|
|
|
|
|||||
|
||||||
Subject: Re: TWL: Re: 15 KW Onan
pgslo@XXX.XXX
Date: Sun Sep 02 2001 - 17:09:17 EDT
On Sun, 2 Sep 2001 12:13:16 -0400 "Wil Andrews" <captnwil@XXX.XXX>
writes:
> This is just what inverters were made for. Install a 2500W or
> larger
> inverter and wire it properly. Have a proper sized and designed
> house
> battery bank Unless you need AC, you may go days without starting the
> genset
> while cruising.
This is presuming that the boat has a large house battery bank. That is
a piece of critical information that is missing from Jim's list. The
fact that the boat has no inverter and large generator aboard, presumes
that the house bank is minimal. Therefore, the cost of additional house
bank batteries and a 2500W inverter could be substantial. If Jim wants
to power everything off an inverter, as Capt Wil, says he needs to add a
proper (huge with the way this boat is equipped) house battery bank. An
energy audit will tell him how large that house bank should be.
I am going through the energy audit exercise myself right now. I am
setting up an energy efficient boat that will rely on minimal electrical
requirements, i.e. no air conditioning (fans only), diesel cooktop,
diesel water heater, energy efficient fridge, etc. I have determined
that most "experts" (Calder, Wing, etc.) recommend a house bank that is 4
times your daily requirement. Therefore, I am going to install a house
bank of approximately 450 to 650 Ah.
Mark and Suzanne Richter aboard POOH are energy mizers and experts at
getting the most out their house bank. I believe they have a house bank
of around 450 Ah with inverter and have no generator, no a.c, etc., and
can hang on the hook for 4 or 5 days at a time in the Bahamas.
On Sun, 02 Sep 2001 10:36:28 -0400 Arild Jensen <elnav@XXX.XXX>
writes:
> > Even without specific numbers I come up with 12 Kw so 15Kw is not
> unreasonable.
> As for doing a pot of coffee only, well that is what inverters
> are for.
This strategy only works if Jim runs everything (stove, fridge, A/C, hot
water heater, etc.) when he wants the power to make a cup of coffee
without an inverter. Is it worth a $3K to $5K inverter (including
wiring, installation, etc.) just to run the coffee pot? Only Jim can
answer that question.
Jim had two questions.
1. Is it good to run a genset with a light load. The answer is, no.
2. Does he need to run the genset to make a cup of coffee. The answer
is no if he runs only the coffee maker for a short period of time, and
he purchases an inverter, and if he has an appropriate size house bank.
But if he has a small house bank and he doesn't have an inverter, then he
will be running that generator several hours each day, just to keep the
water hot and the refrigerator cool. And that means that when that 15Kw
generator starts up to keep the water hot and the fridge cool, he should
turn on the stove, microwave, a.c., battery charger, hair dryer, lights
and everything else electrical on board to put a proper load on the
generator, whether he has an inverter or not (if he doesn't have a large
house battery bank).
Jim did not say how old the Onan was. Some of the older Onans did have
some mechanical problems that could shorten the life of the genset under
some conditions according to mfg. Cummins. The new Onans are much better
in my opinion.
Patrick
WILLARD 40PH
,¸¸,ø¤º°^°º¤ø,¸¸,
ALOHA
|