Homebrew emergency power system - advice needed please

Hi

I could use some feedback regarding a brainstorm of mine. I'm in the
process of building an emergency power system for home use.

The main questios are regarding supply and re-charging.

For the supply, for now I'm using 12V starting batteries. The plan is
to pick up 2 (or possibly 4) 6V 156Ah golf cart batteries.

For the charger I mated a 63A Delco alternator with internal 12V
regulatioin to a gas snowblower engine.

I want to use a 1500W inverter to supply about 180 watts of AC, 8x IR
LED surveillance cameras, and about a dozen 20mA LED lamps for
emergency lighting all operating at their native 12VDC

The questions are:

Would I be able to use my alternator/generator to charge the golf cart
batteries without damaging them?

Until I'm able to get the golf cart batteries, would the couple
starting batteries I have work OK?

TIA

Bob

 

[N_Cook]

<bobvalli@NOSPAMcomcast.net> wrote in message
news:39ej77lt1t0n77800vnvbmf64oi2thqu4e@4ax.com...

Hi

I could use some feedback regarding a brainstorm of mine. I'm in the
process of building an emergency power system for home use.

The main questios are regarding supply and re-charging.

For the supply, for now I'm using 12V starting batteries. The plan is
to pick up 2 (or possibly 4) 6V 156Ah golf cart batteries.

For the charger I mated a 63A Delco alternator with internal 12V
regulatioin to a gas snowblower engine.

I want to use a 1500W inverter to supply about 180 watts of AC, 8x IR
LED surveillance cameras, and about a dozen 20mA LED lamps for
emergency lighting all operating at their native 12VDC

The questions are:

Would I be able to use my alternator/generator to charge the golf cart
batteries without damaging them?

Until I'm able to get the golf cart batteries, would the couple
starting batteries I have work OK?

TIA

Bob

Will you need a clutch between blower motor and alternator? what sort of
control system to monitor the starting and running of the motor?

 

[Geoffrey S. Mendelson]

bobvalli@NOSPAMcomcast.net wrote:

For the charger I mated a 63A Delco alternator with internal 12V
regulatioin to a gas snowblower engine.

Is that really a good idea? Gasoline is dangerous to store, without
special tanks you may have building code or insurance problems.

Propane is a much better choice unless you are in a very cold climate.
No one seems to be upset if you have a large "bottle" of propane around
for your gas grill, RV, etc.

In many places, you can have two of them strapped to the back of trailer
and no one pays attention to them. Try that with gasoline.

Would I be able to use my alternator/generator to charge the golf cart
batteries without damaging them?

12 lead acid battery chargers are cheap enough. You can buy ones that
will not cook your batteries.

You also want more than 12 volts to charge the battery, that's why car
electrical systems are 13.8 volts.

Until I'm able to get the golf cart batteries, would the couple
starting batteries I have work OK?

Depends upon how often you use them, how you charge them and how low you
let them go. If you discharge any lead acid battery, it will stop working.

There are devices that control the output of batteries and shut them off
when they get to the point they will be damaged. You probably want one,
but at some time may have to decide if you want light or batteries.

Another cheap source of stored electricity is the NiMH slow discharge batteries.
If you buy a bunch of them for your battery operated devices and cycle through
them they will come in handy. They can easily be charged, there are lots of
devices to do it.

Though IMHO, you would be better off not buying any of this stuff and
spending your money on Solynda solar arrays while you can still get them,
especially if you buy them at "gone out of business sale" prices.

Geoff.


--
Geoffrey S. Mendelson N3OWJ/4X1GM
Making your enemy reliant on software you support is the best revenge.

 

[Michael A. Terrell]

N_Cook wrote:

Will you need a clutch between blower motor and alternator? what sort of
control system to monitor the starting and running of the motor?

You don't need a clutch. if the motor can't handle startup with the
alternator, put a switch or time delay relay between the alternator &
the load. Since the current output of the alternator doesn't rise at
lower RPMs, the motor should have no problem coming up to operating
speed without a clutch.


--
You can't have a sense of humor, if you have no sense.

 

[bobvalli]

On Sep 21, 7:19 am, "Geoffrey S. Mendelson" <g...@mendelson.com>
wrote:

bobva...@NOSPAMcomcast.net wrote:
For the charger I mated a 63A Delco alternator with internal 12V
regulatioin to a gas snowblower engine.

Is that really a good idea? Gasoline is dangerous to store, without
special tanks you may have building code or insurance problems.

Propane is a much better choice unless you are in a very cold climate.
No one seems to be upset if you have a large "bottle" of propane around
for your gas grill, RV, etc.

In many places, you can have two of them strapped to the back of trailer
and no one pays attention to them. Try that with gasoline.

Would I be able to use my alternator/generator to charge the golf cart
batteries without damaging them?

12 lead acid battery chargers are cheap enough. You can buy ones that
will not cook your batteries.

You also want more than 12 volts to charge the battery, that's why car
electrical systems are 13.8 volts.

Until I'm able to get the golf cart batteries, would the couple
starting batteries I have work OK?

