9-Volt Batteries - Part 1 : The Tear Down - Battery No.1 thru No. 5

[user 30299]

Every so often there are posts about the use & qualities of 9-volt batteries for rocket electronics.

I thought it would be interesting to grab a handful of 9-volt batteries and test their volts and
amps over several months.

Below are some pictures from the testing. I chose 11 batteries. I used two multimeters so that
I could watch voltage on one, and used another meter to “short” the battery and read the amps.
The last step in all this work was for me to tear apart each battery, take pictures, and see how
they were constructed.

It’s not super scientific. I did not have a data logger to collect the voltages and amps through
a test cycle. I read the numbers straight off the displays. What I did was read the voltage before
shorting the battery. I would short the battery for 2 seconds, then wait 15 seconds to short the
battery again for another 2 seconds.

I stripped the jacket off the 9-volt clip so that I could short the battery through the top contacts
with one multimeter, and at the same time read the volts with the other multimeter.

I read the amps after the 1st 2-second short, then read the volts at the end of the 15-second
“recovery”, and then read the amps after the 2nd 2-second short. I did this over a number
of months. I started back in May. Sometimes it was a few days between each test cycle,
sometimes it was a week, and sometimes a couple of weeks. It was irregular, just like what
we experience between launch dates and events. Each battery was tested 14 times between
May and December.

The two shortening events were to represent a dual-deployment launch for the firing of
two e-matches. Most fight controllers appear to use a 1 second count for firing (shorting)
the e-matches. I used 2 so as to make sure I put the battery through a solid shorting.

The 15-second recovery was not an arbitrary number. I looked at the flight simulations,
and actual flights, on some of my dual-deploy rockets and picked a happy medium.
This time period will vary greatly depending on a person’s rocket and launch conditions.
But hey, you have to start somewhere . . .

I thought I would start with some pictures of the batteries and what they look like inside.
Some have the nice (6) cell arrangement with welded connections. They always had the
highest amp readings; 4 to 5 amps. Four batteries are in this class.

Then there were the ones with a flat stack design, and a solid, clear plastic shell. Their amp
readings tended to run between 2 and 2.5. I have not cracked open a shell yet to see how
the top and bottom plates are anchored. The plastic shells looked to be very durable.
Five batteries are in this class.

Then there were two batteries that barely put out 0.75 to 1.0 amps. Look for the pictures
of the No. 5 and No. 7 battery. I will let you use your imagination as to what you think is
actually wrapped in the plastic wrap. Yup, no solid shell - just plastic wrap.

I plan on a Part 2 for this which will have some graphs showing how each battery's volts
and amps performed over time. It may be a week or two before I get that posted.

This exercise was not meant to create a definitive answer on the use & qualities of 9-volt
batteries. I did it because of shear curiosity. There are probably a hundred other ways to
test the batteries, and some may do a better job of replicating what we put these batteries
through in our rockets. I had fun, and I learned some neat things about 9-volts.























Pictures for Battery No. 6 thru No. 11 are in a second thread.

 

[Hobie1dog]

so what were the voltages at 100% charge 50% charge and 0?

 

[mh9162013]

Interesting...

Looking forward to the graphs.

 

[Hobie1dog]

oh by the way thanks for the pictures of the insides and being 66 years old, I finally get to see the inside of a 9 volt battery

 

[cls]

great research! thanks for posting. 9v batteries have been re specced recently, in a downward direction. I am beginning to trust LiPos more. kinda like how we moved from flash bulbs to ematches so long ago.

 

[user 30299]

great research! thanks for posting. 9v batteries have been re specced recently, in a downward direction. I am beginning to trust LiPos more. kinda like how we moved from flash bulbs to ematches so long ago.

Good point about how we moved from bulbs to e-matches.

 

[user 30299]

One interesting item about the 9-volt batteries is where they are all made. Most of the 9-volts
were made in China with a couple made in Malaysia. Not a single one was made in the US.

The "Flat Stack" batteries (#2, #3, #4, #10, #11) appeared to have 100% identical plastic cases and construction.
Once you tore the metal jacket off you could not tell them apart. The battery brands were Duracell Copper Top,
Energizer and Rayovac.

It makes you wonder if this group of batteries were all made in the same factory.

 

[neil_w]

Only the 10th of January and already a strong candidate for best thread of the year. Great work, this is really interesting!

What jumps out already is that the current iterations of the Duracell and Energizers, what we would normally refer to as "high quality batteries", were not the highest performing.

 

[FredA]

It makes you wonder if this group of batteries were all made in the same factory.

That would be no surprise.

