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Residential situation with mounted 2-ton hydraulic 12 V crane. Have 120/240 available, need to create 12 V 300 A available power for intermittent use, boat launch. Average power used 150 A 12 V DC, with peak at 300 A very occasionally. Loads measured at under 1000 lb.

Dave Tweed
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Brad R
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    And how far have you come in your design? Show us. – MiNiMe Nov 04 '23 at 18:26
  • Can't you use 48V or 36V or at least 24V crane motor? 150-300A is really a lot and would require a very big transformer and very very thick wires else, these wires would melt away in short notice, with risk of fire. – Fredled Nov 04 '23 at 22:50

1 Answers1

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Well, you'd need a power supply capable of delivering that. 3.6kW at 12V is a pretty hefty one though, that might be hard to find and probably expensive.

If it's for intermittent use only, I'd seriously consider a car or truck battery + trickle charger. Likely much cheaper, and will still work even if the crane needs higher current spikes, e.g. on start/stop.

Some back of the envelope math; the average car battery is like 50Ah. At 150A, the battery would last 50/150 = 1/3 hour = 20 minutes, probably a little less. If that's not enough, a truck battery or multiple car batteries may be required.

As for charging, 10A battery chargers are ubiquitous. They'd require 150/10 = 15x the usage time for charging, so an hour of charging gets you 4 minutes of operation. If that's not enough, heavier (say, 20 or 30A) chargers are also readily available.

marcelm
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    This is likely the right answer. Perhaps a couple of identical car (or truck) batteries wired in parallel. And a trickle charger. Or maybe traction batteries from some electric utility vehicle. But if it's to lift a boat or pull up some kinda doc or pier or something, having the 12 volt batteries there around the water *without* the more dangerous 120/240 volts might also be good. The batteries are moved back to a building with power for charging and then brought out to the boat launch for safe use. – robert bristow-johnson Nov 04 '23 at 18:35
  • Only worry is if you need to use the crane to lift something heavy off somebody (that you perhaps have just dropped) it could be rather awkward to need to wait for the batteries to recharge. – D Duck Nov 04 '23 at 20:30