Fitting Smartbank - Relay Placement Advice

[Stormbringer]

Hi All

 

Have just picked up a Smartgauge / Smartbank set-up and am wondering about relay placement.

However - the battery wiring on our new (to us!) boat is a bit of a mess! There are feeds and negatives to all of the battery posts and the inverter draws

its feed from the domestic battery bank (middle battery!!) - and the negative returns to the starter battery negative terminal ! I know they are all connected together

but surely that is not best practice?

I have read Gibbo's excellent site numerous times and think it's time to make a better job of the battery wiring, whilst fiting the smartgauge and smartbank.

 

My Vetus M4.17 has a single 55W (I think) alternator and already has a Nagares RL12-180 relay for split charging. House bank is 3 x 110Ah - starter is 1 x 110Ah

My question really is this - what should I do with he relay that is there now ?

I was thinking of taking a direct feed from the alternator main output straight to the load side of the house bank isloator switch and removing the cable that

feeds the existing split charge relay (via the starter positive terminal). Would this be the best way forward ?

That would leave the starter motor on it's own circuit and all the alternator charge going via the house bank isolator to the batteries and through the smartbank relay as required....does that sound ok?

 

If that is OK - then the next question would be what do I do with the trigger wires going to / from the Nagares relay? I can't really follow them as they go into a loom and are not colour coded! Would it be OK to leave them connected ? I wondered if they were fed from the alternator warning light circuit ?

 

Finally - once all that is sorted out I will be fitting the Smartbank relay. I'm thinking of putting that between the load side of the two battery isolation switches.

Would this be the best position for it or would anyone recommend it be fitted somewhere else ?

 

I've got some very crude and childishly drawn diagrams and when I remember my photobucket password I'll post them up if that helps...

 

Appreciate your thoughts...

Cheers

Andy

[David Schweizer]

Gibbo recommends Albright relays available here :- http://www.thetoolboxshop.com/albright-sw180-series-single-acting-solenoid-contactors.html

 

Just fit with the shortest cable runs as space and access will allow.

Edited February 12, 2013 by David Schweizer

[MikeV]

I was thinking of taking a direct feed from the alternator main output straight to the load side of the house bank isloator switch and removing the cable that feeds the existing split charge relay (via the starter positive terminal). Would this be the best way forward ?

On my boat the domestic alternator is connected to the battery side of the isolator switch. I believe this is done to avoid the possibility of the switch being opened while the engine is running which will damage the alternator. There is a fuse between the battery and the isolator switch.

[Stormbringer]

Thanks David, that relay looks like the one I have.

Between the isolation switches is only about 10 inches so that looks like a good point to connect (physically anyway)

 

Cheers

Andy

[Stormbringer]

On my boat the domestic alternator is connected to the battery side of the isolator switch. I believe this is done to avoid the possibility of the switch being opened while the engine is running which will damage the alternator. There is a fuse between the battery and the isolator switch.

Thanks MikeV

There is a distinct lack of fuses on all my battery cables, another job to get sorted along with the battery rewire!

Point taken about connecting to the battery side of the switch, and exactly the reason I asked the question. I know opinions

differ on where exactly is best so hopefully the answers I get will help me better understand the issues, and make the right decisions! Not murdering my alternator is a great reason!!

 

 

Thanks again

Andy

[Stormbringer]

I have managed to re-draw my diagrams and have uploaded them to a gallery. Just trying to work out how get them to show on this thread now lol...

If any of you kind electrical experts could have a quick look and offer any advice it would be much appreciated.

 

Cheers

Andy

[by'eck]

 

Just a couple of comments regarding your proposed re-wire above.

 

I would route the Victron inverter DC positive input via the domestic bank battery isolator as well. Make sure its well over-rated for the current flow though.

 

I would also use one of the three Sterling battery charger outlets to feed the starter battery with just a single strap to remaining one.

 

Apologies if you intend to do this anyway, but for your positive domestic and negative battery distribution, use a single busbar for each, close to the batteries but after the isolator. You can buy propriety ones or make them up from thick copper strip and several M10 nuts and bolts. Ensure the positive one is in an insulated housing and run a single battery cable strap from the negative one to boat hull.

Edited February 13, 2013 by by'eck

[churchward]

 

Just a couple of comments regarding your proposed re-wire above.

