# 9V 0.5A battery pack

I have this adaptor. Do you know what kind of battery power pack that can output at least 9 volts 0.5 ampere?

This is the spec sheet:

https://www.jameco.com/Jameco/Products/ProdDS/163628.pdf

It's the adaptor included in the world's cheapest (and only) 2 channel pm2.5 monitor. A 16 channel unit costs about $25000. This only costs$260 but it should be plugged into wall. If I can get a battery pack, I can bring it anywhere like outside. The manufacturer doesn't have any battery pack for it. They recommended using 20 meter extension to bring it outside, but it's too long, and didn't want to comment what kind of battery pack available for it because they have none.

https://www.amazon.com/gp/product/B004AWEG0Y/?tag=pfamazon01-20

I would just use some classic USB powerbank with 2A output, and buy something like these.
Be careful with the output connector and the voltage/current selection.

Ps.: how long operation time is needed?

chirhone
I would just use some classic USB powerbank with 2A output, and buy something like these.
Be careful with the output connector and the voltage/current selection.

Ps.: how long operation time is needed?
Minimal operation time like 15 mins. For small square 9 volt battery like this, what is usually the ampere rating?

https://www.amazon.com/dp/B00MH4QM1S/?tag=pfamazon01-20

Minimal operation time like 15 mins. For small square 9 volt battery like this, what is usually the ampere rating?
Third question on the product page there:
9V alkaline batteries are meant for low current applications. If subjected to high current they will suffer voltage depression (aka droop) below the typical target range needed for a 9V battery. In other words try to keep the current under 80mA unless you just don't care about voltage droop and even then, you might be better off with a 4 x AA battery and a boost circuit to achieve the target voltage if the current is much over 150mA.
If you want it work then you need far more beef in that battery. I still suggest a powerbank. They are dirt cheap these days, and with a step-up 'cable' it'll work just fine.

Third question on the product page there:

If you want it work then you need far more beef in that battery. I still suggest a powerbank. They are dirt cheap these days, and with a step-up 'cable' it'll work just fine.

Here the owner used 7 pcs of 1.2v battery. Do you have rough idea how many milliamps it can output?

It's too large and bulky. I just want to buy a readily available one and not build it. I'll check out your powerbank and step-up cable.

It's too large and bulky.
And all those cables...
No idea how much current can it supply (and, more importantly: how long).

Part of the reason why I suggest the powerbank+step-up cable is, that all of that is made to be portable, so you can just plug it together and it'll work without any further hassle.

And all those cables...
No idea how much current can it supply (and, more importantly: how long).

Part of the reason why I suggest the powerbank+step-up cable is, that all of that is made to be portable, so you can just plug it together and it'll work without any further hassle.
Which is more pure and safe dc, the 7 pieces of 1.2v rechargeable battery, or 5v power bank with 5 to 9 volts step up adaptor? And why?

... pure and safe ...
Those words just does not apply.

I would consider a direct 9V-ish battery pack only for some overly sensitive, certified measurement devices.
Yours is not this class, not even close.

In quality of the supplied power the powerbank+cable thing beats the usual wall plug adapter (like the one you linked before) by far.

There is no connection to any interference from the line and the usual ripple voltage is lower and at higher frequency (easy to filter). The original adapter likely has an ugly ripple at 120Hz, since based on the provided data it's nothing more than a transformer, a graetz and a capacitor - maybe with an irrelevant fuse. The most basic thing.
If your device can work with that then it likely has some internal power supply anyway.

Asymptotic and chirhone
anorlunda
Staff Emeritus
Do you know what kind of battery power pack that can output at least 9 volts 0.5 ampere?

I don't understand your difficulty. It is trivial to do an internet search. For example "AA alkaline battery specifications" I did that and within seconds I found this.

http://www.evergreencpusa.com/alkaline-battery-specifications

Just choose a candidate battery model and look up its specifications.

jrmichler
Mentor
Try one of these: https://www.adafruit.com/product/248. I don't know how good it is, but should know soon because one is on its way as of two days ago. And the price is hard to beat.

