Aux Generator

SKIP · January 29, 2007, 06:42:45 PM

It would be interesting to see how many of you handle the problem of either to much or to little generating power. Many times while dry camping, we will only need generating power to charge house batteries. Other times, more amperage is needed for air conditioning and hot water heating . In these times our 18 kw generator is more than capable of running all the air conditioners and water heater at the same time. When we are only charging batteries, the draw in small and it ends up wet stacking. I am considering an aux generator of 3-4 kw, but redundancy adds weight and an additional maintenance item along with WHERE DO I PUT IT. Any suggestions? ( 89 Prevost )

DrivingMissLazy · January 29, 2007, 06:48:47 PM

In commercial applications we often utilized resistive load banks to supply artificial loads to gensets to eliminate your problem. Basicly a box with a bunch of electric heating elements and an electric fan to remove the heat.
Richard

Quote from: SKIP on January 29, 2007, 06:42:45 PM
It would be interesting to see how many of you handle the problem of either to much or to little generating power. Many times while dry camping, we will only need generating power to charge house batteries. Other times, more amperage is needed for air conditioning and hot water heating . In these times our 18 kw generator is more than capable of running all the air conditioners and water heater at the same time. When we are only charging batteries, the draw in small and it ends up wet stacking. I am considering an aux generator of 3-4 kw, but redundancy adds weight and an additional maintenance item along with WHERE DO I PUT IT. Any suggestions? ( 89 Prevost )

TomC · January 29, 2007, 10:39:59 PM

I have three roof airs, two electric water heaters, electric heat in the bathroom, inverter/charger, etc. I use a 10kw gen with the gen easily powering the three roof airs and electric water heaters at the same time. Would suggest going smaller then your 18kw. Personally, my next bus, I will be using a 3600 rpm direct drive 10 kw gen, like what is available from Panda gen (expensive though). An 1800rpm gen will last 20-30,000hrs. A 3600rpm gen will probably get at least 15,000hrs out of it. While some say they are noisy, I was at a boat show and Panda had their 8kw 2cylinder in a case as a demo. With the noise outside, almost couldn't hear it run. Then with a 3600rpm gen, it will be smaller, and lighter than the 1800rpm. Good luck, TomC

Gary '79 5C · January 30, 2007, 02:54:10 AM

Skip,
I am of the unwashed, I must ask What is wet stacking?? I have never heard of this, or can imagine what this refers to within the gen set. I know that an under-utilized generator is not good, but I still am unsure...

...

I use a 12.5 KW and have had not problems. I run it very little when operating the coach, but I do operate it twice monthly as a PM effort.

kyle4501 · January 30, 2007, 04:59:24 AM

What about a higher capacity charger to bulk charge the batteries quicker & start the absorption charge cycle?
Then solar panels to finish the absorption & float charge after the generator is shut off.

It wouldn't take much extra space, except on the roof.

Just a thought.

Dallas · January 30, 2007, 05:18:48 AM

Quote from: Gary - 79' 5-C on January 30, 2007, 02:54:10 AM
Skip,
I am of the unwashed, I must ask What is wet stacking?? I have never heard of this, or can imagine what this refers to within the gen set. I know that an under-utilized generator is not good, but I still am unsure......
I use a 12.5 KW and have had not problems. I run it very little when operating the coach, but I do operate it twice monthly as a PM effort.

Gary,

Wet stacking, (or Cold Stacking), has to do with running the engine with no load so that it never reaches optimum operating temperature.

This causes the cylinders to be too cool and therefore the fuel doesn't burn completely, and is pushed out through the exhaust into the manifold and the exhaust pipe.

When the exhaust heats up, like when under a load, that extra fuel burns and makes lot's of smoke.

local campers near you can become extremely disgruntled with you especially if your smoke is going into their nice clean quarter million dollar S&S.

By the way, this is what happens when you idle your Detroit too much too. The plumes of smoke can last for miles and miles and miles!

Dallas

H3Jim · January 30, 2007, 08:17:03 AM

I have had a 13k wrico generator installed for about 2 years now. I have 23 hours on it. I just bought 600 watts of solar power that will keep my batteries completely charged every day. The only time I envision using the generator is when I need to run some or all of my 3 roof airs. That should be enough load for the generator.

