Generac home standby generators

[GaryM]

Jerry,

Yes, I did get that kit. It consists of nothing more than heavier guage wires to connect to the load center. No changes to the generator unit itself. All I had to do was call Generac and tell them I had purchased a unit from the Electric Generator Store. The upgrade kit arrived via UPS a few days later.

[rlevan]

Thanks for the info guys. My decision to go LP over diesel had as much to do with the amount of diesel I normally keep on hand as it did with anything else. I know you can use fuel stabilizers and antimicrobial treatments, but the stuff in a standby generator's tank eventually gets grungy unless you are running it out on a regular basis.

Also, there are times we are away and a boarder is taking care of the horses. I've got a 1000 gal. LP tank that runs the water heater, stove, clothes dryer, and gas logs for backup heat when the power goes off. We are on top of a mountain with no NG lines, and I want to know that if we are gone for a few days, the generator is not going to run out of fuel because none of the service stations in town have power to run the diesel pumps or the boarder didn't know how to fuel and service the generator. I want an idiot proof solution.

In answer to the battery question, I have never used the Optima batteries, but I have a lot of experience with Interstate. I have a 60 month Interstate in my farm truck that I bought 89 months ago. This was a daily driver until 2 years ago. Now, it is started once a month or so. It cranks in a couple of seconds every time. If I need a starting battery for the Generac, it will be an Interstate.

[Pat]

rlevan, Seems to me you have a good handle on your specific requirements which transcend issues of FIFO diesel consumption, "Biobor", and the like. A couple things came to mind: 1. It is difficult to make things fool proof because fools are so ingenious at fouling things up. 2. What about a run time limiter or scheduler?

Since the BIG BLACKOUT of 2003 and the expectation of repeats, not to mention weather induced local failures that can last over a week (in our area), it occured to me that a standby genny installation could profit from a runtime limiter/scheduler.

For example, your power fails, your geny comes on line and all is well but the commercial power is out for a long time. Will the genny consume all your propane and leave you freezing in the dark?

What happens if your genny only runs part of the time on a preset schedule with manual overide for activities requiring electrical power? That will stretch your fuel supply and delay the time when you will be without hot water, backup heat, A N D electricity. If the conditions requiring your use of a genny are severe and or extended in time, you might not get a timely propane delivery on request.

I had a recent "cluster" of failures with my small farm truck, a Dodge Dakota. Plastic upper radiator tank split stranding me and requiring a new radiator, then two days later the battery (60 month Interstate) developed a shorted cell stranding me. I netted about $5 on the waranty and replaced it. A few days later we were stranded again when the fuel pump (inside the tank) failed to make enough pressure.

What does our different experiences with Interstate batteries mean? Not much. It is just two samples out of the zillions of batteries they sell. You can't prove a trend or family characteristics by one sample, good or bad.

Batteries tend to deteriorate over time, even when not being used much and even when kept topped off with distilled water and kept properly charged. A typicall first indication of a problem is when the engine won't start. Not a good thing with a standby genny. I would recommend a couple things. 1. Install a larger capacity battery than the MFG says is needed so you have considerable reserve capacity in the outyears and 2. measure battery capability with a battery load tester at least once a quarter. This does not guarantee you'll catch a failing battery but it ups your chances A BUNCH.

An unattended start by the automatic exerciser might "just barely make it" and you won't know it if you didn't just happen to be there. Battery load tests put you in a position of knowledge and eliminate the wishful thinking. If you have a DC voltmeter and don't want to buy a load tester (a real load tester is a handy thing if you have many starting batteries in various vehicles and pieces of equipment) you can still get a fair indication of starting performance of your genny.

Shut off the fuel supply to the genny, attach the DC voltmeter to the battery and note the voltage. Leave the meter attached and crank the engine for say, 10 seconds while watching the meter. Note the voltage while cranking after 10 seconds. As soon as you stop cranking the voltage will likely rapidly recover to a value close to what it was before cranking. That is why you want to note the value at 10 seconds but while still cranking. Over the useful life of the battery this 10 second load voltage will continue to drop until it will be marginal to give a reliable start, especially in cold weather. Be warry of a battery that sudddenly reads much lower in this test than it usually does as it is likely to fail. Temperature plays a big part in battery performance and a cold snap can cause a battery to give poor performance in a load test just like it could fail to give adequate cranking power in a real startup situation in cold weather.

Final comments: I have had several Interstate batteries and find them to be good performers, not better or worse than other "good" brands. In batteries, buy cheap and get cheap holds true more reliably than for many other automotive parts. Over the years (decades) I have evolved a battery buying policy that seems to work(and is only slightly re$ource intense). If the battery is in something that demands reliable starts then when replacing its battery I buy the largest electrical capacity best warranty battery that will fit in the space available. I don't think of it as overpaying, I think of it as anti-stranding, anti-hassle insurance.

