LIPO Batt Charger - for onboard installation

Sailfish1957

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I’m looking to find out what battery charger is used in the attached photo of an ebay sled that has a FW GPS Tracker, magnetic switch, charger and LIPO battery ….. All in line. And any pointers on the wiring would help.

This is going in a 6” long payload bay in an LOC IRIS 3. 3” diameter.

Thanks
 

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Kelly

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Hard to tell from that photo. But Sparkfun is usually a good place to start, especially if you need help with schematics etc. For example, https://www.sparkfun.com/products/14380 would fit the bill. Most of these I think use the MCP73831 charging chip, so you could also google that to see what other boards/currents are available.
 

Sailfish1957

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That looks like the Adafruit LiPo charger.

Here's a link : https://www.adafruit.com/product/1904

I use these chargers for my 1S lipos.

If you buy one - be sure to check which USB cable you need.

This shows one of my charger setups.

View attachment 536281
Thanks. I thought it was an Adafruit. Note how the charger is used in line and the down stream Mag switch is connected. Which terminals on the Adafruit would that go to?
 

Sailfish1957

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Thanks. I thought it was an Adafruit. Note how the charger is used in line and the down stream Mag switch is connected. Which terminals on the Adafruit would that go to?
Hard to tell from that photo. But Sparkfun is usually a good place to start, especially if you need help with schematics etc. For example, https://www.sparkfun.com/products/14380 would fit the bill. Most of these I think use the MCP73831 charging chip, so you could also google that to see what other boards/currents are available.
I like that charger. How would you mount it on the ebay sled?
 

Kelly

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Hmm, yeah it looks like the sparkfun module doesn't have mounting holes! So craft a slide-in holder for it, or go with the adafruit or other. It looks like either of these have solder pads to take off the voltage you need to power the circuit. Read the docs that come with them.
Be sure you get a unit that supplies the proper current for charging, or that is adjustable. Also note that these are 1S chargers; you're going to need something else for other batteries.
 

Sailfish1957

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Hmm, yeah it looks like the sparkfun module doesn't have mounting holes! So craft a slide-in holder for it, or go with the adafruit or other. It looks like either of these have solder pads to take off the voltage you need to power the circuit. Read the docs that come with them.
Be sure you get a unit that supplies the proper current for charging, or that is adjustable. Also note that these are 1S chargers; you're going to need something else for other batteries.
Many thanks. I can definitely craft a slide-in holder. And agreed on the 1S issue. Great input!
 
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There are plenty of up down regulators available with current limiting and and of charge cutoff. The up down converters take any 0-30 v in and give any 0-30 out. You lose a bit of efficiency with the double regulation up to 32 then back down to anything you need, but these are the most useful bits of kit I've come across.
 

QFactor

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Here are some pictures of the assorted 1S LiPos I use for rocket electronics and other hobby electronics.

The LiPo trickle charger from Adafruit uses a simple cell phone charger block; 5-volt, 1-amp. The charging
block in the picture is one of my old Iphone chargers. You can pick these up for a few bucks on Amazon
or Ebay - and you may have some sitting around from other devices.

I show a pair 300mAh LiPos (20C) with pigtail wires (in Series). I use this for electronics that need 7.4-volts,
but not a whole lot of amps. I can separate the batteries and charge them with the Adafruit unit. They have
a smaller footprint than the 9-volt battery.


Lipo-Adafruit-Charger-01.JPG

LiPo-BatterySize-mAh.JPG

LiPo_300_20C-9V-02.JPG
 

Steve Shannon

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I’m curious why you would add the charger to the sled instead of leaving it outside the rocket? Granted it’s not much mass and the wiring is about the same either way. Will you add one charger for each electronic device?
 

Sailfish1957

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Here are some pictures of the assorted 1S LiPos I use for rocket electronics and other hobby electronics.

The LiPo trickle charger from Adafruit uses a simple cell phone charger block; 5-volt, 1-amp. The charging
block in the picture is one of my old Iphone chargers. You can pick these up for a few bucks on Amazon
or Ebay - and you may have some sitting around from other devices.

I show a pair 300mAh LiPos (20C) with pigtail wires (in Series). I use this for electronics that need 7.4-volts,
but not a whole lot of amps. I can separate the batteries and charge them with the Adafruit unit. They have
a smaller footprint than the 9-volt battery.


View attachment 536503

View attachment 536505

View attachment 536507
Thank you very much for the expertise. I will use your advice. In the bottom close-up photo it looks as though you tape over the top connection on the battery. Is that to prevent damage to the delicate connectors?
 

