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Topic: How many cell phones can I run concurrently (Read 6 times) previous topic - next topic
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How many cell phones can I run concurrently
Yahoo Message Number: 157591
So one day, after someone rang my doorbell at 3 a.m., I decided I wanted to put a security system in at my house.  My dog went crazy at the door, so that probably scared off whoever was there, but I still wanted a security system of some sort.  After investigating I realized I couldn't afford one...wow those prices!  So, I set out to find another way.  I bought a bunch of cracked screen cell phones off the Internet for $1 each and set each one up as an IP camera around my house.  I downloaded a free viewing app and I was done.  I really like being alerted to anything going on inside or outside of my house when I'm not there and at night when I'm sleeping.  I'd like to do something like this in my LD when I go full-time.
 Will I be able to run say, 5 cell phones day and night without running out of power?  I don't know how much they draw, but I was hoping solar panels would be enough.  It would really only be when I wasn't there during the day, so it would be all night and off and on during the day.  I could get separate small solar chargers for the phones in the sunny windows, but I'd rather plug into power because I think it might be more reliable.
 Thanks for any info... I hope this is the right place for a question like this.

Mimi
Re: How many cell phones can I run concurrently
Reply #1 –
Yahoo Message Number: 157594
"Will I be able to run say, 5 cell phones day and night without running out of power?"

We can't answer that without knowing how much power you have to work with. But assuming the cell phones draw about half an amp apiece, that would be 2.5 amps times 24 hours equals 60 amp-hours per day. Since Lazy Dazes come with 225 Ah of batteries, of which you can safely use about 110 Ah without risk of damaging the batteries, your five phones, by themselves, would be consuming half of your usable battery power.

And that is not considering what it would take to replace the 60 Ah you'd be drawing from your batteries each day. I have five 100 W solar panels and four extra-large batteries (500 Ah total capacity)--an unusually large and correspondingly expensive solar power system--and I barely got 60 Ah yesterday. Granted, it's winter and I'm in a location where the sun sets early, but you get the idea. A typical 200 W/225 Ah solar power system would not be able to supply the power to run your five phones around the clock.

Even if you had unlimited power, you will not have unlimited internet bandwidth. Most RVers are limited to ten to twenty GB of internet usage per month. Even that is much more costly than the typical unlimited-bandwidth internet setup in a fixed house. Things are very different on the road, and connectivity is a limited and costly resource. Each of your IP cameras is streaming video, chewing through bandwidth like a hog chewing through a corn crib. Five cameras at once? I don't even want to think about it. I don't know any RVers who have even one streaming video camera. We just can't afford it.

Andy Baird
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: How many cell phones can I run concurrently
Reply #2 –
Yahoo Message Number: 157602
Well, I was hoping I could take my unlimited data plan with me as a mobile hotspot because I want reliable Internet.  I also wouldn't need the phones on all day, only when I wasn't there,.  I would have them on all night, 8 hours I guess.  It sounds like it's impossible for me to do this,.  That's depressing.
Re: How many cell phones can I run concurrently
Reply #3 –
Yahoo Message Number: 157604
I think you assumed a far too high amp draw for each phone, and did not account for the fact it's at  3.7 volts instead of 12 volts, so here's my much lower estimate, which I suspect is also too high.

At 0.5 amps, a cell phone would need a 2.5 AH battery (about 9 watt hours, given the nominal 3.5 volt output) for only 5 hour talk time, and is much bigger than a cell phone. More likely, the battery is 1 watt hour or less, the drain is only 0.3 A, and you'd need 5ea x 0.3A x 3.5V x 24hrs = 126WH per day. For a 12 volt power source, the AH needed per day is 126WH/12v = 10.5 AH.

Eric
  [lifewithalazydazerv] wrote on 12/14/2015 5:12 PM:
2005 Jayco 24SS
Re: How many cell phones can I run concurrently
Reply #4 –
Yahoo Message Number: 157605
I do wish I understood more about this.  Reading the details reminds me of doing my taxes.:-)  So Eric, Andy, is it impossible or, would it be more possible if I reduced them to 3 phones?  I can always charge two of the phones on their own solar chargers.
 Even if I could only have one phone, it would be better than none, for me.

