Installing a Leisure battery

[Barrym]

hello,

Can anyone help please.

I need to install a leisure battery, inverter and a charger (not charging from alternator or car battery but from mains.)

This is to power lights and then recharge when mains available.

Can someone provide a diagram of where I should fuse this and what size fuse.


Grateful for any advice.

Thanks.

 

[rosalan]

 

[tonyidle]

If you're thinking of just a couple of lights then fuse close to the battery with a fuse rated for the combined lighting load + 50%. If you intend running more than a couple divide them into groups according to their location & fuse as above for each location.

Fuse size: total Watts divided by 12v then add 50% = fuse Amps.

For example: 25W / 12v = 2A add 50% = 3A fuse

 

[Barrym]

Hello Tony,

Thanks for the reply.

I presume I fuse between the leisure battery and the inverter.

(Is it obvious I'm clueless!!!)

Regards,

Barry

 

[PhilandMena]

Hello Tony,

Thanks for the reply.

I presume I fuse between the leisure battery and the inverter.

(Is it obvious I'm clueless!!!)

Regards,

Barry

Barry, Try Google and You Tube. There's loads of stuff on both sites that will fully answer your questions and take you step by step through the process.

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[Barrym]

I've looked on google and YouTube without luck as mostly it is either about installing two batteries or charging from the alternator not form the mains.

Or have missed the one I need!

 

[PhilandMena]

OK! I'm guessing with these but they may point you in the right direction. Not to worry if they don't as there are some very good experts on this forum who will pop up shortly and steer you in the right direction.

 

[Nasher]

Barry, why do you need an inverter to power lights?

Surely you will install 12v lights to run off the leisure battery & then re-charge via a charger?

I'm a bit concerned you are playing with 240v and you're not sure what you are doing.........

 

[autorouter]

First, you need an battery isolator switch and big fuse close to the battery for safety. The fuse size depends on the inverter power.

Next, the charger. Find the battery capacity in amp-hours (Ah) and divide by 10 to give you the best amperage for the battery charger. Don't confuse the battery capacity (Ah) with the battery 'cold cranking amps' (CCA) current capacity. That's not relevant for this application. The charger should be connected to the battery negative and the main fuse/isolator.

Next, the inverter. They can have many different power capabilities. A 100 watt type will plug into a cigarette lighter socket and can run with a 15amp fuse. A 2000 watt beast will require a 200 amp Megafuse and wires as thick as water hose, permanently wired in with 8mm or M10 connection lugs.

The inverter should have its own isolator switch and fuse mounted next to it. You may want to switch it off if it is not being used, because inverters draw a small current even with nothing connected to the output.

Small loads like lighting should not be on the same circuit as the inverter, because a 200 amp fuse will not protect relatively thin wires used for the lighting circuit. They should be on a separate circuit to the inverter, with its own fuse of suitable smaller size.

Leisure batteries are not intended for heavy current loads, like a starter motor or big inverter. If you try to draw current of more than capacity/3 amps this will shorten the life of the batteries. So for a typical 100Ah leisure battery you should not try to draw more than 100/3 = 33 amps. That means if you want to draw 165 amps you will need five 100Ah batteries in parallel (ie 33 amps from each battery).

 

[Barrym]

Thanks PhilandMena. These don't quite do the job.

Nasher,
The reason we need an inverter is that the lights are 240v and we previously lugged around a generator! Now want to have battery in the van and an inverter and then charge the battery through the appropriate charger from the mains when available.

That all makes sense (and I took advice on the appropriate battery, inverter and charger) I guess I need to fuse this (Tony's advice above). Just need to double check that the fuse is between Battery and inverter. Can't imagine otherwise but.....

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[pappajohn]

I would consider other means of charging as well.
Solar
Battery to battery
Split charge

1/2 dozen 10watt lights will deplete a 100ah battery, to a safe 50% discharge, in 10 hours then you need to find a mains supply to recharge for maybe 8 or 10 hours at least.

 

[Barrym]

Thanks Autorouter.

That's giving me a great steer.

 

[pappajohn]

Just need to double check that the fuse is between Battery and inverter. Can't imagine otherwise but.....

Yes, you need a fuse between inverter and battery but the fuse rating depends on the inverter output watts.
A 150watt inverter will need a 15 amp fuse.
Bear in mind, an inverter still draws 'standby' battery power even if nothing is plugged into it.

Plus on the 230v side of the inverter I would fit a 230v 6amp MCB rather than an automotive type fuse.

 

[autorouter]

I don't know what type of lights you are powering from the inverter, but most lights are LED these days, and they often run from 12V power bricks that seem to be described as 'transformers'. It would be a waste of power to bump the voltage up to 240 volts just to power a transformer that drops it down to 12 volts again.

Also if you are running 240 volt equipment outdoors you need to be careful. Weatherproof fittings and connectors are essential. Also you need a Residual Current Device (RCD) for electric shock protection. If you don't know what an RCD is, you need to take advice before proceeding.