JA5ONS

As you may know, i have a reasonable power consuming electronics system in my car (HU, Amp, LCD, Computer, TV tuner, Inverter) along with a few other things i can plug into the system, all isolated to run off a second battery when the car is off.

My question, is there a way, that i can have a 240v plug, so when i have access to a outlet, i can plug it in and charge the battery, WITHOUT disconnecting the battery/open up the water plugs of the battery.

I am sick of flattening the battery well working on it in the shed type thing, and more long term, if i go away, roll out the swag at a caravan park (powered site) and leave the music playing for ages, and not having to bother about starting up the car and running it for ages to keep charge in the second battery.

I always thought, simple battery charger, however, my understanding is that when charging, the battery should be disconnected, as well as the water plugs opened.

Ideally, i want to have this device(whatever it is) next to the second battery under the tray, permanently wired to the battery, and i can set up a little 240v male plug (like those on the sides of caravans) in the tray, so i can plug a lead in, and away we go, no need for taking out 20 screws, disconnecting the battery, not been able to use the system until its charged, bla bla bla.

Any ideas would be greatly appreciated.

PS. for any sparkys, what should i do in terms of earthing, im a big fan of proper earths when playing with 240v, should i have a nice little spike that i hit into the ground when im parked , with a cable attached to the body? or is that un-needed?

cheers.

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76lxhatch

A small trickle charger shouldn't present you with any problems using it this way. You can get the small ones that are basically just a DC adapter and plug into the cigarette lighter socket too - relatively easy and compact. One of these small ones wouldn't keep up with any significant drain of course but might provide just enough charge to avoid problems.

Given the rate of drain that you seem to be experiencing though I'd venture to suggest two other options. Firstly perhaps you need a bigger battery if it never lasts long? Secondly with the caravan park thing it might be simpler just to set it up so that your 240V gear can run from the external power instead of the battery and inverter to save draining it.

Edit - the caravan equipment doesn't usually use a standard plug and requires some sort of electrical cert. A competent auto sparky or mobile home place should be able to help you with this but there will most likely be some cost involved.

JA5ONS

thanks mate,

well, the battery normally lasts decent, its a decent size AC Dalco that is only 9 months old, it lasts a good 16 hours with all my shit running, but im thinking of a few days running it all, without starting the car type thing.

as for the caravan stuff, we use a 15amp socket, wich has the larger earth pin, but that bits easy, the old man was a sparky for 25 years. the brother is a sparky. and I'm about to get into a sparky apprenticeship.

So these trickel chargers, if i was to leave it plugged in 24/7 for a few days, and i only use the system for 1/3 of the time, would you think they have a chance to keep up with me?

I'll have a quick Google about them,
thanks 76lx!

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Bundy & Coke, now cheaper than petrol: drink, don't drive.

76lxhatch

A trickle charger probably wouldn't keep up with much, I just thought of that when you said you didn't want to disconnect the battery and open the caps. Sounds like you'd be better off setting up an external power supply that you can switch to when plugged in just like a caravan. If you wanted to automate this and be able to run it via batteries seamlessly, maybe a computer UPS? They take 12V batteries (alter it to use yours instead of the tiny one inside the unit) and include the inverter as well as spike protection etc. Plug in the power and it charges the batteries and runs the appliances, remove it and they run via battery without switching over or having to turn off. You'd want to disconnect the warning beeper though, it would piss you off!

Lucas' Deville

Just remember when the car is running, so is the altenator, charging the battery. I'm and electrician and auto installer. The plugs don't need to be off when charging, that's why they have small breather pin holes in the caps. You can get kits from repco, autobarn etc... where you can charge to batteries of the 1 alternator, eliminating the need for a 240v Ac charger. There is a bit of wiring involoved but you do seem to have some idea about it. Narva make's a kit to do that, plus and isolator to prevent both batts being used at once. If you would prefer to put a charger on the batt via 240V AC you can get small smart chargers which you can either leave connected, or the terminal plug stays connected so all you gotta do is plug it in. The chargers internals have a large diode in the circuit to prevent power reversing back. A lot of motor bikes leave these charges conected in parallel for that reason. You don't need to worry about an earthing rod, where the 240V plug is connect in the wall GPO it has to by law have it's own MEN (multiple earth / nuetral) line protecting you, when it goes through the charger it's transformed to 13.5V DC not requiring an earth, that's why most plastic cased chargers wont have an earthing pin. I think check out the duel chargers from Autobarn, repco etc so you just use your alternator.

70rey

if you check with someone like battery world they may have something like what your chasing.

Lucas' Deville

Yeah Ja5ons, i'm with 70rey. Battery world should stock duel batt systems.