2017 Yamaha Drive 2 Loss of Power

[GSFR39]

New to the group and new to the golf cart world. I have an 48 volt Yamaha Drive 2 that I recently purchased. We were in a Christmas parade in our community the other night and after about an hour of riding around we started to slow down. We eventually made it home but at a very slow speed. Prior to the parade my batteries had a full charge and the water levels were fine. The next morning I went out to look into my issue and found the cart to be operating normally with out having put it on the charger. This is the second time this has happened to us. Looking for ideas on what to look for. I did put a meter on the batteries. Each one read 7.9 volts and total they read 51 volts. (after driving for about 2 hours and not recharging it). I do not have a battery indicator so I do not know what the volts were reading when I had this problem. I find it hard to believe that the batteries recharged by themselves over night. Thank you in advance to anyone who helps me out with this.

[cgtech]

7.9 x 6 = 47.4, not 51.

And "recharge by themselves" is exactly what they did. After the load was removed, the batteries recovered enough to allow the cart to act normal again for a minute. If you drove it around, it would quickly die again. You have discovered how much range your batteries offer.

[GSFR39]

Thank you for your input. So do different batteries have different ranges? We were told we should get 15 to 20 miles out of the batteries. I would be surprised if we went 5 miles.

[cgtech]

There are many variables involved in what range each cart will get, like stock or upgrade controller? Stock motor? Stock gear ratio? Tire size? How many passengers? Terrain used on? What brand and model battery? Battery age?

[GSFR39]

So this evening I tried charging the cart. It was on the charger for roughly 5 hours. With a meter the batteries read 53.1 volts after I disconnected the charger. However the charger never read that they were fully charged. I have a Yamaha charger and Crown batteries (CR-150). On the charger there is a label that states the charger should only be used with Trojan batteries. Could this be an issue. I have worked in the 12 volt automotive industry for many years and I can not understand why a simple battery charger would work for one brand and not another. Could someone please explain or provide some guidance. Thanks

[cgtech]

Different brand golf cart batteries have slightly different finish voltages needs, due to different electrolyte chemistry. The trojan mode is about the "softest", with the lowest finish voltage, so at least It wont overcharge your batteries. I would let the charger run till it completes, which could take over 12 hours, as long as 16 hours.