The break and battery lights turn on when at about 1000rpm or lower, but not 100% of the time. I replaced to alternator a day ago because the old one wasn't working. I made sure everything was plugged in right, I've checked fuses, ground wires, itook the battery back to Walmart and they said they charged it to like 15 volts, but idk what that means. I'm at a loss and idk what to do, now it's almost stalled twice while at idle. Idk what to do, does anyone have any advice?