# Using a generator to charge batteries??



## YoungOne (Aug 22, 2006)

I finished installing an Outback 3600 FX. this system rocks but because of money I have no panels yet. I am charging the whole system with a 3500watt Generator.

Problem is that the generator was used when I bought it and not well maintained. The power output is not of great quality and I am curious about a possible remedy. It makes sence to me but I haven't much experience.

Here is my idea. A UPS for your computer (Uninterupted power supply) is a power conditioner and will condition much more than they will back up. If I were to put the UPSbetween the generator and the Outback might it clean up the power enough to get a better/faster charge. Currently the generator power fluxes about every ten to twenty minutes between 112-121volts this puts the charger into protection mode and just passes this crappy power into the house and stops charging the batteries for 5-10 minutes while it stabalizes.

Any ideas? I realy can't affor a GOOD generator and I hate spending money on an OK one that I know I'll replace.


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## 12vman (Feb 17, 2004)

Quote..
"Currently the generator power fluxes about every ten to twenty minutes between 112-121volts.."[/blue]

I would look at the r.p.m. control (govener) and see why it's changing. Could be a fuel issue too. I had one that would go silly if the gas tank got down below half full..

I don't believe the UPS will correct the problem but mebby it will.. I've been wrong before.. LOL


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## MELOC (Sep 26, 2005)

didn't i get squashed on here for suggesting a UPS will clean the power? i think it actually went as far as links to schematics, lol... and i was wrong...hehehe. they exist, but they are really expensive and the UPS units readily available to the masses for a couple hundred bucks do not clean the power.


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## Jim-mi (May 15, 2002)

If the voltage regulation of that <"gen"> is that p*** poor,
then be gone with it.

Spare the Outback with putting up with that grief.

In the long run you will pay dearly when using a cheapie generator.

I know these were not the words you wanted to read . . . .but

the truth sometimes hurts.


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## ET1 SS (Oct 22, 2005)

I spent a lot of time charging batteries underwater [but of course those lead-acid batteries are four foot tall]. I would recommend that you use four BIG diodes [arrange them into a full-wave bridge rectifier] and rectify the current into pulsed DC and run it straight to a battery bank.

Then who cares if the voltage level flutters? The battery bank will not care.

There are times when DC is just easier to work with.


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## vicker (Jul 11, 2003)

You don't give any info on your generator. but I would also suggest that you don't want that generator anywhere near your Outback 3600 FX.


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## Jim-mi (May 15, 2002)

Another option could be to use a good sized "car" battery charger to charge the bats.

Let the inexpensive "car" bat charger take the grief of p*** poor regulation of the generator. . . . . . . . .

When and if the poor reg gen burns up the "car" charger . . .Oh well . . . . . . . . far far cheaper to replace than the Outback. inverter.

The Outback has pretty wide voltage tollerance's . . . .so if the gen fluctuates outside of those tollerences enough to auto shutdown . . . . . .that ain't good.

As ET said, a full wave bridge, big diodes, big heat sinks, fan cooling . . . . and metering.


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## ET1 SS (Oct 22, 2005)

Big diodes you will never burn out.

Dont need no fans or heat sinks.

A battery charger will only consumer watts that you want going into the battery bank.

Pulsed DC is fine running straight into a bank of batteries.

Generally 120 Volts? fine, ten batteries. next problem.

If you are really sweating that the voltage drops too often then only use nine batteries. Big deal. If you are wrong the only difference it will make is how often you will need to top the batteries up with water. It is really no big deal either way.


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## stonykill (Jun 3, 2007)

try this link. I plan on building one soon to try it out. With some scrounging you should be able to build it for real cheap. Its a homemade battery charger using a push mower engine and a delco alternator. By sizing the pulley correctly you are supposed to be able to keep the rpm's down, for greater fuel economy and longer engine life. Long life is not what cheap store brand generators are about. I know my generac is running on borrowed time, and I plan on experimenting with this, in 3.5 horse and with a 10 hp tecumseh I have. Good luck!!!

http://theepicenter.com/tow02077.html


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## Ed_Stanton (Dec 28, 2004)

Tell us more about your generator type & it's engine. What kind of battery set up do you have, how many, how many AH's each and it's total. What are you using them for and how much are you discharging them between charges? Are you using a meter of any kind and are you checking the SG of the batteries? Are you running any other loads while the generator is "charging" the batteries? Is your generator set up as a single phase or can you split it and have something else use the second phase? If it's already set up as a two phase system, and you are only using one side of the generator, than that can produce poor power as well as hurt your generator. So we need a bit more info from you.

Right now we don't know if the generator Engine is the problem or if it's the electrical generator and why "crappy" power is being output. I would think that your least expensive option is to take it in for a repair inspection and estimate and see if the generator can be repaired and power quality improved. That is what it was designed for, vs. a UPS backup. But depending on the model that you have and it's estimated repair cost, there are also "pretty inexpensive" options at places like Costco that I've seen, such as 4 KW gas generators for a few hundred dollars. Not ideal maybe, but it's a low cost solution which might get you by for a while and if your battery system isn't too large.

