Hello all,
I'm new to lipo's and am looking to minimize potential risks as much as effectively possible.
When it comes to changing I'm using a IMAX B6-AC Charger, with kypomm 3s 3300mah 35c-70c, and Gens Ace 3s 850mah 30c and Eflite 3s 1800mah 20c lipo's.
From my understanding I need to charge them using the balanced charge setting at 3s, but here's where i'm a little unsure,
Do I set the charge setting to 3.3c for 1 hour to getting 3300mah or 4.18 per cell? Thus same goes for the 1.8c for 1 hour to get 1800mah? And finally .8 for 1 hour to get 850mah? or am i missing something?
Also upon doing many hours of research I've notice theres a big stigmatism towards the large risk of lipo's, is this really that accurate or is there some slight hysteria (maybe old articles and newer safer technology?)?
I'm in an apartment an charging may be tricky is fire hazard is that extensive although being able to constantly supervise is not an issue. An am considering a pyrex dish with sand at the bottom while rapping lipo in fire proof material with a bag of sand for emergencies?
Just looking to eliminate the need for 2 lips (flight & video) lipo's to (flight) lipo only.
First off, is this scenario plausible? Or would the power cost on flight time outweigh the benefits
(3DR 5.8 ghz transmitter) + (GoPro using internal battery) (Flight Lipo = kypomm 3s 3300mah 35c-70c)
Secondly what are potential wiring solutions (is beneficial)?
Possibly wiring (soldering) directly to power distribution board main inputs?
Possibly connecting to pixhawk for power?
I should note that i'm using 6 jdrones 20A ESC's and 6 jdrones 850kv motors.
Thanks in advance for any advice.
Replies
So i tried to narrow my question down to will this set up in the following diagram work?
Providing I stay with 3s (might go for a larger 5000mah 3s). Thus eliminating the need for 2 lipos on the Y6.
Thanks in advance.
Your antenna arrangement still bothers me. :)
My video transmitter is powered by 12v, which I think comes off of the power distribution board, but I can't swear to it. I knew a week or two ago. If I recall, there is a JST lead coming off the PDB to which the TX's JST is attached.
Yes, your amperage settings for the charger sound appropriate. I can't tell you anything specific about your charger, unfortunately. Most taper the voltage and charge current to prevent overcharging. I could assume yours does, too, but then I'd be assuming. That's why a charge that starts out at a 1C rate generally takes more than the theoretical hour.
Set the battery monitor up now. It is pretty easy to do and not worth crashing over.
As far as batteries go, a "35-70C" is pretty much a 35C. Anything can handle lots of current if the time interval is short enough, so I consider mentioning 70C to be a worthless marketing gimmick. I'd be happy to learn otherwise, if I need to be corrected on that.
My 4S 6000mAh can be bought from 3DR for $75, and a HobbyKing variant can be had for less. Why would you pay $75 for a 5000mAh 3S? Maybe it is extra super special. Mine weighs 600grams, with the XT60 connector on it (the way it comes).
Unfortunately my pdb that came with my y6 doesn't have a jst lead coming off it just merely the mains and the pixhawk 6 wire + 2 wire servo cable also connected to pixhawk. So perhaps i need to just solder a connection direct to the pdb itself? I was using the 850mah 3s 30c gens ace lipo for the tx currently so my assumption would be the flight lipo provides the same energy load as the 850mah?
As for lipo prices, I had looked into other options but it's just a result mere location, I'm pretty much as far north as the transcanada highway goes in ontario canada, so shipping from either of those places takes at least 2.5 weeks up to a month (hobby king to ship north costs 40$ min) and with the short window of reasonable flying season (not to sure how it would hold up in our winters), a month of waiting would pretty much eliminate 1/3 of the flying season. And to make matters more inconvenient the nearest rc retail is 8hrs away, so i'm rather limited to options. The lipo i was considering for 75$ wasn't even a brand I've heard of but rather the retailers own brand of lipo's (Team great hobbies). Far less weight at from what i can recall aprrox 402g's shipped? And doesn't come with the standard xt-60 but instead a deans connector or something alike, so it definitely isn't the best option but one that would suffice. I'd like to get an actually weight of the entire y6 without lipo but haven't had time to bring it into my research lab yet where a sufficient scale is.