Borek
Mentor
9 V is rather difficult to maintain with just a battery, I would go for 3S LiPo and step down converter.

davenn
Those words just does not apply.

I would consider a direct 9V-ish battery pack only for some overly sensitive, certified measurement devices.
Yours is not this class, not even close.

In quality of the supplied power the powerbank+cable thing beats the usual wall plug adapter (like the one you linked before) by far.

There is no connection to any interference from the line and the usual ripple voltage is lower and at higher frequency (easy to filter). The original adapter likely has an ugly ripple at 120Hz, since based on the provided data it's nothing more than a transformer, a graetz and a capacitor - maybe with an irrelevant fuse. The most basic thing.
If your device can work with that then it likely has some internal power supply anyway.
Your confidence above makes me get this 5v to 9v adaptor plugged to powerbank and it works! Thanks. Now I can bring it anywhere and split hairs or dusts.

Rive
Those words just does not apply.

I would consider a direct 9V-ish battery pack only for some overly sensitive, certified measurement devices.
Yours is not this class, not even close.

In quality of the supplied power the powerbank+cable thing beats the usual wall plug adapter (like the one you linked before) by far.

There is no connection to any interference from the line and the usual ripple voltage is lower and at higher frequency (easy to filter). The original adapter likely has an ugly ripple at 120Hz, since based on the provided data it's nothing more than a transformer, a graetz and a capacitor - maybe with an irrelevant fuse. The most basic thing.
If your device can work with that then it likely has some internal power supply anyway.
You said the original adapter likely has an ugly ripple at 120Hz. But is it not we only use 60Hz electricity? What effect does this 120Hz has on the output? Maybe harmonics?

I was googling for the output of an ac adaptor but couldn't find one for typical ac to dc adaptor (google wildcard "ac to dc adaptor vs powerbank oscilloscope output") Can you share how the output of an ac adaptor looks like in an oscilloscope compared to the powerbank bank 5v output?

I'm deciding whether to use the powerbank as permanent power supply to the air monitor unit even in home and not use the ac adaptor anymore (to avoid surges too).

Btw. I got interested in all this when my cousin gave my parents an air purifier as Christmas present last december. Before that time. I didn't even know an air purifier exist. It has a built-in pm2.5 monitor and I bought individual monitor just to confirm it's accuracy. But even the individual monitor made in china was not accurate. So got this model as it can individually measure 0.5 and 2.5 micron particles.

Your confidence above makes me get this 5v to 9v adaptor plugged to powerbank and it works! Thanks. Now I can bring it anywhere and split hairs or dusts.

View attachment 256435
Guess what. The 5v to 9v adaptor died after using it for 15 minutes continuous. The LED displayed 4.8v instead of 9v and multimeter tested it as 5v instead of 9v. Yesterday I only used it for 5 minutes each time and not long. This is similar to a reviewer at amazon:

https://www.amazon.com/product-revi...e=all_reviews&pageNumber=1#reviews-filter-bar

"Woked fine at first, but after a couple of hours running about a strip of about 20 white 12V LEDs (very small load), it now outputs only 4.8V to the barrel connector, and moving the switch doesn't change anything."

The seller replied: "If the current is too large, it will generate too much heat and thus cause burnout."

This is the internal components of it:

The Dylos is still working. I tested it with a PowerMeter using the original ac adaptor and powering it. I got:

The Dylos consumes 5.1W. I'd like to know the following:

How did the adaptor above come up with 500mA in the 9V output from the input of 120v and 8.5W?

Using the formula P= VI, and I=P/V = 8.5W/120 = 0.071mA

and since 120v/9v = 13.33 x 0.071mA = 0.950A or 950mA. How is this connected to the output of 500mA and 9v?

If the Dylos consumes 5.1W at the 120v ac adaptor side. What is the equivalent ampere in the output at 9v dc?

