Using windlass or starter confuses my plotter

[Tranona]

I think I will stick to turning everything off first. I am sure your kit is excellent but I want to keep everything as simple (and understandable) as possible.
Thanks for your reply though

But what you have is not simple. The separate banks with their own isolators and a VSR to automatically split the charge favoring the start battery as Brian suggests is as simple as you can get. No need to remember to change over, no need to worry about starting having any effect on the rest of your system. What could be simpler?

 

[Jamesuk]

Buy a UPS device for your plotter with its own battery

 

[john_morris_uk]

But what you have is not simple. The separate banks with their own isolators and a VSR to automatically split the charge favoring the start battery as Brian suggests is as simple as you can get. No need to remember to change over, no need to worry about starting having any effect on the rest of your system. What could be simpler?

I claim a Lakesailor...

(Isn't what you are saying what I just said?)

 

[Tranona]

I claim a Lakesailor...

(Isn't what you are saying what I just said?)

Yes. Just reinforcing the point as there seems to be some illogical attachment to a less than satisfactory system.

 

[Storyline]

But what you have is not simple. The separate banks with their own isolators and a VSR to automatically split the charge favoring the start battery as Brian suggests is as simple as you can get. No need to remember to change over, no need to worry about starting having any effect on the rest of your system. What could be simpler?

I am sure you are right but I also said understandable. I have an Adverc between the alternator and the batteries and I did not fit that as it came with the boat so I don't really understand how that works. I just feel more comfortable with a switch so I can see with my eyes what is getting charged and when.

 

[KellysEye]

All the yachts I've seen have an engine starter Cold Cranking Amp battery and a house battery preferably a deep cycle one such as a Trojan, that will fix the problems. We also had a dedicated anchor winch battery in a box under the front berth.

 

[john_morris_uk]

I am sure you are right but I also said understandable. I have an Adverc between the alternator and the batteries and I did not fit that as it came with the boat so I don't really understand how that works. I just feel more comfortable with a switch so I can see with my eyes what is getting charged and when.

If you are worried about seeing if the domestic batteries are actually charging, fit a suitable battery monitor.

Part of your original problem seemed to be worrying about ensuring you could always start the engine. The solutions suggested for completely independent batteries but with a charging system that charges both would fulfil all your wishes. The really nice thing is that it just looks after itself.

Fit a monitor and you would have even greater peace of mind...

 

[Spi D]

Just to add a real-life observation:

My boat is set up with 3 separate battery banks. Engine 1, Engine 2 and Domestic. Charged by one 3-channel charger incorporating monitor, banks connected via a separator. All automated and works fine.

The bow thruster was connected via fuse and rather long heavy cables to the domestic bank, hence making everything else flash, beep and go weird then in use.
To avoid this annoying behavior, I fitted a separate battery near the thruster and a solenoid breaker that simply isolate the thruster circuit when put in 'ready' mode on the thruster switch.

 

[Skylark]

All the yachts I've seen have an engine starter Cold Cranking Amp battery and a house battery preferably a deep cycle one such as a Trojan, that will fix the problems. We also had a dedicated anchor winch battery in a box under the front berth.

My experience is the same as this. On my last boat, starting the engine, say approaching the marina at the end of a cruise, would always kill the plotter. The battery bank was made up only of engine / cold cranking types. I changed the domestic bank to leisure / deep cycle and the problem disappeared.

 

[Marsupial]

The OP's question was instrument problem on starting, 1,2,both switch will not stop it, diodes will give charge problems from volt drop and require rewiring alternator feed.

I have supplied over 5,000 vsr's mainly to production boat builders, I do not mind what people fit, I've been in in this game for over 40 years and just point out problems to people, if you love diodes that's fine by me.

Brian

Brian,

I am not in love with diodes but you have to admit that properly installed they no longer suffer from voltage drop. The 1,2, both switch is very primitive and has no chance of preventing the OP problems without his input switching all his instruments off.

The VSR is in many respects an elegant solution but its not straightforward.

Not all VSRs are created equal, there are issues with alternator/battery capacity ratios and on top of that charge state and alternator rating can be critical.

Some types (not necessarily the cheap ones) can and do chatter themselves to oblivion. MOFSETs also chatter but silently and without harm - allegedly.

As far as I can tell the Cyrix offering is the best of the bunch it has most of the features that would make it trouble free (see below).

Very few manufacturers (only found 1 so far and its not cyrix) suggest a large fuse to protect from massive currents frying the device and associated wiring which leads me to believe my comments and analysis on another thread about the possibility of massive discharge through a VSR setup and ensuing fire are probably true.

So IMHO while the VSR may be/ could be / should be a simple solution for a layman clearly it isnt.

Will I fit one - yes probably when my diode throws in the towel.

cheers

 

[john_morris_uk]

VSRs can be very effective and I can understand why people like them so much when they achieve the aim.

I also know about voltage drop on diodes, but provided you sense the battery voltage from the battery side of the diode, the alternator compensates perfectly. I have had boats wired this way for the last fifteen years and it means I never have to worry about a mechanical relay and its contacts eventually wearing out. And before anyone asks, I carry a spare splitter diode pack on board.

