charging a leisure battery when hooked up

[colouredFunk]

Hello,

I've got a 110 amp leisure battery on a rely split charge from my alt. I want to add a 240volt battery charger when I'm hooked up to 240 volts

I've got loads of stuff connected to the battery; stereo, lights, fridge, zig unit etc.

Can I just connect one of these directly to the leisure battery with everything still connected?

http://www.ctek.com/EN-GB/Buy-Charger.a ... er=mxs3600
or
http://www.tayna.co.uk/Numax-Leisure-Ba ... P6127.html

or any other chargers better?

[bigherb]

Hasn't your Zig unit got a charger built in?
If not then the answer would be yes.
The Ctek chargers are good bits of kit but not high output, Sterling Power do some good battery chargers for leisure use I use the 6A one paid about £30 for it, as they are fan cooled can work for long periods at high output.
http://www.sterling-power.com/products- ... budget.htm" onclick="window.open(this.href);return false;

[Willoughby]

If you have a 12V output when conected to the mains Maplin sell a Lead Acid Battery Split Charge Module for £8.99.
It's rated at 8 Amps continuous.

Using this module it is possible to charge two 6-24V lead acid batteries (e.g. car batteries) from the same power source. The charging current is distributed in such a manner that a discharged battery is charged more intensively than a battery which is almost charged. Ideal for use in motor homes, boats or caravans where the TV, radio, etc. is operated from one battery and the second battery must remain charged for starting the motor.

http://www.maplin.co.uk/Module.aspx?ModuleNo=37767" onclick="window.open(this.href);return false;

Kev

[Red Westie]

My two pence worth.
You need a staged charger that switches to float (min charge) so if left connected for long periods it doesn't boil the battery dry.
In my opinion with such a large leisure battery and so many consumers you need a minimum 10amp charger (poss even higher)

Here is another I found:
http://www.charger.co.uk/switch-mode-de ... -2955.html" onclick="window.open(this.href);return false;

I would be looking for 12/16amps like the charger second from the top.

http://www.caravantechnology.com/Error. ... rgers.aspx" onclick="window.open(this.href);return false;

Then again I know this has been discussed several times so others will be along soon with their suggestions.
Martin

[Willoughby]

What model of Zig and fridge u got?

There may be a better way to sort things out. If it was me I would put the fridge on it's own circuit and only connect it to the battery while driving.

K

[colouredFunk]

Cheers for all the replies!!

My zig unit is completely separate from the 240 hook up, it only has 12volt features. I installed the 240 recently...

The fridge is just 12 volt.

Is the Ctek too small then you think? I like the space saving you get with it, and it's also possible to mount it!

This is the leisure battery I've got :
http://www.halfords.com/webapp/wcs/stor ... 65475#dtab

I don't mind turning the charger off when it's finished charging the battery, I just can't be bothered to discount everything each time it needs topping up...

[Red Westie]

I should have explained ......and given that your fridge is only 12volts, this is more serious than I first thought. When parked up and plugged in to the mains the ancillaries (lights/fridge/radio etc) will be running directly from the leisure battery. If you were to connect an ameter in series to check current draw you are likely to get a reading well in excess of 10amps, especially considering your fridge has a permanent power draw of 6-8amps.
A smaller/less powerful charger unit will effectively be working at 100% trying to maintain the batteries stutus quo BUT with it's output being less than the current being drawn there would be an effective shortfall so the battery will be on a slipperly slope backwards and go flat. More importantly though is the fact that the charger would be under extreme load and likely to overheat or turn off (if it has overheat cicuitry)
The point is, your charge circuit needs to be higher than the current draw and with a permanent 6-8amps demand from the fridge, the charger will need to be at least 12amps....of course this is just an estimation but won't be far off.
To give you some idea...I think the original crude charger in a factory westy conversion is 10amps but remember, they do have a 3 way fridge so will run on mains when hooked up.
Martin

[colouredFunk]

Ahh I see, the picture is becoming clear now

There seems to be 2 different models here... one for just charging the battery when not in use...and the other (which I hadn't thought of ) is charging the battery whilst all 12volt appliances are running. The charger will have to have enough AMPs to handle the load from the appliances and charge the battery at the same time.

For model 1, which is pretty much my original post, I think I've got enough understanding of it all, with the CTEK or similar charger doing the job.

Model 2 however looks slightly more complicated....
Would you always leave the charger running when hooked up? If so, will it not eventually overheat, or damage the battery?

[Red Westie]

To answer that last question of: can it be left plugged in and will it overheat and damage the battery well NO IT WON'T!
Modern multi stage charger units sense battery charge condition and vary their output to a minimum 'float' state (trickle) when fully charged so DON'T damage the battery if the mains is left on. Incidenltly... this is more than can be said for the original black box charger found in a T3 Westfalia.. which hasn't got the sophisticated staged charging circuitry of a modern charger so WILL boil the leisure battery dry.
Martin