How To Test Your Golf Cart Batteries

How To Check If Your Golf Cart Batteries Are Still Good

This will be an ongoing How To article because it is important to note the proper way to do something does not mean everyone has the tools required to do so. Surely not the average electric golf cart owner that is starting to experience performance issues with their golf cart. So they start to ponder possible options – which human instinct would suggest oh… great I will just replace the batteries. This is until you call to get someone to do the job for you as it is kinda overwhelming to a novice or someone who has never seen so many batteries in one place before much less wired together, oh and the size and weight…. Jeez those batteries look heavy. Average golf cart battery weight is 60 lbs ea… Then the shocker – the cost associated with replacing your golf cart batteries with a quality battery. Heck even the cheapest of cheapest made in Mexico/Korea black boxes will cost you 90-100 bucks each for a 6 volt, 100-120 each for an 8 volt, and even more for 12 volt batteries.


Golf Cart Battery Testing Methods

So back to square one… my golf cart is not running right or providing good range – Example – cannot complete a full 18 holes of golf. How do you determine what is wrong and if or how can you fix it?

Digital Volt Meter Test

A digital volt meter is only going to get you so far in the event you want to check the health of a battery. The digital volt meter test is great for checking voltage and testing a circuit for power when wiring things to power up, but for this purpose they will only determine if the battery in fact has some electricity in them. I will check the battery bank as a whole to confirm power. Then I will check batteries individually to see how they stack up or if one battery might be the culprit vs the bank as a whole.

Testing Your Batteries With A Hydrometer

Check the electrolyte specific gravity with a hydrometer. If the specific gravity measures between 1.100 and 1.220, the battery must be
recharged. If the specific gravity is between 1.225 and 1.265, the battery is ok to test. If the hydrometer has a temperature correction chart, be sure to adjust the reading for the battery’s temperature. Variance of specific gravity between cells is not significant on discharged batteries (batteries with specific gravity below 1.225).

Special Note – If there is a variance of 50 points (0.050) in a battery whose specific gravity is 1225 or more, that battery is bad and should be replaced.

Battery Load Test

For example – On a full charge a good set of golf cart batteries will allow you to surely play a few rounds of golf. Using a 48 volt Club Car for example you can play a round of golf with a new set of fully charged batteries and after round is complete the cart will still be above the 48 volt threshold on the battery banks capacity. One because the start / stop load not very demanding vs all out start stops continuously without letting the golf cart or batteries catch their breath per se… Though this is also because a fully charged 48 volt cart with say 6x 8 volt batteries will be around 51 volts not 48 volts.

Proper Procedure For Load Testing A Golf Cart Battery

  1.  Charge the batteries completely. If the batteries do not take a charge this is a good indication they need to be replaced. Unless your golf cart battery charger needs to be replaced or repaired because it is in fact the problem and why the cart is not performing as it should.
  2. To get an accurate assessment you will need to make sure they are fully charged ( No Exceptions) and slightly rested ( Cool to your touch-Room Temperature)
  3. Check voltage before each test with Digital Volt Meter or If you purchase the Load tester Pete recommends it has a volt meter on it to help facilitate a proper test.
  4. Apply the load required based on Quick Guide below
  5. Load the batteries to the advertised Amp Hour Ah rating at 20 hrs…. This information can be found on the top of all golf cart batteries – See learn how to interpret a Battery Information Sticker.
  6. Test results you will want to see. See Golf Cart Battery Load Testing Results Explained below… the following to confirm they are still in good shape.

Quick Golf Cart Battery Capacity Guide –

  • Average 6 volt golf cart batteries are 210-225Ah,
  • Average 8 volt golf cart batteries are 165-170Ah, and
  • Average 12 volt golf cart batteries are 150Ah….

Golf Cart Battery Load Testing Results Explained

  • 6 volt battery will need to maintain 5 volts for 15 seconds at the advertised 20hr Ah rating,
  • 8 volt battery will need to maintain 7 volts for 15 seconds at the advertised 20hr Ah rating, and then the
  • 12 volt battery will need to maintain 11 volts for 15 seconds at the advertised 20hr Ah rating.

Lester Charge/Discharge Tester


Reasons For Battery Failure

Age of Battery: If the date code on the battery indicates it is fairly old, the failure may be due to natural causes.

Incorrect Installation: Loose battery hold-downs cause excessive vibration, which can result in damage to the plates and internals of the battery. Especially important with new batteries as the lead has not cured yet and is very soft.

Improper Maintenance: Low electrolytic fluid and corrosion on battery connections can greatly reduce battery life and performance.

Overcharging: Overcharging caused by a rogue battery charger can cause excessive gassing, heat and water loss.

Undercharging: Undercharging caused by using a cheap golf cart battery charging system ( One that does not apply enough amperage in the charging cycle) can cause lead sulfate to gradually build up and crystallize on the plates greatly reducing the
battery’s capacity and ability to be recharged.

Wrong Battery For Your Application: Wrong size battery may not have inadequate performance rating for vehicles electrical system and specifications. (This is for those people thinking they can save a few bucks by putting 3x 12 volt batteries in a 36 volt golf cart that usually uses 6x 6 volt batteries.)

Battery Testing Safety Precautions

Wear eye protection when working around batteries.

Keep sparks, flames, or cigarettes away from batteries.

Provide adequate ventilation to remove battery gases.

In extremely cold temperatures, check for frozen electrolytic fluid before applying load. Do not attempt to Load Test or charge a
battery under 20 degrees. Allow the battery to warm to room temperature before testing or charging.

Be sure each test is completed before removing load clamps to prevent arcing and potential explosion from battery
gasses. Never remove load clamps while testing.

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