generator use question

 

could i ask a question?  please forgive my ignorance on this subject.

(short version...)
do people use one of those regular old automobile battery chargers plugged
into your generator to charge up deep cycle batteries?

(long version...)
something i've been curious about.  i've been thinking about buying a 5500
watt diesel generator for a while now.  what i was wondering is (and this is
going to be a convoluted question because i can't figure out how to phrase
it simply)  if the power goes out, and i'm running the generator, wouldn't
it be nice to, instead of running the generator constantly, with the noise
and all, to be able to shut it down for a while and run off batteries?  i'm
wondering if the standard procedure is to have a portable
(gas/propane/diesel) generator and have 2 deep cycle batteries with an
inverter.  i'm thinking just "survival mode", to keep the boiler running in
the winter and the refrigerator/freezer(s) running in the summer, and maybe
to keep the wiring hot in the house so i could turn on and shut off lights
as i moved from room to room instead of having to illuminate w/ a
flashlight.  the thing i'm wondering is, doesn't it take hours and hours to
charge up lead acid batteries?  i'd have to run the generator for 7 hours to
charge up the batteries and it'll take like 1/2 hour to discharge them?
isn't that a tremendous waste of capacity and fuel to charge up batteries, i
mean, especially if i'm not using all those 5500 watts during the entire
time the generator is running?!  i was thinking maybe it would be better to
get the smaller capacity generator (4000 watt) so i wouldn't be wasting
diesel to charge up the batteries but then when i DID need more power i
wouldn't be able to generate it.  i was hoping to not have to buy a bank of
10 (or whatever) deep cycle batteries.  do people use one of those regular
old automobile battery chargers plugged into your generator to charge up
deep cycle batteries?
the power rarely goes out here in s.e. new york state.  i was hoping i could
buy a generator to use as a portable generator occasionally, but have it on
hand on the rare occasions the power goes out as a "standby generator".

 

On Wed, 25 Apr 2007 21:40:41 GMT, "William Wixon"


It's sometimes done to save money. But regular battery chargers aren't
up to long term use, and don't tend to be multi-stage like more
expensive models.


A nice setup for what you've described might be a Honda EU model
generator http://www.hondapowerequipment.com/gensup.asp , and an
inverter-charger. The generator will run slowly and sip fuel when
demand is low, such as when a proper charger is throttling current
during finish charging. Or you could save the finish charging for
later, and power that portion when the grid is available. The EU2000
is a nice size for most regular 110V loads. Here's an example of an
inverter-charger http://www.outbackpower.com/Inverters.htm , but there
are many other models. The idea is that the inverter will switch
seamlessly from powering your emergency loads from the battery, to
using a multi-stage process to charge the battery from a generator.

Wayne

 


And it does not save money. Problems - inefficient chargers - piddling
away input energy, charging at non-optimal rates. Wastes fuel. Abuse of
battery bank though improper charge parameters, shortening its life -
wastes life of expensive battery bank - which is $ out of your pocket.

The latter, especially, makes a good charger very worthwhile, and
ultimately saves money.

--
Cats, coffee, chocolate...vices to live by

 

Yup, that's essentially the way the electrical system in an RV works.

Genny->AC/DC converter->battery bank-+->12 volt appliances
                                     |-> inverter for 120 vac loads.

In my rig I have a 4kw inverter generator (Generac Impact)

http://www.neon-john.com/Generator/Impact_3600/Impact_home.htm

that feeds an 80 amp progressive dynamics Intellipower 9200 with
built-in charge wizard

http://www.progressivedyn.com/hotdeals.html

 that feeds 350 amphours of deep cycle batteries.  Connected to that
are the "house loads", 12 volt lighting and appliances, and a 1500
watt inverter.  The inverter runs the microwave, toaster, toaster
oven, coffee pot and the dorm-style refrigerator.  When the generator
is running, an automatic transfer switch moves the line loads over to
the generator from the inverter.  When shore power is available,
another transfer switch moves to line loads including the Intellipower
to shore power.

I highly recommend the Intellipower because it is a "smart" charger
that takes good care of the batteries.

I have a similar setup here in my mountain home.  The house's loads
are divided into "vital loads" and "balance of plant" loads, borrowing
terminology from nuclear power plants.  Vital loads including CF
lighting, the refrigerator and freezers, the wood burning fireplace
insert's fan and my computer.  The vital bus is fed from pretty much
the same setup as in my MH.

Since power can be out for a week at a time, I have redundant
generators.  For usual stuff there is a Generac QuietPack 55G

http://www.neon-john.com/Generator/Quiet_pack_55G/Quiet_home.htm

This is an almost silent running generator that gets quite good gas
mileage.

To back that up and to run all the heavy loads at once, I have a
homemade diesel powered 10KVA generator.  It's a bit more noisy (no
soundproofing yet) but is very economical to run and handles overload
well.  I can run the heat pump, the water heater and the electric
stove at the same time.  I like having a diversity of fuels.  I have
provisions for running either on propane from the 1000 gallon tank.
The two can be paralleled.  I've never done it under adverse
conditions but in "test mode" it works well.

This

http://www.neon-john.com/Generator/CBC/CBC_home.htm

Is another method I have for charging 12 volt batteries and supplying
12 volt loads.  I used to carry this unit on dry camping trips (back
in the woods with no utility connections) to rapidly replenish my
battery bank each day.

Now I carry around one of these in the MH:

http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200313480_200313480

A cute little lightweight 1KVA generator.  Northern ran these on sale
for $90 back around Christmas so I got a second one.  It'll run a 60
amp Intellipower well but won't quite pull the 80 amp version.  I had
to fiddle around with DC output lead lengths to insert enough
resistance to let it drive the 80 amp version at less than full power.
I use this little unit when all I'm doing is charging batteries and
running the 4kw genny is overkill.

If you don't want to fool around with batteries and inverters and such
but still want good fuel economy during an outage then you ought to
take a look at the various inverter generators.  These generators make
high voltage DC that is inverted to 60 hz by the built-in inverter.

yamaha, honda and Kipor (chinese honda klone) are major brands.  The
advantage of the inverter genny is that the engine only runs at
whatever speed is necessary to supply the load.  At light loads, the
generator is almost idling.

If you strictly want to charge batteries then you need to combine a
smart charger with the appropriately sized generator so that the
generator is running at full load most of the time.  That will be the
most efficient charging regime.  The little 1KVA generator and the
Intellipower 60 amp unit, for example.  For about half the money as
the Intellipower, you can get a Vector/Black & Decker (wallyworld) 40
amp smart charger.  It has to be manually started each time but that
may not be a problem in your case.  I have one and like it but the
Intellipower is soooo  much better.

John

On Wed, 25 Apr 2007 21:40:41 GMT, "William Wixon"


John De Armond
See my website for my current email address
http://www.neon-john.com
Cleveland, Occupied TN
All great things are simple and many can be expressed in single words:
Freedom, Justice, Honor, Duty, Mercy, Hope.  -Churchill

 

Same here William.

Generator charges battery bank (and we run house loads from the genny
when charging is needed) via a smart charger (some chargers are not
generator friendly - I've got a nifty melted Vector if you need a
paperweight) plus our genny has a 12 volt/10 amp output for an extra
boost to the charging when needed.

You can either switch house loads over to the generator during
charging cycles or simply keep running off the inverter(s) but you'll
be extending the charge cycle.



Max
http://www.northernmichigansolar.com
now with explosions!