LiPo for StratologgerCF?

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Mike Haberer

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I'd like to know if anyone is using LiPos to run their Stratologgers. Since it has a 5 amp max rating and requires a 4V minimum voltage, does anyone use a 1 cell LiPo with this altimeter? The 4.2V max of a fully charged 1S is the bare minimum and I have no idea how long one would last before the voltage would drop to under 4V. 2S batteries tend to have a max amp rating greater than 5A (haven't looked deeply at the zillions of battery choices that are out there). I would really prefer to avoid using 9V due to weight and size. TIA.
 

0011001100

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You can always put a resistor inline with the 2s lipo to limit the current. A 1.5 ohm would limit a fully charged lipo to 5.6 amps, but you have to size the resistor properly so that it doesn't burn out when an ematch is fired.
 

timbucktoo

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I use Ternegy 180 mAh 2s lipo with my stratologger SL100 & CF with no problem. I talked to Peter at perfect flite about it a few years ago and he said that was what he used for all his testing on all his products.
 

Mike Haberer

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You can always put a resistor inline with the 2s lipo to limit the current. A 1.5 ohm would limit a fully charged lipo to 5.6 amps, but you have to size the resistor properly so that it doesn't burn out when an ematch is fired.
Yeah, trying to avoid extra circuitry. Fewer components = better reliability.
 

RocketDestroyer

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Specifications:
Output current: Do not exceed 5 amperes

I believe they are referring to the maximum load current drawn by the igniters, not the max current that the battery can supply.
I've used a small 2 cell Lipo for years with no issues.
 

Mike Haberer

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I use Ternegy 180 mAh 2s lipo with my stratologger SL100 & CF with no problem. I talked to Peter at perfect flite about it a few years ago and he said that was what he used for all his testing on all his products.
Tenergy or Turnigy? I'm assuming Turnigy as Tenergy doesn't have anything that small and Tenergy batteries cost a fortune.

Do you have a source? HobbyKing has it listed as discontinued and I can't find stock anywhere else at this point.
 

Mike Haberer

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You are right. My bad. Would be nice to know what they use for testing. I've put in a support request. I'll see if I get a response.
 

timbucktoo

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Tenergy or Turnigy? I'm assuming Turnigy as Tenergy doesn't have anything that small and Tenergy batteries cost a fortune.

Do you have a source? HobbyKing has it listed as discontinued and I can't find stock anywhere else at this point.
Turnigy but they have been discontinued. Seems like a lot of their batteries are going that way.
This is the closest replacement I have been able to find:
 

Buckeye

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There are are dozens of threads on this topic, enough to make your head spin.

The SLCF will exceed 6A and raise an error on a 2S battery. Here is my story.

Exceeded 6A firing current on SLCF | The Rocketry Forum

Good luck finding a low capacity and low C rating 2S LiPo that will remain below 6A. They don't exist any more. The Venon 300 mAH mentioned above is not much smaller than a 9V and still needs an additional resistor. Or, just use 2 ematches in series. That is the simple solution.

LiPos are a PITA for rocketry altimeters, since few altimeters are actually designed to use them. I only use LiPos as a last resort.
 

Cameron Anderson

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There are are dozens of threads on this topic, enough to make your head spin.

The SLCF will exceed 6A and raise an error on a 2S battery. Here is my story.

Exceeded 6A firing current on SLCF | The Rocketry Forum

LiPos are a PITA for rocketry altimeters, since few altimeters are actually designed to use them. I only use LiPos as a last resort.
Wwwhhhaaa???

Not sure which electronics you're flying but lipos are basically the standard for every brand, from Featherweight to Marsa and everything in between.
 

Buckeye

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Wwwhhhaaa???

Not sure which electronics you're flying but lipos are basically the standard for every brand, from Featherweight to Marsa and everything in between.
OK, my statement was too broad. However, so is yours. Let me re-phrase it this way:

Two of the most popular altimeters (probably THE most popular), Missileworks and Perfectflight, are not designed for LiPos. From the user guides:

"The RRC3 is designed to be operated with a standard 9‐volt alkaline battery. Standard 9V alkalines are an optimal choice, providing an inexpensive and widely available battery type with secure snap connectors."