 

I would route the Victron inverter DC positive input via the domestic bank battery isolator as well. Make sure its well over-rated for the current flow though.

 

I would also use one of the three Sterling battery charger outlets to feed the starter battery with just a single strap to remaining one.

 

Apologies if you intend to do this anyway, but for your positive domestic and negative battery distribution, use a single busbar for each, close to the batteries but after the isolator. You can buy propriety ones or make them up from thick copper strip and several M10 nuts and bolts. Ensure the positive one is in an insulated housing and run a single battery cable strap from the negative one to boat hull.

I would leave the inverter directly wired to the battery bank and fused. That is a lot of amps for a switch to handle you will need some beefy switches to cope. In any case the BSS is OK with direct connection as long as there is a fuse.

 

I would also directly connect the smartbank relay to the battery banks rather than via the switches as the fewer connections and shorter cable lengths the better.

[by'eck]

I would leave the inverter directly wired to the battery bank and fused. That is a lot of amps for a switch to handle you will need some beefy switches to cope. In any case the BSS is OK with direct connection as long as there is a fuse.

 

I would also directly connect the smartbank relay to the battery banks rather than via the switches as the fewer connections and shorter cable lengths the better.

 

Your choice but I like battery isolators to isolate batteries

 

There are isolators available that will safely take 600 amps continuously and 2500 amps intermittent.

[jelunga]

Your choice but I like battery isolators to isolate batteries

 

There are isolators available that will safely take 600 amps continuously and 2500 amps intermittent.

Victron recommend direct connection to batteries with fuse. Less volt drop.

[churchward]

Your choice but I like battery isolators to isolate batteries

 

There are isolators available that will safely take 600 amps continuously and 2500 amps intermittent.

Indeed you can but there are few that can reliably handle this kind of power. The normal cheapo ones you see in the Chandlery are not up to the job. The Bluesea ones that can handle 600A which are very good are around £50-£60 each.

 

 

...and stop winking at me we haven't even been introduced.

Edited February 13, 2013 by churchward

[by'eck]

Indeed you can but there are few that can reliably handle this kind of power. The normal cheapo ones you see in the Chandlery are not up to the job. The Bluesea ones that can handle 600A which are very good are around £50-£60 each.

 

 

...and stop winking at me we haven't even been introduced.

 

Sorry

 

Here's a BEP isolator well capable, ignition protected and available with remote operation. I use both types on my boat.

 

 

I believe the greater concern regarding volt drop is cable gauge and length of runs. I do take your point regarding minimising connections though.

[ditchcrawler]

I would leave the inverter directly wired to the battery bank and fused. That is a lot of amps for a switch to handle you will need some beefy switches to cope. In any case the BSS is OK with direct connection as long as there is a fuse.

 

So why not do away with battery isolators completely and just put a fuse in the positive lead from the batteries?

[churchward]

So why not do away with battery isolators completely and just put a fuse in the positive lead from the batteries?

That is what I am saying to do for the inverter setup and as pointed out in another post this is what Victron recommend.

 

It is not a good idea to connect everything like this one would get in a spot of bother with the BSS for a start but it is a good idea to be able to isolate the batteries from the main boat cable distribution system.

Edited February 13, 2013 by churchward

[smileypete]

 

Not bad at all! But I'd put connect the alt to batt positive via a BIG fuse at the batt end. That way it can't get disconnected when the engine is running.

 

Also why is the fuse in the -ve lead of the Sterling charger? I'd put it in the +ve lead at the batt end. Also fuse the Webasto wires close to the batt too.

 

cheers, Pete.

~smpt~

[churchward]

Sorry

 

Here's a BEP isolator well capable, ignition protected and available with remote operation. I use both types on my boat.

 

 

I believe the greater concern regarding volt drop is cable gauge and length of runs. I do take your point regarding minimising connections though.

Yep they are an example of high capacity switch as well as the Bluesea ones I mentioned. I didn't say you could not get them just that you need a beefy switch if you do connect to an inverter via one. I still do not think it is the best way to wire an inverter and I would not do it.

[smileypete]

 

Not bad at all! But I'd put connect the alt to batt positive via a BIG fuse at the batt end. That way it can't get disconnected when the engine is running.

