connecting car to mains...

I'm having constant problems with battery charging now that winter is here. My drive to work is about 1 mile, and involves starting the car twice (I have to back the car into the road then lock up while I close the gates behind me). I keep having to boost start the car then give it a decent drive at the weekend or a trickle charge if it's lucky.

The problem is worsened by sharing my usage across 3 different Land Rovers, so they can spend a few days stood idle between journeys. The batteries (all brand new) are getting hammered.

What I want to do (certainly on the Burrt, which may be getting a load of PC kit fitted to it and gets less use than the other two) and probably the Disco and Ernie as well is engineer some kind of electric hook-up as per caravan sites. If I can find someplace to mount the socket (a bit of a challenge on the Discovery, but could perhaps be done at the same time as the LPG filler is fitted) I want to fit a battery charger to each vehicle and have it permanently wired into the battery. So I then get home at night and plug the car into the garage to recharge the battery overnight.

Does this sound feasible? Is there any problem charging the battery whilst it is still connected to the vehicle? It strikes me that it is just the same as the alternator does, albeit more gently.

Reply to
Tim Hobbs
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Reply to
the ickys

Good point. All three live outside, which is part of the problem I guess, as they get so cold. Ernie in particular is a sod to start (being diesel) if he's left for a few days and needs a lot of glow plug to get started.

I had only envisaged a low current charge, rather than a fast charge. If the batteries are kept topped up (they are, and one is actually sealed) and the current is low, are they likely to boil up at all?

Reply to
Tim Hobbs

I dont know the practicalities of this, but could you rig a trickle charge mechanism that plugged into a caravan socket?

having had a lot of battery problems lately i was toying with the idea of rigging a socket to socket connection (cos IIRC the caravan socket is always live because of fridge connections) so that I could jump start from a car in the car park at the station without having to worry about popping bonnets. Then I figured the wiring wouldn't cope with starting at that level - but it might just work for your keep the battery topped up requirement

Si

Reply to
simonk

|| What I want to do (certainly on the Burrt, which may be getting a || load of PC kit fitted to it and gets less use than the other two) and || probably the Disco and Ernie as well is engineer some kind of || electric hook-up as per caravan sites. If I can find someplace to || mount the socket (a bit of a challenge on the Discovery, but could || perhaps be done at the same time as the LPG filler is fitted) I want || to fit a battery charger to each vehicle and have it permanently || wired into the battery. So I then get home at night and plug the || car into the garage to recharge the battery overnight. || Just a thought: if you are going to fit a charger into the car, make sure the cable runs to the battery are as short as possible. The voltage drop between (say) the load area and the battery may be too long to allow a good charging voltage. This advice is from a book on caravan repair & maintenance, on the topic of wiring in a battery box (now illegal) into the boot of a car to allow the caravan battery to be charged up in the back of car while separate from the caravan. The writier reckoned that unless you use heavyish cables and keep the wiring runs short, the alternator won't deliver the voltage necessary to kick a decent charge into the battery. No experience of this, or whether it's right or wrong, just passing it on.

On your other point, I have always seen it advised that you disconnect the battery while charging, but like you I can't see any difference between mains charging and letting the alternator do its work, except that a trickle charge is gentler.

HTH

Reply to
Richard Brookman

I did think about just putting a couple of 12v connector somewhere under the car and modifying my battery charger to have a couple of long leads that just plugged in. It would be much simpler than mounting a 240v battery charger on the vehicle.

However, I then couldn't run it on a camp site, nor could I coil up the lead and use it at anyone else's house unless I take the whole battery charger ensemble. I also have bigger ideas for Burrt - he's about to have a PC rig fitted up in the rear and for that I may wish to put standard 13amp sockets in the back. It would be good to pipe

240v straight in and not mess about with inverters while he's used at home, just put the inverters on when I'm out and about.
Reply to
Tim Hobbs

Thanks Richard. It won't be an issue for Ernie or Burrt, but I guess if I fit the connector at the rear of the Discovery (which would be the worst place given the layout of my drive and garage) I could run

240v down the vehicle and have the battery charger in the engine bay. A little challenge for Warren methinks!
Reply to
Tim Hobbs

Only that if you try to turn the engine over with the charger still connected, you'll be pulling a lot of current out of the charger and will blow the fuse, if not something worse.

Surely, from the point of view of safety in the outdoor environment, you'd be better keeping the 240v charger indoors and running 12v out to the vehicles? If you use solid core copper mains cable you shouldn't get much voltage drop.

David

Reply to
David French

In Tim's case, I wouldn't expect this to be too much of a problem. If you're charging a caravan battery, you're looking at putting (say) 25A into the battery for 2 hours in order to charge the battery quickly from the alternator. Tim, instead, will be putting maybe 3 amps into the battery for 16 hours. As the current is so much less, so any voltage drop in the charger wiring be commensurately reduced.

