through 9 different posts on 9 different forums to get it done :)

can I copy this over to the other thread?
 

M

min0nim

Member
Please post it where you see fit.

I received so much help from other posts and guides here - I hope this can make it easy for someone else starting out.
 



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