Power draw from alarm when plugged in?

[DCTenor1]

Hi everyone,

I keep my Segway in the basement of my apartment building, plugged in with the alarm on, and someone has been unplugging it during the night. Usually the battery is fully (or mostly) charged by this point, so it hasn't really negatively affected me. For right now, I am assuming that someone is unplugging it in good faith, assuming that there is no need to waste electricity. So I want to post a little note saying that the Segway does not draw much electricity when it is fully charged and the alarm is on. My question for you, then, is:

How much electricity does the Segway draw when it is fully charged and plugged into the wall? How much electricity does it draw when fully charged, plugged in, AND the alarm is set?

Any way of estimating this stuff? If it is someone from building maintenance, I'd be willing to compensate them the electricity cost if only I knew how much it was...

Thanks for your help!
Matt (458 miles!)

[DarthSegVator]

Hi,

Bystander has (had) a "kill-a-watt" electricity consumption logging device and has done some studies in the past. Although I'm not sure if he has checked to see the power draw with the alarm on vs off.

Others have done studies as well. Search for kill-a-watt.

[KSagal]

I agree, Bystander is the place I would go for this information. He appears to have a big brain, and knows how to use it... LOL (unlike me)


Anyway, I am sure that the energy used is very small, once the batteries are charged.

You may want to talk to the building superintendent, and instead of offering money, buy some of those compact flourescent light bulbs. If they replace a half dozen 100 watt bulbs with their 17 watt equivilent, I believe you will not only reduce the energy consumption of the building more than the energy used by the segway, but the savings goes right to the same place. It should more than compensate and continue to do so for the life of the bulbs... Win-win.

[japaneezy]

i keep mine not plugged in but with alarm on at work everyday for about 6 hours and i usually will get a 1 bar drop in power. i also did not know you were able to charge it with the alarm on. lol now im gonna try charge it armed.

[japaneezy]

oops re-read that.. don't know how much more it draws if the alarm is onwhen plugged in.:confused:

[ryan_walters]

I did some tests on this when I was borrowing a kill-a-watt.

In this post: http://forums.segwaychat.com/showpost.php?p=151728&postcount=14 I found that alarm mode enabled with the segway fully charged used very little more than alarm disabled with segway fully charged. I guessed at 10-20 watts (total).

Once I got to the 'quick flash' maintenance stage of charge (while in alarm mode), I only noticed slightly more frequent 'long flash(es)' during charge. These long flashes are the only time during idle charge you get more than about 1 watt of draw.

If someone's unplugging your segway, I'd be tempted to put a sign on it something to the effect of: "If you don't own me, please don't touch me or my power cord."

[byped]

The alarm will draw 2 bars on the battery for 10-12 hours. I would assume a similar amount would be drafted indirectly from the charger by having to nominally increase the pulse charging load.


So - figure it equates to an extra charge a week for rondish numbers? Leave the quarter at the door, fifty cents if you need to sleep well at night.

[bystander]

Hi everyone,

I keep my Segway in the basement of my apartment building, plugged in with the alarm on, and someone has been unplugging it during the night. Usually the battery is fully (or mostly) charged by this point, so it hasn't really negatively affected me. For right now, I am assuming that someone is unplugging it in good faith, assuming that there is no need to waste electricity. So I want to post a little note saying that the Segway does not draw much electricity when it is fully charged and the alarm is on. My question for you, then, is:

How much electricity does the Segway draw when it is fully charged and plugged into the wall? How much electricity does it draw when fully charged, plugged in, AND the alarm is set?

Any way of estimating this stuff? If it is someone from building maintenance, I'd be willing to compensate them the electricity cost if only I knew how much it was...

Thanks for your help!
Matt (458 miles!)I don't know if I can be as helpful as claimed by the other posters, but here's what I can say.

I have a "kill-a-watt" and have found that my gen1 consumes 14 watts when fully charged and plugged in. ryan_walters has indicated on the thread he linked to that his gen2 is experiencing a 4 watt draw when fully charged and plugged in. Not enough others have posted their measured wattages to know for sure if these results are representative for their generations. No one with a gen2 has used the "kill-a-watt" to measure power draw when charged and plugged in and set in alarm mode and reported the power draw figures yet.

