2007 TXT PDS with 2017 Batteries Slows Down 75% charge and struggles on hills

bearcat22

I recently purchased a 2007 TXT PDS. It has March, 2017 Duracells that I have kept charged periodically throughout the winter in my heated garage (I live in Minnesota).

I have recently checked the battery cables and connections and they are tight and basically flawless. Completely clean and new cables. I checked the battery fluid levels at full charge and they appear full.

The car has a Kenwood CD receiver and 2 6" speakers in the dash which I connect my phone via bluetooth to play music.

I have been testing my car around the neighborhood and the digital battery meter starts at the top and every 5 minutes or so drops another bar. As soon as I get to about 70% or below the car struggles on hills and gets slower. 50% or below and I cant get up my 50 degree driveway.

Any other possible reasons this is happening? I feel like the batteries should be lasting longer. Is my stereo and music draining the battery faster than normal?

BGW

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bearcat22

Also, I use a charger with auto shutoff so I assume they are fully charged. I used a basic DC volt meter and it looks like I am getting around 6.2v for each battery at fully charged. Do I need to disconnect all the cables before testing at each battery terminal? I am connecting the leads to the open battery terminals, not the ones with cables.

JohnnieB

At 6.2V the battery is only about 70% charged, which is the minimum before recharging when in storage. Should be 6.37V for 100% SoC. (SoC chart attached)

What charger are you using?

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Your audio system and any other 12V accessories ought to be powered by either a 36V to 12V voltage reducer or by a separate 12V battery.

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The bar-graph battery meters are notoriously inaccurate. Install a DVM type if you want to accurately track your battery pack voltage.

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I'd be surprised if a stock PDS cart could climb a 50° incline since the max recommended incline is 14° or 25% grade. (Specs attached)

Perhaps you mean 50% grade, which is still twice the recommended incline. (Grade conversion chart attached)


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No need to disconnect cables to measure battery voltage and the unused terminals ought to read sane as used terminals.

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Are you running stock height (18" tall) tires?

Attached Images

	JohnnieB's SoC Chart.JPG (63.9 KB, 0 views)
	Grade conversion chart.jpg (167.3 KB, 0 views)
	EZGO - Stock Incline.jpg (94.4 KB, 0 views)

bearcat22

Thanks for the response JohnnieB. I just talked to the guy I bought it from.

1. I am using a Power Wise 28115g04. Image of a similar one

2. The audio system and lights are wired directly to only 2 of the batteries "so it is only 12v". According to the previous owner. I confirmed this visually. I also have attached a photo.

3. You are correct, I meant grade. It is a steep driveway but not unreasonable. The cart could climb it no problem last year.

4. I just recently put on new 12" tires with low profile wheels. (Tire Options: Arisun Cruze 215/35-12

5. Also, the previous owner mentioned he put a speed chip in the controller. He suggested taking it out, resetting the controller using the FWD/Reverse toggle switch, and seeing if it helps. I am searching for that process online. He still thinks it sounds like something with the batteries.

Attached Images

	battery image.jpg (85.5 KB, 0 views)
	powerwise1.jpg (32.1 KB, 0 views)

JohnnieB

1. That charger shuts off when the on-charge voltage climbs to 45V +/- 1V and using a fixed cut-off voltage doesn't necessarily fully charge the batteries. Since your battery pack is tapped for 12V, it is imbalanced, and the 45V cutoff is the average voltage of the six in series, so some of the batteries will overcharge while others undercharge.

2. As mentioned, tapping the 36V for 12V causes charging problems and shortens the batteries usable lifespan.

When you measure the 6V batteries, all six of the ought to be within 0.1V of each other.

You will most likely find the two that are used to power the 12V stuff are lower than the rest. Connect a 12V charger to those two and give the a good charge (max on-charge voltage of 8.4V)

Then do several back-to-back charges with 36V charger. That is, start a new charge after the regular charge cycle ends.

3. 50% Grade is still mighty steep for a stock cart.
Check the high current cables after climbing to the garage. If any are hot, they need to be repaired/replaced.

4. 12" is the Rim diameter. 215/35-12 works out to a tire height of 17.9", which is essentially stock height.

5. You need torque to climb your driveway and the torque is the same in all four PDS modes. The different "Chips" only change top speed and amount of regen braking. However, he is right about it being a battery problem.