Yeah i kinda figured the 70c was just there as a draw point for purchasing without any really value.
I guess as the industry builds up momentum closer retailers will open up.
I'm somewhat of a perfectionist so i'm constantly looking to clean up my rig as well as minimize components trying to keep things as simple as plausible. Which is probably why i've spent hours researching proper prop assembly & balancing (apc props). Can't seem to figure out if i glue the collets in and do i also bore out the hole with some device to get a cleaner fit onto the shaft adapters (jdrones motor adapters) as the threads somewhat resist the prop from easily sliding on requiring some force...
Ahh the joys of being new to specialized technology.
Thanks Again!
Think of "C" as being Capacity per hour. If you charge a battery at 1C, it should be charged in 1 hour. A 3300mAh battery can deliver 3300mA for one hour. 3300mA is 3.3 Amps. So, it can deliver 3.3 Amps for one hour. To charge it at 1C is to charge it at it's capacity per hour. So that's 3.3Amphours per hour, or 3.3 Amps.
If the battery really were empty, and it really had a capacity of 3.3Amp hours, charging it at 3.3 Amps should take one hour. In reality, most chargers taper off to lower charge rates as the battery gets more full just to be nice to the battery and charge it most effectively. So even if it starts out at 3.3Amps, it will probably taper off to a lower charge rate and won't actually finish for 1.5 to 2 hours, as an approximation.
So, if you can tell your charger you have a 3S 3300mAh and want to charge at 1C, it will deliver 3.3Amps maximum. If you tell it to charge an 800mAh 3S at 1C, it will charge at .8Amps. That's assuming your charger is actually asking for C. If it is just asking you what amperage you want, then 3.3 would be the right answer for the first one and .8 for the smaller one. If you are not in a rush, 1C is a good way to go. If you have any reason to go to 2S, most batteries will tell you that's OK, and many will allow much faster charge rates. Check your battery specs.
My 3DR Y6 flies on a single 4S 6000mAh. It is a $75 30C battery. That powers the copter, pixhawk, gimbal, and the GoPro. The GoPro has a battery in it, but I let the copter power it. I get around 11.5 minutes of good moderate flight out of that. I didn't want more than one battery to worry about. I do have a small 3S 800mAh for my ground station video receiver and monitor. That will power both of those for about 25 to 30 minutes, I think.
So i checked the charger and it is in amperage, so basically what i'm getting from this is that the 3300mah would convert to a amperage of 3.3 in hour right from empty. So with the 3300mah i'd set to balanced charge 3s 3.3 amps for 1 hour
or lets say the 3s 850mah is at 10.56v (3.69,3.54,3.67) then i would set the charger to blanched charge at 3s with 0.8 amperage until i reach 12.59v (approx 1 hour)?
Would the charger inform me of when i'm at such a range of 12.59v or is there a way to check or better yet a automatic shut off?
I'm new to this IMAX B6AC, but i have read the manual, although some of it I'm a little uncertain definitively what they're saying at certain points.
I do also plan on getting a larger lipo perhaps the same specifications as my current 3300mah perhaps a 3s 35c-70c 5000mah (75$)? This would definitely increase my flight time i'm hoping, although i don't have any idea how long my current time is (still need to set up voltage warning in apm planner via telemetry as to run some flight time tests).
I included a photo of my y6, i don't currently use a tarot gimbal (why i use the go pro batt) but merely a basic anti vibration gimbal rig in order to limit my overall weight, as i'm looking at using this for conservation research so the potential for sensors in the future will make up for the weight saved i'm sure.
My question is how do you obtain power for the 5.8ghz transmitter from your single lipo? a speciality wire?
I currently have a standard jst connector, would removing the connector and soldering direct to the pdb be the best option or would obtaining its power through the pixhawk be a more viable option?
Just looking to keep things clean and simple.
Current Lipo: http://www.kypom.com/pro_detail.asp?id=819
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