The solar will make my batteries last longer since they will always be fully charged up. I found I did not run the generator long enough to get to the float stage of charging. and if I did, it would be hard on the generator due to the light load.

white-eagle · January 30, 2007, 06:32:21 PM

Can i add to the questions? i found out at bussin 07 that my house battery is my genset start battery. the 300 watt inverter that ran the TV killed it watching letterman. so i've been toying with the idea that a 2kw quiet honda would be better than $4k worth of batteries and pure sine inverter. With just a couple golf cart batteries to run the computer all day with that small inverter. the honda would be started just for coffee, tv, toaster and hair dryer in the am, maybe a battery charge up. the regular 12kw would be for heavy uses like A/C or heating.

i'm trying to think why a small, really quiet genset wouldn't be better than a bunch of expensive batteries. anyone got an opinion to help decide. other than the fact that i'd have to carry gas.

niles500 · January 30, 2007, 07:16:32 PM

manasst -(since this thread has already been hijacked - sorry SKIP) how about Trojan 8d AGM batt's? - 4 of them would be about $700, and some people have reported the availability of refurbished SW4024's for as little as $1500 (or less) possibly - now your just about twice the price of the the Honda - IMHO this should be quite adequate - HTH

TomC · January 30, 2007, 10:24:43 PM

Manasst- I think using the Honda 2kw quiet power with just a couple of deep cycle batteries is a great idea. If you need more power you can buy a second 2kw and tie it together to make 4kw. Hondas are very reliable. The only draw back is that you would be carrying gasoline that is of course very flammable, deteriorates after a very few weeks, and have to contend with the dangerous exhaust fumes. Personally I would use a small Diesel, but you can't go wrong with the price of the Honda. Good Luck, TomC

kyle4501 · January 31, 2007, 05:50:57 AM

Multiple generators? You have got to be kidding, right?
It ia hard enough keeping up with the maintence of ONE!
Then there is the volume of space & the different fuel they will require.

Keep it simple! He already has a generator that can bulk charge his house batts to 80+% while making hot water. A solar array can top them off. The added benefit of the solar is the batteries will be kept it top shape even when he isn't using the coach (as long as it is in the sun

).

Also, what do you propose to do when running the genset for light loads during certain hours isn't desireable?

Better batteries & solar will provide what you need with out extra fuel storage issues & minimal space issues.

FWIW

trailblazer2 · January 31, 2007, 01:40:08 PM

I have 15 kw aux gen on my coach ,and have the same OVERKILL! A lot of folks refer to this as "slobber". I was told by a owner of several large rigs,to get the engine temperature up to 180 degrees and this would burn up the access. I would certainly like to know what you experts feel on this thought.
Bill

white-eagle · February 01, 2007, 06:47:59 PM

thanks for the replies. i'm not sold on a solution yet. part of the issue is also space and weight. i've heard the Honda is quieter than a busnut conversation, so i thought when i remove the bus air, i would use the space to add a couple GC batteries, the HOnda and a gas can. i'd never add a 2nd Honda since i have the 12kw. i need something to power the computers all day, with the tv, lights and so on, but that isn't a load for the 12kw until recharge time. or i could run the Honda on 5 gal a day. i was also thinking about the cost of replacing the batteries every 4 years if i had 6 GC vs the Honda should last forever. obviously, if it's too hot or too cold outside, i'll be running the 12kw instead of the honda or a battery bank since the heat is currently electric also, and obviously the A/C is.

i've got a Honda 2kw priced at about $900, tax and ship included. a quote on a new set of batteries and a 2.8kw pure inverter was $4k. the Honda sounds smart so far, if it's not too loud.

TomC · February 02, 2007, 04:20:56 AM

That sounds smart to me. I've heard the 2kw Honda run and it sounds like a room air conditioner running. Good Luck, TomC

SKIP · February 02, 2007, 06:55:34 AM

The one problem that I see, and you might want to check your charger, is that my Xantrex draws 21 amps. That's more than the Honda 2000 is capable of producing. Then it would mean a Honda 3000 at upwards or $1800. I need to find a better way to keep my Onan at temperature. Maybe using an electric, thermostatically controlled water pump or radiator shutters. No easy answers.