VSR active only when engine on?

[JumbleDuck]

I'm rejigging the boat's 12V system at the moment. There will be two batteries, house and start, charged both by solar panel and by engine. I would lik eto use a VSR to charge the start battery first when the engine is running. However I have bought a nice two-channel solar controller which preferentially charges one battery, and there is the possibility that that would trigger the VSR, which is undesirable.

So ... what I'd really like is a VSR which only works when the engine is running, or at least when the ignition is "on". It's not too hard to think of ways of doing this - I could, for example, run a wire from a switched supply on the ignition switch and use it through a relay to connect the VSR - but I wondered if there were any obvious off-the-shelf solutions?

I have a diode splitter in a box somewhere and could always use that, but finding a site for it is a bit of a problem and I'd prefer VSR if possible. I can't afford a Sterling alternator-to-battery charger!

 

[sailorman]

http://www.victronenergy.com/upload/documents/Manual-Cyrix-i-120-EN-NL-FR-ES.pdf

 

[Puggy]

I think you will end up spending more money on the intelligent VSR solution than the solar splitter cost in the first place. An alternative is to buy the VSR you fancy, and a single battery solar regulator and connect that to the same connection as the engine charge and let the VSR do the regulation for both power sources. Then put the split solar regulator on eBay to recoup some of the cost...

 

[BabaYaga]

what I'd really like is a VSR which only works when the engine is running

What you need is a non-VS relay, connected between the starter and domestic battery and controlled by a wire to the D+ terminal on the alternator (charging light circuit). This set up will do what you are looking for: Connect the batteries when the alternator starts to put out, disconnect when the engine is shut down.

 

[Puggy]

What you need is a non-VS relay, connected between the starter and domestic battery and controlled by a wire to the D+ terminal on the alternator (charging light circuit). This set up will do what you are looking for: Connect the batteries when the alternator starts to put out, disconnect when the engine is shut down.

Well, to a certain extent. The VSR will priority charge the engine battery first and when that is up to voltage, then connect in the others. Your solution will certainly work but will connect all the batteries together as the alternator starts to output, which could be undesirable if the domestic batteries are low and the engine battery is also low due to excessive cranking etc...

 

[BabaYaga]

Well, to a certain extent. The VSR will priority charge the engine battery first and when that is up to voltage, then connect in the others. Your solution will certainly work but will connect all the batteries together as the alternator starts to output, which could be undesirable if the domestic batteries are low and the engine battery is also low due to excessive cranking etc...

In normal operation a VSR will reach the preset voltage within seconds, so a VSR and a non-VS relay will perform essentially the same thing.
If the starter battery is low from excessive cranking, the boat owner will be aware of this and let the engine run for a while.
Besides, it is always a good idea to arrange so that the engine could be started from the domestic battery in an emergency.

 

[Nigel-in-Oxford]

Put a relay in the negative line of the VSR and power that from the ignition. (this is the setup I have)

 

[JumbleDuck]

I think you will end up spending more money on the intelligent VSR solution than the solar splitter cost in the first place. An alternative is to buy the VSR you fancy, and a single battery solar regulator and connect that to the same connection as the engine charge and let the VSR do the regulation for both power sources. Then put the split solar regulator on eBay to recoup some of the cost...

The regulator was only thirty quid, and will happily work with one battery. However, for another thirty quid I was able to get quite a nice remote battery monitor which goes with it, so if I use the dual output of the regulator I have a handy remote display of the state of both batteries.

Put a relay in the negative line of the VSR and power that from the ignition. (this is the setup I have)

Thanks. I think that's probably going to be the solution. It's annoying, though, that all the VSR adverts I find say "New design doesn't need supply from ignition" when that's just what I want.

 

[halcyon]

Thanks. I think that's probably going to be the solution. It's annoying, though, that all the VSR adverts I find say "New design doesn't need supply from ignition" when that's just what I want.

The reason is to allow bi-directional charge ( 30 years old now ) that is to charge the engine battery with a single output charger on service battery. Alternative ti ign link, is a voltage sensing interlock that drops out the VSR, initially to stop starter load on second charge source, but can be anything that generates a voltage.

Brian

 

[William_H]

OP has not indicated how big his solar apnale is and how big the batteries especially the house battery are. with a smallish solar array it may not actually raise the voltage of the engine battery to that required to actuate the VSR. ie usually around 13v. he should check in sunshine midday to see if there is actually a problem. If the VSR does actuate then it will not necessarily do any harm except waste a little power. That to actuate the relay.
But then the VSR sensor should be disconnected when leaving the boat ie with engine battery isolator open or "ignition' off because VSR sensor will always waste a little current while sensing.
So ideally isolate both batteries for all but solar charge then no concerns when the boat is left and probably no problems when you ar eusing the boat.(or have I got it all wrong) good luck olewill

 

[JumbleDuck]

OP has not indicated how big his solar apnale is and how big the batteries especially the house battery are. with a smallish solar array it may not actually raise the voltage of the engine battery to that required to actuate the VSR. ie usually around 13v.

100W of panels (2 x 50W), 130Ah house battery (2 x 65Ah), 40Ah start battery, probably, when I have worked out what fits.

 

[nigelmercier]

So ... what I'd really like is a VSR which only works when the engine is running, or at least when the ignition is "on"...

I've done exactly this, to prevent the VSR from activating when the shore power chargers are running.

The VSR has a low-current ground wire as part of the sensing circuit; put the relay contacts in this, with the relay coil in the ignition circuit. For completeness I've added a double throw switch, giving me the option of VSR on, off, or auto.

Total cost for less than a pint, for 1A relay, switch and small box. Perhaps I should send this idea to PBO.

[Later] I see Nigel IO has the same idea, Go Nigels Go!

 

[bedouin]

100W of panels (2 x 50W), 130Ah house battery (2 x 65Ah), 40Ah start battery, probably, when I have worked out what fits.

With that set up why not just connect the panels to the house batteries?

Unless you are going to leave the boat unused for months at a time the engine battery should not need topping up. Or just connect it to the VSR and don't worry about the charge being shared.

 

[JumbleDuck]

The VSR has a low-current ground wire as part of the sensing circuit; put the relay contacts in this, with the relay coil in the ignition circuit. For completeness I've added a double throw switch, giving me the option of VSR on, off, or auto.

Sounds good - thanks.

With that set up why not just connect the panels to the house batteries?

I've got the dual-battery controller now ... and, as I said, I like the idea of being able to use the remote display for it to check what's going on in both batteries.

 

[david100952]

I put a VSR Cluster from BEP on the boat a couple of years ago and it works very well. I recently upgrade my fuse/switch panel and downloaded a wiring diagram which does have reference to solar or other charger connections....
http://www.power-store.com/view-item.asp?itemid=1155&search=vsr cluster&page=2&