What is the battery pack voltage when measured after sitting for about 12 hours after charger shuts off?
Should be 38.2V for fully charge Duracells.

If you can get the batteries to charge up close to that, the cart ought to be able to climb the hill it did last summer.

BTW: You don't have to disconnect the cables to charge the two low batteries with a 12V charger.

bearcat22

Thank you so much for the info. Super helpful. I wish I could virtually send you beer.

Do I have to charge the two accessory connected batteries with a 12v charger every time? Wouldn't it make sense to buy a 36v to 12v converter and install that so I can use the 36v charger I have? How much power am I draining using the audio receiver? I could always bring a bluetooth remote speaker and use that instead but its not as cool!

Should I get a new 36v charger? Seems like I am not really getting a full charge based on what you said?

Also, it seems to me like the audio receiver has a trip or safety switch and right before the cart slows down, the receiver shuts down and then starts back up again. I imagine this is connected to the same issue as above.

Are these Duracell batteries any good?

I will test your method outlined and see what the full battery pack gets after 12 hours.

bearcat22

OR, should I get a separate 12v battery to power the receiver and lights? Seems like a lot of people are suggesting that.

JohnnieB

1. Only when they are more than 0.1V lower than the other four.

2. & 7. Either use a 36V to 12V reducer or a separate 12V accessory battery. Both ways work. The voltage reducer uses power for all six batteries equally, but reduces how far you can go on a single charge. How much the reduction is depends on how much power the 12V accessories use and if you aren't using the cart for long trips, it may now matter. The separate 12V battery doesn't reduce the cart's range, but is more of a hassle since it has to be charged separately. It also adds some weight, so it is like have a kid onboard all the time.

3. How many watts does the audio system put out? Divide that number by 12 and you'll have the approximate number of amps it draws. The actual number will be a bit more since the system isn't 100% efficient. If you have the owners manual, it might tell you how many amps it draws.

4. I use a DPI Accusense and the Yewy 1200z is good also. They use dV/dT (change in voltage over change in time) technology to fully charge the batteries. The on-charge voltage stops increasing when the battery is fully charged and they monitor the rate of change to trigger the shutoff. http://www.cartsunlimited.net/chargers-36-48v.html

5.Lead-Acid battery voltage drops as amps are drawn and the radio probably has a low voltage cutoff. The lower the battery's state of charge, the more the voltage drops per amp drawn.

6. Duracell doesn't manufacture golf cart batteries, they slap their label on batteries made by others. They could be made by Trojan, Johnson Controls, Deka, Exide or someone else that produces batteries for relabeling. However, there is less difference between different brands of the same grade battery than there is differences in the different grades within the same brand. The key factor is the Run-time rating (Minutes @ 75A) followed by the AH rating (AH @ 20Hr). The standard 6V battery used in a 36V battery pack is the Trojan T-105 which has a Run-time of 115 minutes @ 75A and 225AH at the 20 hour rate.

There are several grades of Duracell cart batteries, which do you have?

bearcat22

1. I think I want to get a voltage reducer. The receiver says 50 watts so maybe 5 or 6 amps. The headlights and tail lights are LED and they are rarely on when I need full range. Any suggestions on a voltage reducer?

2. Is the $250+ investment in a new charger worth it?

3. I have the Duracell SLIGC110 / 20 AH Cap 215 / 105 MIN @75 Amps. Sounds like these are the value model.

I will be using the cart for golfing. Any idea how many minutes you are actually driving while playing 18 holes?

Thanks again for all of your help!

JohnnieB

1. Get one with remote On/Off (turns off when cart key is off). These are examples: http://www.cartsunlimited.net/12v-reducers.html

If your radio needs to have 12V to it all the time to remember the settings, get #3, it has a constant 12V output as well as a switched 12V output.

2. If you use the cart often (every day or other day) and put on charge after each use, the PW will keep the batteries pretty well charged, if it is working correctly. However the batteries will last longer if kept fully charged. I upped the battery pack voltage to 42V (which is the sweet spot for a PDS cart), so I had to get a new charger anyway.

3. Yep, economy grade. Standard is 225AH.

4. That depends on what your handicap is.
With a standard battery pack (225AH), a cart will typically do at least 36 holes on a single charge. More when the batteries are new. Your batteries have 10AH less than the standard, so it'll do about 5% less.