A Question - Battery isolators

Warren-Pat_01 · Guru

A Question - Battery isolators

macka17 · Guru

Yea.
You tell me and we'll both know hey.

I'm not a sparky. Just a bloke that's done a bit over the yrs.
With HIS toys.
My Van has a 12\240 v rocker sw as you go in the door?
Coromal..

All plugs are 240. (apart from a coupla 12v I've put in)
ALL lights are 12v.

My solar system is wired in and coupled direct to battery.
Anderson goes into van to battery, from battery's in tray..
With a switched bypass to van fridge if needed.
IE, No sun for panels.
AC smart charger in van boot goes to battery.
And Genny goes to all.

Not the neatest. but the way it ended up and covers most situations.

The only Batt 1. Batt 2 OFF and combined I've ever used are on my boats.

If I lay up.
The only "isolation" I'd ever do is Negative cable OFF poles.

Off through a switch.
You "can get leakback\drain. over a period of time.
Cost me 2 110a AGM's on my last van cause of that.
14 yrs van not a prob.
2 yrs layup without looking. 340w of panels and good reg.
One batt developed a fault. drained both.

You laying up.
Fully charge. then disconnect Neg's Off ALL battery's..
You KNOW then.

If you going the straight on\off sw. not dual.
I'd look at the "bussman" type isolator there.

You can get both from Jaycar. at similar pricing and local.
I have a dual Breaker from Jaycar for batt's,
One to\from each batt, in Tray.

These ARE breakers.
Switches aren't.

Now the Techies can adjust me hey.

iana · Guru

"Do modern day caravans have a 12v DC isolation switch?" I would say no unless you have specified it in the build. By 12v DC isolation switch I take it you mean to isolate the batteries from all the electrics. You're talking about a truck type master switch, or the same type of switches found in boats, 40-70 Amp.

There is a "DC" switch inside the vans - from what I can see, this switch only couples the SETEC battery power supply/charger to the battery. This switch activates a relay in the SETEC unit, and isolates the house batteries from any load running through the SETEC unit, and via the fuses in the SETEC unit. Any power coming direct off the battery is not effected.

Solar on my van is direct to the battery, battery charging 240volts is through the SETEC charger. I think a trickle charge is maintained even if the battery is switched off.

So yes you would need two isolating switches, i.e. 1 the switch installed that isolates the SETEC charger, and another to isolate the solar, but why? The battery will loose charge, even if it is not connected to anything, solar would just keep it topped up.

Warren-Pat_01 · Guru

Thanks macca, Ian,
It was just something that passed my mind regarding safety. Especially while on the road & in case a an accident. Your van is the same as mine with the "DC" switch.
last week I rebuilt the pantry from the poorly supported slide-out wire shelf affair to shelves so we can carry almost double the amount of food there now. I installed a LED light strip & although I removed the soldering iron from the power socket, I still managed to "test" a fuse in the SETEC panel!

I'm very much aware of self discharge in batteries as well as short/open ccts in them. When I worked on the E-W microwave system (Pt Pirie to Eucla) we had 2v cells that had 40mm stand offs to prevent the broken off lead from shorting the plates. Someone in their wisdom at one stage ordered float batteries to save costs. They lasted around 2 years, not the usual 5 for charge/discharge cells!

macca, I'm a supporter of Jaycar Townsville & joined their rewards club. I generally go elsewhere when I can't get anything local. My solar goes straight to the battery via the regulator.
Might do some more thinking about it for a while before I do something about it. I hear we might be going out to Bladensburg NP soon bird watching so that's another interruption. And some say you've got lots of time to spare when you retire!

macka17 · Guru

Warren.

20 ish yrs ago.

GPS tracking stations.
US had a couple located in Aust. for their GPS systems one in SA.

They replaced under contract. the battery banks.

Local company labour. US supplied Battery's 12v
Around 60 of them.(2 x pallets)
Weighed a ton each.

4 were faulty, They replaced the whole bank.
And contractor got them.
I bought 12 at $50 each. (All checked first.)
resold 10 at $60.

Everybody happy.
I got mine for cost of fuel to depot to collect.

They were in my yacht for 11\12 yrs.
and still working when I replaced them..
General Maint. 1 was losing capacity.

And it took 2 blokes my size to put them in,
and out of the cabin.

Starter batt, was separate again.
Those 2 took place of 4 x House Battery's.

I tried to replace with same. (went on net.)
Nope. US Gov't spec's. Not avail to public.??.

Shame. they were WAAAAY better than any
you can buy on open market.

Those 2v tall cells. were the ones we used on solar and generator banks out bush, yrs ago. Blue.

Linked to give 24\48v systems.

Same ones? Can't remember the name.