I'm looking for a 5v to 9v adapter with bigger capacity. Also I guess the ic temperature increase and burnout because of the plastic casing of the unit and lack of heat sink of exhaust?

Borek
Mentor
How did the adaptor above come up with 500mA in the 9V output from the input of 120v and 8.5W?

Using the formula P= VI, and I=P/V = 8.5W/120 = 0.071mA

and since 120v/9v = 13.33 x 0.071mA = 0.950A or 950mA. How is this connected to the output of 500mA and 9v?
No idea what you are doing here. What converter does it takes some power in and puts some power - different combination of voltage/current - out. What happens inside doesn't matter - plenty of ways of converting (yours was most likely some kind of https://en.wikipedia.org/wiki/Switched-mode_power_supply - even that means dozens of solutions). One thing we can be sure is that the output power is lower than the consumed power.

If the current is too large, it will generate too much heat and thus cause burnout.
Based on the wall plug adapter the maximal current draw on 9V should be below 0.5A. The specification of the USB thing says 1.1A on 9V, which is sufficiently higher than the consumption. You have sufficient reason to return the thing or request a replacement.

The Dylos consumes 5.1W.
Sorry, no. First: those power meters has really bad measurement error on the low end of the scale: second, you measuring the loss of the plug adapter too. The real consumption is likely lower.

By the way, 5.1W at 9V means 570mA. The USB thing still should be able to supply that => you should request a replacement.

Also I guess the ic temperature increase and burnout because of the plastic casing of the unit and lack of heat sink of exhaust?
Unless you insulated the thing with something, then these details are for the manufacturer/vendor. They are selling that thing enclosed: they should present the specs accordingly.

Asymptotic and chirhone
Based on the wall plug adapter the maximal current draw on 9V should be below 0.5A. The specification of the USB thing says 1.1A on 9V, which is sufficiently higher than the consumption. You have sufficient reason to return the thing or request a replacement.

Sorry, no. First: those power meters has really bad measurement error on the low end of the scale: second, you measuring the loss of the plug adapter too. The real consumption is likely lower.

By the way, 5.1W at 9V means 570mA. The USB thing still should be able to supply that => you should request a replacement.

Unless you insulated the thing with something, then these details are for the manufacturer/vendor. They are selling that thing enclosed: they should present the specs accordingly.
I ordered 2 pcs of 5v to 9v adapter so have extra. I use the 2nd one only 5 mins each time
and it doesnt get busted.

I also got an 8 compartment battery holder and will use 6 pcs of AA battery of 1.5v each. But lets assume each AA battery only output 50 mA (instead of 100mA) for total of 300mA. If the device draw 500mA. What would happen to the battery or device?

Tom.G
AA Alkaline batteries have a 1 Amp-Hour capacity, although they drop to less than a Volt if discharged that far. So go for it! In fact I was thinking of suggesting that approach until I noticed you didn't want to build anything.

Cheers,
Tom

chirhone and Asymptotic
I ordered 2 pcs of 5v to 9v adapter so have extra. I use the 2nd one only 5 mins each time
and it doesnt get busted.

I also got an 8 compartment battery holder and will use 6 pcs of AA battery of 1.5v each. But lets assume each AA battery only output 50 mA (instead of 100mA) for total of 300mA. If the device draw 500mA. What would happen to the battery or device?
Guess what. The 5v to 9v adaptor died after using it for 15 minutes continuous. The LED displayed 4.8v instead of 9v and multimeter tested it as 5v instead of 9v.
In post #14 you mention the Dylos DC1100 demands 5.1 watts. Is this value supplied in the user manual?

Does your multimeter have a current range?
If yes, what you could do is set it up for current operation, and measure what current the DC 1100 actually draws.

A cheap and dirty way to make the connection for testing is to insert a piece of thin cardboard, or plastic in between one pair of batteries in the battery holder, and insert the ammeter leads (taking care to use correct polarity) at the (-) side and (+) side of the cells so isolated.

