We have had pretty much all of the problems that everyone has had on here with our Ultra. The spraying was very weak, batter issues with it not staying charged and so on. What we decided to do is put a whole new wire harness in with the voltage regulator. I didn't want to hot wire because I think its important not to have the spray volume be effected by the RPM's. Also we upgraded out battery to a battery that is used for the emergency braking system on trailers. It is a perfect fit and everything works great! It actually starts right up with the auto start and pumps. We haven't used it in the field yet because we have a dusting of snow on the ground right now, but we will be out there next week. We are actually waiting on a Z-max to arrive so we can really get moving.