trying to avoid a "hoo doo"

elesaver · January 2015

I'm back again with more thoughts about buying a generator for use when there are multiple cloudy days in a row. After asking some things about generators earlier, reading lots of info, I'm honing in on what may be the best choice for this back-up generator plan. My solar components are: 1800W of panels, 720aH 24V battery bank, VFX3524 outback inverter/generator, mate 2, midnight solar 200 charge controller, psx-240 transformer. I never let the batteries drop more than 25% of full charge. If the sun is playing hide-and-seek, I just go back to full grid power.

OK, so to use this generator in the best way, I know I need an electric start so that the mate can start it automatically when needed to keep those batteries up. I usually don't buy "new" items, especially when...with some research...a good buy can be found from someone who overbought, so to speak. Which leads to my situation about generator purchase. I have located a couple of used honda generators not too far removed from my location. Both of these have electric start. One is a honda em5000s and one is a honda em3800s and they are both priced the same ($900) and appear to be in the same cosmetic condition. The pictures indicate that the battery tray and battery were added, although I don't know that for sure since I haven't discussed anything with the seller yet. BUT, I cannot find any generators that are em5000s or em3800s. All the hondas of these sizes have the SX with the wattage number. Neither seller has indicated how old these generators are or how many hours of run time they have.

My plan would be to see the generators and at that time, test the output with my kill-a-meter and voltmeter and see if I can find a compression tester. Of course I can look at the oil, air filter, etc., but I don't know if there is anything else I can check. Is there someone who could bolster my knowledge to help me know if either of these would be a good purchase. I will have to travel over an hour to see either of them so if I make the trip, I want to be able to come to a decision on the spot and either buy or not.

Originally, I had planned to get a used eu2000i or eu3000is but the 2000 would be almost as much as these larger models and the 3000is would be much more and harder to find as a used generator, I think. So, for the money, I thought...more watts for the same price...why not?

I'd appreciate any advice or help that someone cares to offer. Thank you.

Alaska Man · January 2015

Re: trying to avoid a "hoo doo"

Do you need a genny that big? Fuel is the biggest expense for us we run small and light when we can.

BB. · January 2015

Re: trying to avoid a "hoo doo"

Do you really need/want AutoStart?

You need to find a genset that will have autochoke/automatic mixture control to start cold--Or come up with an autochoke solenoid/controller.

So--Find a genset controller and somebody (or a controller spec'ed) that has successfully and reliably setup autostart.

I understand the need for electric cranking--But that is a long way to full autostart (and all of the interlocks needed, low oil, over heat, long crank time, out of fuel, etc.) that you can leave alone reliably.

Are you ready/able to do that level of integration/service?

-Bill

elesaver · January 2015

Re: trying to avoid a "hoo doo"

I'm open to having my "calculations" revised. In order to re-charge a battery bank with a generator through an inverter/charger, amps are needed to get the batteries to 90% SOC plus the amps needed to continue powering the load. A 5000W generator, at full throttle, could generate approx 41 amps but I doubt it would ever reach quite that high and 40 amps if all of that was used to re-charge the batteries, it would harm the batteries. So, a 5000W generator running at half-throttle could re-charge the batteries in a shorter time than an eu2000i could at 13 amps. So, that was my thinking. Plus, on a dollar-for-dollar basis, why not have more power available?

elesaver · January 2015

Re: trying to avoid a "hoo doo"

BB, help me out a little more. I thought the mate 2 (programmed with the outback VFX3524) was designed for this function through the Advanced Generator Start Mode. Have I totally missed the boat on this? According to the mate manual, the system can be programmed to start a generator at set times, or set to start at designated battery V levels, or set to start to run at a particular day of the month and run for a specified period of time, etc.

BB. · January 2015

Re: trying to avoid a "hoo doo"

My question is the "Black Box" and connections on the generator side. In general (I do not know the details)--The usual generator controller from an Outback and such is, more or less, one or several pairs of wires--On/Run, Start, etc.

The whole engine management side "black box" is usually another box. It can be part of the genset (if configured for auto start/run), or it can be an add-on black box.

It is a pretty complex subject/set of interactions between various components. Here are some older threads:

auto gen start
Auto Choke/ Propane Conversion
Automatic Generator Starting

Not saying that you cannot convert/run autostart on those gensets are you looking at--But it will require a bunch of research to ensure that you can get it done safely/reliably.

-Bill

elesaver · January 2015

Re: trying to avoid a "hoo doo"

OK. Thanks for the info. I'll have to continue to research all of this. Good info from all.

Ralph Day · January 2015

Re: trying to avoid a "hoo doo"

" If the sun is playing hide-and-seek, I just go back to full grid power."

You can do this? And you want to have a generator to use in it's place? Have you looked at the cost of running a generator as opposed to utility power for the same charge/loads carried?

A genset for longer outages/end of civilisation scenarios, but if you've got grid...you've got the cheapest power available per kwhr (unless you live on a Carribean Island).

For me, my 10kw diesel genset burns 2.5litres per hr delivering say 10kwhrs over that time (not in the real world). Fuel costs 90cents per litre...$2.25/hour, result, $0.225 per kwhr. Utility power at peak time is only $0.16 per kwhr. Where is the savings with a generator? And if you charge at night...less than 10 cents per kwhr.

The utility is my multi billion dollar generator, thank you very much.

Ralph

706jim · January 2015

Re: trying to avoid a "hoo doo"

And a 5kw Honda burns 3 liters an hour at full song.

Neither cheap nor practical as the engines don't last that long at 3600 rpm's.

And awfully noisy to boot.

Alaska Man · January 2015

Re: trying to avoid a "hoo doo"

elesaver wrote: »

I'm open to having my "calculations" revised. In order to re-charge a battery bank with a generator through an inverter/charger, amps are needed to get the batteries to 90% SOC plus the amps needed to continue powering the load. A 5000W generator, at full throttle, could generate approx 41 amps but I doubt it would ever reach quite that high and 40 amps if all of that was used to re-charge the batteries, it would harm the batteries. So, a 5000W generator running at half-throttle could re-charge the batteries in a shorter time than an eu2000i could at 13 amps. So, that was my thinking. Plus, on a dollar-for-dollar basis, why not have more power available?

You are looking at AC numbers at 12 volts you will have more than enough amps like around + 400A, also the charger handles all the power needed based on the batteries SOC. a 5,000w genny is a lot of power. I charge and run the house with 2,800w. Granted I'm set up for it, but you could take a look at your loads and do some conserving I'm sure. Anything with Electric heat............ chuck it out the window for starters.

trying to avoid a "hoo doo"

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trying to avoid a &quot;hoo doo&quot;

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trying to avoid a "hoo doo"