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Anonymous Poster

Battery Discharge

03/14/2008 4:32 PM

I recently replaced my Club Car batteries with new Trojan T105 six, six volt batteries. Upon checking them after use, I have found that one battery is at almost full charge, one battery is very depleted and the other four are at the mid-range. Why are all six not discharging at the same time. I charge with a Club Car charger with an automatic shut off and have maintained my battery water at the correct level using distilled water. The terminals have been kept clean. I have felt the last two times out that the car loses some power early on but thought it might be some kind of electircal motor problem. Any suggestions.

Thanks

T.

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#1

Re: Battery Discharge

03/14/2008 5:27 PM

First what method are you using to check the state of charge. Are the jumpers connected properly. How does the charger charge the batteries all in series, three banks of two, or individually.

This one battery could be bad. A bad connection between the plates of one of the cells would cause the battery to drop a load across it. Load test the battery if it has a bad cell voltage will fall off.

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#2

Re: Battery Discharge

03/15/2008 12:46 AM

Hello Guest,

I had to first find out what a "club car" was.

It is an electric cart for use on a golf course.

Yours is a 36 volt system.

Quote below is from: http://www.clubcar.com/Services/PreOwned%20Vehicles/Pages/Pre-OwnedFAQs.aspx

<"I need a set of golf car batteries. What kind should I buy?

When looking for a golf car battery first determine if you have a 36 volt or 48 volt vehicle. A 36 volt vehicle has six 6 volt batteries, and a 48 volt vehicle has six 8 volt batteries. These are specialized "Deep Cycle" batteries designed for electric vehicle use, DO NOT attempt to use 12 volt automotive batteries. Club Car uses TrojanĀ® deep cycle batteries in our vehicles because many experts consider them the best golf car batteries available.">

I have not the circuitry of the golf cart here, but almost certainly the battery will not have tappings off it, to run equipment at voltages other than the full 36 Volts of the battery.

Your "Trojan T105 six" batteries are "Deep Cycle" batteries, so they should be OK.

During manufacture, no two cells are exactly alike.

When any cells are connected in Series to make a battery, there will always be a cell which has a higher internal resistance that the others.

On discharge, that cell heats up faster, loses more water from the cell, and on re-charge it heats up faster and also loses water faster than all the rest of the cells in the battery.

So....what you have, is probably a single faulty cell of the 3 cells in that 6 Volt battery, which has a very depleted charge.

Thus the only remedy is to replace that faulty battery with a new battery.

The new problem which may then occur, is that you will have one battery new, and 5 batteries used, in a series circuit.

That means the next "weak cell" is going to be next to fail, and it will in turn give you the "depleted charge" indication on the 6 Volt battery it is part of, in turn.

If your batteries were recently totally replaced, and to be used in a series circuit, always ensure that the cells are matched properly, or you are going to have the further same problems.

I would take the matter up with your battery supplier, pronto.

Incidentally, I always thought golf was for exercise, so why buy an expensive golf cart, to trundle around the course, depriving you of that essential exercise?

Kind Regards....

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#3
In reply to #2

Re: Battery Discharge

03/15/2008 6:02 AM

Incidentally, I always thought golf was for exercise, so why buy an expensive golf cart, to trundle around the course, depriving you of that essential exercise?

Even a bit of exercise is better than none. On the course I play we have several 'disabled' members who can no longer walk the course but manage to play still with the aid of a cart. We also have a member with only one arm (he's much better than me ).
I use an electric trolley as a golf bag is rather heavy. Much better to get some help so that we can enjoy fresh air, some exercise and and a pint afterwards rather than curling up and feeling sorry for ourselves.
Alternatively maybe he's just a lazy git

Del

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#7
In reply to #2

Re: Battery Discharge

03/15/2008 11:07 AM

I have not the circuitry of the golf cart here, but almost certainly the battery will not have tappings off it, to run equipment at voltages other than the full 36 Volts of the battery.

Sparky,

They do tap off for 12 volts they use automotive horns and lights if the have them. In the ones made for industrial use some have cabs with windsheild wipers that are 12 volts.

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#8
In reply to #7

Re: Battery Discharge

03/15/2008 4:57 PM

Hello ozzb

If the cart battery has equipment running at 12 volts, example lights, horn etc, the proper way to run that equipment is from a 36 Volt to 12 volt DC to DC electronic converter.