Using byped's and others' estimates of 2 bars per 10 hours, and assuming the battery packs hold 800 wh, and assuming the bar gauge is linear, and that charging efficiency is high, that would be an extra 200 wh / 10 h, or 20 watts on top of the 4 watts for alarm-idle charge mode, or 24 watts total.

That may be too many assumptions to provide an accurate number. The more accurate way to figure this would be to get your own kill-a-watt. We still don't really know if all gen2s idle charge at 4 watts. Some may be different, as the batteries seem to have gone through a revision and the i2 itself has had minor cosmetic revisions since it's inception.

In this thread ryan_walters has estimated the alarm-idle draw to be 10-20 watts. There's no disputing that until someone hooks up the equipment, makes the measurements and posts their results.

So 10, 20, 24 watts (or more), take your pick. If you require a more concise answer, you'll have to do a little legwork.

Sorry I can't be of any more help than this.

Link to kill-a-watt web page:
http://www.p3international.com/products/special/P4400/P4400-CE.html
Link to a place that sells them for $30:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93519

[DCTenor1]

Thanks for the calculations, everyone, I do appreciate it. So, just to clarify, is that 24 watts per hour? If so, that's .024 kW/h. Assuming it's already fully charged, then leaving it plugged in with the alarm on for 12 hours at night would (by these admittedly iffy numbers) equate to .288 kW total, which at about 10 cents per kW/h would be a little less than 3 cents per night.

Sound about right?

Perhaps I will buy a kill-a-watt. Until then, I agree with Ryan -- I'm putting up a sign.

[bystander]

Sound about right?Yup.......

[ryan_walters]

Yes, saying 24 watts is the same thing as saying 24 watt hours / per hour. Or 0.024 kw/h's per hour.

The dumb thing about somebody unplugging it while it's in alarm mode, is that they're not really saving power. The power drained from the batteries while not plugged in will have to be replaced the next time it's plugged in. A matter of 'pay me now, or pay me later'.

[DCTenor1]

Very good logic, Ryan, but I don't think such logic would be as effective on a sign as "DON'T TOUCH MY F'IN SEGWAY". :-)

[KSagal]

I believe it is nice of you to presume that the reason that someone is unplugging the machine is because you are guessing that they are trying to save the building electricity...

That may not be the case at all.

You may wish to consider that this person is just an unhappy person who is choosing to be a pain in the butt.

This person may just be unhappy that you are plugged into a building outlet on principle without authorization or care if you have permission.

This person may have any number of other reasons. Some may be positive and they think they are helping. Other reasons may be negative in all manner of ways...

I believe a sign will at least express your desire, and you can see from there what affect it has, if any. (YOu may also consider a nanny cam or some other similar recording device...)

[DCTenor1]

I know full well that it might just be someone trying to be malicious. But I'm hoping it's something less malevolent for now.

I've also thought of the hidden-camera solution. But let's hope it doesn't come to that, Karl.

[KSagal]

I did try to wait for two pages and even offer the idea of energy efficient bulbs, before I let my cynacism get to my typing fingers...

[bentbiker]

I don't know if I can be as helpful as claimed by the other posters, but here's what I can say.

I have a "kill-a-watt" and have found that my gen1 consumes 14 watts when fully charged and plugged in. ryan_walters has indicated on the thread he linked to that his gen2 is experiencing a 4 watt draw when fully charged and plugged in. Not enough others have posted their measured wattages to know for sure if these results are representative for their generations. My measured draw is 12 watts when fully charged (average over a 20 hour period).

No one with a gen2 has used the "kill-a-watt" to measure power draw when charged and plugged in and set in alarm mode and reported the power draw figures yet. No longer the case. I measured 24 watts (average over a 4.5 hour period).