QFactor

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Thank you very much for the expertise. I will use your advice. In the bottom close-up photo it looks as though you tape over the top connection on the battery. Is that to prevent damage to the delicate connectors?

The batteries came with the tape over the top. And yes - that is to protect the wires and circuit underneath.

If you cruise around on the web looking at LiPo batteries you will start to see other manufacturers do the same thing.

A lot of people are used to seeing the sleek 1S LiPos with the yellow-tinted end and a clear view of the protection circuit.

LiPo_300_20C-9V-05.JPG LiPo_300_20C-9V-06.JPG

These are pictures of the batteries before I changed their connectors to the typical JST PH connector.
 

Sailfish1957

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I’m curious why you would add the charger to the sled instead of leaving it outside the rocket? Granted it’s not much mass and the wiring is about the same either way. Will you add one charger for each electronic device?
Sorry for the delay in responding…..the on-board charger will allow the battery to stay in place and always connected, thus avoiding pulling on the delicate connectors for removal to charge externally. A mag switch isolates the FW GPS Tracker.
 

Steve Shannon

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Sorry for the delay in responding…..the on-board charger will allow the battery to stay in place and always connected, thus avoiding pulling on the delicate connectors for removal to charge externally. A mag switch isolates the FW GPS Tracker.
I understand wanting to protect the connectors. I would leave the connectors connected, but wire in a charging port in parallel to the battery connector to allow a charger to be plugged into the switch-band while the electronics are turned off. That way you don’t carry the mass of the charger on every flight.
 

Sailfish1957

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I understand wanting to protect the connectors. I would leave the connectors connected, but wire in a charging port in parallel to the battery connector to allow a charger to be plugged into the switch-band while the electronics are turned off. That way you don’t carry the mass of the charger on every flight.
Yes, also a good idea. Probably simpler too!
 

MidOH

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Sorry for the delay in responding…..the on-board charger will allow the battery to stay in place and always connected, thus avoiding pulling on the delicate connectors for removal to charge externally. A mag switch isolates the FW GPS Tracker.

If that's the game plan, chop the connector off, and hardwire it to the switch.
 

Dan Griffing

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I’m looking to find out what battery charger is used in the attached photo of an ebay sled that has a FW GPS Tracker, magnetic switch, charger and LIPO battery ….. All in line. And any pointers on the wiring would help.

This is going in a 6” long payload bay in an LOC IRIS 3. 3” diameter.

Thanks
I’m looking to find out what battery charger is used in the attached photo of an ebay sled that has a FW GPS Tracker, magnetic switch, charger and LIPO battery ….. All in line. And any pointers on the wiring would help.

This is going in a 6” long payload bay in an LOC IRIS 3. 3” diameter.

Thanks
This picture was from me for a nosecone GPS payload with a 54mm motor form factor.

This was an Adafruit 1s LiPo usb charger.

My main reason for using it was to remove the stress from the Featherweight GPS and battery wiring from repeatedly removing the plug to charge the battery.

All I had to do is make sure that the Featherweight switch was OFF, and then plug in the USB port to charge the battery. Be careful while handling the charger with your fingers while plugging in the USB cable because you can feel a shock while doing this.
 

Sailfish1957

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Thanks. On the Adafruit charger, what is the placement for the pos (+) and GND/neg (-) wires that go to the switch? It’s hard to see in the picture, but looks like you have the output to the switch on the “BAT” and “GND”. Correct?
 

Dan Griffing

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Thanks. On the Adafruit charger, what is the placement for the pos (+) and GND/neg (-) wires that go to the switch? It’s hard to see in the picture, but looks like you have the output to the switch on the “BAT” and “GND”. Correct?
That is correct.

Because the charger needs to connect to the battery’s + and -, I use the terminals on the Featherweight where these wires are attached because there is no other place where they are directly connected.

The Featherweight’s + connection to the battery is disconnected when the power switch is in the “off” position. This protects the Featherweight from a power spike when you plug the USB into the charger.
 

Sailfish1957

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That is correct.

Because the charger needs to connect to the battery’s + and -, I use the terminals on the Featherweight where these wires are attached because there is no other place where they are directly connected.

The Featherweight’s + connection to the battery is disconnected when the power switch is in the “off” position. This protects the Featherweight from a power spike when you plug the USB into the charger.
Last question: what size screw do you use for mounts ?
 
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