A few comments on this topic:
1. I got a dual fuel generator because of the problems with gasoline
carburetors - apparently you have to clean them out after each use.
Not so with propane.
2. The output waveform is kinda crappy - lots of high frequency trash
on top of a not too good sine wave. This waveform is BETTER than the
three level square wave that comes from most UPS and power inverters
which usually is a 165v square wave with zero volt times to make the rms 115v.
3. I made up a power loss detector and line changeover switch to turn
a 12v to 115v inverter on and switch the load to it. Simple 3PDT
relay with held in with power line. When the line goes away, two
contacts switch the power line and the third shunt across the
inverter power switch. The switchover is too slow for some computers
which was solved with a bottom line (ie: cheap) UPS for that computer.
3a. I really should do a proper design for a power loss detector to
switch the inverter ON and power line changeover switch.
4. Check the inverter current consumption when turned OFF - many draw
significant power when off.
5. Once you have 12v battery power, you can add as many batteries as
desired for long run times and get a battery charger to run off of
the generator.
6. I am using a pair of 12v deep cycle marine batteries of about 100
Ahr. Since these are expected to only cycle once every few years,
ordinary auto batteries may have been a better choice.
I am not convinced of the value of replacing wall warts with step
down or step up converters because of the issue of ground isolation
(or not) and some that put out ac. Plus any power efficiencies may
not be worth the cost and hassle compared to buying another 12v battery.
thanks
JK
At 03:02 PM 9/29/2017, Keith Lofstrom wrote:
>Three weeks ago, a suicidal squirrel (or "Rocky the Frying
>Squirrel") tested his electrical "mettle" on the power feed
>to our street, and lost. We were without power for a few
>hours, until PGE diagnosed and fixed the blown fuse.
>
>We were involuntarily reminded that the cordless POTS
>phones in our house are powered by wall warts. We lost
>landline phone service until I plugged in an ancient
>princess phone from a basement junkbox, so we could call
>PGE (using caller ID to verify the outage location).
>
>The grid will become increasingly unreliable in coming
>decades; it wasn't designed for intermittent "alternative
>energy", electric car charging, and squirrels frightened
>by climate change predictions. It could be ... but "why
>not" is a whole 'nother rant.
>
>Anywhoo, the bottom line is that we will be on battery
>power and generator backup more often in the future, and
>it is prudent to prepare. For example, alternative power
>strategies for essential wall-wart-powered devices, like
>the cordless phones, the firewall computer, and the
>wireless access point.
>
>Most of the wall warts are 12V or less; the phone base
>sets are 7.5V *DC*. Chinese suppliers on ebay sell
>little 3 amp LM2596S step-down ("buck") converter boards
>for less than $1 ... and a longish delivery time. I
>plan to put a 12V marine battery in an unused fireplace
>(to vent hydrogen, if any) and distribute (fused!) 12V
>power to a few places in the house.
>
>I will replace the essential wall warts with properly
>adjusted step-down converters. Then the phones and
>the wireless power will keep running for a few hours
>while the battery discharges. For extended outages
>(and we had a two week outage a decade ago) I'll fire
>up the kilowatt Honda portable generator. That won't
>power motor startup on our older refrigerator and
>freezer, but we will replace those soon. I presume
>we can find refrigerators with "low inrush current"
>soft-start electronic motor controllers; I expect those
>have been developed for off-grid solar homesteading.
>
>In any case, relevant to PLUG, I have a bag of these
>buck converters to play with, which might be useful for
>powering your low-power computer gizzies after Oregon
>plunges into darkness. Or powering them in your gas
>guzzling car(*). Let's schedule a play date here for
>fooling with them; contact me via email.
>
>Keith
>
>(*) visions of the Personal Telco 500, a high speed
>automobile race where the lead car with the access point
>races around the track, while distracted drivers race
>behind it with their laptops, debugging and uploading
>kernel patches; Indy Indie networking! :-)
>
>--
>Keith Lofstrom kei...@keithl.com
>_______________________________________________
>PLUG mailing list
>PLUG@lists.pdxlinux.org
>http://lists.pdxlinux.org/mailman/listinfo/plug
_______________________________________________
PLUG mailing list
PLUG@lists.pdxlinux.org
http://lists.pdxlinux.org/mailman/listinfo/plug
