Great job, I see progress. It’s nice to see someone explain things as the video moves along. Sometimes its hard to know what’s going on without a narrator.
Quick question about batteries. I would like to cut the cord on my biped. Would like to use
or try some lipo batteries. I picked up a couple of regulators but when it came to picking a battery I was lost. most of the one’s i found locally looked like bricks. I did find a smaller 2200 mah (2S 7.4 volt). and was wondering if i ran them in parrell (they look like they would fit nicely on the sides of my ARC-32) should still give me 7.4 volts and 4400 mah. would that work?
Yes and no. Don’t parallel couple two LiPo’s unless you really know what you are doing. There is a risk of high current discharge/charge between the two LiPo’s and that is dangerous!
I would recommend using only one of the 2200 mAh cells, you also save weight. If you want to use 2 LiPo’s you can use two power circuits (S1 and S2) and two regulators, thats the safest way.
I guess in theroy it’s ok, but I had some doubt. thanks
I guess I’ll get a larger battery. thats about the same size.
Thanks
May I ask why you wan’t a larger battery than the 2200 mAh?
Hi Zenta,
I’m not sure if 2200 mah would be enough power. if 2200mah works then my search is done
Phil
My guess is that the 2200 mAh LiPo can handle around 20C an thats 44 Amps! So thats more than enough…
Great! I just dont understand how you get 44 amps out of this 
I tried to find a link that would clear this up but all I did was confuse myself more.
Do you know of a link that might help me understand this better?
Thanks for the help
1C = 2200 mAh for a 2200 mAh LiPo. Do the math for 20C. 20*2200 = 44000. 
Do a search on LiPo capacity. lipo-battery.com/Lipo-Capacity-Rating
Zenta,
This explains alot. Thanks for the explaination. I now feel more comfortable making a selection.
Thanks again.
Hi,
This the game plan i plan to use
Do I really need to use these?
If any one see’s anything wrong with this approch,
please let me know. Or I just find out tomorrow
Thanks
The UBEC is a switcher, makes a lot of RF noise. These ferrite cores form a “choke” to keep the RF out of the rest of the electronics. Most important if you have receivers nearby. I’d leave them in as long as you have the room.
Alan KM6VV
Hi,
I agree with Alan, leave the ferrite on. I’ve always used them. It would probably work without though.
I’ve two comments to your power circuit:
- Use one main fuse between the LiPo and the rest of the circuit. For example a 20 amp mini auto fuse work fine.
- Connect the VL on ARC-32 directly to the LiPo voltage (after the main switch of course). In that way you can read the LiPo voltage (P33) for safety.
I’m having trouble understanding this. I’m not seeing how to make this connection in the documentation
I found P33 under Internal Pin Assignment Overview
P33 • Analog Pin.
• Detects Logic Voltage
Page 16 of the ARC-32 manual under voltage level detection says
P32 returns S1 voltage,
P34 returns S2 voltage,
P33 will return logic voltage.
These are already wired up on the board.
Alan KM6VV
I understood that P33 was internal.as it’s used by the code here
wLiPoVad = HSERVOSTATE P33 ; Read VL But this is what I’m understanding how to wire it up
Hi,
Would recommend to move the main switch a little. I don’t recommend having the UBEC connected all the time. Unless you plan to disconnect/connect the LiPo every time.
Ok, I’m off to get the materials to make this
Since I’m using a 7.4 lipo i should not have any concerns connecting it to VL? I wasn’t able to find the voltage limitations in the documentation for the ARC-32.
Zenta and Alan thanks for your help
That’s better. VL up to 9v should be fine (12 max).
Alan KM6VV
Looking good!
Just a little advice: When using LiPo’s I always test the circuit for eventual short circuit or other fault by using a “safe” power supply for the first time.