galvanic isolator

jimbo · Guru

galvanic isolator

jimbo · Guru

C'Mon Guys and gals I see 8 lookers...I need to know ASAP Or else I'll have a flat Battery again tomorrow..Long weekend has buggered me till Tuesday

the crow25 · Veteran Member

Hi.If you have access to Google just print in galvanic isolator.You will have all the info you will ever want.Good luck mate.The Crow.
biggrin

brickies · Guru

I have look up Wikipedia I suggest you try that very good explanation

jimbo · Guru

Yes I already did that.....It didn't explain enough to me.......Maybe I'm stupid But I couldn't make heads or tails out of it really.....It's explained as if one should know almost already.......Are they necessary I asked No reply........Thanks anyway for your help.......I'd like to know if any one has one .....

jimricho · Guru

welcome wrote:

C'Mon Guys and gals I see 8 lookers...I need to know ASAP Or else I'll have a flat Battery again tomorrow..Long weekend has buggered me till Tuesday

Sorry, out of my league here....I thought they were mainly used in marine applications to isolate the earth curcuit when connected to shore power, what they have to do with, or why one would be installed in a caravan/RV I have no idea.

If it's flattening the battery disconnect it....is it that or the inverter that's the culprit or are you talking about one and the same thing....you don't give much detail so that may be why no one else is responding, I have very poor mindreading skills too wink

A properly designed inverter should provide galvanic isolation between the 12v input and the 240v output anyway, maybe that's what you're referring to?

Why is your inverter connected to your starting battery and not your house battery?? that's a recipe for problems.

Is this a separate thingy that's installed to extend the battery life (allegedly), it will achieve the opposite if it's flattening the battery.

Sorry to be of little help but a bit more information about just what it is, how it's wired in, and what it's meant to do would help.

jimbo · Guru

Thanks Jimricho....No my Inverter is a separate item It runs the Reversing camera and CB..That's how I bought the lemon.And I make sure it's off before I close shop....This Isolator is I know a Marine thingy..I am leaving it on tonight process of elimination I am home so I can easily charge the battery again tomorrow..Once again thanks......I'll have it checked out at the Auto Electricians on Tuesday

PeterD · Guru

Jimbo

It may assist us if you provided some info like make and model and how it is connected into circuit and in which circuit it is located. I'm at a bit of a loss as to where and why someone would install a galvanic isolator in a motorhome.

BobnBev · Senior Member

Hi All, Looks like a one to one transformer, they have fitted two diods back to back to bring the earth up by 1.2 volts THEORY OF OPERATION
Boats with metal in contact with water are subject to
galvanic corrosion when connected to shore power as a
result of connection to the common AC grounding conductor.
This connection will affect the vessels cathodic protection
system resulting in abnormal deterioration of the zincs and it
can result in damaging corrosion of the underwater
equipment.
It is necessary for safety reasons to have the hull and
exposed metal fixtures connected to ground to prevent
electrical shock in the event of a failure in the AC wiring or an
appliance. Without that ground connection, the boat could
become alive at the line voltage which could injure or kill
when stepping onto the boat, or swimming in close proximity.
If an electrical fault doesnt trip the breaker, the ground
connection has to be able to withstand rated current
indefinitely to conduct the fault current and prevent
dangerous voltages. The Yandina Galvanic Isolator is rated
for 50 amps AC continuous current and is individually tested
to 135% of this rating.
Naturally occurring electrolysis voltages are typically less
than 1.5 volts. The galvanic isolator provides a very high
resistance to these voltages to isolate them from the boat.
Once the 1.5 volt threshold is exceeded the connection is
established to conduct current and protect from shock.
I lifted this from googel..See one can learn some thing new each day... I still can not under stand why some one would fit one to a van, unless it was going to go to sea....smile
Bob n Bev

jimricho · Guru

Hi Welcome,

As alluded to above, I doubt the galvanic isolator is doing anything other than potentially causing problems so I would suggest the best option is to take it out put it with your collection of useless thingies (I have half a shed full of useless "come-in-sucker" stuff!). If it's (allegedly) there as a safety device, the (mandatory) earth leakage circuit breaker on the 240v input will take care of that. Note that 240v wiring must be done by a licensed contractor.

Why is an inverter necessary to run a reversing camera and CB? These should be 12v powered and connected directly to 12v system. The reversing camera should be connected in such a way that turning off the ignition also turns off the camera, as should the CB unless it is connected to the house battery. (my CB is wired to the car's "house" battery)

Allowing any battery to run dead flat (including deep cycle batteries) will seriously shorten the life span of the battery. (ok pedants, I know some "high end" AGMs and Gels have better tolerance to this). Maybe this is the cause of your problems?

It seems from here that the wiring of your set-up is a box of mysteries. Maybe it was wired by someone who is less than "au fait" with RV and caravan electrics?

Hope you can soon sort it out,

Jim

PS: Thanks B&B, I've learnt something new too from your post. I was composing this epistle when you put yours up. Further confirms my view that it's serving no purpose in this instance.

You're also right about learning something new each day, although the day will arrive when there is nothing new for me to learn, it will be a couple of days before I take up residance in the garden at Beresfield Crematorium.

