Ok so as some of you know Ihave an EZ* that I am currently working on. Ihave an upgraded motor with a 25-30A ESC and a 2300mAh Lipo pack. What I would like to do is get a power switch to turn the plane off and on but Iwould also like a way Ican charge the plane from the outside without having to open the plane and take the battery out every time. Then again Ihave heard of the dangers with these lipo packs so what do you all think?

It is much safer to charge the battery outside the plane. And as far as a switch is concerned, well, there are not many small switches that will handle the current flow you are talking about here. It is not a good idea. Just go with the standard and remove the battery after flying and recharge it that way.

If you want more than one flight, then get a second or a third battery pack.

CGr.

Even if you made up a switch of your own, like Dick mentioned, it just isn't a good idea to charge these batteries inside the plane. As great as they are, there are a couple of draw backs to them. I only have one small electric but I have a couple of good packs for them. I get about 25 minutes of air time with each pack and find it easier to charge at home. I no longer even take the charger out with me.

So then just so I understand this correctly, every time I want to fly I will have to connect the battery to turn it on then disconnect it to turn it off? I actually didn't think hooking up a switch to something like this was a big deal but my electronic know how is pretty basic so thanks for pointing that out.

Yes that's how you do it.

And yes a switch is a big deal.

Remember your household circuit breaker may only be rated for 20A, but the ESC on your airplane may be pushing 30A+ ( or in many of my planes 100A + )... and yes there is a voltage difference but the effect is similiar.

Your home also uses AC current while your battery is DC... so there's a relatively high amount of power being pushed out.

The small size of this stuff can be a bit deceptive... until you get a nice shock!

For most large electrics switches are never used, instead there is a heavy removable arming plug which is typically very similiar to the connectors used on the battery packs.

The idea is not to introduce additiona resistance points that may impact current flow.

Now when its time to fly would it be ok to disconnect motor from ESC, plug in battery, then plug motor back into ESC when Im ready to throw it and have it do its thing? My connectors for the motor and ESC will be external so thats why I was asking. That way I can open the plane install battery and put it back together without the prop spinning

Second questions sense it still deals with the topic of Lipo packs, is it a good idea to get one of those "bags" that your supposed to put the pack in while you charge or is something like that more of a gimick?

I use an old baking pan, I have seen old ammo cans used. There is a crock pot you can buy or you can use an old flower pot. My motor/ESC stay connected. I have tried plugging in my battery with and without turning on my radio first. Without the radio on the motor doesn't turn but like any plane the servos start glitching a bit. I started plugging in with radio on again but I watch where I put my TX so no one touches it, these little electrics may be small but that prop really gets to spinning in a hurry. My Deans connectors are hard to get off so I leave a small gap between them so I can get my finger nails between them to take them apart. Nothing conductive EVER!!! You know, there is a forum/site just for questions about the electrics at the bottom of the header. It has the best information I have ever found for electric planes!! Go sign up.

The problem with disconnecting the motor from the ESC is if you have one that is NOT color coded, then it's easy to get the leads mixed up and you could have a reverse running motor. Not that big a deal because all you have to do is swap any two leads and you're good to go (brushless that is). For brushed, well, red to red and black to black.

But, as already mentioned, I never disonnect them, just remove the battery pack, swap or re-charge, then put it back in.

I have a "LiPo Sack"... sold somewhere on the web.. that I charge my LiPo packs.. ALWAYS outside.

CGr.

Can't edit for some reason, so I'll just put my additional 2 cents worth here. There are several safety precautions to take with LiPo and you have already heard of several ways to help you out. As I said, I have the LiPo Sack.. it's not a gimmic, they work.. but only once if you DO have a fire.

One members wife made these neat little ceramic "pots" to recharge our LiPo's in.. he gave me one. Neat. But, there are several ways to protect yourself and your property.. but the most important one is to charge it outside away from stuff, on dirt or concrete.

CGr.

So what your saying is that when I am ready to charge my battery I should...
1) Make sure fire pit is cleaned out.
2) Grab some twigs and lay them in the pit.
3) place battery just under the twigs and with a long cable going to the charger.
4) In case this puppy sparks have some bigger logs ready.
5) Grab some beers and brats.
6) If there is ignition then party must fallow after. If it doesn't well then you get to fly and have fun that way.



But seriously, yeah I do understand what you guys are saying. So I will get a lipo sack, maybe a few even, and be sure I charge at a safe distance and in a safe environment. Thank you all again for your advice. I greatly appreciate it.

Here is where Dick and I disagree, not a big deal but I tend to forget things, like right away. I also tend to read a lot so I hook up the charger so it is right next to me and put my battery in the safe pot then charge while I'm reading. If the charger is too far away I can't hear the 10 little beeps. Most the time I can't hear them with the charger right next to me. So far I haven't even had a battery come off the charger at anything I would even call warm, always feel like room temp. I have one old friend that didn't have his in a safe pot and was charging it in his shop and forgot it. It burnt down most of his shop but the house was saved. Nuff said!!!!

As mentioned already, not this is not a good idea.

Your best bet is to make sure you can disconnect the battery pack when you need to.

Most Electric planes feature easy access hatches for this purpose. People who convert glow planes to electrics tend to cut their own access panels to get at the battery.

If this seems impossible consider an arming plug instead...



I charge my Lipo's on a table top. I put the packs to be charged onto flagstones or bricks, in case the packs catch fire.

I have a fire detector above this area, and I also use a thermal sensor off my charger, which I periodically test to make sure it shuts off the charge current if the LiPo's start getting warm or hot.

You pays your money and you takes your chances!!!

I've never had one go bad either. I did have one that got really puffed up during a charge, got kinda warm, but never went kaboom. I found it next to the charger about 30 minutes after I put it on the charger, all puffed up and warm... not hot. I disconnected it and left it there for about two days. I still have that thing somewhere in the back room... [X(]

Dick.

Fallow: Land that has undergone plowing and harrowing and has been left unseeded for one or more growing seasons.

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Sorry, I had to do that. [X(]

CGr.