 

Also why is the fuse in the -ve lead of the Sterling charger? I'd put it in the +ve lead at the batt end. Also fuse the Webasto wires close to the batt too.

 

Might even be worth using the 400A fuse as a 'master fuse' protecting Victron and cable to isolator. You could take the fused Webasto feeds off either side of this fuse to reduce the connections at batt bank positive. Even daisy chain the fused alt feed off the batt side of the 400A fuse.

 

Similarly are you planning to install an ammeter shunt in the negative? Again this or the hull earth bond can serve as a useful common point.

 

So ultimately at bank +ve and -ve you just end up with batt cables, Smartguage feeds, and a cable that feeds everything else, so there is less need for a bus bar.

 

cheers, Pete.

~smpt~

Edited February 13, 2013 by smileypete

[Keeping Up]

 

...

 

Also why is the fuse in the -ve lead of the Sterling charger? I'd put it in the +ve lead at the batt end. Also fuse the Webasto wires close to the batt too.

 

...

 

 

IIRC this is the way Sterling recommend it, so that you have just one fuse in the negative rather than a fuse in each of the positives of a multi-output charger. Presumably the logic is partly that its is simpler; also perhaps that for a 30A charger, for example, you can have 30A on any one output so in theory a total short-circuit at the charger could have 90 amps flowing into it from three batteries before the fuses blew, whereas in the negative a single fuse of just over 30A would blow more quickly.

[smileypete]

IIRC this is the way Sterling recommend it, so that you have just one fuse in the negative rather than a fuse in each of the positives of a multi-output charger. Presumably the logic is partly that its is simpler; also perhaps that for a 30A charger, for example, you can have 30A on any one output so in theory a total short-circuit at the charger could have 90 amps flowing into it from three batteries before the fuses blew, whereas in the negative a single fuse of just over 30A would blow more quickly.

But if the +ve cable between charger and batts is unprotected, any short to hull on this cable will allow virtually unlimited current to flow, probably causing a fire.

 

If the charger is next to the Victron but a way from the batts, the OP could daisy chain the charger output to the input of the Victron, then have have an extra fuse in the +ve by the Victron to protect those cables or use cable thick enough to be have adequate protection by the 400A fuse.

 

Really the charger should have it's own built in user-accessible fuses for internal protection. I really hope they don't recommmending fitting an external fuse in the wrong place!

 

cheers, Pete.

~smpt~

[Stormbringer]

 

Just a couple of comments regarding your proposed re-wire above.

 

I would route the Victron inverter DC positive input via the domestic bank battery isolator as well. Make sure its well over-rated for the current flow though.

 

I would also use one of the three Sterling battery charger outlets to feed the starter battery with just a single strap to remaining one.

 

Apologies if you intend to do this anyway, but for your positive domestic and negative battery distribution, use a single busbar for each, close to the batteries but after the isolator. You can buy propriety ones or make them up from thick copper strip and several M10 nuts and bolts. Ensure the positive one is in an insulated housing and run a single battery cable strap from the negative one to boat hull.

 

Cheers by'eck

 

I hope to eventually upgrade the isolators - and when I have done this I will reconsider my wiring for the Victron - however for the timebeing, I will have to just add a fuse and run it straight from the batteries

 

RE - the Sterling - would feeding both batteries still be worth doing considering I am fitting a Smartgauge / Smartbank ?

 

And busbars - the boat already has two negaive busbars but no positives so I think I will be fitting one to tidy the feeds up

 

Thanks for the input

Andy

 

That is what I am saying to do for the inverter setup and as pointed out in another post this is what Victron recommend.

 

It is not a good idea to connect everything like this one would get in a spot of bother with the BSS for a start but it is a good idea to be able to isolate the batteries from the main boat cable distribution system.

 

Thanks churchward

 

I am going to go with the fused feed direct from the batteries for the Victron.

Partially due to my isolators not being man enough - and partly to do with the phyical location of the inverter.

 

Cheers

Andy

[Stormbringer]

 

Not bad at all! But I'd put connect the alt to batt positive via a BIG fuse at the batt end. That way it can't get disconnected when the engine is running.

 

Also why is the fuse in the -ve lead of the Sterling charger? I'd put it in the +ve lead at the batt end. Also fuse the Webasto wires close to the batt too.

