This should be my last novel, as I think I covered it all already more than once...
Again, some of these points are only for people looking into this and not addressed to you're video or anything. Obviously you know what you are doing.
Couldn't agree more. Rechageables are a great money saver and also better for the planet and such.
As low of the amp draw of that led is, there is still an amp draw there. If the pack gets down to near 9V and you put the machine away in storage somewhere for a long time, eventually that led is going to dip the voltage below 9V. The amp draw of an RX and servos is pretty low in RC too, (but higher of course), but if a plane is near LVC and sits in a tree for a few days it will drop the voltage below 9V. I've had it happened more than once, and on RXs that shut off the motor for sure so there is no falsing when they lose TX contact with your remote control. Same deal with the servos. Blocks out jitter with lost TX contact, so the amp draw is pretty low...But not as low as that led of course. But very low in respect to the capacity of a good lipo pack. Just saying if that buzzer is left plugged in and the detector put in storage, sooner or later the buzzer comes on, which means more amp draw, and that pack will go below 9V. How long that will take? Who knows without measuring the amp draw, but sooner or later it will happen if nobody noticed the thing sounding off in storage or something. Not saying it's not a good idea to use. Just saying people better make sure they remember to unplug it just to lesson draining the lipo too far which could ruin it.
Didn't mean to come across at knocking your video if I did. Not my intent. Just offering a few of my own views on stuff. Of course others may differ. Most of the content of my messages wasn't even intended for you, but rather people exploring the idea of doing stuff like this themselves. That's why I'm trying to make it very clear to them that it can be very dangerous if you don't know exactly what you are doing. But so is driving a car or pumping gas like I said. Nothing is ever safe, but risk can be limited by knowledge and skill, so it's up to people to learn on their own from many sources before they even think of a project like this.
Yes, as I said...it's up to people to know the low battery alarm point of their machine. If it's above 9V then no need for a buzzer add on. Or, if the machine doesn't have a low battery alarm but does have a voltage display (such as some analog detectors that use the meter to show voltage, or a computerized detector that might only sound low battery below 9V but will show the actual voltage of the pack)...Then if you are careful to check your voltage often there shouldn't be a need for the buzzer, but if you think you'll forget or you can't read the voltage on the meter/screen of the detector, then for sure use that buzzer. Or, you could time your usage and figure out how long you can run the pack without hitting 9V by knowing the amp draw of the machine. Or, you could just check the voltage after say 10 hours of hunting time and see if it's still high. Use it another 5 and check it again. Perhaps risk another 5 hours to make it 20 hours total and check again. I wouldn't push it too far though because you risk going below 9V, but then you'd have an idea of how many hours roughly you can hunt between charging. That's still risky though, so I'd undershoot it a good bit. Even though my GT will sound off at 10.2 volts or so, I still charge my lipo about every 10 hours just so I don't run out of power on a hunt. Gives me piece of mind that way, but I also have another lipo handy should the first die on me.
Lipos are just as idiot proof as lithium ion for the most part. Pleny of plug-n-charge simple chargers for lipos out there. Many don't even have a switch to set the amp rate, because they already have a built in super low one. Just have to make sure the pack can be charged at that high of set rate. But, just as simple, many simple lipo chargers will say have a switch on them that says (for instance)...".250 amps (that's POINT 250 amps), .500 amps (thats POINT 500 amps), 750amps (point again), and say 1.2 amps. Or, they might be listed as 250ma (meaning without the point in front of the number), which is the same thing as above...250 millamps, instead of saying ".250 amps" (POINT 250 amps)....Both mean the same thing. Now let's take the pack. Say a 1000ma 3 cell lipo that has a charge rating of 1C. What do you set the amp charge rate at? Well, since the pack is rated 1C charge ability, that means you can charge it as high a 1 amp (or 1000ma). So you would not use the highest 1.2 amp setting of the charger. The fastest rate you could charge it at on that charger is the 750ma setting. At that setting it will take about 1 hour and 15 minutes to a half hour or so. Simple as that. Plug it into the 3 cell balance socket (called a Molex plug) on the charger and off it goes. Some chargers want you to press a start button, while some will just auto start once the pack is plugged in. Some know the cell count because you plugged it into the 3 cell plug, but still others want you to set a switch to 1, 2, 3, 4 cells, or so on. Many these days use that switch setting as double insurance, and then will refuse to charge the lipo if the switch cell setting doesn't match the voltage the charger is reading from the pack as an added saftey feature.
