05 PDS question

[sdc19982002]

I dont know if I have a problem or not. It seems like after the first 10 minutes of driving I loose alot of my get up and go. It has a problem going up inclines but will still move good on flat ground. I load tested my batteries tonight and they showed good. What else can I look for?

[scottyb]

How did you load test your batteries?

Can you attach a meter to the pack and drive?

[sdc19982002]

I used a 100 amp load tester. Yes I can attach a meter and drive. Should I hook to batteries or charging port. What am I looking for?

[Gale Hawkins]

We just got an 100 amp load tester and it did not fail these old deep cycle batteries that I have been playing with when each has dead cells it it. It stayed in the high yellow and were not even fully charged by any means. We can go like 20 miles and it will still go up hills at the same speed where the SOC is at 100% or 50% per the GPS MPH feature. It is a 2007 PDS with Oct 2006 T-105 batteries.

Look at getting some new battery cables that gets the power to the controller. There is about 8 of them but scottyb can be specific on that. When I used the temp gun on all the battery connects after some hard hill pulls I found some heat rise. When I replaced them the old ones was swollen up due to green powder build up inside the plastic outside jackets.

Based on our case cables should be well inspected after 5 years and replaced if needed I expect.

Wal-Mart has a simple 4 ball specific gravity (SG) tester for $1.54 that is a no brainer to read (unlike the $9 I got at NAPA). If you have any cells after the charger kicks off that do not pop all balls in a flash to the top of the tester you can bet your batteries are sulfated to the point it is hurting performance. Do not count any lazy balls that just float up ever so slow. If at 1.275 all four will POP up top. Counting the lazy balls will give you a false high readout because like the four ball antifreeze testers they are ball park estimation of the true values.

If you do not have any like dead cells a BatteryMINDer can help get the crystal sulfate off the plates. We bought the 36v version from this source.

http://www.batteryminders.com/batter...n-p-16143.html

I hooked up the free 12v meter at the head light wiring connection at the batteries and pulling any kind of hill it will stop it from burning even read due to the voltage drop.

[sdc19982002]

Ok, I just took the cart out after a full charge. My starting voltage at the charge jack was 38 volts, I drove around for about 30 minutes at normall speed and I finished at 32 volts. The voltage fluxuated while driving and accelerating down to 28 at times. Does that tell you anything?

[Gale Hawkins]

It seems like they are showing their age. Next time before you put it back on the charger let it sit for an hour and check the voltage after some recovery time. The larger the bounce back the better.

I may be wrong because I am just comparing to our 2007 PDS with Oct 06 batteries. After two hours (about 20 miles) we tested at 36+ before any resting time.

As a question what amp readout to you get when you first connect the charger to the bank and how long is it before the charger finally tops off the battery bank?

Our charger is labeled 36v 21a on the back but even after the 20 miles it only hit 12 amps for maybe two minutes then settled on 10 and tapered from there.

From my normal charging experiences the charger will peg the meter after much use then start the taper. I think the readout may be 25 but as noted I have never seen it over 12 and only for a couple minutes. Others see the same or with a heavy discharged bank does your EZGO automatic peg briefly?

It would charge the bank faster if it would start at 25 then taper.

[scottyb]

Originally Posted by sdc19982002

Ok, I just took the cart out after a full charge. My starting voltage at the charge jack was 38 volts, I drove around for about 30 minutes at normal speed and I finished at 32 volts. The voltage fluctuated while driving and accelerating down to 28 at times. Does that tell you anything?

100 amp load tester is not enough to really test golf cart batteries... Customer just called and said he is consistently popping a 175 amp main fuse. Golf carts have 275 - 800 amp speed controllers.... Stock motors can draw 4-500 amps for brief moments.... Those 100amp tester are made for car batteries.
Draw down testers are made for golf carts. Based on your usage results I would say your batteries are toast. Good batteries will run that cart 90 minutes. Your batteries are at about 30% or less capacity based on your lowest voltage reading..... I hope this helps.

And Gale your interest in learning about golf carts and golf cart batteries is great but you need to check and double check your info before handing it out as gospel. That ball float tester you got is for antifreeze NOT BATTERY SPECIFIC GRAVITY readings. You need a dial gauge with temperature compensating readings. Any good auto parts house will have one. Leave the floating balls for checking the antifreeze.

[Gale Hawkins]

Originally Posted by scottyb

And Gale your interest in learning about golf carts and golf cart batteries is great but you need to check and double check your info before handing it out as gospel. That ball float tester you got is for antifreeze NOT BATTERY SPECIFIC GRAVITY readings. You need a dial gauge with temperature compensating readings. Any good auto parts house will have one. Leave the floating balls for checking the antifreeze.

scottyb was your day too long or did you start your night too early?

Do not give your mistake a second thought because I too get confused.

http://www.buggiesgonewild.com/elect...unction-6.html

Read what DrBob posted in post #55 about floating ball battery testers. That is the type battery tester I posted about.

http://www.corradoworld.com/article/batteries-101.html

Here is a picture of one that has been in use for 25 years. It is similar to the one I got at Wal-Mart the other day for $1.54. I can see how younger guys could confuse these battery SG testers and antifreeze testers.

