Golf Cart Batteries

I Googled on "charger is a "Power Wise" 36V made by Lester" and got plenty of hits. You can try this site, be careful though:

http://www.gobookee.net/36-volt-ezgo-powerwise-battery-wiring-diagram/

I did try that first, but only got schematics, which is not what I am looking for. I already have the schematic and the charger has been updated with the module.

Good, schematics are the key (at least to me), but I sense that what Lyn said in #5 is probably true, many sophisticated chargers check the battery voltage and "decide" whether to actually charge based upon the state of the battery. I just went to the Lester site but it needs the 5 digit model number. Some of their models have microprocessors to "...prevent over and under charging...".

Just a thought, if you have access to the individual cells' terminals why not try using an ordinary 12 volt charger on each string just to get the battery voltage up?

I would start by checking the input power source all the way to the transformer.

If you don't have a hum when its plugged in and turned on it's not getting power on the AC side.

It could be as simple as a bad cord, bad timer switch or relay, or simply a blown primary fuse.

ronseto-

Have you checked the cables for resistance such as a bad wire, bad connection, bad crimp or bolt on connector. Just checking them without power and an ohm meter will most likely not show any significant resistance. Put the load of the batteries on them while the charger is on and take the voltage at each connector and the wire that leads to it. Only a small resistance will show as a small voltage drop. i.e. put the charger on, test the charger end of a cable vs. the battery end of the cable. There should be negligible voltage drop if all is ok. If a bad connection there will be near the voltage drop you have gotten. With #4 welding cable there should be only a slight voltage drop. This is the same way you would test a car battery cable or battery terminal.

Alternate way would be to measure the voltage drop by putting a volt meter in parallel with the suspect cable or fitting. High drop = bad item, low drop = good item. The higher the current the more the voltage drop. I=E/R

#4 cable is rated somewhere near 100 amps for a welder. I have used them in the past for very flexible and longer battery jumpers. They are extremely nice, especially on a very cold day.

Good Luck, Old Salt

I don't remember the brand, but one of the chargers I have will not charge a flat, discharged battery. Works fine if the battery has some charge. Maybe put a partial charge on one battery with a cheap charger, then try the "good" charger.

Good point, this fact is not uncommon....

The ones I build do this too, its a good design point I feel....a fully discharged battery has a very low resistance AND may be severely damaged too, depending upon type.

You don't want to connect to it without first being alerted to the possibilities....

The newer,"Smart" battery chargers indeed do sense the battery voltage before allowing a charge.This makes it impossible to charge a deeply discharged battery.This is a bit of overkill (a lawyer involved).

Foldback current limiting is easy to implement which could accomplish the same thing at a low amp trickle charge.The "Smart Chargers" will not even allow a trickle charge on an old battery.This prevents you from bringing the charge up slowly and desulphating the cells.

It took a long time to find a charger that would allow a set amperage to flow.It is just smarter than the average ""smart" charger.

"It took a long time to find a charger that would allow a set amperage to flow.It is just smarter than the average ""smart" charger."

Most any old ferro resonant type did the current limiting automatically plus could care less about a battery being dead or not. If it needed charging it charged it. No fuss no complaints.

The key word here is "OLD". What you say is true of the previous generation of chargers.

Trying to find a new model that will do that is difficult.

They are making things more complicated just for the sake of complication.

What was wrong with the old charging technology?

Someone blew up a battery,and the insurance companies got involved with their lawyers and consultant engineers and designed a very safe charger.Safe,but not very useable except for topping off a slightly discharged battery.

Too "SMART" for their own good.

Well the old ones are the only ones I tend to work on so.....

To be honest of the new ones I have worked on for a few people every repair tended to involve removing some stupid circuit board that controlled a big SCR on one of the the output leads.

Maybe thats why they wouldn't charge some batteries until I took that circuit out?

Hmmm.. Maybe I have worked on the new ones. I was just assuming that something went wrong with those circuit boards so I just fixed them by getting rid of the control circuit entirely to make them work like the good old reliable chargers.

Actually, the lower the state of charge of a lead acid cell, the higher its internal resistance.

This is mainly due to the fact that as the cell becomes discharged, the electrolyte becomes progressively less acidic until when dead flat it is almost pure water, the conducting ions of the acid having been almost entirely absorbed into the plates.