Depends upon how often you use them, how you charge them and how low you
let them go. If you discharge any lead acid battery, it will stop working..

There are devices that control the output of batteries and shut them off
when they get to the point they will be damaged. You probably want one,
but at some time may have to decide if you want light or batteries.

Another cheap source of stored electricity is the NiMH slow discharge batteries.
If you buy a bunch of them for your battery operated devices and cycle through
them they will come in handy. They can easily be charged, there are lots of
devices to do it.

Though IMHO, you would be better off not buying any of this stuff and
spending your money on Solynda solar arrays while you can still get them,
especially if you buy them at "gone out of business sale" prices.

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
Making your enemy reliant on software you support is the best revenge.

Thanks for the quick replies. As for the DC generator, the unit is
belt driven and will be left outside. There are terminals on the
generator that turn on the field once the engine has started. I
explored solar but its too much for my budget, and again, for now this
is for emergency use only. My idea is that with the 63A generator,
that I'd like to get 6 to 8 hours of battery time (discharging the
batteries to about 40%) and then use the DC generator to do a quick
charge for an additional 6 to 8 hours of run time, ad infinitum.
Monitoring would be done manually. My biggest question is whether
this "quick charge" will destroy the golf cart batteries.

 

[Robert Macy]

On Sep 21, 3:30 am, bobva...@NOSPAMcomcast.net wrote:

Hi

I could use some feedback regarding a brainstorm of mine. I'm in the
process of building an emergency power system for home use.

The main questios are regarding supply and re-charging.

For the supply, for now I'm using 12V starting batteries. The plan is
to pick up 2 (or possibly 4) 6V 156Ah golf cart batteries.

For the charger I mated a 63A Delco alternator with internal 12V
regulatioin to a gas snowblower engine.

I want to use a 1500W inverter to supply about 180 watts of AC,  8x IR
LED surveillance cameras, and about a dozen 20mA LED lamps for
emergency lighting all operating at their native 12VDC

The questions are:

Would I be able to use my alternator/generator to charge the golf cart
batteries without damaging them?

Until I'm able to get the golf cart batteries, would the couple
starting batteries I have work OK?

TIA

Bob

Need similar system. Would you post a description of your camera
system? Where you got it, costs, pros/cons, etc?

 

[Robert Macy]

On Sep 21, 3:30 am, bobva...@NOSPAMcomcast.net wrote:

Hi

I could use some feedback regarding a brainstorm of mine. I'm in the
process of building an emergency power system for home use.

The main questios are regarding supply and re-charging.

For the supply, for now I'm using 12V starting batteries. The plan is
to pick up 2 (or possibly 4) 6V 156Ah golf cart batteries.

For the charger I mated a 63A Delco alternator with internal 12V
regulatioin to a gas snowblower engine.

I want to use a 1500W inverter to supply about 180 watts of AC,  8x IR
LED surveillance cameras, and about a dozen 20mA LED lamps for
emergency lighting all operating at their native 12VDC

The questions are:

Would I be able to use my alternator/generator to charge the golf cart
batteries without damaging them?

Until I'm able to get the golf cart batteries, would the couple
starting batteries I have work OK?

TIA

Bob

Need similar system. Would you post a description of your camera
system? Where you got it, costs, pros/cons, etc?

 

On Wed, 21 Sep 2011 06:30:30 -0400, bobvalli@NOSPAMcomcast.net wrote:

Hi

I could use some feedback regarding a brainstorm of mine. I'm in the
process of building an emergency power system for home use.

The main questios are regarding supply and re-charging.

For the supply, for now I'm using 12V starting batteries. The plan is
to pick up 2 (or possibly 4) 6V 156Ah golf cart batteries.

For the charger I mated a 63A Delco alternator with internal 12V
regulatioin to a gas snowblower engine.

I want to use a 1500W inverter to supply about 180 watts of AC, 8x IR
LED surveillance cameras, and about a dozen 20mA LED lamps for
emergency lighting all operating at their native 12VDC

The questions are:

Would I be able to use my alternator/generator to charge the golf cart
batteries without damaging them?

Until I'm able to get the golf cart batteries, would the couple
starting batteries I have work OK?

TIA

Bob

Starting batteries don't last long if discharged below the 80% of
charge level. The golf cart batteries will last much longer, but the
best life will be achieved if the discharge is limited to 50% or less.
The 63A altenator will only provide 63A if running at high speed
(5000-6000 rpm) so you'd need to adjust pulley sizes to get full power
when driving it with a 3000-3600 rpm engine. The rate of charge is
also dependent on the battery's state of charge, so it's unlikely that
your proposed setup will harm the golf cart batteries. The bigger
concern is what the end of charge voltage of the golf cart batteries
should be versus the end of charge voltage the alternator and its
regulator are designed for. The golf cart batteries are deep cycle
and *may* have a different end point voltage - check the manufacturers
specs.