The key is to read the package and look at the printed values on the glass tube.

http://www.jcwhitney.com/motorcycle-.../p2006082.jcwx

While on the high side here is a floating ball battery tester from JC Whitney.

http://www.ehow.com/how_7456626_use-...ry-tester.html

Just a bit if info for those interested in floating ball battery testers.

scottyb if you ever try a pocket size SG floating ball battery tester you will understand why they are better for most cart owners than the kind you use because we are looking for gross info unlike you when tweaking for the race track.

If they are off by a ball that is still fine. When we are looking at a cart or some used batteries for $1.54 we can learn all we want to know. If each cell floats 4 balls at is great. If they all float 2 balls that is still cool.

We start getting concerned when testing a 6v battery and every cell floats a different number of balls.

Keep in mind scottyb many of us grew up without electronics and battery powered this and that in the shop. A buck floating ball battery tester could find dead cells and the SOC at a glance. There was nothing to plug in or batteries to replace to check out a wet cell battery.

Not good but a very common way to check a battery in the field was to short the posts with a wire and judge from the spark and pop if it was enough to start the vehicle.

[rib33024]

Hey Gale maybe you should read that link again, because you may be the one that started early

Now when a man has been in the biz since 1945 I think I would listen to him

Originally Posted by OLD MEC

DR BOB- wonderful explanation of OBC operation and parts required. Not to be critical of your fine acurate testing BUT?
On 7-9-2009 post with pictures of OBC torn down you added a Tutorial Voltage Report chart that stated that you were using a MULTI BALL ANTIFREEZE TYPE TESTER as being accurate??? I would be more than happy to send you an OLD FASHIONED UNIT with a ACCURATE SINGLE FLOAT HYDROMETER WITH TEMPERATURE CORRECTING SCALE? I have been in the auto and battery field since 1945 and have used the above hydrometer to correctly analize battery problems during the whole period. When the multi ball type of antifreeze tester came out the manufacturers need a broader field so pushed them as accurate battery acid testers WHICH THEY ARE NOT?
JUST MY .02 WORTH.

Originally Posted by DrBob

Hi,

OK I am BUSTED. I forgot those notes were on that plot. I had one of the good old fashion single float, temperature compensated hydrometers, but the thing was dirty from years of use. When I took it apart to clean, the rubber fell apart. So I got a 4 ball unit at ACE Hardware, as that is what my "battery guy" uses. At the time, I suspected I had a bad battery, so I figured I would use something he was familiar with, in case I had to make a case for a replacement.

You are right about their consistency. I got another 4 ball unit at Walmart and the 2 agree to about 1 ball, which is not that good since only 4 balls cover their measurement range.

Now I have a relatively inexpensive EZRed SP101
http://www.ezred.com/Product_Pages/B...er_EZSP101.htm

which has the advantage of automatic temp compensation (not much of an issue in Florida), an expanded numerical readout scale which for me, is much faster to read than the good old style. It is easily readable without taking it to eye level and is much less susceptible to hanging bubbles (on the float) and wall resistance than the 4 ball testers.

However a good OLD FASHIONED UNIT with a ACCURATE SINGLE FLOAT HYDROMETER WITH TEMPERATURE CORRECTING SCALE is still the gold standard.. One day, I will get another one of them.

I do not depend on the hydrometer for determining anything except the approximate state of charge of the battery. It is pretty straight forward to calculate the number of ampere-hours under the amps vs time charging curve by breaking it into a few "straight-line" sections and multiplying the average current by the time in that section. If you multiply the amp-hours in each section by the average charging voltage during that section, you get the watt hours for that section. Adding the results for the sections gives the total watt hours added during the charge.

From the manufacturer's specs, you can use the number of minutes (convert to hours) that the battery should operate at normal running amps while it maintains above 1.75 volts per cell, to get it's capacity. Use 1.92 volts as the average cell voltage while the battery discharges to 1.75 volts. Comparing this to what you restored on full charge, and you get the % capacity you had when you started the charge.

For a Trojan T875, use 117 minutes at 56 amps at an average of 7.68 volts.

This gives 117/60 x 56 x 7.68 = 839 watt-hours. So a 6 pack of these batteries has 5.034 kilowatt-hours.

If you restored 2000 watt-hours, then the battery was at 2000/5034 = 39.7% discharged when you started charging it.

I will give a full example if anyone needs it.

Getting the Club Car CDM meter will give you a relative readout much more directly as determined by the OBC. If it reads that 43 EU have been used since last charge, then the battery is 43% discharged as far as the OBC is concerned.

I do not know if the OBC is smart enough to adjust for decreasing capacity as the batteries age or to a new maximum capacity if you replace the T875s with batteries of lessor or greater capacity. It has the possibility to do both of those things if you run the batteries down to 42 volts (for a 48 volt T875 pack), which the OBC senses, as it can then measure the amount of energy needed to fully charge the pack and could use that as the new pack capacity.

[scottyb]

"However a good OLD FASHIONED UNIT with a ACCURATE SINGLE FLOAT HYDROMETER WITH TEMPERATURE CORRECTING SCALE is still the gold standard.. One day, I will get another one of them."

The above is Quoted from your own references ????