At this point the electrolyte exhibits its greatest resistance to current flow and is the reason that intelligent chargers (as different to smart chargers, which are designed to charge batteries that have built in electronic control circuitry) find it difficult to determine the voltage reading and capacity of the connected cell and so fail to proceed.

By contrast, a normal dumb charger will put out its 14 odd volts irrespective of battery terminal voltage, and its current output will be controlled only by the rising terminal voltage of said battery.

'....At this point the electrolyte exhibits its greatest resistance to current flow and is the reason that intelligent chargers (as different to smart chargers, which are designed to charge batteries that have built in electronic control circuitry) find it difficult to determine the voltage reading and capacity of the connected cell and so fail to proceed......

.

This explanation doesn't make sense to me.

.

A 12V lead acid battery that is dead will still be registering several volts as long as the current flow is near zero. Pretty much no new charger will provide a charge is the battery is showing less than 11V. But who has trouble measuring 10V? It isn't difficult to determine the voltage reading at 10V.

Good point. It explains why a flat dead battery will often times only take fractions of an amp, if even that, when being charged at its rated charging voltage for hours then have its amp draw start creeping up at some point as the acid starts to regenerate.

Some years ago I played around with heavily discharged LA batteries trying to see how much of an amp draw they will take if a voltage source of high enough amp capacity was available.

To do that I used the constant voltage DC output of my welder for the power source being that it can maintain 14 - 15 volts DC at 500 - 600 amps for several minutes without problems.

What I found was that the absolute peak charging amps most batteries would take was about equal or slightly less than what their cranking amp rating was and their recharge rates at those amps only lasted for a few tens of seconds at most before tapering off rapidly to about 1/10th of their CA rating which seemed to be their own way of keeping from cooking themselves at those power levels.

That is to say a 500 CA rated automotive battery when deeply discharged would draw around 400 - 500 amps peak at 14 volts but only for 20 - 30 seconds before dropping back to a rather steady 40 - 50 amp draw or less which it would then tend to stay at for half an hour or more.

After that I never really put a bit of concern into how many amps a battery gets charged at just as long as the proper charging voltage was maintained.

If a battery can put out 500 amps for 20 - 30 seconds before starting to run down they can also take 500 amps while charging for 20 - 30 seconds and not be harmed either.

You've probably left them discharged for too long....I think that is below the minimum charge....You could try rejuvenating the batteries by any of the methods found on the internet, or just go ahead and replace them....

How to Desulphate/Revive a Lead Acid Battery (with Pictures)

Never tried this myself. I'd use much caution if you try it.

Good luck.

Many chargers will not charge a battery that is too far discharged. Here's a trick that I have used: connect a good charged battery in parallel with the discharged battery and connect the charger to them. The charger detects the voltage of the good battery and proceeds to charge both batteries. The Optima battery site tells about this method:

http://www.optimabatteries.com/us/en/support/faqs/#charging.

I know zip about golf cart batteries, but this guy seems to have some ideas:

http://www.youtube.com/watch?v=r0XxnaWO8JA

Use a battery electrolyte tester to check each cell of each battery.This is a better indicator of battery condition than voltage.Any weak or bad cells will show up.

Make sure you have all of your batteries in series and that you have not accidentally mis-wired one in parallel.I almost did this once myself.

If you do not hear a click and a hum when connecting the charger,the charger is not putting out.Could be it does not sense enough battery voltage to turn on,dirty socket connections on the cart or charger(spiders love to nest in those holes, (and spider silk is a good insulator).

Since the batteries have been sitting for over a year, they probably are severely sulphated, and even if fully charged, will not have much capacity.

A lead acid battery needs to be kept fully charged to prevent sulphation.

Some people think they are like a ni-cad, which needs to be totally discharged,but that will mean sudden death to a lead acid battery.Keep it charged when not using it.

There are plenty of de-sulphation methods out there,but I am not sure if any of them work.

Good luck.

ronseto-

The plug in connection you speak of, was the voltage measurement you took on the battery side of the connector or the charger side of the connection? Also was there any voltage difference between the charger output wiring at the charger and the connection between the connector to the batteries while the charger was running?

Also, do you have one of those old style DC ammeters for checking starter currents and alternator currents? They look like a panel meter with two small pieces of channel on the back instead of terminals. They usually have a double scale. If not clearly the charger, it might help to try it on some of the wiring and connectors.

