You would be amazed at what you can glean from a simple google search and reading some of the returned links. Both those which apply to stand alone batteries and ones in EVs like the GEM.
https://www.google.com/search?q=what+does+it+mean+to+load+test+a+12V+battery
Thanks a lot sir, I understood how to perform the load test. As I don’t have the required device to do so, I will take the cart to a battery shop and revert back to you with the result. Kind regards
well, one way to do a battery load test is to do something like loading the batteries and looking at the voltage to see how much it sags. For GEMs that is done by putting a meter on 1 battery and then putting the brake on and give it some throttle then do the same to the next battery until you’ve tested all batteries. Or you can take it to a shop and have all the batteries individually tested with a reistive load tester but you probably already knew all this.
Thank you sir for the information, I have a simple meter ( photo attached which I think I can’t perform the load test with it right?). So I will take it to a shop to test them individually as instructed. I will come back with what the the shop reported. As usual, highly appreciated and best regards
11.42 vdc is a very bad teading for a 12v battery. What are the curcumstances surrounding that reading?
Greetings sir, how are you, hope all well either you. I just want to inform you with important and strange update simultaneously. Just to remind, the issue I was suffering from is not reaching the complete charging cycle but instead a red error at the end of the cycle. Also, when the charging cycle reach green blinking light and after 20 mins, the volt reached (16.5)so I used to unplug the charging when the volt reaches 14.5 ( just 5 mins after reaching the green blinking light to avoid that high volt stage ( this have been the case for almost 2 years ). I was instructed by your good self to check the temperature sensor and the condition of the battery. Right before going to the workshop few months ago to check that, I ran the cart for a charging cycle and forgot to unplug it when it reaches 5 mins after the green blinking stage, but (fortunately) I found the cart ram complete charging cycle with solid green and hello light as before!!! Later on, I ran the cart for 9 complete charging cycle with same solid green and yellow light at the end. That made me happy! The question is : does such accurate complete charging cycle ( solid green/yellow light at the end) means that the voltage of the batteries are charged correctly without any over charge? Or do I need to check anything? Many thanks and have a great day
(filterON)
The question is : does such accurate complete charging cycle ( solid green/yellow light at the end) means that the voltage of the batteries are charged correctly without any over charge?
No- It means that the charger managed to get the pack(as a group) to some state where it was happy and decided it was finished. The charger only sees ONE big number.
Difficult for anyone here to say without actual numbers.
If the charger was set to charge 86V - (fictional numbers only as example)
What this state of your pack ACTUALLY looks like at this point is still unknown.
You have a meter. Note all of the battery voltages.
Check after the charge cycle.
Then let the batteries cool down for an hour with the cart completely shut down(battery switch off) and check the Voltages again.
I would not trust only just the lights.They are not a good indicator of battery condition. They are only meant as a quick glance at charger status before unplugging.
Thanks a lot for the deep professional explanation and guidance.
Per your instructions, I ran the car for a complete charge cycle ( till green/yellow solid light), then unplugged it and switched off the main switch. I waited for an hour for the battery to cool down then I took a reading for the batteries which were as follows:
13.2
13.1
13.1
13.1
13.1
13.1
Tot : 78.7
Appreciate your comments.
Have a great day
These are quite good numbers. It seems your batteries have managed to balance themselves.
Next, monitor one or more of them as you take your car for a ride. do they stay balanced throughout the run?
Try and keep track when the first one reaches ~12.0 v. (without looking up the specs on this battery. This is a guess where the safe 50% level is going to be) Is the range sufficient for your needs as this pack stands?
Hello sir, thank you so much for your reply and I am happy for the good news. Just to make sure I follow your instructions correctly. So, do you want me to drive the car for 5 miles for example then I stop the car and take a riding for 3 different batteries, then I repeat that process for another 2 times?. If yes, I will do that and report back the reading.
Regarding your second paragraph, I am so sorry because I am not a perfect English speaker so I didn’t understand exactly what you are instructing me to do. Do you mean that I need to drive the and monitor when one of the batteries reaches 12.V. ( then I see how many miles I drove ?) and if the rest of the batteries reading is similar to 12.V?. Your point of ( 50% )and your question about ( the range sufficient for your needs as this pack stands), I can’t understand them so pls I would appreciate if you can rephrase them so that I can follow your instructions accurately. Your patience and time is highly appreciated. Kind regards
The general rule when using Lead Acid batteries for maximum lifespan is to not drain them lower than 50%. Since it is difficult to judge this just by feel, I thought it important to identify that condition and judge by miles consumed.
Also when at that state, measure the complete set in order to make sure all batteries are still within range of each other.
Thank again for your clarifications and time. So, I will drive the cart until the batteries reach 12.v and report back the mileage cut. I also understood that you are urging me to try not to drain the batteries lower than 50%. The question here is that does it mean for example to 12.5Miles (Half of the usual distance the car can cut on complete charging cycle), then it would be better to recharge the cart again. Pls confirm. Again many thanks
That is correct. 50% State of charge is considered a depleted battery. Your battery may be considered a bit lower, but use according to your own research.
Sure, it is possible to go lower, but you will most likely be replacing these batteries within the year.
Thanks a lot. I will report back to you with the data required. Warm regards
Hello sir, hope all well at your end. Pls note that I have implemented the given instructions as explained below and the reading is also stated below:
I ran the car for a complete charging cycle ( solid green/yellow light) then I drove it for 12.5M so that I can reach approximately 50% of the draining the batteries. I stoped the r and switched off the master switch for 5 mins. I took the reading 
f the batteries which was as follows:
12.36
12.36
12.37
12.30
12.40
12.27
I highly appreciate your comments / instructions. Kind regards
Very good, thanks for the report.
This looks like about 15M is about the safe range these batteries will be able to support in their present condition. Make sure the charger starts and finishes every day and keep an eye on it.
Good afternoon sir, thank you again for your assistance and time, As usual, to ensure the accurate implementation of the given instructions, you are requesting me to charge the car everyday and make sure that the charger will go for a complete charging cycle ( green/yellow solid light). Right?. Many thanks and warm regards
