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Is My Golf Cart Battery Charger Over Charging My Batteries?

Yamaha Golf Cart Battery Charger 48 volt Lester 48V 13A

This question was asked by a customer of our the other day and Pete wanted to share this information with you as well because it is a question Pete has found himself explaining over and over again over the years.

Question: From Rick in Florida – Over Charging Batteries?

​”​I have a new links charger and it seems to be over charging the batteries. The batteries were bubbling and the charger was still running. Charging at about 5 amps. 2 hours after I disconnected the charger batteries read 12.94 V Batteries are new Trojan 1275  Any suggestions?”

Answer :

A Transformer style charger

The Lester Electric Golf Cart Battery Charger you purchased is a transformer style charger that is designed to apply amperage and voltage for a length of time that replaces the energy used from last discharge. This is fairly old technology but very effective to charge your golf cart batteries. Depending on the battery chargers output (Amperage), the batteries size (Capacity), and DOD(depth of discharge), all this will determine the amount of time required to fully charge the battery bank in question. In the process as they reach maximum capacity the more electricity that is forced into the batteries the more it excites the electrolyte and gets electrons moving in the battery itself…(That is the boiling sound you hear)

The gurgling sound is common – and okay!

This is common… especially with NEW batteries…. this process actually needs to happen to positively charge and electrify the lead plates and cure the new lead…. any new battery pulled off the line at the manufacture will only test out at about 80% advertised Ah rating because the lead hasn’t been cured (still too soft). Something that is really impossible for the manufacturer to do in house because of the process involved.

It takes 15-20 charging cycles to “cure” the lead plates

It takes on average 15-20 cycles at 50% DOD “Depth of Discharge”, to completely cure the new lead plates in a new lead acid battery and allow the battery to reach full capacity (That will be the advertised Ah rating at the 20hr rate.)

So no worries as the charger is just doing its thing… Trojan batteries actually like to get hit harder ( More Amperage applied) than others thru the bulk phase and finishing phase of a charge cycle because the lead plates are thicker than most competitors.

Add more water during this phase

You will most likely add more water than ever over the period of time we will call breaking in phase. This is from the charger forcing electrons into the lead, once the lead is cured electrons cannot pass thru as easily.

The boiling sound will become quieter

At this point the batteries will not be as excited (loud boiling sounds) when charging/complete charge.

There will (and should) always be a bubbling noise

Make no mistake lead acid batteries will always make noise in the charge process and finishing phase because of the specific chemistry and design that make a lead acid battery. It is also an important part to insure good battery health as well. Without this boiling the lead plates sulfate rapidly and severely hinder battery life per charge and cycle life.

This process helps the battery to charge and function

This process actually helps to clean the lead plates and keep them clean to better react to the electrolyte in the cells to create electricity. AGM and Gel style batteries are even more picky than traditional lead acid batteries because they like more voltage and amperage to complete the same process.

Hopefully this was helpful and insightful to ease your worries about your golf cart batteries and the golf cart battery charger. For more information you can also read our “how to test golf cart batteries” post.

Power On…


Rick – response

Thanks for your response. So I understand the bubbling and sulfur smell are normal and I should not disconnect the charger. What should the Voltage be when fully charged? Should I charge even when reading about 12.5 volts after 9 holes? – Great service, by the way.

Pete – response

No worries … I have seen 48v systems run as high as 58-60v when charging, but it is normal to see voltages around 50v-52v when sitting static for several days after a fresh charge cycle. Most common size lead acid batteries will be from .6 volts to .8 volts over advertised voltage on battery when fully charged. Always good to re-charge cart at the end of the day, never let it sit 1/2 -3/4 charged. re-charge then store when not in use.


Pete please help…. Batteries Expelled Acid on Charge

Hi i charged my cart with my new charger. Thanks for the fast shipping but the batteries folded expelled acid do i have to change the settings on the charger my batteries are Trojan t-875, 8 volt, 170 ah @ 20hr, 145ah @ 5hr

Pete – response

No Worries – You should be fine with the factory setting…These golf cart chargers come pre set for lead acid batteries and your Trojan batteries are well within the settings range. It sounds like the batteries were over filled. Always check the level of the electrolyte after batteries are fully charged and only fill each cell about 1/4 – 3/8 inch above the batteries plates… which leaves about equal distance to the bottom of the cell cap tube.

Pete’s Team

13 thoughts on “Is My Golf Cart Battery Charger Over Charging My Batteries?

  1. I have Trojan batteries 2 years old. I’m concerned about overcharging my club car batteries and would like to leave the automatic charger connected for 5 or 6 months while storing. Is this OK?

    1. Granted you have the right charger you can do this. What year is your Club Car? Are you talking about using the original Club Car PowerDrive model charger? If so, it will not work because it will not turn itself back on – you would need something like the new DPI Gen IV charger that actually has a built in Micro-processor that runs on the power of the golf cart batteries and keeps track of time. It turns itself back on every 28 days to top off the batteries then when charge is complete it shuts back off again to repeat cycle. Feel free to give us a jingle should you have any further questions about ordering the correct charger for your cart. It will be determined by the fact your Club Car either has an OBC or it does not.


