[AT] OK, oddball question...

Tue Jul 16 11:44:28 PDT 2019

“Short answer is no, they don't have any built-in protection.”

If I had thought about that for a few minutes, I should have realized that was the case at least for externally regulated alternators.  The power out wire from the alternator goes straight to the battery, typically not even passing near the regulator.  Actual output current isn’t available to the regulator.  My old diagrams (at least 20 years old) of internally regulated alternators show the same connections, just all stuffed inside the alternator housing.

On the very late model cars, there is computer control of charging.  I have no idea whether they look at current level.

Jim Becker

From: Stephen Offiler 
Sent: Tuesday, July 16, 2019 12:28 PM
To: Antique Tractor Email Discussion Group 
Subject: Re: [AT] OK, oddball question...

Jim, your memory is remarkably good! 

Short answer is no, they don't have any built-in protection.  (Disclaimer:  This may not be universally true, and it may not be true in the modern day, but that's how they worked a couple decades ago)

Fusible links and "megafuses" take care of the protection externally.

SO

On Tue, Jul 16, 2019 at 12:36 PM Jim Becker <mr.jebecker at gmail.com> wrote:

  Once generator based vehicle charging systems were equipped with full voltage regulators, there was a built-in current regulator that (at least in theory) kept the maximum output within the safe working limit of the generator.  If the total load on the system was more than the generator capacity, the generator simply provided as much current as it could and the battery would be gradually drained because it was making up the difference.  The older 3-brush generators in cut-out systems were self-limiting on output and tended to take care of themselves, although probably less reliably.

  Steve, you have worked with internally regulated alternators and I am sure you know their inner workings better than I do.  But I would expect those alternators to have built-in current regulators that would prevent overload of the alternator itself.  The situation I would compare to is jumpstarting an engine from another vehicle with a running engine.

  Jim Becker

  From: Stephen Offiler 
  Sent: Tuesday, July 16, 2019 6:40 AM
  To: Antique Tractor Email Discussion Group 
  Subject: Re: [AT] OK, oddball question...

  The problem with trying to operate while charging (presumably, charging off a 36-volt alternator driven by a small engine) is that, basically, your alternator is supplying some/most/all of the cart's electric motor current.  How much depends on the batteries' state of discharge as well as the demands of the cart, so it's a pretty big variable.  But the problem is that you risk overloading the alternator.  Now if it is sized appropriately then you minimize or eliminate the problem. 

  Have you ever put a tractor battery (obligatory tractor reference) on a small, say 10-amp charger, forget to disconnect it later, and try to start the tractor?  Well OK at least *I* have made that mistake.  What happens?  Even with a pretty well-charged battery, the internal circuit breaker in the charger trips.  That is pretty much analagous to what I'm talking about above.

  SO

  On Mon, Jul 15, 2019 at 10:57 PM Indiana Robinson <robinson46176 at gmail.com> wrote:

    Some good stuff here... The batteries are a matched set just under 2 years old. None have ever been low on water or even discharged very badly or sat for any length time while low on charge.  I've spent a fair amount of time on cart sites but they had not discussed these particular things.
    Stephen, I had read on one of those sites that you should never use a frame ground for anything for the reason you said.
    I don't actually have any power drawing accessory items installed on the cart, not even a backup alarm. If it had one somebody took it off. I have an older 3 wheel EZ-Go that we are not currently using that has one. It is "in-line" for a set of batteries and a general go-through but it is low priority and is so far back in line it may be in the next county...  :-)  One of those kind of projects... "Maybe someday if I get to it but no big deal if I can't.
    Even my horn on the Club Car isn't electric, it is an above average chrome bike horn with a squeeze bulb.
    I do have a set of lights for it but not installed yet. They are all LED so low power needs. Still, I think the voltage reducer Bo mentioned is the best answer for tapping 12 volts. I have considered several times (especially this week  :-)  ) putting a couple of fans in the front up under the roof.
    Now, my original question was really based more on being able to extend range especially if I am using more power than normal. You know, like running the air conditioner...  :-)  :-)  :-)
    My old chargers are big and heavy but I've noticed that many new cart chargers are quite small (and far less expensive) than the old style. I had considered a 36 volt alternator regulator like Cecil mentioned but I think I might consider just charging one separate 12 volt deep cycle with the built in regulator in the alternator and then using one of those small new chargers powered by one of several power inverters I have. I think I would get more use out of a 12 volt system for other things since most camping stuff is 12 volt. Sometimes when travelling you end up some place completely without power...
    Does anybody know if it would be problematic for any reason to operate a golf cart while it is charging?

