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24V or 12V/24V PDM

PDM Installation & Configuration

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Is anyone aware of a 12V/24V PDM? I have a late 80s Toyota Diesel Land Cruiser from Europe and all the onboard electronics are 24V. I am swapping the engine and will end up with a mix of 12V and 24V loads throughout the build hence doing a full rewire and would love to know if there is a PDM that can work with 24V or even better yet, both voltages. I'm comfortable with doing it all analog and through various converters and relays, but it seems like something solid state could be ideal to solve a lot of the issues especially on the motor side.

Seems like a lot of the PDMs I have found are limited at 20V and would love to know if there are other options I'm not seeing. It seems maybe the Motec PDMs can get into that range for the inputs, but I can't find any confirmation that the actual battery input can be 24V though I see reference to the outputs being a function of the input terminal so I suspect I could at least get a full 24V PDM setup.

The MoTeC PDM's are rated to 30V.

With a PDM, they are only distributing the power that they are supplied, so if they are on a 24V system, that is the power that will be available from the outlet pins. If you have a vehicle with 12V and 24V systems, you would need a PDM on each circuit.

Three other options are

Centre tapping between the two batteries, so you have a 12V-ground as required. One potential issue is the uneven draw on the batteries may cause the unloaded one to run a little higher charge voltage. this may be balanced if you can run independent circuits off the second battery, like 12V audio?

If you're doing a full re-wire to go with the repower, you may find converting to a pure 12V system is a viable option - 24V seems to be quite uncommon in the USoA, so you may find 12V components as a direct replacement - maybe even sell the 24V for more than you pay for the 12V, due to rarity?

A third would be a simple 24>12V inverter - the best ones will actually condition the output so can be cleaner than running directly off an alternator.

For example - https://waveinverter.co.nz/shop/accessories/dc-converters/24v-to-12v-dc45a-transformer/

The quality and rating will vary a lot, as will the price, and you may find boating and truck forums better able to comment of the good and bad ones. Oh, watch out for ones that don't give a continuous current rating and, even for those that do, I'd over-spec by 50+% to allow for thermal and other issues.

Thanks for the responses! I was looking at the Motec which makes it realy clear about the inputs being able to be up to 50V but the battery + documentation is a bit lacking but certainly implies that it would work. Though it isn't clear that the motor and higher amp outputs all work at ~30V. If they all function for 24V it may be worth going with Motec.

I will have more 24V than 12V so I think it might not make sense to swap everything out but it is certainly a potential option. I can probably run a few easy 12V circuits off of a battery equalizer that helps eliminate the battery drain from the center tap.

https://redarcelectronics.com/products/40a-charge-equalizer

Alternatively, I have thought about a 24V-> 12V battery charger circuit with a small 12V battery.

https://redarcelectronics.com/products/20a-in-vehicle-dc-battery-charger-ignition-control

Nothing is cheap though for sure. I certainly don't need for 12V PDM but had some wishful thinking that I could kill 2 birds with one stone.

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