-- Edited by macka17 on Thursday 20th of April 2017 12:16:28 PM

swamp · Senior Member

hi
Machinery has used ON / OFF isolaters for years .
In a van application for emergency or if the c/van is in storage
I install then in the neg cable
Prevents all small amp loads [ clock , radio et etc ] from leaching power and killing battery over a long period
Blue seas ,Narva , Hella About 30--45 $

Run solar straight to batteries

Tony Bev · Guru

The picture tells the story

My second hand vehicle had a 100 Amp Hour deep cycle GEL battery, of unknown age and quality

I fitted a 55 Amp Hour, Spiral Bound, crank/deep cycle/starting AGM battery as backup

The two batteries had to be kept apart, when being used or charged

I fitted the battery switches as per the picture, the fuses are just common house fuses, of 20 amp

I then fitted a DC/DC charger obtaining its input from solar and engine battery

I now have 2 x 120 AH AGM batteries, and have no need for the switches, but have left them in place, as somewhere down the track, I may want to fit a lithium battery

Like some other Jayco vehicles, there is a very small switch, which isolates the batteries from the SETIC system

Fuses at battery - Copy.JPG

Warren-Pat_01 · Guru

Thanks Tony,
One reason for wanting to put in an isolator was to prevent any lights from being left on. I added a strip LED to the newly refurbished pantry - found if left on for hours, the silicon between the LEDs gets soft. Plus, I've discovered the TV is constantly on standby!

I like your fuses - thought they looked familiar!

Macca, my memory has gone too - cannot remember the brands of those cells. The ones in question had clear cases & they were bloody heavy (140lbs rings a bell). And the only lifting apparatus was two blokes! They were 2v 500A (the system from Port Pirie to almost Perth was 24v, modern xges are 48v).
It's a wonder you didn't get hold of some of those NIFE cells that we had as starter batteries for the standby diesels. They had metal cases. All they needed was some maintenance & they lasted for donkeys' ages BUT the modern (even 15 years ago) Telstra does not like to pay for maintenance! They were all disposed of & 6v batteries were installed (24v system).

macka17 · Guru

Warren.

Yep that's them. Solid lead methink's\Felt like
We set them up as 48v for homestead to run everything.
Diesel Genny was 48v too..

Those NIFE Batt's.
Yes very good. and avail.
But Steel yacht. steel battery cases welded to hull.

Hmmmmmmm.
Any leak back. = nasty pits in steel and leaks from sea.
You never know.

I've seen a coupla steel yachts that got electrolosys.
One changed from a 50ft Ocean Goer.
to a Below waterline sieve.
In around 8 months. Beautiful Flush decker Boden.

I had the 42 ft "South seas", flush deck too.
single stick cutter. Not Ketch.
Slow old dogs in that rig normally.

Had to pull it out of water.
and over a yrs solid Spot welding hull to get it seaworthy again.
I helped when I could and gave him my 3 Phase welder to do it with.
Every ZZap. a full plug melted in. No washing needed.
Fairing was a bitch though.

Was a much betterer machine than single ph.
and quicker by far than my MIG.

Wish I'd kept that thing.
Memories.

I remember making wind genny on mates farm
with huge blades on windmill pump (did both jobs)
and old 110v alternator from a ships shaft genny
stepped down to 48v.
Bloody things we used to do when young.
Could have cooked ourselves.

PeterD · Guru

Warren-Pat_01 wrote:
Do modern day caravans have a 12v DC isolation switch? My Jayco Discovery & a friend's StarCraft are the same as each other. There is a "DC" switch inside the vans - from what I can see, this switch only couples the SETEC battery power supply/charger to the battery. It does not isolate the battery from any load.

Whether your van has a battery isolation switch or not depends upon the maker. They all have different methods of wiring their vans. all the later model Jaycos have the isolation switch.

Does your Jayco have the Setec ST III? If it does it should be wired as the diagram in the operators handbook. You will note that at the bottom of the diagram there is an input to a relay that switches the battery on or off. this should be switched on whenever you are on power or you wish to use battery power.

If your van is in its manufactured condition and nothing has been wired to the battery then you should be able to isolate the battery completely from the house loads. If there are some extra leads on your battery that feed some of the house loads then this is a modification subsequent to the delivery of your van. If there are these extra loads on your battery I suggest you relocate them to the fused outlets on the rear of the Setec. You will then will not need an extra switch.

I believe the earlier models did not have the internal battery switching in the power supply (Setec) but the external switch carried the full battery current. The same thing applies there, if all the loads are connected to the back of the Setec then that switch should isolate your battery completely.

ps, I have attached the diagram mentioned above.

-- Edited by PeterD on Friday 28th of April 2017 10:42:01 AM

rockylizard · Guru

day...

My van has this fitted -

Van 12V switch.jpg

Sorry for the big pic ...

[edit: was able to re-size the pic) ...but you can see the switch has three positions - I II and 0.

When at the "I" position as it is there, it allows all 12V items, lights etc, to operate from VAN battery.

When at the "II" position it allows all 12V items, lights etc, (despite the wording on my 'tag'), to operate from the VEHICLE battery. If the vehicle is not connected then nothing works.

When at the "0" position (red arrow) the 12V items, lights etc, will not operate - they are isolated from any battery supply, including the vehicle should the connection still be in place. This is the position to put the switch if there is work to do on the 12V system.

Therefore, I would assume this would be called an "isolation switch".

Of course, 240V items don't operate unless the van is connected to 240V via the cord to an external 240V source.

Cheers - John

-- Edited by rockylizard on Friday 28th of April 2017 11:40:05 AM