VSR Vs DC to DC

[ranmar850]

A couple of things there. That switch/VSR combination looks like one I had on a 20ft quintrex CC, with 2 batteries and an old school 1/2/Both switch. The batteries kept going flat. I mean this thing only had a GPS and a small fishfinder. So, on advice, I fitted an all-in-one Battery switch /vsr unit such as you have above. The batteries still kept going flat. Effectively, they are still a 1/2/both switch with a VSR built-in. I ended up troubleshooting it with a meter, connections had come mis-labelled ( stick-on labels) from the factory, it was On all the time. I corrected that, it worked OK for a few more years, running a 90hp Yamaha 2-stroke. But that setup you have shown is not the same as the one I have shown above. I believe they can fail closed on both, ie, their normal state is closed, they open on command from a voltage signal? I could be wrong, but that would explain it. Just the way it is sensing BOTH Battery 1 and Battery 2. With my original setup ( shown), the VSR only looks at the Start (1) battery, no input from the House (2) it doesn't care what's going on with House, it just gets its orders from Start. Start battery voltage is high enough (typically 13.2v) , it closes the switch so the House can get charge from the alternator. If Start drops below 12.7v, it opens again. (with a built-in delay) So, failure to operate means that the Start is unaffected, just means that House gets no charge. Which you can alleviate by closing the middle switch, to bridge it out, then carry on as if nothing has happened. Of course, this then opens you up to flattening your Start battery if you leave a lot of House load running. with the motor off.

So, to re-iterate, for a small CC like yours, I'd just go with a simple 2 battery setup such as i have described above, stick with a VSR between them, with a bridging switch, but fit a better VSR. Don't go with one of those all-in-ones with dual battery sensing/switching.

The Redarc SBI 12 is not IP rated as such, but it is designed to be fitted under the bonnet of a 4WD where it might get submerged anyway, and will certainly get more splash than your average boat setup. All the circuitry is encased in resin. Mount it inside your console? Where are the batteries located?

[docaster]

And why everyone should have voltmeters visible even when the batterys isolator is off. When it's parked up, stick your head in there once a week to see if the charger needs to go on.

Sent from my SM-G950F using Tapatalk

[Flex]

I have been using Bluesea systems VSR and Isolators for many years and not had a problem.

firstly. I suggest have a look at the 4 pole isolator they make. I think this should be stardard across the board. The crap 3 pole isolator is a horrible idea and this will give you a more robust and safe system. heres a diagram
bluesea systems.png


what size outboard and VSR did you use? was it correctly rated? is it possible you are using one much to small and causing the contacts to weld shut?

VSR can fail in the open or closed position. If a VSR contact tries to open during heavy load conditions (especially inductive loads like electric winch use or even a starter motor being fed off insufficient battery then this can cause contacts to weld shut. which would cause both your batteries to eventually drain down.


I think running a DC-DC system for a house battery isnt a good option. gets complicated when you want to combine the batteries.
In addition a DC-DC charger is less reliable than a VSR.

onboard DC-DC charger is only really applicable when charging different battery types eg. Lifepo4 off a lead acid.

[ranmar850]

These little "140 amp rated" VSR's typically do not have contacts to weld shut, they are solid state switched, no moving parts. The heavier duty ones like Redarc, made to manage high currents, have actual contacts.

I think running a DC-DC system for a house battery isnt a good option. gets complicated when you want to combine the batteries.
In addition a DC-DC charger is less reliable than a VSR.

onboard DC-DC charger is only really applicable when charging different battery types eg. Lifepo4 off a lead acid

Definitely agree , except for the DC-DC being less reliable than a VSR, too many variables, ie how good a DC-DC ( Kings vs Redarc) and what type of VSR, ( electronically switched or actual solenoid)

[Flex]

Did you do any testing on your VSR after it failed? See what it’s not doing? Or check if it welded shut?
Doesn’t have to have the entire contact fail closed
Only requires ever so slight connection
Or generally they do fail open.
But I can’t see how a fail open would drain your battery. Could be somthing unrelated .

[Berger4]

Hi everyone

Thanks for all the replies, have been MIA for a couple of nights in hospital(all good). Lot to catch up on not sure what happened with the camper van fire looked a complete mess, yes I have always assumed Lifepo to be as safe as houses. I do know that he did the install himself as he was talking about it the previous Christmas as the van originally had AGM batteries and this wasn't enough with 4 teenage sons and wife all running different things including an induction cooker. However I will say he is an engineers(Civil mind you) so I can't imagine the install was dodgy but you never know??

As for the VSR's I had can't tell you what rating they where as I didn't think about it( talk about DIY and not knowing what you are doing) I know the first one was cheap however the second one was a BEP marine DSVR same as the one below. This one only stopped charging my house battery.

