DC-DC Converter

[CaptainJacks]

Hello can anyone shed any light on how I would test to see if a converter is galvanically isolated, so the input negative has no contact with the output negative?

Cheers.

[Kae]

Multimeter set to check continuity

[Keeping Up]

Or, if you don't have a multimeter, a light bulb from input positive to output negative (if it's isolated the bulb won't light)

[RLWP]

Or, if you don't have a multimeter, a light bulb from input positive to output negative (if it's isolated the bulb won't light)

Low voltage dc light bulb and battery, please

 

Richard

[Keeping Up]

Low voltage dc light bulb and battery, please

 

Richard

 

Agreed low voltage bulb (12v if the unit has a 12v input)

 

What's a dc light bulb?

 

I was assuming that the input is already connected to the boat's battery so only the light bulb would need to be connected.

[CaptainJacks]

Thanks.

I have a multimeter but at what points would I test its a closed unit with a male connector that plugs into a cigar type socket?

How would I resolve the problem if the test fails?

[smileypete]

Why do you want isolated?

 

Any link to what you have?

 

cheers, Pete.

~smpt~

[MyLady]

Thanks.

I have a multimeter but at what points would I test its a closed unit with a male connector that plugs into a cigar type socket?

How would I resolve the problem if the test fails?

 

1. Plug in the converter

2. Test from either side of the output plug, with your multi-meter set to 12V+ (e.g. to 20V) to another part of your boat electrics.

3. If that shows 0V, retest with the meter set to 'continuity'. If that shows no continuity, there is isolation.

 

Having said that, may I ask why you care? I have at least 3 converters (2 phones and a laptop - and soon to to have a dc-dc converter for an Aldi 15V rechargeable vac - why I'm reading this thread) and in every case, the item has a plastic casing, so it won't hurt if it touched the boat hull. I don't care if the neg., or even the pos. is shared with the boat supply's. If a short like that is your worry, just make sure the output from the converter is plugged in, so not available to short, before you plug the converter into the boat supply.

 

'Galvanic isolators' tackle a completely different problem - galvanic hull corrosion when you share a mains supply with other boats in, for instance, a marina.

 

Roger

Edited September 17, 2014 by MyLady