36V TXT charged with one battery cable off

[yurtle]

Easiest way to load test them is to connect a volt meter to the pack and see what they drop to while trying to go. You can also do this to each battery, in case one is worse than the others.

[slashpine]

Curious...are you pulling 12Vs off just two batteries ?

[JohnnieB]

Originally Posted by Jlk696

What seems odd is that they have been good up until this winter. (Indiana) this is my first cart. Do they gradually go bad or do they go down hill quickly when they go? I guess I could check them with a 12v load tester two at a time. I will get a lead acid tester also and can check each cell.

When new, Deep-Cycle, Lead-Acid, Wet-Cell batteries only have about 75% of the rated storage capacity (AH) and it takes a couple dozen charge cycles for them to reach their rated capacity. Once the peak capacity is reached, they lose some of their storage capacity with every charge cycle until they no longer have enough energy to operate the cart satisfactorily. (See attachment-1)

Notice there is no information on that chart except naming the three stages in the battery's lifespan. That is because there are many factors that determine how long the batteries are usable, the three biggies being how high the average SoC (State of Charge) is maintained (See attachmeent-2), the climate they are used in (See attachment-3) and how well they are cared for (watering, cleaning, etc.).

Not much can be done about the climate, but for maximum lifespan, charge after each use, don't let the batteries sit in a partially discharged state for any longer than necessary, keep them watered and the connections clean.

Lead-Acid cart batteries self-discharge at about 1% SoC per day, so they are technically in a partially discharged state the moment the battery charger stops charging them. While in storage, they need to be recharged at least every month, sooner if possible. The best answer is to use float charging during storage.

In addition to the natural ageing, a lead-acid battery can fail at any time, so the answer to your question is a battery pack can die gradually over time, or die suddenly without warning.

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Tapping the 36V battery pack for 12V accessories, imbalances the pack and shortens the lifespan of all six batteries. Use a 36V to 12V voltage reducer and discharge all six equally, or use a separate 12V battery for the 12V accessories.

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You already have a load tester, your cart. Drive it up the same hill with a voltmeter attached to the battery pack and if problems appear, do it with the voltmeter on individual batteries.