 

[user 30299]

Here is a quick listing of each battery's initial voltage and amps, and what they were
after 14 tests. The 14 tests mean I "shorted" each battery a total of 28 times.

Here are the four batteries with the setup of (6) welded round cells (AAA batteries).

No. 1 – Amazon Basic : Started with 9.12 volts / 5.37 amps. Finished with 8.74 volts / 3.17 amps.

No. 6 – PK Cell Ultra Alkaline : Started with 9.23 volts / 5.08 amps. Finished with 8.76 volts / 3.20 amps.

No. 8 – Procell (Duracell) : Started with 9.08 volts / 5.18 amps. Finished with 8.72 volts / 3.17 amps.

No. 9 – Rayovac Fusion : Started with 9.17 volts / 5.18 amps. Finished with 8.77 volts / 3.04 amps.


Here are the five batteries with the clear plastic shell.

No. 2 – Duracell Copper Top : Started with 9.45 volts / 2.53 amps. Finished with 8.99 volts / 1.63 amps.

No. 3 – Energizer Industrial : Started with 9.41 volts / 2.43 amps. Finished with 8.96 volts / 1.71 amps.

No. 4 – Energizer Max : Started with 9.36 volts / 2.22 amps. Finished with 8.96 volts / 1.56 amps.

No. 10 – Rayovac High Energy : Started with 9.39 volts / 2.48 amps. Finished with 8.95 volts / 1.68 amps.

No. 11 – Rayovac Ultra Pro : Started with 9.32 volts / 2.40 amps. Finished with 8.92 volts / 1.61 amps.


Here are the two batteries with the simple plastic wrap.

No. 5 – Panasonic : Started with 9.83 volts / 0.76 amps. Finished with 9.42 volts / 0.65 amps.

No. 7 – PK Cell Extra Heavy Duty : Started with 9.71 volts / 0.94 amps. Finished with 9.46 volts / 0.63 amps.


I listed the amps for the first "shorting" in the test sequence.

The first "shorting" would be the rocket's Apogee event (drogue), and the second "shorting" would be the Main chute.

I'm not an electrical or electronics engineer, or a flight controller manufacturer. But a good
question would be what is an acceptable level and balance between the voltage and amps
to assure the flight electronics will work properly - and fire the e-matches.

And yes - many of them have capacitors for brown-out conditions.

When you look at the numbers, the crudely constructed batteries had the highest voltages
and hardly any amperage. The lower voltages were in the welded 6-cell batteries, but had
the highest amperage.

And finally there is a lot of "chemistry" involved in the battery types. You can drown in the
amount of information on 9-volt battery chemistry.

 

[FredA]

When you look at the numbers, the crudely constructed batteries had the highest voltages
and hardly any amperage. The lower voltages were in the welded 6-cell batteries, but had
the highest amperage.

Good current flow requires a good connection - makes senses.
GREAT WORK HERE!

 

[neil_w]

From my reading of these results, in the future I would only ever buy one of the first four... although vigilance is needed to check if any of them change construction at some point.

Further, it looks like those four might actually work reasonably well in the (highly not recommended) 9V launch controllers, whereas pretty much any of the others are almost guaranteed to be miserable failures. Very disappointed to see Duracell and Energizer in group 2.

 

[mh9162013]

If for some reason you still believe it's 1988 and you absolutely must continue using 9V batteries, another option to consider are rechargeable versions, whether NiMH or lithium chemistries. My gut tells me they can provide higher voltages and more amps, with less voltage or amperage drop off under load. They should also save money in the long run.

 

[user 30299]

Good current flow requires a good connection - makes senses.
GREAT WORK HERE!

Thanks!

 

[FredA]

If for some reason you still believe it's 1988 and you absolutely must continue using 9V batteries, another option to consider are rechargeable versions, whether NiMH or lithium chemistries. My gut tells me they can provide higher voltages and more amps, with less voltage or amperage drop off under load. They should also save money in the long run.

We may have lived in the 80's but not all the tech from the 80's needs to be thrown away.

Alkaline batteries are still my choice for rockets - here's why:
- ZERO maintenance - I don't need to charge, or check charge state. One battery lasts all season without question.
- I don't remember to charge my rockets -> rechargeable die and become single use which is way more expensive and more work to switch out.
- Current limited - can't hurt output devices - no longer as important as it was now that FC's PWM, but not all do - do YOU know what your outputs can take? Higher current is NOT needed.
- Cheap if bought in bulk and usable in other things like smoke detectors in my house. I can't think of another 9V-driven device I own that would like a rechargeable situation.
- Connectors are cheap, reliable and NEVER reversed polarity - some FC manufactures messed up on their polarity choice and things get killed easily.

So don't dismiss well-built 9V's so quickly - they have their place.