Couldn't find power requirement specs at the Dylos website, but chanced upon a review that claims a current draw of 220 milliamps. http://www.air-purifier-power.com/dylosdc1100proreview.html

The 5.1 watt value doesn't quite add up. The Jameco model 100853 supply is rated for only 4.5 watts. It is an unregulated, transformer-based supply with a full wave diode bridge and capacitor per the specification sheet, and I'd expect it to run on the hot side, and output voltage to fall below the rated 9V if demand was actually 5.1 watts. See the spec sheets at:

https://www.jameco.com/z/DCU090050Z...r-Transformer-4-5-Watt-9VDC-500mA_100853.html

The 5-to-9 V converter you have claims an output of 1 amp (9V at 1A = 9 watts), and should have no problem powering the air particle tester.

One of the selections in Amazon's "Compare with other items" list costs another $3, but has a built-in voltmeter and ammeter that'd come in handy. #### Attachments • 98.3 KB Views: 49 In post #14 you mention the Dylos DC1100 demands 5.1 watts. Is this value supplied in the user manual? Does your multimeter have a current range? If yes, what you could do is set it up for current operation, and measure what current the DC 1100 actually draws. A cheap and dirty way to make the connection for testing is to insert a piece of thin cardboard, or plastic in between one pair of batteries in the battery holder, and insert the ammeter leads (taking care to use correct polarity) at the (-) side and (+) side of the cells so isolated. Couldn't find power requirement specs at the Dylos website, but chanced upon a review that claims a current draw of 220 milliamps. http://www.air-purifier-power.com/dylosdc1100proreview.html The 5.1 watt value doesn't quite add up. The Jameco model 100853 supply is rated for only 4.5 watts. It is an unregulated, transformer-based supply with a full wave diode bridge and capacitor per the specification sheet, and I'd expect it to run on the hot side, and output voltage to fall below the rated 9V if demand was actually 5.1 watts. See the spec sheets at: https://www.jameco.com/z/DCU090050Z...r-Transformer-4-5-Watt-9VDC-500mA_100853.html The 5-to-9 V converter you have claims an output of 1 amp (9V at 1A = 9 watts), and should have no problem powering the air particle tester. One of the selections in Amazon's "Compare with other items" list costs another$3, but has a built-in voltmeter and ammeter that'd come in handy.
View attachment 256636
Thanks for your information. Ill ponder on them.

Im testing my Energizer Max AA now. The voltage across one battery is 1.636 volts instead of 1.5V. But does the device see 1.5v or 1.636v? 6 pcs in series is 9.8 volts instead of 9 volts. So i wonder if the dylos will see 9.8v or 9 volts. But for any device with rating of exactly 9v, doesnt the AA battery at 1.636v instead of 1.5v is overvoltage when connected in series such as 6 pieces?

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In post #14 you mention the Dylos DC1100 demands 5.1 watts. Is this value supplied in the user manual?

Does your multimeter have a current range?
If yes, what you could do is set it up for current operation, and measure what current the DC 1100 actually draws.

A cheap and dirty way to make the connection for testing is to insert a piece of thin cardboard, or plastic in between one pair of batteries in the battery holder, and insert the ammeter leads (taking care to use correct polarity) at the (-) side and (+) side of the cells so isolated.

Couldn't find power requirement specs at the Dylos website, but chanced upon a review that claims a current draw of 220 milliamps. http://www.air-purifier-power.com/dylosdc1100proreview.html

The 5.1 watt value doesn't quite add up. The Jameco model 100853 supply is rated for only 4.5 watts. It is an unregulated, transformer-based supply with a full wave diode bridge and capacitor per the specification sheet, and I'd expect it to run on the hot side, and output voltage to fall below the rated 9V if demand was actually 5.1 watts. See the spec sheets at:

https://www.jameco.com/z/DCU090050Z...r-Transformer-4-5-Watt-9VDC-500mA_100853.html
The specs above mentioned:

"
• Input: 120 VAC @ 60 Hz, 8.5W
• Output: 9 VDC @ 0.5A, 4.5W"
In message #14, the photo showed 5.1W. Was it not the power for the input which has 8.5W limit? Why did you mentioned 4.5W?

