Battery charger installation

[david100952]

I am out of the water for the winter and currently overhauling (read replacing) the electrics. Last year I bought a Halfords "smart" charger to keep the batteries topped up over the winter and as part of the re-fit I am concidering putting in a shorepower plug for use in marinas. I know I need to consider a galvanic isolator but I wonder if anyone has any thoughts on opening up the charger and using the components to hard wire a chrging system rather than spending another lump of money buying Merlin or Blue Sea stuff to do essentially the same thing. We keep the boat (26ft sailing) on a swinging mooring so it's not worth going over the top with the electris but at the same time it wuld be nice not to have to have wires and extention leads all over the boat when we visit marinas every so often.
Any thoughts or ideas gratefully received with thanks..... David

 

[dt4134]

I'm not certain I understand exactly what you mean, but I don't see the need to open up your charger.

Plan A
Once you've got your shorepower fitted (there was a good thread about a month back on the what you need to do to ensure a safe installation) then you can just wire the mains cable of your Halford charger into that.

Plan B
If you don't want to do all that, you can buy a standalone trip switch unit (about £60 from Force 4, last time I looked, so if a chandler can do it for that price...) which you can stow away when sailing. All you need is a means of leading a mains cable on board, which is probably a 50:50 chance you can lead it down the companionway even with the hatch locked.

You could hardwire in the charger to the batteries, with some convenient stowage for the mains cable when unplugged.

 

[VicS]

Before connecting a portable smart charger permanently check what it will draw from the battery when not powered up ....
Mine, a Ring Smartcharger, bought from Halfords draws nearly 80mA.
Nothing to worry about perhaps over a few days but significant over say a month.
I assume the current draw by one intended to be connected permanently will be less. ??

 

[mitiempo]

A true marine charger totally isolates the incoming AC from the DC output. Automotive/portable chargers often don't do this. I would buy a proper marine charger.

 

[VicS]

A true marine charger totally isolates the incoming AC from the DC output. Automotive/portable chargers often don't do this. I would buy a proper marine charger.

Would they be legal?

Would they pass a PAT or is that something a PAT would not cover.

The possibility sounds pretty dangerous whether on a boat or in the workshop

 

[jontifosi]

Take the batteries home in the winter.
For shore connection i have 13amp plug sockets down below on a trip switch, i just plug the trickle charger or tv or heater in when required.
If you hard wire it in, i think you may need to do something tricky when you intend on running the boat not sure if the starter loading might damage a trickle charger or if you forget to turn trickle charge off and run the engine with alternator charging at same time?

My friends philosophy is to just buy a new battery once per year, he leaves it on a swinging mooring and it starts everytime, give it a 15min charge off the engine each time he goes out - lot cheaper than wasting time with wind generators and solar panels.

 

[dt4134]

Would they be legal?

Would they pass a PAT or is that something a PAT would not cover.

The possibility sounds pretty dangerous whether on a boat or in the workshop

Presumably it just means the DC isn't isolated from the mains earth.

 

[david100952]

Sorry if I did not fully explain my goal but here goes...We were on a training course late last year aboard a Bavaria 34 and it had a plug fitted on the transom for shore power and on the fuse panel was a switch to choose battery or shore power. When switched to shore power the batteries would be topped up and undoubtedly there were components similar to those in the Halfords chager permanently wired into the system in order to do so. The purpose of my "opening the box" was to use (canibilize) the components, swithes etc within my new panel rather than buying Stirling or other expensive marine modules to accomplish the same end, i.e. have an integrated system that did not involve draping wires down the companionway but did not cost a fotune.

 

[dt4134]

You can do it in two stages. First fit shorepower. So you need an inlet plug, RCD breaker, RCBO etc. There are safe and dangerous ways of doing it, see earlier thread for details.

It would also allow you to add a mains socket for general use.

Then you wire in your shorepower charger (with a mains on off switch) to the battery. Take serious note of the point made earlier. If your Halfords charger is connecting one pole of the DC to the AC Neutral or Earth that could have serious consequences to any metal hull fittings via galvanic corrosion.

 

[nigelmercier]

I bought a Halfords "smart" charger...

I very much doubt that a smart charger from Halfords is all that smart.

 

[VicS]

I very much doubt that a smart charger from Halfords is all that smart.

How smart their own brand of smart charger is I would not know but they do offer a number models from the Ctek range. They are all 8 stage chargers I believe.
Also the Ring Smartcharge+12. I believe one of the Ring Smartcharge+ range was voted best buy or something in a recent review in PBO or one of the other boating comics

 

[nigelmercier]

Also the Ring Smartcharge+12. I believe one of the Ring Smartcharge+ range was voted best buy or something in a recent review in PBO or one of the other boating comics

In that case I withdraw my tongue-in-cheek remark

 

[VicS]

In that case I withdraw my tongue-in-cheek remark

You should have used the tongue in cheek smiley ......

 

[jontifosi]

I very much doubt that a smart charger from Halfords is all that smart.

Not usually anything too smart about halfords, pretty much a last resort shop

 

[concentrik]

Sorry if I did not fully explain my goal but here goes...We were on a training course late last year aboard a Bavaria 34 and it had a plug fitted on the transom for shore power and on the fuse panel was a switch to choose battery or shore power. ........

Interesting that Bavaria have adopted the dedicated charger / dedicated 12v PSU option. It's what I decided to do after lots of helpful replies on this forum....

http://www.ybw.com/forums/showthread.php?t=296249

and from several electronics fora, on which the overwhelming opinion was 'seperate systems'. I also got an earful (but no cogent explanation) from Mr S. In the end it seems that a parallel DC load turns a smart charger into a simple charger. I'll shut up about it now.

 

[mitiempo]

We were on a training course late last year aboard a Bavaria 34 and it had a plug fitted on the transom for shore power and on the fuse panel was a switch to choose battery or shore power,

This doesn't make sense. Shore power and 12 volt power are totally separate systems. The 12 volt system - lights, pumps, etc - should be active whether or not shore power is selected. If shore power is selected it allows the use of the charger, hot water heater and any other AC appliances but does not replace the DC system, but adds to it.

 

[concentrik]

This doesn't make sense. Shore power and 12 volt power are totally separate systems. The 12 volt system - lights, pumps, etc - should be active whether or not shore power is selected. If shore power is selected it allows the use of the charger, hot water heater and any other AC appliances but does not replace the DC system, but adds to it.

Unfortunately they're not totally separate on many installations. Have a quick look at the thread, it explains the thinking behind it:

http://www.ybw.com/forums/showthread.php?t=296249

adds to it is the problem.

 

[DavidGrieves]

on the fuse panel was a switch to choose battery or shore power. When switched to shore power the batteries would be topped up.

This switch on the Bavaria... was it not just to switch between 240v being supplied via shore power or 240v being supplied via an onboard inverter?

Why not fit your 240v mains shore power with a few 240 outlets abound the boat, then just secure your smart charger somewhere (dry and well ventilated) on the boat. Plug it into one of your sockets. Switch it on, off or unplug as required.

I don't think there is any need to take apart your existing charger. You might have to extend some wires though...

 

[mitiempo]

Unfortunately they're not totally separate on many installations. Have a quick look at the thread, it explains the thinking behind it:

http://www.ybw.com/forums/showthread.php?t=296249

adds to it is the problem.

I am familiar with the other thread - I posted on it 3 times.

A proper charger (any marine charger I have used or installed) can cope with any loads as they are turned on while charging. If on float(13.4 - 13.6 volts) the charger will go into bulk/absorption mode to make up for the draw on the batteries. They are not totally separate but work together without problems.