However don't cheap out on a generator in the long run. 

Also, from what I've learned about generators is that they are FAR from equal especially when it comes to charging batteries vs. running direct AC off of them, the latter which is what they mainly designed for rather than charging big setups of batteries. To properly charge batteries the batteries really like a sustained "PEAK" voltage, which is the highest and lowest point of a sine wave/curve, and is well over 110-120 volt average (middle) and is ideally in the area of 165 volts or so. A poor generator won't be able to put out that kind of quality power curve and in the long run, your batteries may not get a great charge or equalization and reach the proper specific gravity. So IMO, if you're in it for the long haul, no matter which generator/engine set up that you get, try to find the one that you can afford that puts out the highest peak voltage. That info though isn't always in the specs or easy to find from the salesmen as they stare at you with a blank look.


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## Ed_Stanton (Dec 28, 2004)

You might also want to search, read or ask the same questions on the Outback User Forum. http://www.outbackpower.com/forum/


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## michiganfarmer (Oct 15, 2005)

ET1 SS said:


> Big diodes you will never burn out.
> 
> Dont need no fans or heat sinks.
> 
> ...


very neat information. DC is pretty cool stuff


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## ET1 SS (Oct 22, 2005)

michiganfarmer said:


> very neat information. DC is pretty cool stuff


Thanks.

Life onboard submarines was largely dependant on keeping those battery banks charged, and low-tech does not break down nearly as often as high-tech.

So I have seen battery banks in use for 20+ years, thankfully I am now retired.


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## zant (Dec 1, 2005)

Sounds like you have one of those piece of crap chinese gens.....ETS is right with his concept or you could buy a power conditioner from an RV catalog thats good for 5kw..My gen did same thing(stupid enough to buy chinese crap)so for the first 2hrs we would'nt run anything in house so batteries could charge then taper charge would be low enough so other appliances could run without dropping voltage..


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## ericjeeper (Feb 25, 2006)

Pick up a good used 40-100 amp automobile alternator. with built in voltage functions and a 5-6 horse gas engine. Or whatever engine will pull the alt, depending on size and load drawn.,


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## Blu3duk (Jun 2, 2002)

ericjeeper said:


> Pick up a good used 40-100 amp automobile alternator. with built in voltage functions and a 5-6 horse gas engine. Or whatever engine will pull the alt, depending on size and load drawn.,


I believe the Ford 120 amp alternators are complete units now, at least the one on my 98 expedition is, regualtor built in and when it went out last fall i picked a uised one up fro the wreckin yard for $55 delivered [had to order it from another yard in south Idaho] i could have rebuilt the entire unit for $40 from www.partsamerica.com [schuck's] so i have a new "rebuilt" on the shelf but in all i doubt that a person would find the unit able to charge fully on a small 3.5-5 hp small engine, more tha likely to get efficient use a person would need an 8HP or above, which is gonna consume fuel just as rapidly.

On the note of gensets, I used the cheap ones when working as system admin for a local wireless internet company on our remote towers, the owner had his son putting fuel in them but was going thru a set every couple months, which was hurting the business [we had 4 towers needing more than the solar and wind units were providing at times] anyhow the local small engine fella told me to change oil at least every 24 hours of use in those engines due to the way oil gets to the working parts or go up a notch and get better engines and bigger charging units [we did not need the excess power but required workable units] a friend in the southern Lousianna area commented upon the use of larger units over the short term and long term are cheaper in both fuel consumption and replacement of units as they tend to outlast the small gensets everyone is so fond of ergo a 20kw unit is cheaper to run than a 8 kw if used to power an A/C unit requiring 6500-7000 watts, plus a person can get the 20-25KW units for about $5000 set up ready to run and they will more than outlast 10 of the $500 3-5KW and 6 of the $800 8Kw units, an be mounted upon a trailer if you want to pull them somewhere or installed in about the same footprint as 2 of the little sets are, they really are not as big as one thinks..... nor as expensive as some folks believe.... though they are getting up there. If you think you really want long term running, look around for a lster engine and genset or even the India made "listeroid" imports, heavy machines but they are built for folks who have little knowledge of repairing things and little if any repair shops close by..... in other words just about anyone can fix the things that go wrong with them..... 

William
Central Idaho


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## stonykill (Jun 3, 2007)

ericjeeper said:


> Pick up a good used 40-100 amp automobile alternator. with built in voltage functions and a 5-6 horse gas engine. Or whatever engine will pull the alt, depending on size and load drawn.,


thats the cheap and reliable way to go if your just worried about charging batteries. A 65 amp alternator requires a 4 hp or so engine, up to 100 amp should work fine with a 5 hp engine. Just remember to throw in a cut out switch to disable the alternator to start the engine easier. When you size the pulleys correctly ( a bit of experimentation) you can put out 14 volts at just above idle. Thats good on gas and easy on the engine!


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