Reply to
QrizB

'tis true, but I'm not doing anything that isn't standard practice in caravans and motor homes. They have electric hook-ups and don't seem to have problems. The sockets are horrid plastic things though, which wouldn't look that good on the wing of the Discovery!

Reply to
Tim Hobbs

|| As the current is so much less, || so any voltage drop in the charger wiring be commensurately reduced. || || -- || QrizB ||

True. And I like the word "commensurately". It's so ... exact.

Reply to
Richard Brookman

In my ExRAF 127 Ambulance we have 2 (for 2 batteries) chargers constantly connected to the battery and a non standard industrial style mains socket on the back. Luckily mine came with the plug too. I've put a caravan site connector on the other end of the cable, and have an adaptor so I can run it off a standard UK socket too. Works like a dream! Of course, this is what it was supposed to do in the hanger in service - trickle charge the battery so the vehicle was always ready to go. It also has a coolant and oil heater run from the mains, so there's no need to use the choke! Clever, these MOD guys!

Cheers,

Rich

Reply to
Richard Lock

Thanks Rich - you've got me thinking. Rather than a traditional caravan hookup, I could fit a second towbar socket to the rear of the cars and make up a lead with a towbar plug at one end and a caravan hook-up plug at the other. The towbar electric sockets are made to survive in that environment after all. The question is whether they would carry 240v without something nasty happening?

Whereabouts is the socket on your ambi?

Reply to
Tim Hobbs

Hi guys

Just been reading threw the thread about you needing to charge some batterys up while in situ on the vehicle.

From the original post it sounds like you rotate the use of your vehciles every couple of days but you know what one you will use tomorrow for eg a disco today a 101 tomorrow and the next day and a s3 after that just eg here.

Why not do what the break down crews do and fit a 12v socket on the vehicle I see these fitted regualry on single seater race cars as I spend my time at trakc side and help now and then to strat the odd one. you would need one each of the same type on each vehcil and the opposit end a length of maybe 4 gauge cable this can be bought in halfords or any decent auto sparks supplies then just connect the other end to a charger in the garage or portch eaither way you are going to need to run a cable out of the houes maybe put a waterproof socekt on the outside wall if your just going trickle charge the battery the 4 gauge should be able to deliver a charge with minimal loss over the length this way you can change the charger between vehicles at a moments notice and your not messing around with a 240 mains feed out in all weathers.

If your worried about frying anything fit and isolater switch with a fused link to maintain the memory on the radio and alarm and what not and if anything does draw too much then it will simple just pop the fuse.

Thats also a great way to imobislise your vehicle to isolate the feed as long as you isolate all 12v in or the battery ground to chassie then if you pull the isolator then it will cut everything great if you have an electrical problem or electircla fire would recomend this if your going to be fitting inverters onto anything as you can kill everything in one go hence why they use them on race cars if you pull it and it carrys on running or lights are on etc thats there day over till they can show a working isolator.

Just my 2p oh hell maybe 10p worth just seen the length sorry guys didnt mean to write a book.

hope you get it figgured out just thought it would be easier to use 1 12v feed out than fitting chargers to each then a 240mains feen out the house if that got wet :-(

All the best Paul

Reply to
Paul Henry

Tim,

Glad to be of help! A picture speaks a thousand words, so:

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(or in front, depending how you see it!) the mudflap on the offsiderear tyre - it's the grey box. Cheers,

Rich

Reply to
Richard Lock

It's definitely easier to do this, but it will only work at home. While I'm doing it I'd like to make a solution that will work on camp sites or anywhere else.

I don't actually know which car I'm going to use on a given day.

If I can't be arsed I take the Discovery, because it usually starts and it's easy to reverse off the drive (it has side windows)!

If I'm feeling lucky and it isn't really cold I try to start Ernie.

If I'm feeling lucky, it isn't really cold and I've got time on my hands I back Ernie off the drive, park him up, start Burrt, call the missus to guide me out (there is no way of doing it in rush hour without a guide), park up Burrt, put Ernie back on the drive, close gates, get back in Burrt and do the 2 minute drive to work! So I don't go in the 101 very often TBH.

Reply to
Tim Hobbs

I use an Optimate charger all year round to keep the battery on my bike in peak condition - it plugs into the bike equivalent of a cigarette socket

They are made by Accumate.

According to this page:

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youneed to choose between the AccuMate or AccuMate Pro for car use. HTH Richard

Reply to
Richard Savage

Bung a relay in the circuit, with the charger connected to the n/c contacts and activate the relay from the ignition switch.

Reply to
David G. Bell

If its only 2mins drive to work why not invest in a bicycle, far more environmentally friendly than a v8 starting for 2 mins day............

Reply to
TL

I've given up carbohydrates, I've given up drinking and I work 60 hours a week. And now you want me to ride a bike to work?

:-)

Reply to
Tim Hobbs

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