Fitting 12 VOLT BATTERY SPLIT CHARGING RELAY

[bigcol]

Thanks all

 

I do things the hard way, being tight with the money, getting the wrong size cable and not understanding electrics.

I have made my own problems, but jumped at a post in 2012 that I don't need thick cables, and then making the post work for my by cost cutting.

 

25mm cable from elect quest, who will refund me the split charger as well But is this big enough still?,

See this is me 25mm metioned and it's gospel, but this isn't big enough still.

 

This time I will do the job right!

 

It was 2 x 15 mtrs I ordered last time, only using 2x13 mtrs, as Nicknorman says the engine room is mid or 2/3 rds of the length.of boat

 

Here in the yard I can get big compression tool to crimp.

 

Alan's posted a link is for 70mm,is this the size I should had bought ? Lol. Makes my 7mm cable a joke, then 25mm was metioned ?

 

me being me,I will spend the money today, but if I can get a good price, or a optimal cable in between brilliant.

 

But am looking for cables around 70mm

 

So £200 quid for cable, £300 quid for chain

 

Fagins going to have to find his wallet,I'm always trying to save money, yes I'm tight admit it

 

3 weeks of beans on toast then?

 

Thank you all for your patience, but slowly this post has found the true problem,wheedling out the symptoms, stopping me making possibly other mistakes with split charger, and the connecting to a bigger alternator.

 

But you've finally drummed it in.

 

Beers all round?

 

So 50 mm cable, and uncalibrated anchor chain then?? Lol. Only joking

 

I've learnt my lesson

 

Col

Edited February 10, 2014 by bigcol

[nicknorman]

There is no "right answer" for the cable size. It is a sliding compromise between cost, and swiftness of recharging. Up to you to decide where in the compromise to place yourself. I would price up 25, 35, 50 and 70 and see what comes out of that. My gut feeling is that 35 would be right for you, but that is only a guess.

[bigcol]

I've done it

 

Just ordered 70mm starter cable x 30 mtrs

Will be here by end of the week

Got a good deal with local auto electrics company.

 

 

 

Before I send back the split charger,

I imagine that the 40 amp alternator was not meant to charge more than the engine battery, let alone BT battery's

could I use the split charger re 150 amp alternator, or look out for another alternator.

 

Quote Paul C

I'm thinking, it may be worth having a dedicated mains battery charger instaled near the bow thruster batteries, and using eg an inverter (you may already have one) to power it.

 

 

Or, a dedicated alternator controller with a battery voltage sense wire, so that the alternator could output eg 16V, so that with losses, the voltage at the bow thruster battery bank is eg 14.8V.

 

End of quote

 

Have 30 amp sterling charger which charges the 2 battery banks which does charge BT okay

 

Re dedicated alternator controller Sounds the ticket, but this does not sound like something I could do

 

and out of interest folks with BTs how do they get on?

Or do they do things the right way first time round

 

Anybody on this thread wants 7mm cable red and blk 13mtrs both Foc

Also if I'm not going to need split charger. And it will do you a turn I will send free, or small donation to

macmillan or cancer charity

 

Col

Edited February 10, 2014 by bigcol

[Paul C]

 

Have 30 amp sterling charger which charges the 2 battery banks which does charge BT okay

 

 

Col

 

How can it, if the domestic battery bank and BT batteries are 13+m apart? The idea is you'd use mains power (cable) for the long distance to the front of the boat, then a short run of 12V cable so voltage losses aren't too bad.

[nicknorman]

Now that you (will) have 70mm cable, you need to bear in mind By'eck's point about split charging with the domestic bank. If you use the split charge relay with the domestic bank it means that the domestic battery bank will supply lots of current to the BT when you use it. If you use it excessively you might find that after cruising the domestic batteries are not fully charged, although hopefully the 150A alternator will make this effect not too bad in practice. But your 70mm cable will be able to drain a lot of current from the domestic bank (especially if the BT batteries are flat or knackered) when the BT is on. So the fusing and relay will need to be rated to this current.