 

[user 30299]

We may have lived in the 80's but not all the tech from the 80's needs to be thrown away.

Alkaline batteries are still my choice for rockets - here's why:
- ZERO maintenance - I don't need to charge, or check charge state. One battery lasts all season without question.
- I don't remember to charge my rockets -> rechargeable die and become single use which is way more expensive and more work to switch out.
- Current limited - can't hurt output devices - no longer as important as it was now that FC's PWM, but not all do - do YOU know what your outputs can take?
- Cheap if bought in bulk and usable in other things like smoke detectors in my house. I can't think of another 9V-driven device I own that would like a rechargeable situation.
- Connectors are cheap, reliable and NEVER reversed polarity - some FC manufactures messed up on their polarity choice and things get killed easily.

So don't dismiss well-built 9V's so quickly - they have their place.

Thank you FredA.

Well said.

 

[user 30299]

From my reading of these results, in the future I would only ever buy one of the first four... although vigilance is needed to check if any of them change construction at some point.

Further, it looks like those four might actually work reasonably well in the (highly not recommended) 9V launch controllers, whereas pretty much any of the others are almost guaranteed to be miserable failures. Very disappointed to see Duracell and Energizer in group 2.

What surprised me was the Amazon Basic battery. I had this preconceived notion it would be cheaply made.
In the end it was one of the better built batteries.

I have always used the Procell (Duracell) batteries for my Missile Works and Perfectflite devices. I now know
there are three additional quality batteries out there.

 

[user 30299]

Here is one last bit of information.

Before I tore into the batteries I hooked each one up to the Missile Works RRC3 setup
you see below. I put a voltmeter on the terminal screws for the battery and then flipped
the switch to see what would happen to the voltage.



There was anywhere from a 0.50 volt to a 1.0 volt drop as soon as you threw the switch.
The battery voltage would recovery within several seconds. But the recovery voltage was
anywhere from 0.10 to 0.20 volts lower than the starting voltage. This is with the RRC3
still on.

When the RRC3 hit the 3-beep sequence you would see the voltage drop anywhere from
0.30 to 0.60 volts, but then quickly get back to the recovery voltage before the next 3-beep
sequence hit.

The RRC2 and RRC3 are setup to turn off the beeping sequence and go into a sleep mode
after 5 minutes.

 

[FredA]

Open circuit voltage is always higher.
You are getting a measure of the output impedance - you should find the ones with the lower short circuit current are also the ones with the lower voltage when powering the RRC3.

 

[user 30299]

Open circuit voltage is always higher.
You are getting a measure of the output impedance - you should find the ones with the lower short circuit current are also the ones with the lower voltage when powering the RRC3.

Thanks for that info. I'll take a closer look at which batteries did what on the voltages.

 

[mh9162013]

We may have lived in the 80's but not all the tech from the 80's needs to be thrown away.

Alkaline batteries are still my choice for rockets - here's why:
- ZERO maintenance - I don't need to charge, or check charge state. One battery lasts all season without question.
- I don't remember to charge my rockets -> rechargeable die and become single use which is way more expensive and more work to switch out.
- Current limited - can't hurt output devices - no longer as important as it was now that FC's PWM, but not all do - do YOU know what your outputs can take? Higher current is NOT needed.
- Cheap if bought in bulk and usable in other things like smoke detectors in my house. I can't think of another 9V-driven device I own that would like a rechargeable situation.
- Connectors are cheap, reliable and NEVER reversed polarity - some FC manufactures messed up on their polarity choice and things get killed easily.

So don't dismiss well-built 9V's so quickly - they have their place.

- Alkalines are not zero maintenance, as they are prone to leakage and should not be stored in any electronic device for an extended period of time.
- If you use a rechargeable lithium battery or LSD (low-self dicharge) NiMH, then you don't need to worry about charging before a flight unless you have reason to believe you depleted that battery's capacity during the last flight. But that sitution would apply even if you're using alkaline 9V battery.
- Higher current may not be needed for a given application, but lithium and high quality NiMH cells can deliver current more efficiently than alkalines, even if it's not in a high current application.
- Alkaline 9V batteries are not cheap when compared to many other disposable battery options and even some rechargeable options, like lithium and NiMH. But you buy them in bulk, you say? Well, anything is much cheaper when you buy them in bulk...
- Besides smoke detectors, very few mainstream consumer products still use 9V batteries. Even then, many residential, battery-operated smoke detectors are shifting to AA cells or permanent lithium cells that last as long as the detector itself.
- There are so many aftermarket battery connectors that prevent reverse polarity.

And yes, 9V batteries have their place, but only because many manufacturers don't want to start making products that use alternative battery sources.

