Camper Conversation Electrics

[prunty]

A quick question for anyone with experience/knowledge in this area.

I'm putting together one of those portable fold out camper conversion kits for my M59 van and want to rig up a leisure battery for lights phone charger etc, etc. nothing too fancy...

Anyway I've got one of those charging relay kit from e-bay which seems straight forward enough to keep the leisure battery charged without draining the main battery.

So do I now just connect lights and phone charger directly to the leisure battery, do I need fuses, will a standard 240v phone charger work connected directly to a 12v car battery??

Any comments and/or advice on this would be greatly appreciated.

[ffrenchie]

You need something like this for your phone charger. Accessory points are usually fused at 10 amps so an in-line fuse in the positive wire would do it.

[Gadgetman]

If you get that adapter, please mount a switch next to it. Preferably one with a red light on it.
Otherwise that adapter will ALWAYS be drawing a current from the battery.
Waste not, want not.
You may also want a DC-to-WhateverAC inverter, for those cases when something can't be run off of 12V.
This should also have a switch.

[prunty]

I was just thinking of putting a standard 3 pin plug in one of the panels on the camper conversion kit and connect it to the leisure battery and plug the phone in as normal...

[prunty]

After doing a bit of research on this the Voltage Sensing Relay Unit I got of e-bay isn't really worth a dam as it is a 30 amp unit more commonly used in caravans, apparently it would take hours of driving to have any real impact on the leisure battery. So it looks like I'll need a heavier unit, around the 100 amps and heavier cables to be off any real use. After that all other items can be run directly of the leisure battery unless you are planning on using fridges and the like...

[Gadgetman]

Eh... 30Amps is pretty OK, really.

30A is the amount of power it can draw when charging the leisure battery, not how much power it can supply to appliances.
(Most Berlingos have a 70A Alternator, anyway)

How much power are you expecting to use at any one time, and how much while driving?

Please don't tell me that you plan to use a full-size electric kettle...

[prunty]

I realise that and no I don't intend using and major electrical appliances but I was reading a lot of stuff on the VW Camper web site and the problem lies with recharging the leisure battery with the 30A set up. Yes it'll all work fine if the leisure battery is kept relatively high but when it gets to near flat it'll take ages to get it charged again...

I was hoping to have a system that could recharge the leisure battery fairly quickly if it goes flat but from what I was reading the 30A set up could take 7 or 8 hours of driving to do so. I'm no expert hence I was hoping for some educated opinions...

[Gadgetman]

Exactly how large a battery are you going to put into your car?
Remember, you have a weight limit... ;-)
(A 180Ah 12V car battery weighs in at around 100lbs)

Remember that you are limited by the size of your alternator, too, and that some of the systems in your car will also detract from that. ( 2 x 55W H4 bulbs = 110W, almost 10A out of the 70A your alternator can deliver)

I would suggest taking a long, hard look at what you're going to power, and how much it's going to be used.
Stay away from anything that needs AC as not only does the inverter make an awful lot of noise, but it's at most 85% effective, at worst... yeah... sucks power even when idling.

Planning to bring a laptop?
Maybe time to pick up a more frugal one, such as a netBook?
TV? Go down a size, maybe?
Extra lighting? LEDs is the answer.

Instead of shopping at Caravan-related sites, check out some of the stuff available for boats.
Sure, the stuff may be more expensive, but it's also likely to be more durable.

Also, these batteries can be charged with a normal battery charger...

[ffrenchie]

 will a standard 240v phone charger work connected directly to a 12v car battery??

Any comments and/or advice on this would be greatly appreciated.

No it won't you would need a 12v to 240v inverter to run an appliance like that.

[prunty]

This conversion is only intended for one or two night stop overs, nothing too fancy. So basically something to light up the rear cabin after dark and to charge the phones over night.

I think at this stage I'll just use a second battery as I'd expect it to last a couple of days if I don't leave the lights on all night and see how it goes from there and not worry about charging it at all...

I think I'm in danger of over thinking the whole thing, so I'm just going to get out there and give it a shot and see what happens....

Thanks for the comments...