 

In an ideal world the relay should open when (just before) the BT is used, to prevent these problems, but that is perhaps a bit complex to achieve in practice without some electrickery.

How can it, if the domestic battery bank and BT batteries are 13+m apart? The idea is you'd use mains power (cable) for the long distance to the front of the boat, then a short run of 12V cable so voltage losses aren't too bad.

But it will charge the BT batteries - eventually!

[bigcol]

How can it, if the domestic battery bank and BT batteries are 13+m apart? The idea is you'd use mains power (cable) for the long distance to the front of the boat, then a short run of 12V cable so voltage losses aren't too bad.

 

Yes your right!!!

I don't notice it, because Im not motoring the boat from 1-3 months at a time

And sitting here in the mooring after a trip out, the charger has weeks to top up th BT battery!!

 

Saying that there is a 240 socket in range by the BT batterys so could get a battery charger there.

 

Col

[Paul C]

No I'm talking about a proper, permanently wired, 3 stage battery charger which can be selected to run from shoreline mains AND inverter-supplied mains (something you'd normally never wire a battery charger too). I suppose a plugged-in mains charger into a socket would do the same thing, but you'd need to make sure the cabling and installation are all okay, what with the 12V cables on the end of it having 2 large batteries at the other end. For example it would need to be mounted securely, not just ad-hoc placed on a table.

[bigcol]

Mine and Nicknormans post crossed above

 

Just shows what a cock up I made of this

 

Embarrassed

 

For info. BT fuse is 355 amp

 

Col

[by'eck]

 

How can it, if the domestic battery bank and BT batteries are 13+m apart? The idea is you'd use mains power (cable) for the long distance to the front of the boat, then a short run of 12V cable so voltage losses aren't too bad.

 

It can perfectly well if the BT charge cable is of adequate cross-section. My BT battery banks 50 amp mains charger is situated in the engine room and uses the same 35mm² fused BT charge cable that the alternator uses. I also have a second Victron battery monitor with shunt/sensor located by the BT batteries. I regularly see over 14.5 volts and/or charge current near full capacity of charger.

 

Before I send back the split charger,

I imagine that the 40 amp alternator was not meant to charge more than the engine battery, let alone BT battery's

could I use the split charger re 150 amp alternator, or look out for another alternator.

 

Col

 

The 40 amp alternator should be fine charging the two BT batteries. You can also use your multi-output battery charger to feed down your humungous BT charge cable as mentioned above. This may be useful if its already installed in the engine area. It will not be an issue.

 

Having said that if you were using a dedicated single output mains charger, it would make sense to fit it adjacent to the BT batteries.

Edited February 10, 2014 by by'eck

[bigcol]

Believe me I'm there it's finally sunk it my head

I'm there, wrong cable.

 

I'm scared to ask this question but.....

 

So when I get the cables, what would happen if I connected it to the 150 amp alternator direct

 

Will not a split charger stop power being used/drained from domestic battery's,

but only allow the alternator to direct its charge to the BT bank when needed

 

Is this what a split charger does??

 

It must be frustrating for you folks trying to educate us non engineering people

 

Another thank you

 

Really wish I could buy you all beers

 

Col

[smileypete]

There's also DC-DC converters around:

 

http://www.ebay.co.uk/itm/1pcs-Boost-DC-DC-Converter-Power-Supply-Step-up-Module-10-60V-to-12-80V-600W-mah-/251286948321

 

Bit fiddly as they'd need to be disconnected when the engine is off or the BT is used. Also would need some fan cooling if working flat out. They'd need to run off the main domestic bank too.

 

Nice thick cable would be a lot more straightforward!!!

 

cheers, Pete.

~smpt~

Edited February 10, 2014 by smileypete

[Paul C]

Believe me I'm there it's finally sunk it my head

I'm there, wrong cable.

