a battery pack for eggtimers?

[NTP2]

I wonder if I broke open one of the battery packs used for charging phones and grabbed the power off of the USB ports if id make a cheap pack for rockets, they are not that heavy and most of its probably the case, it'd probably only work in HPR even with that but the price savings of getting a big battery and changing in one is tempting...

PS something like this

 

[Azamiryou]

I wonder if I broke open one of the battery packs used for charging phones and grabbed the power off of the USB ports if id make a cheap pack for rockets, they are not that heavy and most of its probably the case, it'd probably only work in HPR even with that but the price savings of getting a big battery and changing in one is tempting...

PS something like this

It probably has circuitry that limits current, plus pulling the voltage to the 5V phones use for charging. You could probably get rid of all the circuitry and just use the battery... but then you'd lose the charging as well, and might as well just buy a battery for about the same price.

 

[NTP2]

It probably has circuitry that limits current, plus pulling the voltage to the 5V phones use for charging. You could probably get rid of all the circuitry and just use the battery... but then you'd lose the charging as well, and might as well just buy a battery for about the same price.

the one I have doesn't, it gets HOT during charging, if it can pull that much during charging then its likely that it can push that much. an E mach only needs a few milliamps.

 

[Azamiryou]

It's not so much what the match needs as what it actually draws when presented with that voltage. If the circuit "thinks" it's a dead short, it'll shut down.

Of course it's easy enough to try it out if you can spare the twenty bucks. If it'll run your altimeter and fire matches on the ground, it should work in a rocket*.

*Well, you should check that nothing in the circuitry seems like it would be especially vulnerable to high Gs or vibration.

 

[kramer714]

I'm confused about what problem you are trying to solve? Small 1s and 2s lipos are pretty cheep and ready to go. Form Factor works well for rockets. Not sure why you need that big of a pack.

1s Lipo Amazon 1s 850 mAh Less than $5/ lipo INCLUDING A CHARGER
2S Lipo Amazon 2S 650 mAh for 8$ 70C discharge.

Not sure why you need that big of a pack. but if you did..
2S 5,200 mAh Amazon 5,200 mAh for $10 At 80C, im not worried about setting off an ematch, having said that onboard toaster would be something different (with bagel mode of course)

 

[NTP2]

I'm confused about what problem you are trying to solve? Small 1s and 2s lipos are pretty cheep and ready to go. Form Factor works well for rockets. Not sure why you need that big of a pack.

1s Lipo Amazon 1s 850 mAh Less than $5/ lipo INCLUDING A CHARGER
2S Lipo Amazon 2S 650 mAh for 8$ 70C discharge.

Not sure why you need that big of a pack. but if you did..
2S 5,200 mAh Amazon 5,200 mAh for $10 At 80C, im not worried about setting off an ematch, having said that onboard toaster would be something different (with bagel mode of course)

2s lipo chargers are expensive.

 

[lr64]

2s lipo chargers are expensive.

I expect you could find a suitable battery and charger for 25$, plus shipping. How do you charge the big one?

 

[David_Stack]

Define expensive... You are in a hobby where you are literally burning money each and every launch. Invest in a charger, it's not something that is a recurring expense and a good charger will help maintain your batteries and prevent the need to prematurely replace them.

Facebook Marketplace, RC Groups classified, a number of places where you can purchase used, and as long as it was taken care of, it's likely to be a long-term investment.

 

[NTP2]

I expect you could find a suitable battery and charger for 25$, plus shipping. How do you charge the big one?

I tried, the lowest I could see was 50$

Define expensive... You are in a hobby where you are literally burning money each and every launch. Invest in a charger, it's not something that is a recurring expense and a good charger will help maintain your batteries and prevent the need to prematurely replace them.

Facebook Marketplace, RC Groups classified, a number of places where you can purchase used, and as long as it was taken care of, it's likely to be a long-term investment.

I like to spend when I have to and save when I can.

 

[David_Stack]

I tried, the lowest I could see was 50$

I like to spend when I have to and save when I can.

https://www.rcgroups.com/forums/showthread.php?4640493-Tenergy-T6-B-Battery-Chargers

https://power.tenergy.com/tenergy-t...OG0onWXHwcKTI50db1nogz3A2kDQVOKUZqoZInO5hTkZT

 

[Titan II]

I tried, the lowest I could see was 50$

Really?

https://www.amazon.com/SUPULSE-Batt...er+for+xhr+plug+battery+b3v2+,aps,1183&sr=8-1

 

[NTP2]

https://www.rcgroups.com/forums/showthread.php?4640493-Tenergy-T6-B-Battery-Chargers

https://power.tenergy.com/tenergy-t...OG0onWXHwcKTI50db1nogz3A2kDQVOKUZqoZInO5hTkZT

Really?

https://www.amazon.com/SUPULSE-Battery-Charger-7-4-11-1V-B3V2/dp/B099K8XFG6/ref=sr_1_1?crid=ATFXTAEYN0J2&dib=eyJ2IjoiMSJ9.TnV8G6omVRoMS1SfCjMbfKlInZLXZpLPMuGzscdl9uaDiabuPbJtY8gs66zkQu-Nj1hNmPyfkySnwncfQGXg6es-0SoimYl2HdRV9XpT1IduL8nNGQ52rxIj2GNmr1jCK-o74MBjILvjqnbWYYo4sr6Oaa6IgjDlaG5PiIwEqFzcIceB7seNz94gsSCVhj0SY4jp-jgyOeasOZFmZEQEEszSdWfZSLQ_nac606OQIjlhJxtyPNrNZ1hqiYwqIkDhmwiPBvaiBRASSBDKIBPUyJXgo56_P9bAYn6kQShtwFk.tN_4rI2whZEntf0e4oUO9u6Wzayzd77Zi_RgmmN9p2U&dib_tag=se&keywords=LiPo+Battery+Charger+2S-3S+RC+Balance+Charger+AC+7.4-11.1V+10W+Upgrade+Version+B3AC+Pro+Compact+Charger+RC+Car+Charger+for+XHR+Plug+Battery(B3V2)&qid=1731956483&sprefix=lipo+battery+charger+2s-3s+rc+balance+charger+ac+7.4-11.1v+10w+upgrade+version+b3ac+pro+compact+charger+rc+car+charger+for+xhr+plug+battery+b3v2+,aps,1183&sr=8-1

