A battery of questions!

[JimJarvis50]

I am wondering if Stratologger altimerters like the CF and 100 can be powered with 1S lipo batteries. Both manuals say 4 volts minimum, and 1S batteries will quickly fall below that to around 3.7 volts. A statement from Perfectflight on the issue would be, umm, perfect.

Jim

 

[SDramstad]

It has become so difficult to get them it may be a mote point... I love them but need more and they are never available any more.

 

[n27sb]

I am wondering if Stratologger altimerters like the CF and 100 can be powered with 1S lipo batteries. Both manuals say 4 volts minimum, and 1S batteries will quickly fall below that to around 3.7 volts. A statement from Perfectflight on the issue would be, umm, perfect.

Jim

Jim, this is an excerpt from the user manual:

This tells me that it has a diode that protects from reverse polarity. Nice safety feature but the diode kills a half a volt or more of the input voltage. If you bridge the diode you may be able to operate it on a 1s lipo. This has worked on other items.

Keep in mind that this probably kills the warranty.
Proceed at your own risk

 

[UhClem]

Probably depends on the voltage regulator used. If you knew the part number you could look at the data sheet.

Looking at a picture of the CF board I see a diode between the power input and pyro output terminal blocks but cannot tell if that also feeds the regulator. There are a lot of regulators that are reverse polarity protected so it might not.

 

[n27sb]

Worth taking a close look. The advantage of running a 1s is a big deal. It simplifies much.

 

[CPUTommy]

In a perfect world, id have 1 battery running the cameras, beeper and everything extra like a stand alone altimeter, one running my deployment and a second one (9 volt) running the backup.

 

[JimJarvis50]

I tested on 3.8 volts and it works fine. I have a question into PF, but don't know if I'll get a response.

Jim

 

[mikec]

On an SL CF, what I'm guessing is the voltage regulator is a SOT23 with the reference U4 and case marking HU54, adjacent to another SOT23 reference D1 (zener, possibly?), case marking IL43L. But I was unable to figure out the specific part types. If U4 is an LDO 3.3V regulator, then it could easily have a dropout voltage of < 0.1V and work at input voltages as low as 3.4V or so. One would have to probe the board to assess the dropout of any polarity protection. There's a big diode D2 that looks like it's downstream of the regulator.

 

[Bruce]

Might it be possible to hook the altimeter up to a bench power supply and test it to see how low the input voltage can fall before operation becomes unreliable?

 

[n27sb]

On an SL CF, what I'm guessing is the voltage regulator is a SOT23 with the reference U4 and case marking HU54, adjacent to another SOT23 reference D1 (zener, possibly?), case marking IL43L. But I was unable to figure out the specific part types. If U4 is an LDO 3.3V regulator, then it could easily have a dropout voltage of < 0.1V and work at input voltages as low as 3.4V or so. One would have to probe the board to assess the dropout of any polarity protection. There's a big diode D2 that looks like it's downstream of the regulator.

I agree,
On the Eggfinder GPS I bypass the input diode but the 3.3v regulator shuts things down around 3.4v. View attachment 443381 By then you have used over 90% of the capacity.
This works to our advantage because it can help prevent over- discharge. View attachment 443381

 

[Handeman]

Worth taking a close look. The advantage of running a 1s is a big deal. It simplifies much.

I don't understand why a 1S makes things any simpler that a 2S would be. They both use the same charger, you just have to plug in the balance plug when you charge the 2s.

 

[n27sb]

I don't understand why a 1S makes things any simpler that a 2S would be. They both use the same charger, you just have to plug in the balance plug when you charge the 2s.

On smaller rockets it eliminates the balance plug and you can use a simple USB type charger. On 54mm and larger probably does not make much difference.

 

[Handeman]

On smaller rockets it eliminates the balance plug and you can use a simple USB type charger. On 54mm and larger probably does not make much difference.




View attachment 443389

That makes sense. I guess I didn't quite understand because I've never used lipos for anything but gps transmitter and base station. I never use them for altimeters.

 

[Buckeye]

I am wondering if Stratologger altimerters like the CF and 100 can be powered with 1S lipo batteries. Both manuals say 4 volts minimum, and 1S batteries will quickly fall below that to around 3.7 volts. A statement from Perfectflight on the issue would be, umm, perfect.

Jim

Yes. There are several threads on the topic. Here is one:

https://www.rocketryforum.com/threads/alternative-to-9v-battery.135623/post-1609811
Perfectflight altimeters were not designed with LiPo's in mind, leaving the user to fend for himself on battery selection. Here is my go around on batteries for the SLCF that turned into an unexpected electronics project!

https://www.rocketryforum.com/threads/exceeded-6a-firing-current-on-slcf.156675/

 

[JimJarvis50]

Thanks for the links, Buckeye. I'm asking the question because I want to suggest to college teams that they use wifi switches, particularly for two-stage projects. That means dealing with the voltage and resistor issues discussed in the links.

Jim

 

[mikec]

Might it be possible to hook the altimeter up to a bench power supply and test it to see how low the input voltage can fall before operation becomes unreliable?

Sure, but I'd be concerned that this wouldn't catch different behavior over temperature and load. I'd rather do an analysis from the component datasheet values, if we could figure out what parts these are.

 

[cerving]

Thanks for the links, Buckeye. I'm asking the question because I want to suggest to college teams that they use wifi switches, particularly for two-stage projects. That means dealing with the voltage and resistor issues discussed in the links.