 

I'm scared to ask this question but.....

 

So when I get the cables, what would happen if I connected it to the 150 amp alternator direct

 

Will not a split charger stop power being used/drained from domestic battery's,

but only allow the alternator to direct its charge to the BT bank when needed

 

Is this what a split charger does??

 

It must be frustrating for you folks trying to educate us non engineering people

 

Another thank you

 

Really wish I could buy you all beers

 

Col

 

QN1: answered already in post #27

Qn2: no

Qn3: no

 

The circuit diagram for the split charge relay is printed on the side of it. All it does is joins two (big) connections together, when +12V is applied to the other (small) connections.

 

I'd strongly recommend you get a competent boat electrician to look over your suggestions, and possibly do the work, it will possibly save you hundreds of pounds in buying the wrong items etc and also save you from wiring the batteries and other items up in an unsafe manner.

[Paul's Nulife4-2]

Hi ya Bigcol,

Glad it's all been sorted,,(keep it simple & safe) I told you electrics can be a nightmare to understand.

Have you had a BT before ?. Sometimes it's better to just use the main eng in the boat for propulsion, & keep the pointy end of the boat in the direction of travel whilst cruising,,using the BT in 2 or 3 seconds bursts to assist close quarter maneuvering ! . ( you know I'm only joking Col,I use my bow & stern thruster A LOT, seams silly having them otherwise in my book)

 

BTW you could always put a small Solar Panel to the BT battery via a regulator !. Then if the battery hasnt fully recharged when you turn of the main Eng, it may help to top it up.if you have no shore pwr that is.

Oh no,here we go again he he he

Edited February 10, 2014 by Paul's Nulife4-2

[nicknorman]

Is this what a split charger does??

 

Col

Not really. A split charge function can be achieved in a few ways:

 

Using a relay (like the one you have bought) - this just connects the alternator and the relevant battery banks all together (in this case the domestic and BT batteries) thus the BT and domestic batteries effectively become one big bank. This would be fine were it not for the BT's ability to drain lots of current when you use it.

 

Using diodes. This has the advantage of not allowing one battery bank to be drained by the other. However the diodes have an inherent voltage drop of around 0.7v or more, meaning that you have to start off with a higher voltage or use remote voltage sensing for the alternator's regulator.

 

Using an electronic gizmo called a zero volt drop splitter. This is an electronic equivalent of the diode splitter, but it doesn't inherently drop any voltage. Perhaps this is the best option for you, but as with all these things, also the most expensive. Some say that these devices tend to fail relatively often, others don't. I have no personal experience either way. By'eck referred to this concept in post #9.

Edited February 10, 2014 by nicknorman

[by'eck]

Believe me I'm there it's finally sunk it my head

I'm there, wrong cable.

 

I'm scared to ask this question but.....

 

So when I get the cables, what would happen if I connected it to the 150 amp alternator direct

 

Will not a split charger stop power being used/drained from domestic battery's,

but only allow the alternator to direct its charge to the BT bank when needed

 

Is this what a split charger does??

 

It must be frustrating for you folks trying to educate us non engineering people

 

Another thank you

 

Really wish I could buy you all beers

 

Col

 

You might want to look at the splitter I have been referring to on this datasheet. My three output version is linked to an external alternator regulator (booster) on my second alternator as in example 4 below.

Its one of the best bits of electrical kit I've fitted to the boat although I admit not cheap - does exactly what it says on the box, solving many issues in one go whilst offering a second means of charging the domestic bank if my 160 amp alternator goes down. It replaced the diode splitter I was intending to use.

[Loafer]

Wouldn't all the above ar$e and expense be rendered unnecessary simply by not using an unnecessary bow thruster? A car ferry or ocean liner needs bow thrusters. Why does a pleasure boat need one?

 

It only takes a week to learn to steer, doesn't it? Or a day?

 

I saw one Narrowboat coming out of a lock last year, STEERING by sole use of it's bow thruster. The tiller wasn't being used at all except as an armrest.

