Author Topic: Need more power (Read 2984 times)

woodbeard · « **on:** August 25, 2005, 05:47:50 pm »

As I mentioned in my previous thread, my '92 LT30HDG24 is having a real hard time supplying power to the hydraulics.
The bed and hydraulics of this mill were from the prototype of the LT60, and have 2 motors, like a super hyd., presumably to run the chain turner, and possibly bigger cylinders on other stuff.
I spoke with the parts dept. at WM today, and we came to the conclusion that my 24hp Onan is just way too small to run this stuff. The smallest engine on a super is 35hp. I tried disconnecting one of the motors as per their suggestion. It helped a little, but not enough.
A new 35 horse engine will run about 5 grand or so and require a lot of refitting, so I am thinking of putting together a separate power unit for the hydraulics. Any ideas on how I might go about this? The 2 hyd. pumps draw a total of 400 amps. What size engine and alternator do I need?

Tom · « **Reply #1 on:** August 25, 2005, 06:59:50 pm »

It seems to me that you could live with the two motors on the hydraulics if you maximize the alternator and use a battery that will hold a big load.

I'm reminded of dumb situation I was in once when a Motorcycle mechanic suggested that I needed new brakes. Since I was going on a 500 mile trip over the weekend asked him if he thought they would last till I get back. He said, "sure, if you don't use them much".

Since the hydraulics are used only intermittently, the rest of the time can be used for charging.

There are 100+ amp alternators out there that can keep a battery pretty hot.

Before I spent thousands of dollars on a new motor, I would spend one or two hundred on new alternator and battery. It might fix the problem.

woodbeard · « **Reply #2 on:** August 25, 2005, 07:11:10 pm »

Well, the manual states a "105 amp max." rating for the stock alternator, and the battery is a deep cycle/starting battery which is about as big as can fit in the box. I suppose I could ask WM about getting whatever alternator is supposed to go on the super hyd. mills. How big an alternator can a 24hp engine pull?

Tom · « **Reply #3 on:** August 25, 2005, 07:18:28 pm »

The automotive generator place where I got my last alternator (I get them rebuilt) told me that my current one is 120 amps. I never noticed a difference in engine load between it and the 80 amp that was original.

jpad_mi · « **Reply #4 on:** August 25, 2005, 07:21:55 pm »

Generating 400amps of current (4800watts) will take a good bit of horsepower! I can see why there isn't much left for sawing. I purchased the engine on my mill from a guy that owns a company that makes DC gen-sets. You may want to contact the guy to discuss your needs. I'll PM you the website.

I would think that if you end up adding a second engine, that you'd be better off removing the electric over hydraulic pumps and going with a gas engine w/direct coupled hydraulic pump and remote resevoir. The intermediate step of generating DC power seems like it would be very inefficient. Of course this will present a lot of challenges getting it all re-connected.

Ianab · « **Reply #5 on:** August 25, 2005, 07:33:47 pm »

I was thinking along the same lines a JP, is it practical to fit a auxillary gas engine to run the hydralics?
If you need 4800 watts thats like 6hp? and a little Honda industrial engine would do the job. Would certainly be cheaper than fitting bigger engine to the mill.

Ian

Minnesota_boy · « **Reply #6 on:** August 25, 2005, 08:19:53 pm »

I'd take the easy way out and replace the deep cycle battery with a heavy-duty starting battery. I never uear the battery down and leave it that way, so a deep cycle isn't really needed. You only need 400 amps when you are lifting the biggest log onto the mill. The rest of the time the hydraulics are not being stressed out that much. The 100 amp alternator should easily keep the battery charged unless you are loading a big log, taking only one slice and then removing the rest of the log.

johnjbc · « **Reply #7 on:** August 25, 2005, 08:58:39 pm »

105 Amps at 12 Volts gives 1260 Watts.
If 746 Watts is 1 H.P.
Then 1260 Watts is 1.7 H.P.
That load shouldn’t make that much difference to 24 H.P. engine except at idle. Have you tried speeding up the idle.

I doubt that you use the hydraulics 10% of the time So a average charge of 40 Amps should keep your Battery up.

twoodward15 · « **Reply #8 on:** August 25, 2005, 09:07:18 pm »

Multiply that by 3.5 to get the 400 AMPS that he needs and you'll notice a big horsepower difference. 7 horsepower less than 24 makes a big difference.
How about buying a generator to run your hydraulics? A 6000 watt job would do fine and I'm sure you'd find other uses for it like running your house when the power is out!!! If you look hard enough you can probably find one for way under a thousand dollars. Probably even under 500 if you really try!

RMay · « **Reply #9 on:** August 25, 2005, 09:28:52 pm »

I would replace the battery , my mill was doing the same thing with a deep cycle battery.

woodbeard · « **Reply #10 on:** August 25, 2005, 09:41:55 pm »

OK, well the battery will be the first thing I will try, then. I can always use another battery for something or another.
I have tried holding the idle higher by hand while running the hydraulics, but it still wants to conk out.
If I end up getting a generator, how do I get 12vdc out of it?

johnjbc · « **Reply #11 on:** August 25, 2005, 09:42:39 pm »

Not sure where the 3 ½ came from. But when the hydraulic pump is running the load would be split with the battery providing 300 amps and the alternator providing 105 amps. I wonder if your battery could be sulfated and not able to take a full charge.
I think you also need to stay with a heavy duty deep cycle. A regular car battery will fail quickly if charged and discharged reputably like this application requires.

Fla._Deadheader · « **Reply #12 on:** August 25, 2005, 09:47:02 pm »

A few of the guys swear by them round cell batteries

CRS

johnjbc · « **Reply #13 on:** August 25, 2005, 09:50:38 pm »

To get 12 volts at high current you would need a real big battery charger.

Minnesota_boy · « **Reply #14 on:** August 25, 2005, 09:51:18 pm »

Quote from: johnjbc on August 25, 2005, 09:42:39 pm

I think you also need to stay with a heavy duty deep cycle. A regular car battery will fail quickly if charged and discharged reputably like this application requires.

Just to be contrary, I found that the deep cycle wouldn't last 3 seasons, while the standard heavy-duty starting battery has lasted me 6 years. Just make sure you get a heavy-duty one so you aren't deep-cycling it. If it can produce 800 cold cranking amps, it will last a long time.

woodbeard · « **Reply #15 on:** August 25, 2005, 09:53:19 pm »

Hmm.. well earlier today I had to take the battery to the auto parts store to get it charged- it would not start the engine. I figured it was totally drained, but when they put it on the machine it showed a fair charge, and only needed 25 minutes charging. I thought that was odd

Tom · « **Reply #16 on:** August 25, 2005, 10:05:36 pm »

You might have a weak cell.

It might be a good idea to check all of the electrical connections between the battery and the hydraulic pumps too.

Dirty terminals can keep a battery from charging and also keep the power from leaving the battry too.

Buzz-sawyer · « **Reply #17 on:** August 25, 2005, 10:20:00 pm »

How many volts is your alternator putting out at idle and at speed?

woodbeard · « **Reply #18 on:** August 25, 2005, 10:37:15 pm »

Don't know. I will check that tomorrow.

RMay · « **Reply #19 on:** August 25, 2005, 10:38:35 pm »

here is some good info I got when I had a battery go bad http://www.forestryforum.com/board/index.php?topic=9594.msg131219#msg131219

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Author Topic: Need more power (Read 2984 times)