Back on topic, maybe? I've always tried to use a charger with enough voltage settings to allow a slow charge in the 10-15 amp range, and a quick charge capability of 40 amps or a little more. The state of charge of the battery is entirely responsible for how much voltage is needed to achieve a particular charge rate. A very low battery will take a 30-40 amp charge at around 13 volts or a little more, while 14.5 volts or more will be needed to push 10 amps into a fully-charged battery. The more voltage settings the better, but I like chargers with at least 5 or 6 charge rate options. A "Starting Boost" rate of 100 amps is also a good thing to have available, but don't use it for battery charging.
Jerry
