I use a plain old automotive load tester (Around $20.00 from HF). Yes, it does nothing to test the actual amp-hour capacity of the battery. What it is actually doing is testing the internal resistance of the battery, which seems to give me a usable reading on the battery's overall condition, especially if you bothered to write down last year's reading. If gives me far more information than a simple voltage reading!
Vaughn
I think the capacity it shows is proportional to the remaining active plate material, less means higher resistance, lower loaded voltage. They do give a good quick check when buying used batteries swapped out on a maintenance schedule but I've found that I could nurse one they indicate as bad along for several years with equalizing charges, and moving it to a lower draw inverter. When I trade one in it's DEAD.
As you say though the voltage means little, the quantity of charge needed to reach that voltage is much more important.
When I repaired power wheelchairs I used a resistive load tester like that to check the batteries. In that instance the tester approximated the current demand from the traction motors. Swapping a questionable battery was better than having the owner get stuck.
OTOH for [other] batteries the computer-controlled test stand discharged and recharged the pack and recorded the current vs voltage characteristic. This is necessary to reset the Fuel Gauge. It measured the internal resistance by the slope between discharge pulses at low and high current to cancel out other effects. An accurate measurement required a programmable electronic load and a digital storage oscilloscope.
If you have only the scope you could use a small steady load and a larger one on a switch and record the step height, but you still should have a current probe and not depend on E=3DIR; you probably can't measure very low R well enough.
That's where I saw that the internal resistance a load tester actually measures isn't always a good indication of remaining capacity.
jsw
No idea, sorry, I have this set up as a standby system, and it is hardly ever used, I put it in before I installed my diesel generator.
The batteries have only been used a few times and I just keep them charged up and occasionally use the system to run the computers in the house.
The quick, crude test I use for inverter batteries is to run the computer off them and have it monitor its own run time somehow, like write a program that saves the timestamp to a file once a minute.
jsw
The "Big Boys" use a Battery Impedance Meter.... But most regular folks just do a 1 Hour Discharge Test at 20 Amps and see where the batteries voltage comes in compared to when they were NEW.....
Dan,
Why does a generator need an inverter at all? Doesn't it put out pure sinewave A/C to begin with?
I would call Generac to see what they say (their web site was pretty silent about the inverter technology) but refuse a rebuilt, who knows what happened to it, unit and return the item to the store where hopefully you can either try a new one of the same model (which they will probably gladly do since it means you weren't trying to scam them by using it as a free rental) or get your money back and try another brand.
What a pain, though. I suspect that you'd need something like the big toroidal transformers made by Sola we used to use in the color darkroom to keep the enlarger lamps at precisely the right color temperature. I still see those types of transformers (huge - about 18" in diameter and 12" deep) on This Old House when they are doing high end AV installs. You would think modern microprocessor technology could compensate for rotation and load variations enough to "smooth out" the output so it wouldn't cause flickering. I would be interested to see what happens if you add more lights.
Have you tried CFL lamps instead of the incandescents or mixed in with them? It could be that their internal electronics will overcome the flickering. Hey, stranger things have happend!
Besides, in a few years, the Greenie Police will confiscate your illegal tunsten filament bulbs and fine you for your inefficiency.
-- Bobby G.
The inverter type is a unit that varies voltage by rpm, it can run as low as 900 rpm to power a light bulb.. Regular gens run at 3600 rpm, its a big waste of evergy to power a small load and engine life [depending on quality] is about 300-3000 hours, Inverter gens by honda run with a few hundred watts are known to last 11000 hours. RPM directly relates to engine life, this is the main reason a 1800 rpm deisel lasts 4x as long as a 3600 gas engine, and 1100 rpm Lister generators can go 100,000 hours, and deisel boat engines that maybe run at 100 rpm run nearly forever. The Honda inverter also has the Generator as part of the motor, it cuts about 30% of the weight out making for a compact lightweight unit. So for long term low load at a remote site such as a cabin, if the load is kept to a minimum you can with an Inverter get 9-12000 hours life vs 3-350 for the cheap non OHV B&S engine. Inverters 2.5x premium in cost can be worth it for someone living for example on a boat or camper for long periods. Plus Hondas inverters have cleaner power than your power co and are so quiet you cant hear them from 10 ft away. Generac probably stole the design but his batch looks to be infected with a defective part. I would not exchange it for a unit of the same batch. Once I got a cheap Generac power washer, it blew in 2 hrs, the replacement lasted 1 hr, it was the same batch and had the same defect. Inverter technology is great, but there are a few others on the market that have proven reliability like Yamaha
Thanks for the explanation. That Generac unit looked cute and portable enough to use on camping trips. But since I've owned Honda cars since 1980 with great satisfaction, I think I'll see what they have to offer.
-- Bobby G.
Call a few big generator stores that you find online, they know better than me what makes work and which ones break, HD is good for the 30 day no questions policy and the bigger 3600 rpm units. I would like a Tri Fuel gen and just hook it to a Ng line.
No, it's all choppy. Taking a bunch of little square waves to make up one complete cycle. On a scope it looks like steps going up and then down. The more steps the closer it gets to a sine wave. Not just one up and one down like a square wave. It sounds good in theory, but unless it's really a good one, it isn't worth the money.
I've run a few different computers and other electronic equipment off my plain Jane generator (alternator) without any problems. No electronics, just a cheap generator (alternator) at about 60 Hz. Most electronic equipment is marked for 50 to 60 Hz showing that it isn't as sensitive to frequency as one might think.
I know Honda EU series is stated to be cleaner than your AC, the Inverter type can be the best but that generac is just defective junk.
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