Pat

[egon]

To insure a battery has full charge it is possible to have a voltage regulated charger run on conventional ac hooked up all the time. This is a very common practice.

Egon

[Pat]

Egon, That is true. Also you have to exercise caution when leaving battery chargers connected for extended periods. Many have output waveforms with peaks in excess of the desired "float" voltage. They are OK for charging a battery but should not be left connected for an extended time after the battery specific gravity (for the electrolyte temp) has arrived at or near nominal value or in voltage terms when the float voltage is achieved, chargers not specifically designed for long term "float" operation should be disconnected.

Bad things like severe loss of electrolyte and sulphation(sp?) resulting from "over charging" with non-float designed chargers can destroy an otherwise good battery. There are small (look like wall charger/battery elliminator) float type battery maintainers available from around $10 on up. They are essentially useless for a battery that is discharged but are great for their intended use, keeping a battery from "self" discharge during long term storage or in service with infrequent use.

Pat [img]/forums/images/icons/smile.gif[/img]

[GaryM]

The Generac unit, and I'd guess most others, have a built in battery charger. Now, how gentle that charger is to the owner supplied starting batttery...?

I plan to buy a good battery though. I'd like a larger than 250 Gal. propane tank, but the supplier seemed reluctant to supply a larger tank for my low anticipated useage.

The exerciser on the Generac runs to unit for about 12 minutes every seven days. It runs at the time the user initiates the system. So if you do it on Friday at 1800, it will run at that same time every week.

[Bird]

</font><blockquote><font class="small">In reply to:</font><hr />
runs to unit for about 12 minutes every seven days

[/ QUOTE ]

I'm curious; does it just run the engine under no load or do you cut the power and run it under a load? And of course 12 minutes seems like a very short time to me, but maybe it's adequate.

I say that because on one of my RV generators, it was recommended to run 30 minutes under at least a 50% load at least once a month. I know RV technicians who say most of the RV generator problems are caused by lack of use.

When I was first promoted to the rank of Captain and assigned as Commander of the Communications Division, the old city hall had a standby generator powered by natural gas. It was run for 30 minutes once a week, but was not actually powering anything, so the first time we had a power outage, it came on, the lights and radios in Communications worked, but it seemed that whoever wired it up had forgotten about the telephones. [img]/forums/images/icons/frown.gif[/img] No ring; no lights on the buttons.

So when we built the new city hall and new emergency communications center, we had two monstrous diesel generators and every Sunday morning, the power was cut off for 1 hour and everything was powered by those generators.

[GaryM]

Bird,

As far as I know it just runs the engine. No power transfer. Of course you can open the cover on the generator and flip the switch to manual and transfer the load that way. But I think a better way would be to kill the incoming power by switching off the main brakers in your service panel. that way everything get tested. Not just the engine starting system, but the load transfer system too.

I plan to run such a test at least every two months. I plan to make up a calander and post it in my utility room and garage. It will list periodic maintainance items: Change furnace filter, clean dryer lint trap, clean filter on septic tank, etc.

At work we have a big Cat diesel generator set to run our server farm incase of power loss. They run it once a month and run the servers from the generator for at least two hours at a time.

As you mantioned in your tale, you need to test the system, not just the engine.

[Bird]

Gary, I think you've got the right idea and will do well with your maintenance and testing plans.

[Pat]

Gary, Generac has an acceptable track record for their mid-line generators. I would be surprised if their charger was an old technology transformer and rectifier that would "cook" your battery right away when left connected continuously. On the other hand, I wouldn't recommend that you accept on blind faith that they gave you the top of the line high tech (most expensive) technology either.

For something that you want to rely on like a parachute, you might want to check it yourself prior to any operational failure. There are a few simple tests that will give you confidence in its function. What is the batt voltage after it stabilizes in long term charge. If this is too high you may outgas too much for comfort. Even if this voltage reads good, you should check the electrolyte level frequently until your confidence is established. The float voltage as read by a meter could be good but you could still have excessive outgassing and electrolyte loss due to peaks in the charging waveform. A check of charging current with the battery fuly charged would be a hint. Of course, not everyone has or can use an o'scope but that would sure give a direct reading of the quality of the chargers output waveform with the battery at full charge, preferably with a current probe.

The practical low tech approach is to monitor elctrolyte levels and if the cells require too much topping off the charger is set too high or has an unacceptable waveform for long term float operation. Color me old fashioned but I would not personally choose to use a sealed "maint free" battery in this application. Since you can't check them for electrolyte, the first indication of failure would likely be when the battery would not start the genny when needed.

Of course you could buy some of those catalytic caps for your battery. They recombine outgassed hydrogen with atmospheric oxygen and drip the resultant water back into the cell that supplied the hydrogen. These see beneficial use in the solar electric storage battery application and aren't just advertising hype.

Pat