AC Battery Charger

[fridayman]

Are their mains battery chargers (for my leisure battery) that can be left on to charge while the battery is being used (by the fridge, or some lights that are on, etc)?

 

[Crispin]

Most battery chargers will be ok with that. They will rapid charge if the battery is flat and then switch to trickle charge to keep it topped up.

If you have a load on it, it might switch between rapid and trickle a lot but should be ok. Try get an "intelligent" charger and not a cheapy one which will kill the battery if left on for a long period.

 

[fridayman]

What sort of Amps should I be looking at 10A, 18A or 28A..?

 

[Crispin]

What's the size (Ah?) or the battery? What do you intend to run off it all the time.

I think TonyP has a 25A one which he got from Halfords for not much. Works well and so long as your fridge and other toys don't use more than that (not chance of it...) then that would be ok.

Any of the ones you list would do. The only thing would be the charge time would be longer and longer still if your fridge used most of the current.
Put another way, if the fridge is using most of the available current from the charger, it would leave very little for the battery.

 

[TonyP]

Nah I tried the Halfrauds one and it could not cope with the 2 batteries in the 120, so I got one from Machine Mart, a Clarke BC130N (£70).... This one

 

[Steve Wright]

Are their mains battery chargers (for my leisure battery) that can be left on to charge while the battery is being used (by the fridge, or some lights that are on, etc)?

Hi Fridayman

A standard mains charger won't do what you want, as will the Intelligent chargers, as they are only rated at about 10/12 amps for the normal chargers and only 3 amps for the latter,
so if a fridge pulls 10 or more amps then it will never charge it.

What you need is a regulated power supply (PSU) that will give 25 or more amps, that is regulated at 13.8 Volts, then that should give enough to run the fridge, and some to charge the battery.

You need to measure what the fridge, lights etc are drawing ?

 

[Crispin]

but, (assuming) this is a normal travel 12V fridge such as a waeco, Engel or similar, their current there is nothing wrong with doing it this way? (or is there?)

having a quick look at the Engel website, the 40L pulls 2.5A on 12V. You could assume this is only when the compressor is running, which is hopefully not very often.
Whenever it kicks in, it would use the battery and the charger would just top it back up.

I've used this arrangement many times (not exactly the same) without any hassle.

Also, would using a regulated PSU set at 13.8 not fully charge a battery? They should be charged to 14.2V and then held at 13.8V (which is the trickle feature)while on standby (which is essentially what this would be doing)

if we talking double door fridge freezer here, I stand corrected

 

[Jon Wildsmith]

They're out of stock now but I got one of these chargers. Intelligent, 20amp, coped with a pair of elecsol 110ah plus the starter battery. I'm betting you can find them elsewhere with a different label stuck on them

 

[Steve Wright]

but, (assuming) this is a normal travel 12V fridge such as a waeco, Engel or similar, their current there is nothing wrong with doing it this way? (or is there?)

having a quick look at the Engel website, the 40L pulls 2.5A on 12V. You could assume this is only when the compressor is running, which is hopefully not very often.
Whenever it kicks in, it would use the battery and the charger would just top it back up.

I've used this arrangement many times (not exactly the same) without any hassle.

Also, would using a regulated PSU set at 13.8 not fully charge a battery? They should be charged to 14.2V and then held at 13.8V (which is the trickle feature)while on standby (which is essentially what this would be doing)

if we talking double door fridge freezer here, I stand corrected

Hi Crispin

First may I say I am not too sure what those type of fridges take, but if it is a Caravan type fridge, they can draw 20 Amps, so depends what type,and of course that is all the time it on !

But The Intelligent type chargers are fine if it is use just for a battery(batteries) when there is no other load on then (ie when on the bench), they detect the voltage of the battery, and if it is low, it will supply 14.4 volts till it gets to a certain level and then drop back to 13.8 volt, and hold it there, but if you draw any thing off, then it will keep going on and off, and they are not designed for that.

But the " the not fully charging @13.8 volt" is a myth, in fact giving a battery 14.4 (or more) on a constant basis, then that can over charge the battery, now I am not saying don't give it 14.4 volts , but only do that a few times a year,

I have a Caravan and has a on-board PSU rated at 13.8 volt, and it is left on 24/7, and the battery is 8 years old now and is fine, but a couple of time a year I give it a boost on 14,4 volts but have noticed within 20/30 mins it has topped it up and there is no more charge going into the battery.

With playing around with Amateur radio we use adjustable PSU's and I have one in the garage, and is connected to the motor bike battery, and keeps it at 13,8 volts as so it does not go flat while parked up.

 

[Crispin]

Guess that should have been the first question then: What fridge is it and how much does it draw?

Guess then the safest option would be to get something designed for this like Steve said.

 

[Scott]

Have a look at these Ctek chargers: http://www.ctekchargers.co.uk/productindex.php One of these may well be suitable for your needs.

I have the Multi XS 7000, which seems to do everything that you'd need. A few of my friends have them and they are very impressed with them, including one who uses his in his professional workshop and says he couldn't be without it, especially the 12v maintain function, very handy to keep the battery voltage constant during ECU reprogramming.

I sourced mine from Apb trading: http://www.expedition-equipment.com/ind ... 1&Itemid=1

Cheers,

Scott.

 

[Gary Stockton]

I keep my 115Ah leisure battery sitting on a CTEK multi XS7000 charger all the time - no issues. Not cheap though

 

[Scott]

The good stuff never is! It does have the potential to more than recoup it's purchase price by recovering heavily discharged batteries, maintaining batteries to prevent discharge and generally digging you out of the preverbial when a battery starts to play up.

 

[warrenpfo]

You can pick up one of the CTEK Multi XS 7000 for £76 on the Bay which makes it slightly better if that helps with free postage.

 

[Steve Wright]

Have a look at these Ctek chargers: http://www.ctekchargers.co.uk/productindex.php One of these may well be suitable for your needs.

I have the Multi XS 7000, which seems to do everything that you'd need. A few of my friends have them and they are very impressed with them, including one who uses his in his professional workshop and says he couldn't be without it, especially the 12v maintain function, very handy to keep the battery voltage constant during ECU reprogramming.

I sourced mine from Apb trading: http://www.expedition-equipment.com/ind ... 1&Itemid=1

Cheers,

Scott.

As I have said the problem with these type of chargers, they are only designed as a charger, and not a PSU.

Infact the 7000 is only rated at 7 amps, so again need to know the current draw of the fridges !

And some one has mentioned about £70/80 , you can pick up a decent 25 amp PSU for £40/50

 

[fridayman]

They're out of stock now but I got one of these chargers. Intelligent, 20amp, coped with a pair of elecsol 110ah plus the starter battery. I'm betting you can find them elsewhere with a different label stuck on them

I've seen these under a different name. I think it was on the Tayna site... It is on my short list if I can use it as a PSU/charger.

 

[fridayman]

I like the look of the Amperor MV3/250. I read a page where a chap installed it in his caravan and is very happy with it.

 

[Birder]

Accuguard is what I use. It comes with either croc clips or a permanent lead you attach to the battery so you can just plug it on. It's a battery conditioner so you can never overcharge it and you can leave it on forever. There is a smaller one called an Accumate but it's designed for motorcycle batteries but many peple use them for cars.