This maintains the integrity of all the individual batteries in the series circuit.

If that "other equipment" is run from a tap from the 36 Volt battery, the battery/s which run that circuitry will discharge at a faster rate than the other batteries.

This will certainly lead to premature failure of the cells in that (12 Volt circuit).

In the case of the Topic Poster, it was stated that <"Upon checking them after use, I have found that one battery is at almost full charge, one battery is very depleted and the other four are at the mid-range.">

This looks as if the auxiliary equipment is running at 6 Volts, perhaps.

If so, then all references below to 12 Volt should be altered to 6 Volt, except the Trojan Battery reference.

Now we don't know how the Topic Poster is checking the charge state of the individual cells.

The correct way is to use a hydrometer, to measure the Specific Gravity of the individual cells.

At left is a picture of the Trojan T105 six (Six Volt) Deep Cycle Battery, as made for Golf Carts.

The Battery shows removable caps, used for topping up lost water with distilled water, and using a hydrometer for checking specific gravity - thus state of charge.

The 36 Volt battery Voltage, when fully charged, should read 39.6 Volts = (18 x 2.2 V)

If there is a 12 Volt tapping on the Batteries:

If the Golf Cart does have 12 Volt lights, horn etc running from a battery tap, at the 12 Volt point, instead of the better DC/DC (36 Volt/12 Volt) Converter, and the affected batteries are those used by the 12 Volt equipment, the reason for failure is reasonably established.

Someone left the lights or other 12 Volt equipment switched on, (most logical), or else there was a 12 Volt equipment failure or short circuit, and those two batteries supplying the 12 Volt equipment discharged completely beyond the normal discharge point.

Thus those two batteries will now each have their "weakest cell" (see my earlier Post re that) discharged and left in over-discharged situation.

Now when the battery of series connected cells is connected to the charger at 36+ Volts, those over-discharged batteries will be charged last, and never recover to full capacity normality.

The solution:

Check the 12 Volt Circuitry for how the 12 Volt System is done.

A) Converter:

  1. If a DC/DC 36 V/12 V Converter is used, then the converter has failed, with the idle current increasing beyond its normal 70 milliamps or thereabouts = Replace the DC/DC Converter
  2. Check all 12 Volt circuitry for a fault
  3. Check lights etc were turned off after use
  4. Install a relay for 12 Volt circuit, so that lights cannot be left "on" when key is turned off.
  5. Replace the 2 failed batteries, knowing this problem may occur again

B. If a 12 Volt tapping:

  1. Check all 12 Volt circuitry for a fault
  2. Check lights etc were turned off after use
  3. Install a relay for 12 Volt circuit, so that lights cannot be left "on" when key is turned off.
  4. Remove battery tap at 12 Volt position, install a DC/DC Converter (36 Volt/12 Volt), do minor rewire to suit new Converter.
  5. Replace the 2 failed batteries, knowing this problem may never occur again

Remember that a battery tapping in a series battery, is never a good idea, because of the "weakest cell" principle.

C. There are other reasons for premature battery failure:

  1. Seat metal short circuited one battery, because golfer too heavy - remedy: repair seat, lose weight.
  2. Animal entered battery housing with conductor, short-circuited battery - remove animal + debris, screen battery enclosure.
  3. The failed battery is too close to a heated object.
  4. There are further possible causes, getting more and more unlikely, so I shall save your monitor ink, by not placing them here.

Kind Regards....

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Anonymous Poster
#4

Re: Battery Discharge

03/15/2008 9:10 AM

Check out how the supply cables to the cart are hooked up to the batteries...

batteries should be all in parallel with the neg being hooked up on one end with the positive on the other end of the chain

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#5
In reply to #4

Re: Battery Discharge

03/15/2008 9:52 AM

The terms 'parallel' and 'chain' are mutually exclusive.

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#6
In reply to #4

Re: Battery Discharge

03/15/2008 10:19 AM

If the circuit is 36 volt then the batteries should be hooked up in series not parallel.

They should all be hooked up with the positive going to the negative of the next battery in the series. If they were hooked up in parallel you would only get the output equal to the single battery but with a higher amp output. IE : 6 volt at a very high amp output.

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