Using an oversized inverter usually wastes battery power. Inverters
have their "sweet spot" where they have optimum efficiency - usually
somewhere in the 50%-90% load range. For longest battery life, you
should replace the inverter with a smaller one - and look carefully at
the no-load current requirement. Inverter idle drain isn't usually
high on the list of features people look for - most people are looking
at the maximum power they can get from it. I have a PowerStar UPG400
that idles at about 1 watt (that's about 0.1 amps). I would guess
that your 1500 watt inverter idles at 6 watts (0.5amps) - probably
more. The UPG400 was a serendipity buy - $24.50 plus shipping (couple
of pounds) - from a closeout at hsc.com n Dec 2009. Until I did
research, I had no idea that a 1990-91 vintage inverter could be so
efficient. Only wish I had known more about it sooner and been able
to purchase several.

I'm not an expert on backup/standby power, but I've had emergency
generators (one 1850 watt and one 5000 watt) for some time. Two
generators? Yes, the little one if rotating power to one item at a
time -freezer, fridge, etc - is adequate, the big one if multiple
appliances are needed simultaneously -i.e., furnace and microwave
oven. The little gen runs a lot longer on a gallon of gas than the
big one at the same load.

I've been doing a lot of research recently before setting up a small
solar system (70AH battery, 45 watt solar array) for testing. I've
even measured the drain the solar charge controller puts on the
battery - while it's typically in the milliamp range, some use two or
three times as much as others. Solar amps are expensive, so I'm
looking to get as many of them as possible to the load, not the
control electronics. Lots of LED's on the controller *look*
impressive, but require a lot of milliamps to be visible in sunlight.
An analog meter or an LCD panel with no backlight (or a switchable
backlight) requires less power to operate.

John

 

[mike]

bobvalli@NOSPAMcomcast.net wrote:

Hi

I could use some feedback regarding a brainstorm of mine. I'm in the
process of building an emergency power system for home use.

The main questios are regarding supply and re-charging.

For the supply, for now I'm using 12V starting batteries. The plan is
to pick up 2 (or possibly 4) 6V 156Ah golf cart batteries.

For the charger I mated a 63A Delco alternator with internal 12V
regulatioin to a gas snowblower engine.

I want to use a 1500W inverter to supply about 180 watts of AC, 8x IR
LED surveillance cameras, and about a dozen 20mA LED lamps for
emergency lighting all operating at their native 12VDC

The questions are:

Would I be able to use my alternator/generator to charge the golf cart
batteries without damaging them?

Until I'm able to get the golf cart batteries, would the couple
starting batteries I have work OK?

TIA

Bob



It's interesting how a bunch of individual stuff that seemed like

a good idea at the time can get combined into a less than optimal
solution. Been there, done that...lotsa times.

How often does the power go off and for how long?
I got a great deal on an impulse purchase at a garage sale.
Now, I have a 5kw generator and a DIY transfer switch.
When I did the plan to install it, I discovered that the
cost of the permits and inspections cost more than the generator.
Reviewing the outage history, I determined that I only *needed* one thing.
I didn't want the pipes to freeze in the winter.
In 40 years, the power has never been off that long.
The solution was to
put a disconnect on the gas furnace air handler so I could run it off a
MUCH smaller generator.
"Just because I can" was insufficient motivation to continue the project.
Anybody wanna buy a 5kw generator and transfer switch?

I've found that an effective strategy for dealing with a power outage is
to take a nap. I don't need any power at all to do that.

Some things to think about...

Batteries have a temperature coefficient. The alternator's internal
regulator probably
compensates for that...for the designed battery chemistry.
If the batteries and generator are in different locations with significant
temperature difference, that may be an issue. Worth checking.

Golf cart batteries are VERY expensive.
Capacity may be a significant function of temperature.
Most people don't golf in the dead of winter.

If you do the math, you might discover that using the existing
batteries for short outages and running the generator continuously
for the long ones to be cost effective. The losses in the charge/discharge
processes may be more than the difference in efficiency running the
generator in spurts.

Harbor Freight will sell you a 800W 120VAC generator for $90.
It's a crap generator and probably won't last long...but how
long does it have to run? Probably a lot cheaper than golf cart
batteries...and has other uses.

As a matter of curiosity...
More than one person mentioned the security cameras.
Unless you're prepared to confront the gang of pillagers
with your trusty shotgun, what good is a security camera
during a protracted power outage? The cops are gonna be busy
elsewhere.

The 180W is an interesting number. Can't do much at all with
180W. And you can do almost as much with 90W or 30W.
Attacking the load problem at the point of use might
improve the numbers.
You're gonna have to run separate wiring anyway...if you want
to meet code. Might want to review your fire insurance to see
if it says anything about "user installed" electrical stuff.
The cost of meeting code and passing inspections was what killed my
generator project.

 

[(PeteCresswell)]

Per mike:

As a matter of curiosity...
More than one person mentioned the security cameras.
Unless you're prepared to confront the gang of pillagers
with your trusty shotgun, what good is a security camera
during a protracted power outage? The cops are gonna be busy
elsewhere.

As one with zero practical experience - but who has been dabbling
in IP cams since being anointed to set up a surfcam for a local
windsurfing shop....

They may want the still photos that some cams can take/store
automatically - for later use.
--
PeteCresswell