Generator question (to recharge 2 linked 12V batteries and provide basic electrical needs)...

[Melandre]

We recently purchased a small cabin where electricity is not avalable.
At the time of purchase, electrical requirements where met by an old
generator (still works but can't tell what power), a 300A charger, a
couple of 12V generic deep Cycle batteries and a 12V-115V inverter.

The setup is now basically the same except that we have upgraded the 2
12V batteries and we have now a new 2500W generator. Electricity
requirements is generally low: music during the day, a 60W light at
night and occasionnally we watch a DVD on a 27 in TV (so TV and DVD
player running simultaneously for approx. 2 hours or less). Must run
power tools occasionnally but this we do directly from the generator
bypassing the battery system.

Couple of things that are sill unclear to me:

1) if the generator is connected to the charger (with nothing else
runnning) how long should it take for the 2 batteries to be recharged
(say at approx. 90 - 95%) assuming the batteries were down to 50%?
Would I have to run the generator for a couple of hours? 5hrs?
10hrs?

2) if I disconnect the charger and connect the generator directly to
the power bar (from which an extension cord goes to small stereo and
light) could I also use a second extension cord from the power bar and
connect it the charger so that not only would the generator provides
electricity for basic needs (I am assuming music and light would draw
a very small portion of the generator power generating capacity) but
at the same time would provide enough juice to recharrge the 2
batteries?

I guess, the simpler way of asking is, can the generator handle
suppling power simultaneouly to a stereo, a 60W light (or two) AND
recharge the 2 batteries (via the 300A charger)?

Andre

 

[SQLit]

We recently purchased a small cabin where electricity is not avalable.
At the time of purchase, electrical requirements where met by an old
generator (still works but can't tell what power), a 300A charger, a
couple of 12V generic deep Cycle batteries and a 12V-115V inverter.

The setup is now basically the same except that we have upgraded the 2
12V batteries and we have now a new 2500W generator. Electricity
requirements is generally low: music during the day, a 60W light at
night and occasionnally we watch a DVD on a 27 in TV (so TV and DVD
player running simultaneously for approx. 2 hours or less). Must run
power tools occasionnally but this we do directly from the generator
bypassing the battery system.

Couple of things that are sill unclear to me:

1) if the generator is connected to the charger (with nothing else
runnning) how long should it take for the 2 batteries to be recharged
(say at approx. 90 - 95%) assuming the batteries were down to 50%?
Would I have to run the generator for a couple of hours? 5hrs?
10hrs?

2) if I disconnect the charger and connect the generator directly to
the power bar (from which an extension cord goes to small stereo and
light) could I also use a second extension cord from the power bar and
connect it the charger so that not only would the generator provides
electricity for basic needs (I am assuming music and light would draw
a very small portion of the generator power generating capacity) but
at the same time would provide enough juice to recharrge the 2
batteries?

I guess, the simpler way of asking is, can the generator handle
suppling power simultaneouly to a stereo, a 60W light (or two) AND
recharge the 2 batteries (via the 300A charger)?

Andre

Some how I really doubt that you have a 300 AMP charger. Maybe 300 watts.
You do not provide the amp capasity of the new batteries. A WAG would be 7-8
hours.
You charger is more powerful than your generator. Can you generator sustain
full load for 8 hours?

Sensitive electronics can get really pissy when run off small generators.
Some of the electronics use frequency to control stuff. If the frequency is
off on the generator you could fry the TV.

Since the media center is so small use the inverter and the batteries. Start
and use the generator for charging and power tools.
Syn oil in the generator really helps keep them alive. My old Pincor, 2500
watt is almost 30 years old. I change the oil every 40 hours and or once a
year if idle. I use 10-40.

Remember to ground the generator and use a GFCI on your power tools.

 

[Robert Morein]

We recently purchased a small cabin where electricity is not avalable.
At the time of purchase, electrical requirements where met by an old
generator (still works but can't tell what power), a 300A charger, a
couple of 12V generic deep Cycle batteries and a 12V-115V inverter.

A 300 amp charger would probably weigh around 60 lbs.
It would have huge screw lug terminals for the DC cables.
Does this description match?

 

[RF Dude]

1) Even if it were a 300A generator, you would be charging the 220AHr
battery way too fast. Safe recommended charge rate is Capacity / 5. So
like others suspect, you probably don't have a 300A charger.
2) The application you are describing is called "cycle charge". To gain
maximum efficiency you want to run your generator at about 80% load.
Similarly, to have your batteries last longer, you generally don't want to
take them down more than 20%. Cycle charge sites mean large batteries so
that you have some reasonable battery run time before you start the
generator again.
3) 60W light? You should change that to a 15W CF lamp. The savings are
obvious. Make sure ithe lamp likes the output of your inverter (true sine
wave).
4) Ideally, you would have one of the inverter/chargers from XANTREX or
other companies that put an inverter/charger/generator start control all in
one box. You program at what stage of battery discharge you want the
generator to start. It takes care of the rest.

Good Luck.

RFDude

 

[Melandre]

Thank you for the great feedback so far... and of course you were all
right and I was wrong. I went to the cabin this weekend so I actually
had a chance to look at the charger unit. It is a 30A unit NOT 300A
such as the one shown here (SEC 1230A):

http://www.donrowe.com/battery_charger/samlex_batterycharger_12v.html

I am not sure if it is a decent one or not: it was already there when
I bought the cabin.

As for the inverter, I am not sure but I will check. The 2 new
batteries are deep cycle 850 amps (I think!). One is an Energizer,
the other one a Nautilus (again going from memory, next time I go to
the cabin, will write the whole layout!).

How do I ground the generator? Or rather, what can I ground it to,
given that the shed where it sits is all made of wood! Isn't the
ground supposed to go from the generator to something metallic in the
ground? Can I simply drive a metal spike/rod in the ground and run a
metal cable from the generator ground knob to that pole?

Obviously you all realized that I know very little about this stuff by
now but I'd still rather ask the dumb questions than having to deal
with a fire hazard or ???

Andre

 

[Vaughn Simon]

As far as grounding, a ground rod is usually pounded into the ground
and attached via a copper braided cable. Ground rods are generally
6-8ish feet long,

Although they make mechanical clamps, the best way to connect to a
ground rod is with something called a "one-time Cadweld". It is a ceramic
mold with thermite to do the welding. Available at Electrical supply
houses. Impressive and fun! (Disclaimer: Read the directions carefully &
follow them)

Vaughn