  2. Pete…I have a 2010 Club Car Precedent with a Club Car Power Drive 3 charger. My concern is that the charger is still charging at 5 Ampres after several hours and the gage on the cart is pegged all the way to the right past the white and red zones. Is this normal or am I overcharging my bateries. Please note the batteries are fairly new…a month old. Thanks, Walt

    1. Walt – Thank you for your question. I can understand your concern. Though rest assured if all is working properly in the charger and charge circuit it is completely normal and the charger is just doing what it is told. All powerDrive model chargers where used with the Club Car Golf cart from 1995 thru 2014. They worked with a Lester component installed in all Club Car golf carts over those model years AKA “The OBC or Onboard Computer.”

      Basically the charger is looking for voltage. Total voltage achieved. Whereas the battery indicator gauge on your dash console is a 48v meter – so it shows full at 48 volts… When charging those batteries will get into the mid 50v range. and after the charge cycle is complete settle in around 51.7v – 52.3v … Also note the charger has tapered off the charge cycle as it has reached 80% charge and the finishing phase will take just as long to complete as most bulk phase charge cycles as the amperage applied has been reduce 60-70%….

      Furthermore – New batteries are always very hungry for energy. At least lead acid batteries. Usually take approx. 20-25 charge cycles at 50% D.O.D. “Depth of Discharge” to completely cure the lead and energize the plates completely.

      Want more control and want to see what the charger is doing exactly? I would recommend the New Lester Summit II chargers. See Link below – These things are incredible and with Bluetooth connectivity you can check and change or adjust almost any feature you want. Programmable as well for specific battery types.

  3. i just put new Trojan batteries in my Club Car golf cart and the battery charger got so hot you could not put your hand on it and it did not turn off after charging all night. I tried it again and it still got very hot so i turned it off. What could be wrong. Is there a part on the cart that shuts the charger down after they are fully charged. Because it got so hot could this have damaged the charger?

    1. I think all is normal…. even new batteries require power to fully charge – also new lead acid batteries will be very power hungry for about 15-20 cycles to energize the plates…. All old school chargers even new solid state chargers will get hot – the longer they work the hotter they will get. When ever converting AC power to DC power resistance is generated and heat is created. Check the voltage on the battery bank without the charger on and then do so again with the charger on… 36v systems will get as high as the mid 40s and 48v carts will get into the high 50s when charging….

      Though to answer your question all newer Club Car carts from 1995 until 2014 came with onboard computers that told the charger what to do… if newer than 2015 the charger should be smart enough to do it all. If you are looking for a new smart charger for your golf cart check out the new line of Lester Golf Cart Chargers

      Pete’s team

  4. When i check the voltage on my 48v system in registers 60V , should i be concerned. Also there is water on the top of the batteries.

    1. Dean – Thank you for your inquiry… Sounds like the batteries have been over filled… Always check and fill batteries after they have been fully charged! fill batteries to approx 1/8-3/16″ below cell inlet ( or say 1/2 tops above lead plates….

      Next this 60v you are reading with your digital volt meter… I am gonna assume this is while the cart is charging? or after batteries are charged and rested? Are they Lead Acid or lithium?

      Pete’s team

      1. Why does my cart or battery make a beeping sound sometimes when it’s charging?Is it the cart or charger?

  5. Your website answers are so helpful and very simple explanation of battery charging.
    I have a 2014 Yamaha Drive 48v with new powertron batteries which are I believe Trojan brand. I use the cart in the neighborhood average 5 miles every other day or less. I was told to charge after every use. But I find my batteries water level dropping excessively. I added 5 gallons of distilled water after 2 1/2 months of occasionally use. It was garage kept in Florida from end of Aug to end of Oct. I never thought I would loose that much water. My neighbors check theirs every other month and maybe top it off and use less then a gallon of distilled water. After 2 weeks I checked the levels and added a gallon and a 1/4 of water to the batteries. I was told then not to charge it after every use but to charge it apprx after 10 miles of use. I have a Pro-Fit automatic charger PF11539 I hear it bubbling and gurgling and also smell sulphur and after the night and in the morning 8-10 hrs later the green light is steady indicating a full charge it still is bubbling and I have water on top of the batteries. I read that new batteries DO THIS Do I need to worry and when do you charge after every use even for a few miles or what is the rule?

    1. Thank you for your inquiry… the electrolyte level in a lead acid battery will diminish the more that is is charged and discharged… your neighbors obviously do not use the cart as much as you do…. Always charge the batteries after use…. store fully charged….. always check and fill batteries with water after a full charge…. filling then charging will puch electrolyte out of the battery cells….

      Sounds like the charger might be over charging the batteries…. I Recommend a smart charger that we can program specific for your batteries…. allowing for a closer to perfect charge everytime… not just applying voltage and amperage…. Checkout the new line from Lester… Awesome units… come with 4 year warranty as well.

      Pete’s team

  6. batteries are swollen from charging what can I do

    1. Rich – when a lead acid battery starts to show signs of swelling it is usually do to age or over charging. Both cases if performance is lagging we would replace.

      Pete’s team

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