Good Luck, Old Salt

Due to long time unused, the active materials of your batteries got sulphated severely. It will be very difficult to do the desulphation to regain the batteries. You should arrange to charge the battery bank in a higher ampere (one tenth of its ampere hour capacity) to break the sulphates. Most probably your charger has no option to do that. Better you can contact with the nearest battery seller or manufacturer in this regard.

A standard lead acid cell is considered to be dead flat at 1.75 volts.

Yours are at 1.55 volts, and if they have been there for some time (more than a couple of days), then it is unlikely that you will be able to resurrect them with any degree of longevity.

First you said you replaced the wires. Check that the polarity is correct. Most these chargers have an internal relay which sense battery voltage to turn on. The 28V out put may not be enough. To see if you can save the batteries I would put each one on a 6V charger and get them back up to charge first. It would be best if it was one that had an equalize setting to help dissolve the sulfate that has build up do to non use.

The protection circuitry in the charger wants to see at least 30-32 volts at the plug before turning on. Charge the batteries separately, then try the charger. We have several golf carts, i.e. been there, done this.

I think the consensus is correct: that the charger will not charge the batteries because the voltage is too low/they have been left discharged too long.

.

....and that is not typically an easy thing to remedy.

.

.

BUT.... there is a bright side! Deep Cycle batteries (the kind typically found in gold carts) have the best prognosis for recovery among lead acid batteries.

.

The plates are usually solid and not sponge because high amperage is not the goal. This makes the plates structurally more sound and generally heartier.

.

You have your work cut out, but fortunately you aren't dealing with something like a high amp starting battery.

That's pretty easy to remedy. Just use a common automotive battery charger to do two 6 volt batteries at a time.

many of them are 8 volts.....

but on second thought... apparently not for this system.

Still many chargers will not charge at low voltage.

Then what good or what is the purpose of making a battery charger if it won't charge a dead battery?

I have yet to ever find a battery charger designed for charging lead acid batteries that by design won't charge a dead battery and I have worked on hundreds of them.

I've got one.

I have run across many.... in fact it is hard to find one that will.

.

Still I share your dismay... what good is a battery charger that won't charge a dead battery?

I found 2 of the 6 batteries were down to around 2V's. I put a 12C charger on the batteries, 2 at-a-time and was able to get the overall voltage up to 32V's. When I put the cart charger on, the needle creeped up slowly from zero. I left it on overnight and in the morning, the charger did not shut off automatically. I tried to operate the cart, but all I got was the solenoid clicking noise. I now suspect one of the batteries is bad and will have to be replaced. I know this is not a rocket science project, but at 79, even the simplist of tasks can be daunting.

Check the electrolyte in each battery.It will reveal the bad one.Sometimes a low,long term charge will desulphate a bad battery.Put the 12 volt charger on a trickle charge on the lowest reading batteries,and be prepared to leave it a week or more.Keep a daily check on the water level, and if low, add Distilled water only.Not tap water,or spring water,or filtered water.Check the battery voltage with the charger disconnected after 10 minutes.If it is steady,and not drifting downward over time, you are making progress.Continue the trickle charge till the battery voltage reaches 6.3 volts on the battery.If the voltage holds steady overnight, you have succeeded.

Repeat this for a batteries that fail the electrolyte test.Time consuming, I know,but worth a shot.

Insofar as replacing a single battery or two, my advice is don't do it.

When batteries are in series, as these are, they need to be the exact same capacity or the weakest one can actually reverse charge and cause many problems.

I recently had to replace an entire set in my golf cart.I don't play golf, I just use it for getting around in the neighborhood and farm.

(I have only hit 2 balls in my life, and that was when I stepped on a yard rake.)

Intestate makes a good golf cart battery,just as good as Trojan, IMHO, and a little cheaper.

Good luck.

GA

Many do not understand what you wrote, but its true.

Sadly, it will probably be one cell of one battery that is defective.

A usual cause (as HiTekRedNek also posted), is mixing old with new or different sized batteries together, the weakest cell ALWAYS dies first. This is true of ANY battery chemistry.....

In a perfect better world, each 12 volt battery would have its own charger and voltmeter and as soon as one of the batteries goes below a certain value of volts, it would be taken out of circuit and recharged. Not perfect but better!!!

In a perfect world, you would do that for each individual cell, but what the hell!!! That's what you do for submarine batteries.