12v to 24v - easy to do?

[Whitelighter]

I recently purchased a brand new hydraulic pump for an autopilot, only to relaise that it was for a 24v system not 12v. being a prat, I also now cant find the receipt/invoice.

Before I go through the rigmerol of trying to swap it or return it, is it possible to take the 12v feed from the boat and make it 24v? Is there some sort of diode that can do this or am I basically just going to have to try and return the pump?

Or, do you think if I sent it to Raymarine it could be converted to 12v? I only ask because these are quite expensive.

 

[robinstall1]

How many amps does it draw?

 

[Whitelighter]

How do I find that out?

All it says on the back is 24v 100w and a load of other numbers that look like product stuff.

 

[robinstall1]

Tell me the make, model Ill see what I can do

 

[gimmesunshine]

you can get a dc dc converter, search in www.farnell.co.uk. gut feel is that for 100watts this is hefty consumption
probably better off blagging a replacment imho

 

[Whitelighter]

Raymarine Type 1 hydraulic drive - model number is M81119 (I think - at least that is what is stamped on it /forums/images/graemlins/smile.gif)

 

[Whitelighter]

Ok, thanks for the advice. Why do you suggest that? Just intereted to know how it works now.

 

[brianrunyard]

100w divide by 24 = 4.16 amps
So at 12v it'll draw 8.32 amps
Better to try and swap for a 12v version.
Otherwise an inverter to convert to AC, transformer to increase the voltage and rectifier to get back to DC, with loses at each stage.

 

[Whitelighter]

I wonder what is different inside the 12v version then? After all, its just a pump /forums/images/graemlins/frown.gif

 

[bendyone]

If its just a pump driven by a motor can you get a 12v motor and swap them over? or have the motor rewound as a 12volt by an motor repair shop.

 

[robinstall1]

ok, I have search till I get on to the foreign stuff and all I can find is that it is 24v using 24watts. Does it have a in line fuse if it does what is the rating?
I ask this becuase 12v-24v converters can be very cheap at low amps (maplins) any mid amp band up to 10amp could cost around £70-£80 and over 10amp you will have trouble getting hold of one (ask all the eberspacher gang) unless you know a man

 

[Whitelighter]

nope, no inline fuse I can see. Just two wires (red and black) coming out of the unit.

 

[mikefleetwood]

If you can't replace motor or swap for 12V version, then DC-DC converter is the way to go.

As has been pointed out, 24V 100W works out at about 4 and a bit A - should not be a problem. 100VA DC-DC converters are not particularly expensive from Maplin/RS/Rapid etc. However, the start-up current for the motor will be much higher than the 100W rating would suggest. If presented with an excessive load, many (most?) DC-DC converters will refuse to start up, so you will have to rate conservatively, probably go for 200VA. If the motopr information gives a suggested fuse rating, this will help decide the power requirement on starting.

Hope this helps.

 

[Whitelighter]

Sounds like I need to understand this before mucking about with it - which I dont

 

[Divemaster1]

Jez....

If this is for your new 34 ... I would swap it for the 12V version ...

 

[Nick_H]

Is the supplier refusing to swap it? So what if you lost the receipt, they can check their records, and they're still getting the sale.

 

[BartW]

this unit: PST-DU700-24
http://www.powerstream.com/dcdc.htm
does what you need, at 154$
another solution is to put a small 12VDC 200W power supply connected to a 230V invertor that you will probably have in the boat for other purposes.

 

[Whitelighter]

That is my thought. If it had been a case of easily swap something then fine, but in the long run its better to have the right kit.

Will speak to Raymarine and see if I can do a deal with them