"Standard 9V batteries can be connected using a battery clip such as the PerfectFlite CAB9V."

"Power: 4V – 16V, nominal 9V battery"

"Especially if you use a non-standard battery or electric match, make sure you ground test the combination before committing it to flight."


The manuals go into great detail, covering all aspects of Dual Deployment rocketry. However, nowhere in these manuals is a discussion of the myriad of LiPo batteries, connectors, capacities, and discharge rates.

Perfectflight doesn't mention that a 1S may be insufficient voltage, while a 2S may fry the altimeter. Nowhere does it warn you to add resistors to the deployment channels.

So, LiPos are not out-of-the-box ready for these altimeters. If you choose to use a "non-standard" LiPo battery, then you are on your own to figure it out and mitigate the risks.
 

JoePfeiffer

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I've been using a 1S for years with no problem. I don't know how many flights I could get on a charge, as I tend to top it off every few launches.

When I was using a 2S I'd get overload errors on a regular basis, but never had my altimeter actually fail.
 

Cameron Anderson

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OK, my statement was too broad. However, so is yours. Let me re-phrase it this way:

Two of the most popular altimeters (probably THE most popular), Missileworks and Perfectflight, are not designed for LiPos. From the user guides:

"The RRC3 is designed to be operated with a standard 9‐volt alkaline battery. Standard 9V alkalines are an optimal choice, providing an inexpensive and widely available battery type with secure snap connectors."

"Standard 9V batteries can be connected using a battery clip such as the PerfectFlite CAB9V."

"Power: 4V – 16V, nominal 9V battery"

"Especially if you use a non-standard battery or electric match, make sure you ground test the combination before committing it to flight."


The manuals go into great detail, covering all aspects of Dual Deployment rocketry. However, nowhere in these manuals is a discussion of the myriad of LiPo batteries, connectors, capacities, and discharge rates.

Perfectflight doesn't mention that a 1S may be insufficient voltage, while a 2S may fry the altimeter. Nowhere does it warn you to add resistors to the deployment channels.

So, LiPos are not out-of-the-box ready for these altimeters. If you choose to use a "non-standard" LiPo battery, then you are on your own to figure it out and mitigate the risks.
I haven't flown perfectflite stuff in 15 years, but I have friends that do and I've seen 1 and 2S lipos used, along with 9v, with no issues.
I fly lots of missileworks with 1 and 2s lipos with no problems.
I was an ardent 9v flier years ago and then I took less than an hour to read up about lipos and haven't flown 9v since. The information is out there and easy to understand - do yourself a favor and switch to a small, more reliable, more cost effective power source. It's worth it.
 

Buckeye

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I do use LiPos in small airframes. There is a learning curve (capacity, discharge, connectors, adapters, balancing, chargers, and the vagaries of buying Chinese stuff).

What pisses me off the most is that LiPos disappear off the market, leaving you to scramble to find similar replacements and re-work your av-bay layout. Case in point, the Turnigy 2s 180mAh mentioned in this thread. Also, the 1S sold with Raven PowerPerch is now longer than the earlier model, rendering this sled obsolete. I have three of them that I now need to retrofit. A good ol' 9V is not going to change dimensions or disappear from the shelves.
 
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Johnly

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I've been using Stratologger CF altimeters for over 5 years and hundreds of flights with a 2S lipo battery and a current limiting resistor and have experienced >>zero<< issues. The separate balance charging connector allows you to charge the battery without removing it from the altimeter sled.
 

Cameron Anderson

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I do use LiPos in small airframes. There is a learning curve (capacity, discharge, connectors, adapters, balancing, chargers, and the vagaries of buying Chinese stuff).