 

Oh dear...

[Paul's Nulife4-2]

I'm obviously crap @ helming !.

If you got it,,use it,,why not !.

[Alan de Enfield]

I have never had a bow (or stern) thruster on any of my boats - I have had them when I've hired boats.

 

Lets be clear - I dont want one !!!

 

In windy conditions they can be of great assistance entering or leaving a lock - also if there is a by-wash.

I would suggest that anyone who has one will become reliant on it - they shouldn't as one day it will 'break' or the battery be flat then you are 'snookered'

 

Learn how to do it without, then occasionally use it if you get in a mess - don't let it be the 'norm'.

[Loafer]

I once heard an old working boater say that, had there been bow thrusters in the early days of engined working boats, they would have had them.

 

What a sad loss of skills there would have been!

 

I have always advocated training properly, using the minimum of 'toys', then use your toys a bit once you know how to so things 'properly'. After all, many of these toys can fail when you were hoping to use them.

 

The RAF train their expensive fighter pilots to operate with a map, compass, stopwatch and airspeed indicator, before they let them use GPS and moving map displays, autopilots and the like.

 

Learn to do things the old way, then play with the toys once you know how to do without them. PLEASE!

 

Edited to correct some of the syntax.

Edited February 10, 2014 by Loafer

[Paul's Nulife4-2]

Yep,good advice. & it's very admirable to not want, OR not become reliant on advancements in technology or comfort on your boat.

Still having a Horse pull your boat ?, Dedicate 85 % of the total length for cargo carrying. Use candles or paraffin for lighting. & not use cars, phones or computers incase they break down.

Learn to walk,use semaphore & Morse code first.

Edited February 10, 2014 by Paul's Nulife4-2

[Loafer]

Yep,good advice. & it's very admirable to not want, OR not become reliant on advancements in technology or comfort on your boat.

Still having a Horse pull your boat ?, Dedicate 85 % of the total length for cargo carrying. Use candles or paraffin for lighting. & not use cars, phones or computers incase they break down.

There's no need to go to extremes! (Although I DO use paraffin lamps because we like the colour and, weirdly, the smell!)

Yep,good advice. & it's very admirable to not want, OR not become reliant on advancements in technology or comfort on your boat.

Still having a Horse pull your boat ?, Dedicate 85 % of the total length for cargo carrying. Use candles or paraffin for lighting. & not use cars, phones or computers incase they break down.

Adherence to my recommendations will also make you a better operator.

 

(Edited to apologise for the double quote. I don't quite know how that happened)

Edited February 10, 2014 by Loafer

[Paul's Nulife4-2]

Yes,,maybe using semaphore was a bit extreme..the Horse wouldn't see it as it would be in front.

[Paul C]

I'm obviously crap @ helming !.

If you got it,,use it,,why not !.

 

Which situations do you perceive you need a BT? In other words, in which situations can't the engine + steering alone suffice?

[Paul's Nulife4-2]

It's just personal choice & a tool or aid that makes life easier for me or other people at the helm.

Some people like um,some don't. Fine. I say if you have them, Don't be afraid to use them.

Birds have wings,most use them,

Most of us have got two eyes, surly we don't need both of them, but if you've got two, don't be afraid to use them.if you don't want to, then fine. Get an eye patch.

[nicknorman]

It's just personal choice & a tool or aid that makes life easier for me or other people at the helm.

Some people like um,some don't. Fine. I say if you have them, Don't be afraid to use them.

Birds have wings,most use them,

Most of us have got two eyes, surly we don't need both of them, but if you've got two, don't be afraid to use them.if you don't want to, then fine. Get an eye patch.

That would be fine if there weren't the downsides of using them - the bank damage, the noise, the difficulty in sorting the electrics (as demonstrated by big col), the cost and maintenance issues - and the ridicule from pompous non-BTers like me! Edited February 10, 2014 by nicknorman