If you want clean, fresh oats, you gotta pay the price. If you don't mind that they've been through the horse once, that's cheaper.
Waterproof Digital Volt Meters that can take vibration aren't cheap.
Analog State of Charge meters are less expensive.
Check out the setup at the bottom of page:
http://www.cartsunlimited.net/Digita...ry_Meters.html
There are also the LED Bar Graph types, but they cost about as much as a DVM and there have been a lot of posts about them having strange problems.
If you want accurate information, go with a DVM, but by using a hand held DMM (which you'll be needing if you don't already have one), you can add some lines to the faceplate of a Analog meter for specific voltages.
Here is how the break in those new batteries.
http://www.cartsunlimited.net/Batter...n_Methods.html
While there, read everything with the word "Battery" in the title. Tons of good info.
Whoever told you to run them down before recharging was doing you a disservice. That is opposite of what you want to do, if you want you batteries to last more than a year or two, if that long.
Lead-Acid batteries have no memory, so they don't need to be discharged to any specific point before recharging.
In fact, putting the on charge without discharging them at all doesn't hurt them, if you don't make a habit of it.
Here is a chart showing Average State of Charge Vs theoretical Life Expectancy and a chart showing SoC vs Voltage.
As you see, the closer to full charge you keep your batteries, the longer they last.
Basically, if you use your cart more than 10-15 minutes during the day, recharge the batteries that night.
Never discharge your batteries below 50%.
If you are routinely discharging much below 70%, you might want to look at higher Amp Hour batteries the next time you buy, or other means of getting the run-time to match your usage.