Using byped's and others' estimates of 2 bars per 10 hours, and assuming the battery packs hold 800 wh, and assuming the bar gauge is linear, and that charging efficiency is high, that would be an extra 200 wh / 10 h, or 20 watts on top of the 4 watts for alarm-idle charge mode, or 24 watts total.

That may be too many assumptions to provide an accurate number. The more accurate way to figure this would be to get your own kill-a-watt. OK, I did -- now are you happy?:) We still don't really know if all gen2s idle charge at 4 watts. Some may be different, as the batteries seem to have gone through a revision and the i2 itself has had minor cosmetic revisions since it's inception. Don't know if my measured difference in idle charge is between the batteries, the particular measuring device, or the fact that Canadian electrons are just more efficient. Note that all of these measured differences amount to cost differences of a penny or two per night. I agree with previous reports that the initial charge rate is somewhere around 110 watts -- approximately 1KWH to completely charge a fully depleted Seg.

In this thread ryan_walters has estimated the alarm-idle draw to be 10-20 watts. There's no disputing that until someone hooks up the equipment, makes the measurements and posts their results. Looks like I could have accepted his accurate estimate and saved the $30 -- with 12 watts without alarm and 24 watts with alarm, I'm guessing close to, err, 12 watts for the alarm.:rolleyes:

So 10, 20, 24 watts (or more), take your pick. If you require a more concise answer, you'll have to do a little legwork.

Sorry I can't be of any more help than this.

Link to kill-a-watt web page:
http://www.p3international.com/products/special/P4400/P4400-CE.html
Link to a place that sells them for $30:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93519

See responses in red. (I know it is obvious, but vBulletin requires that something be typed after the quote)

[bystander]

See responses in red. (I know it is obvious, but vBulletin requires that something be typed after the quote)Thanks for the data.

[KSagal]

If one set of data was from the United States, and one set was from Canada, it begs me to ask, what is the voltage?

I do not know of any place in the United States that uses other than 110 volts at 60 hertz.

Is Canada the same? For some reason, I recall they use 240 volts. Is this so?

Can this affect the amperage draw?

Please fill me in on what I may be missing...

[ryan_walters]

If one set of data was from the United States, and one set was from Canada, it begs me to ask, what is the voltage?

I do not know of any place in the United States that uses other than 110 volts at 60 hertz.

Is Canada the same? For some reason, I recall they use 240 volts. Is this so?

Hehe. Only our stoves and driers. Standard wall power is 110v at 60hz. I think it's mainly europe that is 220 / 50.

220 would affect amperage draw, however, total power, both watts, and VA would be the same.

[bystander]

If one set of data was from the United States, and one set was from Canada, it begs me to ask, what is the voltage?

I do not know of any place in the United States that uses other than 110 volts at 60 hertz.

Is Canada the same? For some reason, I recall they use 240 volts. Is this so?

Can this affect the amperage draw?

Please fill me in on what I may be missing...

Hehe. Only our stoves and driers. Standard wall power is 110v at 60hz. I think it's mainly Europe that is 220 / 50.

220 would affect amperage draw, however, total power, both watts, and VA would be the same.In addition, the kill-a-watt is only available for use on 110-120 v.

If you needed to know accumulated power draw in the UK & Europe (220 - 240 v), you could use this:

http://www.maplin.co.uk/Module.aspx?ModuleNo=38343

If you were in Australia, you could use this (Also 220-240 v, but different connectors):

http://www.jaycar.com.au/productView.asp?ID=MS6115

I'm not trying to sell these things, but I guess I'm trying to sell the idea that the next revision PT ought to have this kind of monitoring built in - it's so much easier to demonstrate how "green" a product is when it can tell you itself!

The PT already has much of the internal instrumentation built-in to perform these measurements. It's mostly a matter of creating a user interface or means of downloading the info or log file or spreadsheet.

Not a feature most potential customers would be willing to pay extra for, but is something that could be added primarily with software development. Hopefully the costs associated with adding this feature would be more than outweighed by the benefit of being able to nail down exactly how "green" each particular PT is with respect to other competing devices.