 

Might even be worth using the 400A fuse as a 'master fuse' protecting Victron and cable to isolator. You could take the fused Webasto feeds off either side of this fuse to reduce the connections at batt bank positive. Even daisy chain the fused alt feed off the batt side of the 400A fuse.

 

Similarly are you planning to install an ammeter shunt in the negative? Again this or the hull earth bond can serve as a useful common point.

 

So ultimately at bank +ve and -ve you just end up with batt cables, Smartguage feeds, and a cable that feeds everything else, so there is less need for a bus bar.

 

cheers, Pete.

~smpt~

 

Thanks Pete

I like the 'straight to the battery post via a big fuse' for the alternator feed - cheers. Its also a slightly shorter run too ...how big would BIG be ?

 

As Keeping Up has already stated - the negative fuse is as Sterling recommend in the charger manual. That was my only reason for that fuse. What if I fused both positive and negative ? Would that be better - or not worth it ? Should the charger fuses be at the battery end regardless of what polarity they are ?

 

Am going to revisit the drawing board (well M$ paint lol !) and the engine bay and see what the best combination of fuses and or busbars or whatever will give me a workable physical layout. I will probably be installing an ammeter shunt at some point so will incorporate that as a useful -VE common point as you suggest. I will also see if the 'master fuse' arrangement you mention could work for me, that sounds really tidy...

Will post the new arrangement once I've done

 

 

Thanks for all the help Pete ( and everyone else!) - much appreciated

 

Cheers

Andy

 

Edit - cos I pressed post too soon

Edited February 14, 2013 by Stormbringer

[by'eck]

Cheers by'eck

 

I hope to eventually upgrade the isolators - and when I have done this I will reconsider my wiring for the Victron - however for the timebeing, I will have to just add a fuse and run it straight from the batteries

 

RE - the Sterling - would feeding both batteries still be worth doing considering I am fitting a Smartgauge / Smartbank ?

 

Cheers

Andy

 

It will be less advantageous with a Smartbank, but since your Sterling charger has three outputs its a shame just to use one of them.

 

Regarding the Sterling charger the fuse in the negative should be fine. Don't start putting fuses in the positive feed(s) as well unless they are particularly long. It can lead to fuse mania where the installation of multiple fuses on short cable runs leads to less reliability not to mention volt drop.

 

I wouldn't bother with one in the short alternator feed for the same reason.

[boots]

Which Sterling charger do you have? We are using the pro-charge n and the installation diagram shows a fuse in each of the +ve leads (rated at charger output +30%). (I am not saying that what you are doing is wrong though - I am no expert)

[Chris Pink]

I will probably be installing an ammeter shunt at some point so will incorporate that as a useful -VE common point as you suggest.

 

Don't do this. Make your -ve common a different physical connection to the shunt. You will find it physically easier = more electrically reliable. Your diagram also shows lots of connections on battery terminals. With the exception of the alternator output and the inverter they should all be connected to studs or busbar. I also think you should have an isolator for the inverter. Inverter faults tend to be dramatic.

[smileypete]

Thanks Pete

I like the 'straight to the battery post via a big fuse' for the alternator feed - cheers. Its also a slightly shorter run too ...how big would BIG be ?

 

As Keeping Up has already stated - the negative fuse is as Sterling recommend in the charger manual. That was my only reason for that fuse. What if I fused both positive and negative ? Would that be better - or not worth it ? Should the charger fuses be at the battery end regardless of what polarity they are

Even though the alt is 55A I'd stick a 200-400A fuse on it, that way if there's momentary short eg bounce spanner off alt terminal, the fuse is less likely to go instantly or weaken a little so it goes when the alt is running at full output.

 

As far as the inverter goes you could always call Sterling and ask if it's just as good to put the fuse in the positive instead, you may get a fairly forthright answer The positive charger fuse should definitely be at the battery end, the negative doesn't matter so much as a -ve short to hull shouldn't draw a huge current from the batts.

 

Don't do this. Make your -ve common a different physical connection to the shunt. You will find it physically easier = more electrically reliable.

I think a hull earth bond near the batts should serve as a good common point for the large -ve return cables, but I'd consider putting a couple of smaller returns on the correct end of the shunt if it makes things easier and neater.

 

cheers, Pete.

~smpt~

Edited February 15, 2013 by smileypete