# Battery for a StratalogerCF???

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#### ColumbiaNX01

##### Red blooded white American male
What type/kind of batteries are you folks using in your PerfectFlight StrataloggerCF?? I am in limited space so lipos is the direction I want to go otherwise I would use a 9volt. I am using a 3D printed modular sled 75mm. I am using dual strataloggerCF's but there is only one 9volt battery holder on board. Lipos would would great for the limited space available.

#### timbucktoo

##### Well-Known Member
Staff member
TRF Supporter
Global Mod
I use Turnigy nanotech 2S 180mA lipos with stratologgers.

#### dhbarr

##### Amateur Professional
What type/kind of batteries are you folks using in your PerfectFlight StrataloggerCF?
Thanks for asking this, got a StratCF for early Christmas

I use Turnigy nanotech 2S 180mA lipos with stratologgers.
What C rating? Is there a particularly compatible model re: pre-termed connectors?

#### ColumbiaNX01

##### Red blooded white American male
I use Turnigy nanotech 2S 180mA lipos with stratologgers.
any issues lighting e matches? how many successful flights do u have with those baterries.

thanks

#### dhbarr

##### Amateur Professional
Awesome, ordered some

#### scsager

##### Slightly burned-out old guy

Agreed! The 2s 180mah seems like a perfect battery for the CF.

#### ColumbiaNX01

##### Red blooded white American male
Agreed! The 2s 180mah seems like a perfect battery for the CF.
I see there are two sets of wiring harness's coming off the battery. Which one is which? How do you charge your lipo batteries?

Andrew

#### manixFan

##### Not a rocket scientist
any issues lighting e matches? how many successful flights do u have with those baterries.

thanks
If you do a search you'll see there are several threads that recommend the 2S 180mA. These batteries can provide a lot more current to fire an e-match than any 9volt battery. I only have 8 (equivalent) dual-deploy flights with the lipo batteries but I have full confidence in their capabilities.

To charge the batteries you use both sets of wire - one provides the current to charge the battery and the other is used by the charger to monitor each cell so they can stay in balance. Good chargers are not very expensive and you can buy one for either DC source (like a car battery) or for A/C source.

I like the small size and light weight of the lipo's And the are really pretty inexpensive so even if you only use them a few times they are no more expensive than 9 volts. The 180's are about $5 each. The little 130mA hour batteries I use with the Raven altimeters I almost consider to be single use. They are only about$2 each.

Good luck,

Tony

#### bill2654

##### Well-Known Member
I see there are two sets of wiring harness's coming off the battery. Which one is which? How do you charge your lipo batteries?

Andrew
The red connector is called a JST connector and it is your power (+-) and the white connector is the charging plug. All my Av bays are set up with JST connectors. You can get em on Ebay cheep.

#### ColumbiaNX01

##### Red blooded white American male

Thats a 400mAh. Would that be to much compared to the 180mAh?

#### Zebedee

##### Well-Known Member
There are three things to look for:

1) Voltage (V) - is it high enough to run the altimeter (1S ~4V, 2S ~8v etc.).
2) Capacity (mAh) - how much energy can it store (how long can it run things for).
3) Discharge (C) rating - this tells you the max discharge rate as a multiple of the capacity. E.g. 20C * 180mAh = 3.6A max discharge rate. The one I linked is 2C so actually has a lower discharge rate despite the higher capacity.

I have about 20 flights with Stratologgers and Missileworks altimeters (and eggfinder & BRB trackers) on the 400mAh and 800mAh versions of that battery.

#### ColumbiaNX01

##### Red blooded white American male
There are three things to look for:

1) Voltage (V) - is it high enough to run the altimeter (1S ~4V, 2S ~8v etc.).
2) Capacity (mAh) - how much energy can it store (how long can it run things for).
3) Discharge (C) rating - this tells you the max discharge rate as a multiple of the capacity. E.g. 20C * 180mAh = 3.6A max discharge rate. The one I linked is 2C so actually has a lower discharge rate despite the higher capacity.