I don't know why people get so hot under the collar about various systems. Certainly just putting a diode splitter in to divert charge is NOT good practice and has given diode splitter a bad name. The batteries never charge properly and it kills them in no time at all. The problem is often exacerbated by inadequate capacity in the domestic bank.

The problem with batteries and their associated systems is that poor design will work when its new. Things turn on when they should and the owner is happy. Unfortunately poor design is only revealed in the long term and in the profits of the battery sales people.

 

[Jamesuk]

Just to add a real-life observation:
To avoid this annoying behavior, I fitted a separate battery near the thruster and a solenoid breaker that simply isolate the thruster circuit when put in 'ready' mode on the thruster switch.

Sounds like what I would do

 

[Skip 52]

So... thank you very much indeed to everyone for all their input on this. I've decided to go ahead and split the domestic and starter batteries using a Victron Cyrix-I battery combiner kit. There are various complexities to the system such as an AC distribution/shore charging set up and a strange little relay (I think it's a relay) that has been added at some time with a red wire to the starter motor, a couple of black wires I haven't figured out yet and piggy back connector to a blue wire which comes out of a domestic type wire flex (the other two wires in this flex having been cut off completely - effectively it's simply a blue wire leading to, I think, another relay by the batteries). Both relays are slightly warm when the DC circuits are on. I think I need to put some effort into understanding all of this!

Anyway, my question is, there are various books on boat wiring, can anyone give a recommendation?

 

[Marsupial]

http://www.amazon.com/The-12-Volt-Bible-Boats/dp/0713667036

Cyrix-I a good choice, let us know how you get on.

 

[Skip 52]

Cyrix-I a good choice, let us know how you get on.

Not doing too well at the moment (got sidetracked into fitting a holding tank - much simpler!). The Cyrix-i instructions are really aimed at adding an additional battery to the system, not splitting an existing system. Ideally, I am guessing, one would have the starter battery connected to the alternator for charging and then the Cyrix-i charging the domestic battery off that. The problem is that, despite having read up as much as I can, I can't figure out which wire brings in the charge. There is a bundle of three red wires which appear out of the wiring loom and which are connected via a 40 amp fuse to the switched side of the isolator (as opposed to the battery side of the isolator). I assume that one of these brings in the charge and that the other two feed the domestic/electronics circuits (?).

So, QUESTION 1, is it ok to split the batteries so that one does the domestic and electronics and also receives the charge from the alternator. And then to have the second battery doing only the starter and the windlass and to have the Cyrix-i feeding that from the domestic battery? This would save a lot of figuring out (!), but is it sound practice? The Cyrex-i instructions say to connect it closest to the smallest battery, generally the starter. Both batteries are identical (starter type, not deep cycle) at the moment.

QUESTION 2. There is an "All-in-one Power First" shore power/charging unit. It has two +ve charging outputs, one for the starter and one for the domestic. As there is only one system at the moment, only one of these outputs is connected (to the battery side of the isolator switch). Should I leave it at that and let the Cyrix-i do the inter-connection (again guessing here - the Cyrix-i might not like charge coming from both directions?), or is there a good reason to connect up the second output to the second battery?

Any assistance very much appreciated!

 

[Skip 52]

I'm answering my own questions here (as hinted at by the Cyrix-i instructions and confirmed by Brian, at the Nanni Diesel agents, Peachments), in case anyone else follows this trail...

1. The charge from the alternator comes via the starter motor cable, so connect the '87' terminal of the Cyrix-i to the starter battery. This will give preferential charging to the starter battery first, before charging the domestic.

2. Connect one output only from the shore charging unit to the domestic battery and let the Cyrix-i (which is bi-directional) do the relaying of that charge to the starter battery.

 

[GrahamHR]

Sorry, I missed this thread originally. My (Navman) chartplotter used to always shut down when the starter was operated.

No consolation now you've bought some special kit, but there is a cheap effective solution that I've had on my boat for a number of seasons. I think I fitted it before the 2009 season It's home made system using a diode and a small domestic alarm 12v lead acid battery. The chartplotter +ve is fed from the main battery via the diode, but also is connected to the small battery +ve. When the boat +12v drops, the chartplotter still has a +12V supply from the small battery as the diode prevents it having suffering a voltage drop due to the starter. Admittedly, there's always a small voltage drop across the diode but it makes no practical difference to the chartploter or small battery charging ( the small battery is still showing 12.55V, 3+ months after the engine was last run). The small battery is still the original one.

 

[Skip 52]

Thanks for your response, Graham. That's a very neat solution. The battery combiner kit was actually quite reasonable too, £77 including postage (although I see they've put the price up slightly since I bought it - http://www.sunstore.co.uk/VICTRON-CYRIX-I-BATTERY-COMBINER-KIT.html ). The only other expense was an extra isolator switch - £16 off ebay. So I haven't suffered too much in buying the special kit!