Good battery, bad battery
This is a short video I recorded to show the two Optima Bluetop batteries I bought for the bus. The minute they were delivered I had problems with them. After installing them in the bus, I couldn't get the bus to start. After a lot of frustration and tinkering I finally went out and bought a digital multimeter and figured out that the problem wasn't the electrical system of the bus (thankfully), but rather one of the two batteries won't charge above nine volts (it should be 12). I'm guessing that having these two batteries hooked up in parallel was draining the good battery enough to not be able to start the engine.