I have about 20 flights with Stratologgers and Missileworks altimeters (and eggfinder & BRB trackers) on the 400mAh and 800mAh versions of that battery.
Even though this is a 1 cell battery at 3.7 volts its a 400 mAh discharge so it can fire everything good? What I am hearing is some lipos can burn out the strataloggerCF's bu these from spark fun are safe?

#### mpitfield

##### Moderator
Staff member
Global Mod
2S is not required. I use a 1S, 25C, 325mAh Li-Po, with a JST connector.

This topic has been discussed many times and as others posted, if you search the form you may find some threads recommending a 2S, however you may also find some threads that provide the math to show that a 1S is an option as well, and a better choice with this altimeter. I am not overly knowledgeable on this topic, however I trust the person that provided me the advice based on math, not simply an opinion. I also consider him as close as a subject mater specialist on this topic as it applies to rocketry and electronics.

I was not fully on-board with the advice when I was given it either, and I know not many, if any, of the people I repeated the advice to opt for the 1S. In fact I am sure that most decided to ignore it and go with the 2S. I get this because a 1S is non-intuitive being 3.7 volts, and the altimeter's voltage requirements are 4-16 volts, however a 1S Li-Po fully charged is 4.2 volts. I also get that .2 volts does not seem like a lot of margin. Keep in mind that Li-Po chemistry is very different from traditional alkaline battery chemistry, so things like voltage drop and internal resistance are also very different.

However I decided that part of this hobby for me was to be open to advice. Based on this I did some extensive bench testing with four e matches per test (2 per channel), multiple back to back tests and I was very surprised at the results. I cannot recall the number of tests it was a total of 4 or 5, but below is what I recall without any exaggeration to make the point and I would encourage anyone to perform the same tests.

- charged 1S 25C 325 mAh Li-Po to 100 charged, 4.2 volts
- connected two e matches per drogue channel and two e matches on main channel
- connected the battery to the altimeter via the featherweight magnetic switch, which also consumes some power although it is minor
- connected the DT4U to the altimeter, laptop and started up DataCap and fired both channels one after the other with only the time required to click the options between firings
- powered down the altimeter and repeated the test one or two more times, after the 3rd or 4th test I checked the voltage of the battery and it was 4.0-4.1 volts
- left the batter connected to the magnetic switch, but powered off, over night and performed the test for a 4th or 5th test, measured the voltage and it was 4ish volts.

I left the altimeter overnight connected to the magnetic switch because I had concerns with how much current it would deplete the battery while still prepping the rocket, from getting to the launch, getting the rocket prepped, altimeters off and waiting for my launch window.

I do not recall the exact voltages or number of tests, the point of the bench testing was to load up the battery with an unrealistic simulation in order to see how it responded with recovering as well as netted out with voltage. In my opinion my tests validated the configuration and I am pretty sure I could have repeated the test at least one more time before it dropped below 4 volts, but for my usage I was already running a scenario that would load the battery much more than any practical application.

From a practical real-world experience, I have prepped the rocket, left the rocket sitting on the pad for 45 min waiting for launch, launched, retrieved the rocket an hour later, left the altimeter beeping during the drive back to the prep-table, at the prep-table turned off the altimeter, connected the DT4U turned on the altimeter, pulled the data and the voltage on the battery was 4.1 volts. I have repeated this same scenario possibly a dozen ish times now over three flight seasons, with the same batteries.

So two sets of data to draw conclusions from, one a worst case no-realistic bench testing scenario, then a real application. Based on this regardless of the differing opinions on the topic, I can assure you that a 1S is plenty of battery for this altimeter as well as its older brother the SL100.

