Launch Controller Electronics

[Art Upton]

This seems pretty straight forward.
In terms of storage, I've seen that LiPo's need to be discharged down to a certain voltage per cell for storage. Since this will only be launching 10-20 rockets a quarter (After school program) would it be best to use a charger that has a storage capability?
My primary stakeholder wants the controller to have an internal battery compartment so using larger or heavier batteries instead may not work.

Forget what your Controller wants that does not understand how things work. For LiPo you need to charge outside the device in an area that if fire happens will not cause a problem. It seems that your teachers do not understand the Science

I never charge my RC airplanes or Drones LiPo battery inside them; you don't do that

 

[rocket_troy]

Forget what your Controller wants that does not understand how things work. For LiPo you need to charge outside the device in an area that if fire happens will not cause a problem. It seems that your teachers do not understand the Science

I never charge my RC airplanes or Drones LiPo battery inside them; you don't do that

Better pass that wisdom on to a phone company or 2, or a laptop company or 2...

Surely it would depend on how much of a hurry you were in? I can appreciate that RC kit might require high current charging for high power kit which makes sense to separate the battery, but surely not every application needs that?

TP

 

[Handeman]

As Art said, if you use LiPo, you have to be able to easily remove it for charging. If you use a 4Ah SLA, you can leave it inside the controller and just make a charging port. And with an SLA, you can use a simple voltage display that will tell you when it needs a charge.

Our club uses 4Ah SLA in our wireless pad boxes that power 5 pads each, and just plug them into a charger powered by a solar panel at the end of the weekend. They are always ready to go the next month and easily last for 2 and 3 day launches without needing to be recharged each day.

 

[Handeman]

Better pass that wisdom on to a phone company or 2, or a laptop company or 2...

Surely it would depend on how much of a hurry you were in? I can appreciate that RC kit might require high current charging for high power kit which makes sense to separate the battery, but surely not every application needs that?

TP

You are right about phones and laptops, but they have internal controllers that control the charging so they know exactly how those batteries are being recharged and can design that recharge controller with plenty of safety margin.

In this case, to safely leave the LiPo inside when charging, he really would need to incorporate his own charge controller which would greatly complicate the controller even more.

 

[Art Upton]

Better pass that wisdom on to a phone company or 2, or a laptop company or 2...

Surely it would depend on how much of a hurry you were in? I can appreciate that RC kit might require high current charging for high power kit which makes sense to separate the battery, but surely not every application needs that?

TP

You have no idea of the larger picture

 

[rocket_troy]

You are right about phones and laptops, but they have internal controllers that control the charging so they know exactly how those batteries are being recharged and can design that recharge controller with plenty of safety margin.

In this case, to safely leave the LiPo inside when charging, he really would need to incorporate his own charge controller which would greatly complicate the controller even more.

Fair enough, I just naturally assumed he would be using a recharging controller irrespective.

TP

 

[rocket_troy]

You have no idea of the larger picture

Well, thanks for the detailed explanation of the "larger picture". Clear as mud now.

Gotta love cryptic dogma.

TP

 

[Rschub]

Get something like this:
https://www.amazon.com/Adapter-Conv...hvlocphy=&hvtargid=pla-4583726559777039&psc=1There are several styles available. Wire/mount it into your controller box. You can keep the battery on its charger until launch day, install, launch, then put it back on the charger until next time.

 

[Lord Rory Gin]

There are tons of cheap lead acid gel cells available now for kids toys. $20 each, and a 12v 7ah battery will last all season; best of all, a voltage Is a good indicator of charge. I got two old ones for free, and even too degraded to use in the toy, they last for a season's launches without a recharge.

Yep! I got an old 12v 8ah LA battery from a emergency light fixture for free. It was 10 years old before I got it. I charged it up and have been using it for 3 years. It lasts practically forever.

 

[Curtis Enlow]

I charge my smaller 2 & 3 cell LiPo batts outside in a fireproof charging bag. I never leave a LiPo charging - no matter how low a rate - unattended. I trust nothing to Chinese QA or electronics.

 

[Glasspack]

Wow

 

[Nate G]

To the OP, interesting and useful first project. for one at a time launches with a beginner club. the first post of a schematic is Excellent. I have built several over the years and use one with my grandsons regularly. There are several boxes to enclose this on Thingiverse you can 3D print.

I am familiar with that size battery. It will do great! with its ability to launch Literally a thousand rockets, the counter for launches remaining is useless. A simple voltmeter to show what is in the system and that it is healthy should suffice. It should also work great in something like the Losi Mini-B.

The ultimate safety for keeping a launch system disarmed, is to disconnect the battery. That battery uses a common connector that you can buy a mating connector for that is designed with holes for mounting bolts for a dollar. I use XT 60's and simply disconnect the battery and have it in my pocket when students are working at the pad. As a practical matter, the battery can be velcroed to the back of the control box or kept further away from the box with an extension cable.

Have a chat with your teacher and good luck