Didn’t see those, cool, I’ll probably give it a try anyway because I have some of these already but I’ll get one of them if it doesn’t work.

 

[chrisudy]

I use a B6 charger similar to this one…. https://a.co/d/jhlsVyF

 

[cerving]

The B6 chargers are pretty much what most people use. I have a Hobby King Turnigy P606, it's different than the B6's in that it charges through the balance plug... you don't need to connect it to the power plug (JST, XT30, XT60, etc.). That makes it a LOT friendlier to use, because the balance plugs are all the same (JST-XH) so there's only one connection. Sadly, they don't sell it anymore.

 

[thzero]

2s lipo chargers are expensive.

https://a.co/d/iaQLPo7
yeah

 

[RocketPro]

Save up and invest in a B6-type unit. It does more than charging, like discharging and storage charging. Well worth the expense and it will work at home or in the field and will outlast all your rockets and batts!

 

[Art Upton]

Save up and invest in a B6-type unit. It does more than charging, like discharging and storage charging. Well worth the expense and it will work at home or in the field and will outlast all your rockets and batts!

Mine is about 20 years old now and still running. I charge all kinds of batteries with it. I got it as the second one I tried, when R/C started changing to Electric Flite from Glow Engines. Even build an adapter for charging some ham radio Handy Talkie batteries as well.

Have you seen these @NTP2 before ?

https://www.modelaviation.com/glow-engine-basics

 

[NTP2]

Mine is about 20 years old now and still running. I charge all kinds of batteries with it. I got it as the second one I tried, when R/C started changing to Electric Flite from Glow Engines. Even build an adapter for charging some ham radio Handy Talkie batteries as well.

Have you seen these @NTP2 before ?

https://www.modelaviation.com/glow-engine-basics

Yes but didn’t know that they were called glow engines, and I still don’t.

 

[Art Upton]

Yes but didn’t know that they were called glow engines, and I still don’t.

Glow motors don't use a Spark Plug, they use a Glow Plug. A coil that stays hot from the engine heat. you power it with DC current just when starting the motor, then it stays hot on its own. It makes the 2 cycle engine fire similar to a diesel.

The engine burns alcohol and Nitro Methane, plus some lubricant like castor oil or newer synthetics

https://duckduckgo.com/?q=r/c+glow+plug&iax=images&ia=images

 

[lr64]

I tried, the lowest I could see was 50$

I like to spend when I have to and save when I can.

You could get a small battery and charger for just over $25 at Aloft Hobbies. Or probably less on ebay or from Hobby King.

 

[terryg]

I use the SKYRC iMAX B6AC V2 for charging lipos for electonics and also for powering LED's on night launch rockets.

 

[Ronz Rocketz]

eBay is awesome. Plus they don't care about shipping to Hawaii.

https://www.ebay.com/itm/185234827420

Here's my Quantum.

 

[DaHabes]

Why? 300mah LiPos from Hobby King are around $5 apiece. Chargers are reasonable. Don't mess around trying to cobble together your own batteries. You'll end up with a lawn dart.

 

[DumasBro2]

https://www.amazon.com/URGENEX-Batt..._csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWxfdGhlbWF0aWM=

 

[sr205347d]

I wonder if I broke open one of the battery packs used for charging phones and grabbed the power off of the USB ports if id make a cheap pack for rockets, they are not that heavy and most of its probably the case, it'd probably only work in HPR even with that but the price savings of getting a big battery and changing in one is tempting...

PS something like this

Lipo cells that are abused become fire hazards. Circuitry that limits charge/discharge levels and rates are there for safety.

Save a few bucks on batteries like this, but lose a few bucks when your car or house goes up in flames.

 

[Azamiryou]

Lipo cells that are abused become fire hazards. Circuitry that limits charge/discharge levels and rates are there for safety.

Save a few bucks on batteries like this, but lose a few bucks when your car or house goes up in flames.

One with the circuitry removed is no more dangerous than one that didn't have the circuitry in the first place.

You want to be aware of and mitigate the fire risk whether or not your batteries have protection circuits.

 

[Titan II]

Lipo cells that are abused become fire hazards. Circuitry that limits charge/discharge levels and rates are there for safety.

Save a few bucks on batteries like this, but lose a few bucks when your car or house goes up in flames.

The batteries sold for RC that most of us use, do not have any circuitry. That being said, the OP's proposal is a terrible idea.

 

[sr205347d]

The batteries sold for RC that most of us use, do not have any circuitry.

Said circuitry is in the charger and the speed control.

 

[sr205347d]

One with the circuitry removed is no more dangerous than one that didn't have the circuitry in the first place.

If there is no circuitry in the battery, you need to make sure your charger has charge limits and your application has discharge limits.

 

[NTP2]

That being said, the OP's proposal is a terrible idea.

why, I see that there are cheap chargers available but the idea its self seems at least not unlikely.