#### ColumbiaNX01

##### Red blooded white American male
2S is not required. I use a 1S, 25C, 325mAh Li-Po, with a JST connector.

This topic has been discussed may times and as others posted, if you search the form you may find some threads recommending a 2S, however you may also find some threads that provide the math to show that a 1S is an option as well, and a better choice with this altimeter. I am not overly knowledgeable on this topic, however I trust the person that provided me the advice based on math, not simply an opinion, and I consider his as close as a subject mater specialist on this topic as it applies to rocketry and electronics.

I was not fully on-board with the advice when I was given it either, and I know not many, if any, of the people I repeated the advice to opted for the 1S, in fact I am sure that most decided to ignore it and go with the 2S. I get this because a 1S is non-intuitive being 3.7 volts, and the altimeter's voltage requirements are 4-16 volts, however a 1S Li-Po fully charged is 4.2 volts. I also get that .2 volts does not seem like a lot of margin. Keep in mind that Li-Po chemistry is very different from traditional alkaline battery chemistry, so things like voltage drop and internal resistance are also very different.

However I decided that part of this hobby for me was to be open to advice. Based on this I did some extensive bench testing with four e matches per test (2 per channel), multiple back to back tests and I was very surprised at the results. I cannot recall the number of tests it was a total of 4 or 5, but below is what I recall without any exaggeration to make the point and I would encourage anyone to perform the same tests.

- charged 1S 25C 325 mAh Li-Po to 100 charged, 4.2 volts
- connected two e matches per drogue channel and two e matches on main channel
- connected the battery to the altimeter via the featherweight magnetic switch, which also consumes some power although it is minor
- connected the DT4U to the altimeter, laptop and started up DataCap and fired both channels one after the other with only the time required to click the options between firings
- powered down the altimeter and repeated the test one or two more times, after the 3rd or 4th test I checked the voltage of the battery and it was 4.0-4.1 volts
- left the batter connected to the magnetic switch, but powered off, over night and performed the test for a 4th or 5th test, measured the voltage and it was 4ish volts.

I left the altimeter overnight connected to the magnetic switch because I had concerns with how much current it would deplete the battery while still prepping the rocket, from getting to the launch, getting the rocket prepped, altimeters off and waiting for my launch window.

I do not recall the exact voltages or number of tests, the point of the bench testing was to load up the battery with an unrealistic simulation in order to see how it responded with recovering as well as netted out with voltage. In my opinion my tests validated the configuration and I am pretty sure I could have repeated the test at least one more time before it dropped below 4 volts, but for my usage I was already running a scenario that would load the battery much more than any practical application.

From a practical real-world experience, I have prepped the rocket, left the rocket sitting on the pad for 45 min waiting for launch, launched, retrieved the rocket an hour later, left the altimeter beeping during the drive back to the prep-table, at the prep-table turned off the altimeter, connected the DT4U turned on the altimeter, pulled the data and the voltage on the battery was 4.1 volts. I have repeated this same scenario possibly a dozen ish times now over three flight seasons, with the same batteries.

So two sets of data to draw conclusions from, one a worst case no-realistic bench testing scenario, then a real application. Based on this regardless of the differing opinions on the topic, I can assure you that a 1S is plenty of battery for this altimeter as well as its older brother the SL100.

Cool. What is the connector called? From the lipo there is a connector. But on the StrataloggerCF its just positive and negative wire terminal. What is the special connector called to hook up the battery to the altimeter?

#### ttabbal

##### Well-Known Member
Cool. What is the connector called? From the lipo there is a connector. But on the StrataloggerCF its just positive and negative wire terminal. What is the special connector called to hook up the battery to the altimeter?
It depends on the battery you buy. There are a LOT of different connectors, even if you only think about the common ones in R/C use. Based on the pictures, the common one people use is the red JST connector. The only reason I hesitate to use them is that they come apart very easily. If you properly hold them down so they aren't subject to G-forces that want to pull them apart, they are probably just fine though. If you get a battery with a JST connector, get a pack of JST "pigtails" to go with them. It's a connector with wires. Screw the wires into the altimeter, connect the battery, and you're good.