I connected the 6 pcs of AA battery in battery holder with correct polarity. But total measured 9.8 volts instead of 9 volts. Im chicken to plug this to the Dylos. Maybe i should get an AA with measured voltage of 1.3v so 7 pcs is 9.1v just like in the youtube video at msg #5? What AA battery has 1.3v measured brand new?

The 5-to-9 V converter you have claims an output of 1 amp (9V at 1A = 9 watts), and should have no problem powering the air particle tester.

One of the selections in Amazon's "Compare with other items" list costs another $3, but has a built-in voltmeter and ammeter that'd come in handy. View attachment 256636 So i wonder if the dylos will see 9.8v or 9 volts. If the battery pack open voltage is 9.8V, it will drop by some small amount (how much depends on how much load the Dylos provides) when it is powered up. Measure it. Study the Jameco power supply specs. Unloaded voltage for the test subject was 13.67 volts, and dropped to 8.95V when connected to a load that draws 500 mA. Rated voltage output at 500 mA is 9V +/-5%. 5% of 9V is 0.45, so fully loaded voltage could be from 8.55V to 9.45V and still be in spec. It is unregulated, and when the Jameco supply is operated with less than 500 mA load, output voltage will be higher than 9V. If the Dylos draws 220 mA (as indicated in the review article) power supply output voltage will be on the order of 11.6 volts. Measure it. In message #14, the photo showed 5.1W. Was it not the power for the input which has 8.5W limit? Why did you mentioned 4.5W? Like @Rive mentions in post #14, the 5.1 watts you measured is an indication what the power supply demands from the 120VAC source. The power supply has losses, and what the Dylos uses must be less than 5.1 watts. I mentioned 4.5 watts because that's what the supply is rated. 4.5 watts at 9 volts DC is 500 mA at 9 VDC. In the supply specs you'll see an AC current demand of 80 mA at 120V when operated fully loaded. 120V * 0.8A = 9.6 VA, and is higher than the rated AC input wattage of 8.5W. This is due to power factor, which would be about 0.885 (8.5W/9.6VA) fully loaded. The following isn't quite true (because power factor typically drops at lower loads, the transformer draws AC current even at no load, and unregulated DC voltage rises as load decreases), but if you've measured 5.1 watts on a supply rated 8.5 watts fully loaded, it is approximately 60% loaded, or delivering no more than 500 ma * 60%, or less than 300 mA DC. The interplay of these factors is why it is necessary to measure load voltage and current to know what's going on. If the battery pack open voltage is 9.8V, it will drop by some small amount (how much depends on how much load the Dylos provides) when it is powered up. Measure it. Study the Jameco power supply specs. View attachment 256676 Unloaded voltage for the test subject was 13.67 volts, and dropped to 8.95V when connected to a load that draws 500 mA. Rated voltage output at 500 mA is 9V +/-5%. 5% of 9V is 0.45, so fully loaded voltage could be from 8.55V to 9.45V and still be in spec. It is unregulated, and when the Jameco supply is operated with less than 500 mA load, output voltage will be higher than 9V. If the Dylos draws 220 mA (as indicated in the review article) power supply output voltage will be on the order of 11.6 volts. Measure it. View attachment 256681 Like @Rive mentions in post #14, the 5.1 watts you measured is an indication what the power supply demands from the 120VAC source. The power supply has losses, and what the Dylos uses must be less than 5.1 watts. I mentioned 4.5 watts because that's what the supply is rated. 4.5 watts at 9 volts DC is 500 mA at 9 VDC. View attachment 256680 In the supply specs you'll see an AC current demand of 80 mA at 120V when operated fully loaded. 120V * 0.8A = 9.6 VA, and is higher than the rated AC input wattage of 8.5W. This is due to power factor, which would be about 0.885 (8.5W/9.6VA) fully loaded. The following isn't quite true (because power factor typically drops at lower loads, the transformer draws AC current even at no load, and unregulated DC voltage rises as load decreases), but if you've measured 5.1 watts on a supply rated 8.5 watts fully loaded, it is approximately 60% loaded, or delivering no more than 500 ma * 60%, or less than 300 mA DC. The interplay of these factors is why it is necessary to measure load voltage and current to know what's going on. Thanks for the insight. I measured the voltage when it was turned on and it read 9.05 volts instead of 9.8v. Now i can finally focused on measuring. Initially i ordered the Laser Egg which is based on the Plantower 3003 but Amazon didnt send it for days so i changed my mind and got the Dylos instead. These are reviewed in: https://smartairfilters.com/en/blog/how-accurate-are-common-particle-counters-comparison-test/ After some reading i found out a cheaper product from china ($40) has the more latest Plantower 5003:

