Voltage reducer, 36 -> 18 volts

[jdunmyer]

I have a GE ElecTrak garden tractor that's about the neatest toy since my RXV, but it has an anomaly that I'd like to correct.

These things use a 1970's vintage GM window lift motor for the power implement lift, running on 18 volts instead of 12. When plowing snow, the lift gets a real workout, and it tends to imbalance the batteries.

I have a set of batteries that I put in my old CC in 2013, so they're in very good shape. Today, I measured the voltages and found 3 at 6.42 and the other 3 at 6.38, with the lower ones being the set that powers the lift. It's been a week or more since I plowed snow, and it's been charged, but I didn't let it sit on charge for a very long time, maybe only a couple or 3 hours. I have an EZ-Go Total Charge charger with a green front and an added golf cart receptacle, so let it cycle through today; it took 2 or 3 hours before it shut off. Charge rate started off at less than 5 amps.

The lift motor draws nearly 15 amps with the plow, and will probably use more with the snow blower. It is very slow on 12 volts, so using my existing 30 amp reducer is out, it really needs the 18 volts.

Any ideas? I don't need real good voltage regulation, but using a simple dropping resistor won't work, as the current draw is much less when the lift is going "down", as in < 10 amps. When I asked on the E.T. forum about battery imbalance, one of the old-timers said that it's more a theoretical problem than a real one. It probably won't be much of a problem with the mower, as it'll not be up and down like the snow plow is.