Do NOT cut the connector off the battery and strip the wires. Should you short them, there is zero protection built into most lipo cells/packs for R/C use. There is enough power in even small ones to spot-weld the wires together as well, so be cautious with them if you do need to install connectors etc.. I generally cut/strip one wire at a time and finish the heat-shrink before cutting the next. Shorted out and fully charged, having them catch fire is not unheard of. It's not real likely with the little ones in this thread, but treat them with a little respect. Think of it like the reasons you don't install the ignitor in a HPR rocket motor before it's on the pad.

#### dixontj93060

##### Well-Known Member
About a month ago I used a small 1S LiPo for a RW Rapton 38. Previously I had used 2S LiPo's but was always worried about sourcing too much current. Data curves from the CL showed it rock solid at 4.2V throughout the whole flight. I'll probably be using more of the 1S variety in the future.

#### mpitfield

##### Moderator
Staff member
Global Mod
Cool. What is the connector called? From the lipo there is a connector. But on the StrataloggerCF its just positive and negative wire terminal. What is the special connector called to hook up the battery to the altimeter?
As ttabbl said it depends on what the battery comes with. Keep in mind there is a bit of confusion around the "specification" JST, in fact from what I see there are at least a half dozen "JST" connectors https://www.rcgroups.com/forums/sho...t-JST-quot-connector-confusion-the-real-story So make sure you order the proper connector. Believe me I only know the above after I made the assumption that JST was JST and ordered the wrong connectors. Also figuring out what you have, unless the supplier can tell you, can be challenging as some of them appear to be the same, but if you look closer you will notice the differences. I would go by the specs and the physical shape visually, if you have them or can pull them right off the battery it self.

#### kevinkal

##### Insatiable Hobbyist
I initially started testing the StratologgerCF using a 2S 450mAh 20C LiPo with a single Ematch. The Ematch was the inexpensive Chinese made match available on Amazon.com with orange wire and the red cap over the tip. They measure between 0.8 and 1.2 ohms. I quickly found that the momentary current draw was exceeding the maximum recommended current. I was getting current draws between 5A and 8A. For this reason, I stepped down to a 1S LiPo. The 1S LiPo has worked perfectly to fire all Ematches thus far, about 40, with no problems. The maximum current has been between 3A and 5A, under the StratologgerCF's maximum recommended current. I have used both a 1S 850mAh 20C LiPo and a 1S 350mAh 65C LiPo with no problems. The voltage plot will sometimes show a "one bit" dip when the match fires... That is, the voltage plot shows 4.2 or 4.1 volts, but dips for one frame of data to 4.1 or 4.0 volts when the drogue or main charge fire. One drawback to consider when using 1S LiPos is that the StratologgerCF Amplified Beeper isn't quite as loud.
I expect that using the lower capacity 180mAh 2S LiPo might also result in acceptable current draws, given that the battery most likely cannot source as much current as the 450mAh 2S LiPo that I initially integrated.
What do the current draw and voltage plots look like during events for those running the 2S 180mAh LiPos? What is the C rating for your 2S 180mAh LiPos?

Last edited:

#### Crumb fire

##### Well-Known Member
I use a 1S, 25C, 325mAh Li-Po, with a JST connector.
Where can I find them? I just searched two differents places and find something else.
Are you also using these batteries in other altimeter? i.e Raven or Missile works?

And what charger are you using?

thanks,

Steeve

#### Steve Shannon

##### Well-Known Member
TRF Supporter
Thats a 400mAh. Would that be to much compared to the 180mAh?
No, as long as the voltage of the battery is the same it would just last longer.
Here's how that works. The capacity of a battery is the product of its current sourcing capability and the time it can provide that current. So, a 400 mAh battery can provide 400 milliAmperes for an hour theoreticall, or 40 milliAmperes for 10 hours, or 4 Amperes for a tenth of an hour.
A 180 mAh battery can theoretically source just as much current for a shorter period of time or less current for the same period of time.

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