Now running them together.

This is the right one in another location shown so you can see the labels:

Some puzzles. The PM 10 in the right device is higher than its PM 2.5 while in the Dylos. The bigger particles (the right number on the display) are lesser. Which is the more accurate one? Please check these sensors data.

https://aqicn.org/sensor/pms5003-7003/

http://billpentz.com/woodworking/cyclone/dylos.cfm

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Thanks for the insight. I measured the voltage when it was turned on and it read 9.05 volts instead of 9.8v. Now i can finally focused on measuring.

Initially i ordered the Laser Egg which is based on the Plantower 3003 but Amazon didnt send it for days so i changed my mind and got the Dylos instead. These are reviewed in:

https://smartairfilters.com/en/blog/how-accurate-are-common-particle-counters-comparison-test/

After some reading i found out a cheaper product from china ($40) has the more latest Plantower 5003: https://www.lazada.com.ph/products/...ll&laz_token=11c153896d8eb2858ce86dff36d10e5d Now running them together. View attachment 256684 This is the right one in another location shown so you can see the labels: View attachment 256687 Some puzzles. The PM 10 in the right device is higher than its PM 2.5 while in the Dylos. The bigger particles (the right number on the display) are lesser. Which is the more accurate one? Please check these sensors data. https://aqicn.org/sensor/pms5003-7003/ http://billpentz.com/woodworking/cyclone/dylos.cfm I know nothing of the minutiae involved in air particle measurements, and cannot advise on questions of accuracy comparisons. I know nothing of the minutiae involved in air particle measurements, and cannot advise on questions of accuracy comparisons. Oh, found the answer at https://www.researchgate.net/public...y_of_the_Plantower_PMS5003_low-cost_PM-sensor (this proves the$25000 Grim unit is more accurate than the \$40 Pms 5003 in the Pm10 size):

"From these measurements, we conclude that the Plantower PMS5003 is able to measure PM2.5 more
or less correct. With a suitable calibration, it may be calibrated to a reference instrument such as the
Grimm. The PMS5003 however is not able at all to directly measure large particles > 3um. When it
outputs PM10 values, these are pure estimates based on particle sizes it can measure (d < 3um) and under the assumption of a broadly distributed particle spectrum. When the particle spectrum is not containing PM mass contributions at sizes < 3um, the PMS5003 erroneously outputs PM10 values close to zero. It therefore behaves similar to the SDS011 low-cost PM-sensor from Nova Fitness.
These findings intensify the strong suspicion that low-cost PM-sensors, mainly produced by Chinese
manufacturers and designated as PM2.5 sensors but also reporting PM10 values, aren’t able to measure particles larger than 3um and therefore solely extrapolate on PM10 values assuming a certain particle distribution"

Here is a good interactive site about pm2.5 https://www.nytimes.com/interactive/2019/12/02/climate/air-pollution-compare-ar-ul.html

Im aiming for below 5 ug/m^3 in my house. In New Delhi, it reaches 900 ug/m^3 at times. Thanks to all for the battery tips.

Asymptotic