What pisses me off the most is that LiPos disappear off the market, leaving you to scramble to find similar replacements and re-work your av-bay layout. Case in point, the Turnigy 2s 180mAh mentioned in this thread. Also, the 1S sold with Raven PowerPerch is now longer than the earlier model, rendering this sled obsolete. I have three of them that I now need to retrofit. A good ol' 9V is not going to change dimensions or disappear from the shelves.
That's fair, particularly the point about Chinese stuff...I lost a Raven because a connector was mismarked and I reversed polarity. Upon inspection, half the bag was wrong. Thanks Amazon.
 

GlueckAuf

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I'd like to know if anyone is using LiPos to run their Stratologgers. Since it has a 5 amp max rating and requires a 4V minimum voltage, does anyone use a 1 cell LiPo with this altimeter? The 4.2V max of a fully charged 1S is the bare minimum and I have no idea how long one would last before the voltage would drop to under 4V. 2S batteries tend to have a max amp rating greater than 5A (haven't looked deeply at the zillions of battery choices that are out there). I would really prefer to avoid using 9V due to weight and size. TIA.
When I posed a similar question to Perfect Flite's tech support in 2015, here, in part, is the answer I received:

"With a battery that can put out large amounts of current, you do have potential problems. If your ematch doesn't go
open-circuit when it fires (and shorts instead, not common but possible), or if your ematch or wiring is simply shorted
from the beginning, then an excessive current will flow for the entire 1 second. The altimeter has built-in pulse width
modulation current limiting to address this possibility, but it is not 100% infallible since it has to apply full current
briefly to check the current flow. The circuitry can tolerate a moderately high current (about 20 amps) for a short time
while it is making the decision on how much to limit the flow, but it can be damaged if say 40 or 50 amps are flowing
during this time. Unfortunately, many LiPo batteries can put out this level of current when short-circuited. Two

possible solutions are to either choose the smallest LiPo battery possible (a 125 mAh 2S battery is good) or put a 1 ohm
10 watt resistor in series with the positive battery lead. The resistor will limit the maximum current flow to about 8
amps in the event of a short circuit, but is bulky. Or you can just be careful about not shorting the outputs and you will

likely be OK."

I've used Hyperion 120mAh 2S LiPo batteries in every altimeter-controlled rocket I've built ever since. These are, however, getting hard to find of late.
 

Johnly

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There is no need for a 10W rated resistor for this application. 10W is the continuous power dissipation rating, where as the charge firing signal is only a second or so. The thermal mass of 2W(or perhaps even smaller) resistor will keep the temperatures in the safe zone for that brief period of time. That said, a wire wrapped resistor is preferred over a metal film or carbon comp design.
 

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I opt for lipos with a resistor on deployment channels to limit current, haven't had an issue with it so far.
 

nmartin

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I've been using Stratologger CF altimeters for over 5 years and hundreds of flights with a 2S lipo battery and a current limiting resistor and have experienced >>zero<< issues. The separate balance charging connector allows you to charge the battery without removing it from the altimeter sled.
Hi - I have been using 9V with my Stratologger CF for years. Is it possible to port a picture of how you converted to LiPo with the resister?
 

Arpak

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Hi - I have been using 9V with my Stratologger CF for years. Is it possible to port a picture of how you converted to LiPo with the resister?
Not sure how they do it, but I put a 5-ohm resistor in series with both deployment channels. It doesn't need to be a huge wattage one since it's only a burst of current and not maintained, I think I used 1W.

Edit: Here's the wiring diagram for the booster stage of our clubs 2 stage rocket; you can ignore the wifi switch stuff, it shows the placement of the resistors though.
Screenshot_20210830-122310_Drive.png
 

Buckeye

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Hi - I have been using 9V with my Stratologger CF for years. Is it possible to port a picture of how you converted to LiPo with the resister?
 

Mike Haberer

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I found these after a lot of web searching. 20C continuous, 30C burst (3-4.5A). Exactly fits the bill for a StratologgerCF without having to use a resistor...

So, I'm confident these will work for the SLCF without a resistor, but this is the doc that came with the batteries. What is wrong with this picture? Seriously, whoever put this packaging together has sh!t for brains...

Seriously.jpg
 
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