I use a computerized charger myself that will handle nimhs, nicads, lead acid, lipos, life, A123 cells, lithium ion, and a few other types I think. I can also set the amp charge rate at 100ma increments, so I can set it to exactly what I want for a given pack. But to charge all these various battery types, this charger is computerized with a screen, and so you have to know how to set various things to adapt to various battery types. NOT for the novice, as setting this stuff without understand what it does and how it should be set could be a fire hazard or worse. Cheap charger though. Dirt cheap in fact, but I won't name brands here because I don't feel it's appropiate for me to do so in this particular thread.
Now, many of these lipo chargers are only meant to run off around a 9 to 15V DC power source or so. For that reason many in RC run them off their car or truck they drove to the flying field. You can charge packs many times before risking causing the car battery to go dead, but many start the car after a few charges just to be safe, as a weak car battery could drain fast. Many of us fly one plane while we have 2 or 3 lipos charging off the car battery at the same time, so we can always be flying with one pack while the next one in line is charging, and the one behind that is charging too, and so on.
If you don't have a 12V car battery to run one off of, there are cheap DC invertors you plug into your wall at home. You just have to be sure the inverter is in the right voltage range that charger wants, and also to be sure the invertor can handle the amp draw of the charger in it's specs.
One other note of importance and then I'm done. Too much typing today even for me.

Do NOT confuse the C ratings of a pack. There is a C rating for it's charging rate (max rate you can charge it), and there is a C rating for the max amp draw the pack can supply to whatever it's powering. For example, a typical 2000ma 3 cell lipo might say 1C charge rate, 20C amp ability. That means you can charge it at 2 amps (1C, or 1X capacity), and you can power say your plane with 20C ability of the pack. 20 X the capacity of the pack (which is 2000ma) = 40,000ma, or in other words 40 amps is what the pack is able to deliver in amps. Well beyond the amp needs of a detector. Most detectors only need less than an amp that I've ever checked the amp draw on.
Now, one more thing...Don't confuse the capacity of the pack as it's amp delivering ability. That's just the # used to figure out the amp delivering ability and the charge rate ability. The capacity's true meaning is how long the pack will run something. I hear people get confused about this all the time and think a 2000ma pack will burn up their detector because it only came with a 1000ma pack. No, the capacity of the pack is just how long it will allow you to hunt between charges. It doesn't supply more amps to the detector, as the detector (like any device) will only draw the current it needs and nothing more. You could have a battery the size of a house in capacity and it won't blow up the thing it's powering...SO LONG as the voltage is the same. Meaning, the main thing you need to worry about in using your own packs is that the voltage is not above the voltage the device you are going to power it with wants. For instance, a 3 cell series lipo is 12.6V when fully charged. Well within the tolerance of most detectors that run on 8AA batteries in series. Now, if you were to run a 4 cell lipo (16.8V) in that device then you have a very good chance of burning it up due to over voltage. Using too high a voltage will eventually burn a device up if it's way out of the window it wants to see in DC voltage.
One minor other point concerning nimhs and nicads. I've seen many worry using them in a detector will give it less performance, because nimhs and nicads are 1.2V per cell versus 1.5V for regular batteries. Nope, truth is most detectors these days (if not all of them) use a voltage regulator in them to keep the voltage constant to the circuit board so they run stable. So, it doesn't matter if the voltage is 10V or it's 12V, if the voltage regulator is an 8V regulator then 8V is all the circuit board ever sees. They do this to stabilize the circuit board otherwise your machine would constantly drift out of tune while the battery drains. For that reason nimhs or nicads (say 8 of them to replace your regular 8AA non-rechargeables) will NOT give you less performance. And, in fact, a good 2500ma or higher nimh AA these days will give you more run time than most store bought non-rechargeable batteries. Just doesn't make sense to not use rechargeables these days IMO. Saves you a bunch of money. If you don't want to mess around with a complex charger just but the one that often comes with 4AA rechargeables at walmart or such. Then you don't have to worry about amp rates or anything because the charger is meant for those batteries sold with it. But, that still doesn't mean it's safe. Always charge in a fire proof place, regardless of if the charger came with it or not. Any battery poses a risk.
One more tiny tip- Nimhs and nicads self discharge when sitting on the shelf, so if you haven't charged the pack in weeks or months it might be too low to power your detector for very long. Either top off the charge right before you hunt if the pack has sat for a while, or there are now low self-discharge nimhs on the market that claim to hold their charge near full for months without needing re-peaked. Some are better than others at that, so research and find out which ones passed the tests done on them.
OK, that's all I got to say.
[size=large]I know these were long posts but I feel battery safety is of PRIMARY importance at ALL TIMES. Don't muck with this stuff if you don't know what you are doing. Just use packs and chargers meant for your machine specifically. And once again don't trust my advice. Always seek confirmation from numerous sources you can trust, because you could very well burn your house down, get injured, or start a fire or worse. Hope this helps...
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Hey, once again excellent video. Nicely done!