-- Edited by jimricho on Monday 14th of June 2010 08:35:54 AM

jimbo · Guru

Peter..Bobabev Thank you......I am going to have it removed tomorrow..I too do not know why it is there as I can see no useful purpose.......Either......I have tried to ask the former owners But they have gone into hiding......Thanks once again........This is one hell of a great site peoples........If there are others like this....Then we are very lucky......I get more info than I do from Google and How things work......Sites

jimricho · Guru

If I'd realised that you had bought the rig already wired this way I'd used somewhat stronger language on what I thought of the person who wired it. No doubt you're doing that for me!

jimbo · Guru

Jimricho.....To get a Vic Roadworthy I had to have,also a qualified electrician who re wired the whole unite......My fluorescent lighting system (Three of 1 metre long was replaced by three two foot ones lighting for when I use 240 volts in parks.....Also he repaired and changed a heap of wiring says was to dangerous...Hence the reason it's cost a small fortune.....I have just come in from trying to start the unite and the battery was again too low to kick over......I have put my Charger on and it will be okay in and hour or so........Can't afford to go through all this off road.......And I'm not carrying two batteries around all day.......Can't Waite for tomorrow....Once again Thanks People's

jimbo · Guru

I have tried to get a few snaps of this Isolator...I'll have to do some fancy angle shots with mirrows...here's one of the front

jimricho · Guru

You've got every right to be seriously p1ssed off, I sure would be.

If you haven't already done so it would be a good idea to check that the house battery and the starting battery is properly installed using a dual battery system, also that "house" loads are connected to the house battery and not the starting battery. (except 3 way fridge..see below)

In my rig all the "house" lights are 12volt fluoros plus some halogen downlights, no 240v lights. When on 240v power the lights are still on 12v and a "smart" charger (Xantrex 10amp) keeps the battery topped up. If starting again I would consider LED lighting as these are very efficient. The only 240v in the ceiling is for a power point for the TV.

If you have a 3way fridge, the 12v element should be connected to the starting battery, not the house battery, but in a manner that it is only powered when the engine is running. Use the gas or 240v on other occasions.

cheers,

Jim

jimbo · Guru

Jimricho Here is another snap of the Isolator.....I followed two leads one to the rear battery and the other to the cut off switch which closes down all power......I reckon my problems have been because I have left it on of a night......Hence the flat battery...Make sense?

jimricho · Guru

Hi Jimbo,

The whole set-up doesn't seem to make sense at all. It's difficult to really tell what's going on without actually seeing and tracing out the wiring but I wonder whether the galvanic isolator has been mistakenly installed instead of a voltage sensitive relay (VSR).

The VSR goes under a few other names, including "smart relay", "smart solonoid", "voltage control relay" and "dual battery isolator" so I wonder if the previous owner was told he'd need to install "an isolator" and has installed a galvanic isolator instead of a dual battery isolator. (two very different animals)

If the system is installed correctly you should never have to worry about your "house" loads discharging your vehicle (starting) battery. This is the main reason for having a separate battery for the "house".

The VSR enables the house battery to be charged from the vehicle's alternator when the engine is running. It gives priority to the vehicle battery and detects when the vehicle battery has recharged following a start-up, then it connects the house battery to the vehicle's electrical system to recharge it. When the engine is switched off the VSR disconnects the house battery from the vehicle's system. All this is automatic and you don't have to worry about switching anything manually.

More information on VSRs or Voltage Control Relays can be found at http://www.bainbridgetechnologies.com/dual-battery-isolators/baintech-voltage-control-relay-12v-24v-100a

I hope we're on the right track with this as it's difficult to tell without seeing the system.

best wishes,

Jim

PS: 4WD shops are installing dual battery systems on a regular basis so one of these may be able to help out especially if they can refer you to an auto electrician that's familiar with these.

-- Edited by jimricho on Monday 14th of June 2010 06:30:38 PM

jimbo · Guru

The van is firing up at the moment..had it running for a few minutes.....Hopfully tomorrow after I have turned off all possible shorting...Tonight EAT 6.30pm It will be fineTO be continued

Sandym54 · Veteran Member

Don't know if this is the same thing or not:

When we first bought our Toyota Coaster the 2 house batteries kept going flat on us, fridge was defrosting all the time (not on 240v) and Trevor had to keep putting the batteries on the charger, but they weren't coming up too much.

We thought we were up for about $600 for 2 new batteries and so we went to see an auto electrician while we were in Eden and for $45 he found our problem, what an angel!!!!

We have an "isolator" switch on our dashboard that we had not been told about, whilst driving we have it "ON" and it charges the house batteries from the motor etc and when we have pulled up for the day we switch it "OFF", and guess what??

No more FLAT house batteries disbelief

Sandy

jimbo · Guru

Gee thanks for that..I'llmention that to the Auto bloke today....

jimbo · Guru

It seems that my Battery is almost had it.......I am going to get the RACV to install another one tomorrow.....Thanks for the help People's....Next Wednesday My wife Shirley and two dogs are going to Echuca for a couple days...In a Pet friendly 2 nights...Then roughing it on the river to really test things.......