Attachment 127132
The only reason I asked about going to a DC to DC charger is I have a Sterling pro one that I used to use for charging my AGM battery for the the Motorguide which I took out as it was causing interference on my sounder. So thought was to just use this as I already had it. I also have a spare AGM just sitting around as I just went for a larger AGM for the Motorguide which has been fine.

The batteries/switches are all up under the transom well out of the way of splash/rain etc. The only time they may get water is when I clean the boat and get a bit loose carried away.

As for testing the VSR. You have to remember that I am a bit of a numpty when it come to this. The first VSR all I did was check the batteries and charge them up just assume it was the VSR as it was cheap. The second one again charged the house up and asked my mechanic to look at as no light was coming on to indicated it was charging, he check it and agreed it was toast but did say the back of the switch had some corrosion but though this wasn't the cause.

So you guys are saying to just go VSR but get a good one and battery the same chemistry as the start.

Ramnar I will look into the Redarc and may contact you if I think it looks ok. Not sure where you are I.e. posting etc. I may also get somebody to do the rigging/wiring when I get there, depending on cost?? You know what they say poor man pays twice never learn.

[ranmar850]

While we are on the whole subject of boat wiring, I'd like to share something that happened to me re battery switches. as you have worked out by now, I tend to do my own installation-I'm actually a licenced elctrician. learnt the DC stuff mostly the hard way . When I fitted out the Reefrunner, I used the compact type Narva battery switches for the setup I posted above ( 3 switches) . Apart from the 12 month life of the original type of VSR's I was using, switches were fine. So I thought. maybe 3 years ago, I started getting an intermittent misfire on the motor. You slow down, look at things, nothing obvious, get going again, all good. Then it started getting occasionally, mometarily, slow to tilt. Then a pause on starting. Went like tghis for a year, mostly fine. Start battery tested fine. Then it went really bad, and, of course it was on a big trip, out to the Montebellos. Starter seemed to be jamming partly engaged. , remove the cover, tap it back down. Bad misfire just about stopping me middle of nowhere. Trying everything, it was a confusing mix of different symptoms. . Anyway, we finished the trip, got home. Complained to the Merc dealer, all these things mounting up, he said sounds like battery. Battery tests fine, these problems are really intermittent. Check your switch, he tells me.

I pull it apart, this is what I found.




Even after cleaning, the mating surface looked like this.





Yes, it was just the Start battery switch. Now, it was mounted on that swing-up panel which kept it , I thought initially, dry. But it was being dripped on via the rod holders above it which held the bait table. I had picked up on that early in the piece, and rigged a drain under them which funnelled the water right away, but the damage was done. It was not helped by the construction of the switch itself, just look at it.
I found an only slightly less compact alternative with the Blue Seas Mini battery switch, https://www.whitworths.com.au/swch-bat-sec-300a 300 amp continuous, 700amp cranking. And really not much more expensive than a cheap crap one. Because I only need On/Off with my current setup, but they do the 1/2 and 1/2/both in the same size. Well over 12 months since I fitted it, no problems at all. These modern motors are very particular about good power supply.

So you guys are saying to just go VSR but get a good one and battery the same chemistry as the start

yes, that would be my advice.

[Dignity]

Those rod holders happen to drain water in sll sorts of places, switches, batteries etc. I do run some tubing under mine to drain them into the bilge.
The other issue that I came across was using welding cable, good current carrying due to the very thin strands (current travels mostly on surface of strands) and what I thought was well sealed, 2 lots of dual shrink over the lug and cable. Couldn't eork out why I was struggling getting power, found that the cable had virtually disintegrated just past the lugs.
Elektrickery is a strange beast at the best of times.

[ranmar850]

Yes, the green death inside the sheathing is a killer. You can do your best with it, ie, blind lugs ( ot the sort you can't see the end of the copper in), solder the lugs as well as crimp, glued heat shrink in multiple layers overlapping. Tinned copper is by far and away the best, but it will eventually succumb. When I did the lithium upgrade, I had some short surplus leads left over, so I cut one up to check, and they were doing fine. Or at least the one I cut up was. So far. That was only five y,o. , of course.
The actual sizing of OEM automotive battery leads nowadays has certainly gotten smaller, no doubt saving money on expensive copper, but they are not leaving much margin if the lead starts to degrade.

[andoland]

A good quality VSR like the redarc ones should be fine. I’ve had one under the bonnet of my 4wd for 13 years without a problem.

[Flex]

These little "140 amp rated" VSR's typically do not have contacts to weld shut, they are solid state switched, no moving parts. The heavier duty ones like Redarc, made to manage high currents, have actual contacts.

Solid state contacts (SSR's) typically fail in the closed position from my experience.. not technically "welded" shut, but still fail closed

But VSR they can fail in a multitude of various other ways.

like you said Im not sure how the higher rated isolators work, so might be worth looking into.
Battery isolator rating is another over looked item.
Too small and you will pulling to much current through their contacts, causing pitting/damage etc.