reb78 Posted July 8, 2016 Share Posted July 8, 2016 For several years, i have been meaning to get around to installing a second battery and some sort of split charge. Anyway, i still haven't found the time! Next week we are going off camping and it would be nice to have a second battery (just sat in the back) to run auxillary bits off of when parked up without the risk of flattening the main battery. So i can charge this spare battery when on the move, can i simply wire it up to a 12v plug and plug it in to the 12v socket at the front and then connect to the battery with some insulated crocodile clips in the back, or do i need to be more technical than this?! Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 8, 2016 Share Posted July 8, 2016 For a run that length you'd really want fatter cables than a socket will give you, that and a socket is rated to 10A, and very flat battery can take 25A, so all you'll likely do is blow a fuse Some fat wires and croc clips will work though, just wire in parallel across the first battery, unclip both ends when parked. There are better ways,as i am sure you know, but appreciate you are in a hurry Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted July 8, 2016 Share Posted July 8, 2016 To limit the current to the 2nd battery from the lighter socket you could put a sidelight bulb in series.That said, I fitted on of these to the ambulance and it solves the problem nicely, the cheaper version is here, or you can do the classic split charge from the alt warning light using a standard 12v relay and suitably rated wire. Quote Link to comment Share on other sites More sharing options...
reb78 Posted July 8, 2016 Author Share Posted July 8, 2016 Thanks chaps. I have mudstuff sockets rated to 16 amps in the front with some thick cable running to them. I also have a run or 2 core 4mm2 cable that i coudl use for this but i am guessing you mean thicker than that Bowie? I had to go and look up how the bulb works Fridge! Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 8, 2016 Share Posted July 8, 2016 4mm should actually be fine, rated at roughly 36A... Personally I wouldn't risk running it from the sockets, unless you use the above bulb method -though it will increase charge time of course..... TBH, the faff you are talking about, no reason not to do a simple split charge as Fridge outlined -oil pressure switch is a good one as the few the electric things connected to the alternator exciter wire the better, imho Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted July 8, 2016 Share Posted July 8, 2016 I'd take any cig socket rating with a heap of salt, they never manage what they claim - and there are very few accessories that will ever draw more than a few amps out of them for any period of time. Most likely is the end will melt. As long as the circuit's fused you could whip the socket out and connect direct to the spade connectors on the back of it, that's what I did in the rear of the FL. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted July 8, 2016 Share Posted July 8, 2016 Never been a fan of relays on the alternators exciter circuit either. Using the standard Aux circuit, oil pressure light or Volt sensing relay for me.... If i hadn't fitted the 2nd Alt. Quote Link to comment Share on other sites More sharing options...
western Posted July 8, 2016 Share Posted July 8, 2016 I use the LR split charge relay to keep my 2nd battery [for winch] topped up, never given me any problems http://www.allbrit.de/UNI.cfm?PAGE=763565&SPRACHE=EN Quote Link to comment Share on other sites More sharing options...
reb78 Posted July 8, 2016 Author Share Posted July 8, 2016 Heres a question that will make you cringe. I have a cheap 150watt inverter. I don't suppose I could plug my battery charger into that whilst on the move? The battery it's charging would be isolated from any draw at that time. I've run out of time before I go away. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 8, 2016 Share Posted July 8, 2016 What current rating is the charger? Quote Link to comment Share on other sites More sharing options...
reb78 Posted July 8, 2016 Author Share Posted July 8, 2016 0.8/3.8 amps? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 8, 2016 Share Posted July 8, 2016 Should be OK, the sticker says 60W Quote Link to comment Share on other sites More sharing options...
HoSS Posted July 11, 2016 Share Posted July 11, 2016 Heres a question that will make you cringe. I have a cheap 150watt inverter. I don't suppose I could plug my battery charger into that whilst on the move? The battery it's charging would be isolated from any draw at that time. I've run out of time before I go away. It would work but its a slightly inefficient way of doing it. You will lose around 30-50% of the power in the inverter, and around 20-30% in the charger. And end up with a slower charge. On the pro side you do get a managed charge. Quote Link to comment Share on other sites More sharing options...
reb78 Posted July 11, 2016 Author Share Posted July 11, 2016 On the pro side you do get a managed charge. Thats what i was hoping. Quote Link to comment Share on other sites More sharing options...
Bluemoon Posted July 11, 2016 Share Posted July 11, 2016 If your charging a 12v battery, do it without the inverter Quote Link to comment Share on other sites More sharing options...
HoSS Posted July 12, 2016 Share Posted July 12, 2016 If your charging a 12v battery, do it without the inverter Say what? Did you read the thread at all? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 12, 2016 Share Posted July 12, 2016 Don't think so Only other thought is as to whether the Lidl charger you have will like the inverter output, but you can test that out yourself Quote Link to comment Share on other sites More sharing options...
reb78 Posted July 12, 2016 Author Share Posted July 12, 2016 Thanks Bowie. Just tried it and it topped up one of my spares fine. It'll only be used when the engines running etc, so it should work ok! Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 12, 2016 Share Posted July 12, 2016 Why not fit a split charge Rich and save a lot of mucking about ! Mo Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted July 13, 2016 Share Posted July 13, 2016 He doesn't have time Mo. Leaving today.... Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 13, 2016 Share Posted July 13, 2016 Well indeed, but the thread started 5 days ago !? Mo Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted July 13, 2016 Share Posted July 13, 2016 I think Rich has taken too long making decisions and playing around with fridges to do the important stuff like adding "Shinys" to his truck Quote Link to comment Share on other sites More sharing options...
reb78 Posted August 4, 2016 Author Share Posted August 4, 2016 Just to finish this off. It didnt seem to work in the end. Once the battery had lost any real charge, the charger couldnt get it back up to fully charged whilst running on the inverter. It did make the charger very hot, so i gave up. Funny thing was that even when we had an electric hook up at one campsite, the charger wouldnt fully charge the battery there either (that was on a 4amp supply if that makes any difference). Once home, i plugged it into a wall socket and the battery was fully charged in an hour or two. Now i will get a proper split charge system sorted so i dont have this hassle again! Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted August 4, 2016 Share Posted August 4, 2016 Dual alternators Richard..... Quote Link to comment Share on other sites More sharing options...
reb78 Posted August 4, 2016 Author Share Posted August 4, 2016 Dual alternators Richard..... Got a spare alt.... Now, where to get the bracket.... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.