The whitepaper put out by Segway, Inc. indicates the "average" benefit, but there's no easy way to know the benefit in a particular case without access to this info.

Perhaps the cost of development could be defrayed by sharing the collected user data back to Segway, Inc? Identities could be anonymised, but customers could opt out, if they felt their privacy was endangered. By getting performance and usage data directly from participating customers, Segway, Inc. would be able to spot usage patterns and trends in order to adapt better to market changes. (LOL, it would be like a survey for your PT instead of a survey for you!)

And battery failures would be easier to troubleshoot in the field because the battery charge / discharge performance data would be a lot more informative when trying to determine whether one or both batteries need to be replaced, or whether the powerbase needs service. It could cut down on unnecessary shipping charges, and expose the PTs to less collateral damage during the shipping process.

[SegDog]

my quote, 'I like to have all of the facts, before I jump to the wrong conclusion". Probably someone worried about fire, unplugging the cord. It does take some gall to do that, but not surprising. A nice note, asking to contact you, hopefully, should resolve this. If not, in my previous life, used fluorescent fingerprint powder to catch a thief at a school. You thought I was going to say something more devious...not in print.


SDog

[ryan_walters]

I did some data collection. As I mentioned before, I have a device that monitors and records data (volts, watts, amps, etc) 3-4 times per second. The only problem is that it is for DC only. So I hooked up my inverter.

I left it record for about 5.5 hours with the segway in 'maintenance' charge, while not being in security mode. Then I let it record for just over an hour while it was in security mode.

Here it is:

Click for fullsize:
http://forums.segwaychat.com/gallery/albums/userpics/14836/normal_segway_security_mode.jpg (http://forums.segwaychat.com/gallery/albums/userpics/14836/segway_security_mode.jpg)

A couple of things.. This does not show the inverter's draw without ANYTHING being connected, which is 3-4 watts. Also, this power draw is on top of the inverter inefficiency. Finally, I'm pretty sure the inverter itself is not 'power factor corrected'. This would mean an even higher reading than true ac watts consumed.

NOW: taking the 62,000 data samples from the one, and 12,000 samples from the other, I get this as averages:

No security mode = 11.5 watts.
Security mode = 25.7 watts.

I suspect the inverter is about 70% efficient, based on full charge mode current / watts, etc. That makes our number more like 8 and 18 watts.

I don't know how an ac power factor is going to influence the DC input watts, when the power factor is fairly low. I also don't know if the inverters idle draw is still present and a factor when under this kind of intermittent load.

With all these unknowns, I would imagine the ratio between the two is accurate still. That would mean security mode enabled draws about 2.2 times what it does without it. I measured idle charge mode to be about 4 watts averaging over a 40 hour period with a kill-a-watt I had borrowed. Other people have measured 12 watts. I suspect mine is less than 12, as I get 11.5 watts not counting inverter inefficiencies, inverter parasitic draw, and power factor considerations.

Either way, I'd say 20 watts fully charged, in security mode is a safe bet.



If anybody wants the raw data, either in xls, or csv, let me know.

[MJEdelman]

...

A couple of things.. This does not show the inverter's draw without ANYTHING being connected, which is 3-4 watts. Also, this power draw is on top of the inverter inefficiency. Finally, I'm pretty sure the inverter itself is not 'power factor corrected'. This would mean an even higher reading than true ac watts consumed.


What size inverter did you use?

[ryan_walters]

What size inverter did you use?

It a '400 watt' inverter. Rated for 400 watts over something like a 5 minute period. True continuous rating is 320 watt. Would probably do 2 segways, as long as you could supply the DC current.

[KSagal]

So, how many watts does the Kill-a-watt unit itself consume?

[ryan_walters]

So, how many watts does the Kill-a-watt unit itself consume?

I'd consider it inconsequential. There's a small lcd, and the internal microcontroller. I'm sure it would be less than a watt. I imagine it would not count this on its own display though, so readings wouldn't be affected either way.

[SEGsby]

Nice bit of work. :) Impressive.

thanks,
SEGsby

I did some data collection. ...