Thanks...

Mimi
Re: How many cell phones can I run concurrently
Reply #5 –
Yahoo Message Number: 157607
The interior of a LD is so small, I'm not sure a security system like you have in mind adds anything to your safety.
If someone was inside the LD, you would not need a security system to let you know.
Your dog is alarm system you need.
There are small, battery operated motion detector alarms on the market if you feel you need something.

Ed
Re: How many cell phones can I run concurrently
Reply #6 –
Yahoo Message Number: 157609
Hi Ed,
 The reason I like the idea is that, if I'm away from my RV, I can see and hear what's going on inside of it.  I can keep an eye on my dog too.  You're right about at night though.  The only thing is, I like the idea of being awakened -before- someone tries to get inside rather than having them wake me up, up close and personal.

Mimi
Re: How many cell phones can I run concurrently
Reply #7 –
Yahoo Message Number: 157613
"Your dog is alarm system you need."  --Ed

Amen!  Lilly is reliably "alarming" both in the stix 'n' brix & in LDy Lulubelle, powered only by kibble & the occasional snackees...however, I'm still working on getting her off-switch to operate reliably (her battery has never been depleted--summer-time, windows open in the stix 'n' brix, deer/other critters walking through the yard at 2 AM, & she's "alarming" :-(

I'm vicariously enjoying your enthusiasm...I suspect I'm too firmly rooted here in the boonies of north Missouri to become a full-timer, but I do love reading about all who have shared their F-T adventures & your plans for your own.   By the By, I highly recommend joining the Ladeze...a grand gathering of uppity gals who generously give of their knowledge/experience/welcoming "spirits" (which helped to fuel a bit of baying at the moon around the campfire at Moab, among other things).

Lynne LDy Lulubelle, '05 30" TB Lilly, 4-Legged Alarm
Lynne
LDy Lulubelle, Green '05 31' TB
Lilly, the 4-Legged Alarm
Re: How many cell phones can I run concurrently
Reply #8 –
Yahoo Message Number: 157616
"I think you assumed a far too high amp draw for each phone, and did not account for the fact it's at 3.7 volts instead of 12 volts..."

You're certainly right on the second point, Eric; I blush to admit that I made a careless error in my off-the-top-of-my-head calculations, by confusing the voltages. Let's try it again. A typical smartphone charger supplies 1 amp at 5.1 V (the standard USB voltage that most phone chargers provide). But for purposes of estimating, I assume that's the maximum current when the battery is fully drained, and that the average is probably about half that. So that's 0.5 amps per phone at 5.1 V, or 0.2125 ampsper phone at 12V (not factoring in the inefficiency of the charger's voltage conversion).

That yields 1.0625 amps at 12 V for all five phones, and when you multiply that by 24 hours you get 25.5 amp-hours per day. That's less than half what I said earlier, but it's still about a quarter of the usable capacity of a standard Lazy Daze's two batteries.

Then there's the limited-bandwidth issue. And wireless routers require power, as do cell signal boosters (needed in weak-signal areas)--typically at least an amp apiece. You could easily be up to sixty or seventy amp-hours per day when you add it all together.

All this aside, Mimi already has the best possible security system: a large dog. She wrote: "I like the idea of being awakened -before- someone tries to get inside rather than having them wake me up..." A dog will do exactly that: wake you up when there's something unusual going on. A collection of video cameras won't.

"I can always charge two of the phones on their own solar chargers."

Don't bet on it. Solar panels are much, much less efficient when the sunlight they receive is coming through even clear window glass--and a Lazy Daze's windows are heavily tinted.

Even if that were not the case, buying several small panels is far less cost-effective than putting a bigger panel on the roof (or on the ground). The cost per watt skyrockets when you're talking about three- or five-watt panels compared to hundred-watt ones.

Andy Baird
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: How many cell phones can I run concurrently
Reply #9 –
Yahoo Message Number: 157617
Yeah, it sounds impossible.  I may look into getting a sim camera or, maybe I'll just .use 1 ip camera.  It seems like that might work.  I don't really need a router, but I do need signal so, this may not be a viable solution for me.

Oh well.  I'll keep looking!

Thanks Andy!