    .

    On Mon, Jul 15, 2019 at 1:41 PM Spencer Yost <spencer at rdfarms.com> wrote:

      I second Bo’s idea.... 

      Every other idea would be a nearly as expensive or more so, add unnecessary complication and create additional work that detracts from tractor time.   I do understand that rigging something up that is original and ingenious is a badge of honor.   But I suspect this is one project that screams for a plug-n-play solution.

      I’d pull out some green shims($20 bills) and install the reducer.

      Spencer Yost

      On Jul 15, 2019, at 10:29 AM, Stephen Offiler <soffiler at gmail.com> wrote:

        Bo, sounds like a fine idea to me.  30 amps is a pretty decent supply.  Here's a direct link: 

        https://www.buggiesunlimited.com/golf-cart/reliance-36v-48v-12v-power-converter-(universal-fit)/13-030 

        SO

        On Mon, Jul 15, 2019 at 10:01 AM Bo Hinch <bohinch at gmail.com> wrote:

          If it were me , I would use a voltage reducer like below that cost around $100.00 dollars and draws equal voltage from ALL the batteries never making any two batteries weaker than the others . I have installed many of them in my life time and years down the road , it pays off big time .
          Reliance 36V/48V-12V Voltage Reducer/Converter (Universal Fit) on sale now from Buggies Unlimited . Normally 174.95 , sale price is 97.95 .
          Just my opinion for whatever its worth .
          Bo Hinch in S/W louisiana watching Berry as its passing through 

          On Mon, Jul 15, 2019 at 6:28 AM Stephen Offiler <soffiler at gmail.com> wrote:

            Hi farmer: 

            Batteries in parallel will try to equalize each other.  Yours, of course, are in series.  In a series string, if one battery is discharged, it will limit the performance of the whole string.  It will not be recharged by the other batteries however.  That's because you're trying to pull current from the whole string, and recharge requires a push in the other direction.  Your idea to feed recharge to the center two batteries will work fine *IF* you are very careful to isolate the whole thing from the golf cart chassis. Otherwise you'll have some unintended arc welding going on.

            SO

            On Sun, Jul 14, 2019 at 10:45 PM Indiana Robinson <robinson46176 at gmail.com> wrote:

              One of my "old tractors" is IIRC about a 1996 Club Car 36 volt golf cart. With chevron tires (like tractor rears) they will get around well and will pull a lawn trailer about anywhere. I try to not over do it but I have in a pinch pulled one of my smaller tractors a very short distance or for a quick pull start.
              It is as I said a 36 volt one using six 6 volt deep cycle batteries.
              Now for the question... Hoping that some are better at theory etc. than I am. It's been a long hot day and my brain is in granny gear and I can't find what I want on-line. There are a number of golf cart accessories that operate on 12 volts like the back-up alarm, radio, lights, fan etc. You can pull 12 volts from any 2 adjoining batteries. I have read that you shouldn't draw too hard from any one pair or they will not always recharge evenly but apparently if those two do drop some power there is some balancing from the other batteries. Supposedly they try to find a common level with the weakest battery. (shrug)
              What I want to know  is what would be happening if I were to connect a 12 volt alternator powered by a very small gasoline engine to feed 12 volts to the center 2 batteries? Would it move to the other batteries some?

              Sometimes when we are working horse fences a lot we get might get a bit low on go juice when back in a back corner of the farm especially if running in deep snow. Not this week.  :-) 

              I fed the question into my boiled brain and it came back "error 404, page not found"...  :-)

              .

              -- 

              -- 

              Francis Robinson
              aka "farmer"
              Central Indiana USA
              robinson46176 at gmail.com

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    Francis Robinson
    aka "farmer"
    Central Indiana USA
    robinson46176 at gmail.com

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