I mean, I get it: you've built a product a certain way for so long and it works well and uses a 9V battery. Why change things up? Instead, go with a tried and true method. But in that case, you're justifying your production or engineering based off of tradition/stubborness/cost savings/being conservative. Fine, it's your product, you do you. But don't act like it's because 9V batteries are better than current battery options.

As a consumer, if you want to use 9V batteries, knock yourself out. I kinda like them due to their old-school feel and nostalgia. Reminds me of my childhood playing with walkie talkies and listening to a transister radio. But I'm not going to pretend 9V batteries are superior to today's battery options.

 

[FredA]

Would I design new gear to use a 9V, probably not.
Do I plan to continue to use them in my rockets, yes.

Higher current than needed not an upside in this application.

And although I don't change batteries for every flight, I do change them at the start of the season.
Fresh Alkaline do NOT leak after one year of sitting idle in a rocket.....so yes, in this usage, they are zero maintenance.

Yes, there are plenty of connectors out there that prevent polarity issues - those on LiPoly batteries are not standardized like 9V are and you can EASILY buy the wrong polarity. Rocket people are not the most electronic-savvy people in the world. There IS an particular FC family that settled on the opposite of the usual online battery purchase and that leads to a ton of frustration.

Also - many LiPoly batteries have built in protection circuits that can [and have] shutdown the battery on a pyro fire - you need to avoid those - and you need to know to avoid those.

TOO MANY ISSUES FOR TOO FEW PROBLEMS SOLVED - hard pass here.

 

[jahall4]

Only the 10th of January and already a strong candidate for best thread of the year. Great work, this is really interesting!

What jumps out already is that the current iterations of the Duracell and Energizers, what we would normally refer to as "high quality batteries", were not the highest performing.

Agreed! Mega snaps for @QFactor

From my reading of these results, in the future I would only ever buy one of the first four... although vigilance is needed to check if any of them change construction at some point.

Further, it looks like those four might actually work reasonably well in the (highly not recommended) 9V launch controllers, whereas pretty much any of the others are almost guaranteed to be miserable failures. Very disappointed to see Duracell and Energizer in group 2.

Exactly, Duracell Copper Tops used to be welded, they even documented how their construction was superior to their competition then later, quietly changed it w/o updating their docs. See below.

What surprised me was the Amazon Basic battery. I had this preconceived notion it would be cheaply made.
In the end it was one of the better built batteries.

I have always used the Procell (Duracell) batteries for my Missile Works and Perfectflite devices. I now know
there are three additional quality batteries out there.

Agreed, I started using to Procell after I found out the Copper Top were not welded. Glad to know about the Amazon batteries.

Here is a FB post from last year...

 

[user 30299]

TRF limits you to 25 attachments - so I was not able to put all the battery pictures in one thread.
There are two threads for the battery pictures.

Anyway, I wanted to highlight the four batteries that have the (6) welded cells.

Please note that the PK Cell Ultra Alkaline (No. 6) has a fused plastic case surrounding the cells. All the other batteries
have the traditional metal case. I used a coping saw to cut open the the PK's case. It has a solid construction to it.

I looked at the PK Cell batteries because PK Cell makes many of the Lipo batteries we use in other electronics.
You will find many of their Lipos on the Sparkfun and Adafruit webstores, and also Digikey and Mouser.

 

[Hobie1dog]

I love all the pictures you have posted thanks so much.

 

[user 30299]

I love all the pictures you have posted thanks so much.

My wife asked me last night if I was done taking pictures. She wanted her dining room table back . . . .

 

[Rocketjunkie]

When Duracell redesigned the 9V - and denied they did - the current went from 5.5A to 2.2A. It's good to see there are still some that use the 6 AAAA cell construction. Another alternative is the Energizer Ultimate Lithium, containing 3 1/2 AA cells. Unfortunately, the lithium batteries are >$12 each. They do have performance like the old Duracells. Got >10 flights until battery reached my cutoff of 9.2V, new Duracells get 1-2 flights.
Old Duracell
New Duracell
Energizer Lithium

 

[StreuB1]

This thread is ticking all the boxes. Keep going!!

This is like the rocketry version of the EEVblog.

 

[cerving]

So do the 9v batteries with the lower maximum amperage have a higher total mAH capacity? I'm thinking that's what they did... since 9V batteries are generally used in low-current applications (i.e. smoke alarms), it would make sense to redesign them for a higher capacity at the expense of maximum current.

 

[Grog6]

I didb't realize a 9v would source that much current. I've always tested their state of charge by sticking them to my tongue for a sec. I learned not to do that on the 9v lithium that radio shack sold.