Jim

Jim:

It IS possible to switch a 1S Lipo with a WiFi switch, however you still need a 2S to power the switch itself. You connect the "+" lead of the 1S battery directly to the altimeter electronics, and connect the "-" lead of the battery to the "-" lead of the WiFi Switch's battery input, along with the 2S battery. You connect the "-" lead of the output to the powered device (leaving the "+" output disconnected). When the WiFi Switch is activated, it will connect the battery-common "-" lead from the 1S battery to the powered device, turning it on.

 

[JimJarvis50]

Jim:

It IS possible to switch a 1S Lipo with a WiFi switch, however you still need a 2S to power the switch itself. You connect the "+" lead of the 1S battery directly to the altimeter electronics, and connect the "-" lead of the battery to the "-" lead of the WiFi Switch's battery input, along with the 2S battery. You connect the "-" lead of the output to the powered device (leaving the "+" output disconnected). When the WiFi Switch is activated, it will connect the battery-common "-" lead from the 1S battery to the powered device, turning it on.

That's good to know. Thanks. But it's fine to use a 1S to the wifi too, correct? That's what I do, with fully charged 900+ mah, but your approach would give more range to the wifi?

Jim

 

[cerving]

That's good to know. Thanks. But it's fine to use a 1S to the wifi too, correct? That's what I do, with fully charged 900+ mah, but your approach would give more range to the wifi?

Jim

The 1S barely has enough voltage... it will work when fully charged, but it gets sketchy as it runs down. If you need a small battery just for the switch while using a separate 1S, I've used them as small as 200 mAH... they'll power the switch for at least 3 hours.

 

[JoePfeiffer]

I am wondering if Stratologger altimerters like the CF and 100 can be powered with 1S lipo batteries. Both manuals say 4 volts minimum, and 1S batteries will quickly fall below that to around 3.7 volts. A statement from Perfectflight on the issue would be, umm, perfect.

Jim

I've been running CFs on 1S LiPos for quite a while without a failure. All the ones I've used have been sub-200mAh; which specific ones have varied according to what's been available at the moment. The most recent has been
https://smile.amazon.com/gp/product/B00409KTLM/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1I fully charge them before a flight (of course); I've never seen them drop more than a tenth of a volt when firing a charge.

Besides weight and the battery connector, something I like about them is a 1 ohm e-match won't draw enough current to trigger the CF's after-flight high current warning. When I ran 2S LiPo's I got it after every flight (though I've never seen the output stage of the CF actually fail).

 

[JimJarvis50]

I've been running CFs on 1S LiPos for quite a while without a failure. All the ones I've used have been sub-200mAh; which specific ones have varied according to what's been available at the moment. The most recent has been
https://smile.amazon.com/gp/product/B00409KTLM/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1I fully charge them before a flight (of course); I've never seen them drop more than a tenth of a volt when firing a charge.

Besides weight and the battery connector, something I like about them is a 1 ohm e-match won't draw enough current to trigger the CF's after-flight high current warning. When I ran 2S LiPo's I got it after every flight (though I've never seen the output stage of the CF actually fail).

Interesting observations. I haven't used 2S lipos myself, but it would worry me to get that message after every flight. I'm personnally making wider use of resistors on the outputs.

Jim

 

[JoePfeiffer]

Interesting observations. I haven't used 2S lipos myself, but it would worry me to get that message after every flight. I'm personnally making wider use of resistors on the outputs.

Jim

That's exactly why I went to the 1S (I had read someone saying it would work on 4V, so decided to try it). Had that not worked, I'd have gone to resistors -- though reading on here that e-matches do not tend to fail open, running two in series for redundancy would also give enough resistance to protect the transistor.

 

[JimJarvis50]

So, another battery question. A few weeks ago, I ordered a couple of 2S lipo batteries and a charger came with each battery where the charger would connect to the balance connection. Some of these chargers plut into the wall and some via USB to a computer or the like. Are these good/safe chargers to use?

Jim

 

[mh9162013]

So, another battery question. A few weeks ago, I ordered a couple of 2S lipo batteries and a charger came with each battery where the charger would connect to the balance connection. Some of these chargers plut into the wall and some via USB to a computer or the like. Are these good/safe chargers to use?

Jim

Yes, assuming you ordered your equipment from a reputable seller and/or they're from a reputable manufacturer.

 

[JimJarvis50]

Yes, assuming you ordered your equipment from a reputable seller and/or they're from a reputable manufacturer.

I'm not sure there is anything reputable about these chargers. They are cheap. $5 or so. But they come with many of the batteries sold on Amazon.

Just curious since I hadn't seen this type of charger before.

Jim

 

[mh9162013]

I'm not sure there is anything reputable about these chargers. They are cheap. $5 or so. But they come with many of the batteries sold on Amazon.

Just curious since I hadn't seen this type of charger before.

Jim

Then I guess it's a case of "use at your own risk," although you're probably ok...

 

[roc_boy]

A few years ago, when I was doing smaller RC helis and multirotors, I got a Hitec charger for my small multicell LiPo batteries. Sorry, I'm on the road right now and can't recall which model. A good charger of this type can charge several battery packs at the same time, each at an appropriate charge rate for that pack. I know the one I have also has multiple input jacks for each charging channel, allowing you to charge packs with different connectors (JST, Molex, etc) without having to fabricate adapter harnesses or change connectors. It wasn't that expensive - maybe check the threads over at RC Groups forums, see what they're talking about for charging their micro batteries these days.