Maverik Posted November 24, 2011 Share Posted November 24, 2011 Hello people, I'm putting in some more Aux electrics and getting around to wireing up my 2nd battery. I want to be able to choose between batt 1 or batt 2 for starting so I purchased a "marine" isolator/switch which is just what i was looking for except its the size of a small house... quite a suprise! Has anyone got a battery switch that is of usuable proportion in a vehicle? Cheers Mav Quote Link to comment Share on other sites More sharing options...
western Posted November 24, 2011 Share Posted November 24, 2011 various isolators here & more here Quote Link to comment Share on other sites More sharing options...
SORNagain Posted November 24, 2011 Share Posted November 24, 2011 You will need two to select one battery or the other of course, but this is no bad thing since you can turn both isolators on if you get really desperate! Do you have a split charge relay or diode pack to charge the battery even though its isolator may be off? Quote Link to comment Share on other sites More sharing options...
Maverik Posted November 25, 2011 Author Share Posted November 25, 2011 hmm I do have a split charge relay setup... but now you've got me thinking I think a wee diagram is in order. Quote Link to comment Share on other sites More sharing options...
finnarne Posted November 25, 2011 Share Posted November 25, 2011 Would it not be easier to set up a second alternator, and have a set of jumper cables if you ned up needing both ? Then run auxiliary things, such as webasto, winch, worklight, fridge, gps etc. of the second battery/alternator. Quote Link to comment Share on other sites More sharing options...
tacr2man Posted November 25, 2011 Share Posted November 25, 2011 The marine type ie rotary is what is the norm in OZ , you cant use split charge type relays to act as isolators , cant handle the current draw. Quote Link to comment Share on other sites More sharing options...
Maverik Posted November 25, 2011 Author Share Posted November 25, 2011 Ok, I have one of these http://www.ebay.co.uk/itm/360395213654?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 but its pretty big, and I can't think of a sensible place to put it due to its size. Its does everything I want. it does work as an isolator, but I also have independant red key type isolators in place also. As you can see the selector allows you to choose which battery I want to use to start the engine from. I have a heavy duty split charge relay which will be installed and be happy by itself. So really i'm looking for the above type switch but smaller/more compact, I'm getting the feeling they don't exist. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted November 25, 2011 Share Posted November 25, 2011 Something like one of these is what you want.. http://www.ebay.co.u...=item35b4aee64a use it to join both possitives. Then if you have a flat starter battery you just close the switch and hey presto, your 2nd battery starts the car.. I will get around to it one day. As said above, split charge is ok but doesnt beat 2 alternators, it gives you 2 separate electrical systems, and easy to wire up as well.. The other joy of twin alts is that if you have big loads on the go, a winch, a big inverter ect OR an alt gives up, using the same switch above to join the batteries (when the engine isnt running, close the switch,start the car) you can split the load accros both alts and both batteries or use it as a very basic split charge when 1 gives up. I run twin 65 amp alts on my 110 and there more than ample. Quote Link to comment Share on other sites More sharing options...
UdderlyOffroad Posted November 25, 2011 Share Posted November 25, 2011 Mav, I was going to do something similar to this; but haven’t actually got as far as wiring it up….see here. A marine isolater which ‘links’ both batteries means you can self-jumpstart without recourse to jump cables in a cramped battery compartment. Particularly useful if you’ve fitted non-standard seats which aren’t removable… I was going to try to mount the isolator switch where the blank is on the seatbox (which covers the hole where the handbrake would go on a left-hand drive truck). This would probably involve hacking about with the battery box, but as mine needs fettling anyway (due to being a rusty mess) I’m sure it could be made to work. By the looks of things the isolator I’ve choosen is quite small compared to most others/ Disclaimer: My setup is quite complex and doesn’t exist anywhere except on paper yet ;-) Quote Link to comment Share on other sites More sharing options...
Maverik Posted November 26, 2011 Author Share Posted November 26, 2011 Something like one of these is what you want.. http://www.ebay.co.u...=item35b4aee64a use it to join both possitives. Then if you have a flat starter battery you just close the switch and hey presto, your 2nd battery starts the car.. I will get around to it one day. As said above, split charge is ok but doesnt beat 2 alternators, it gives you 2 separate electrical systems, and easy to wire up as well.. The other joy of twin alts is that if you have big loads on the go, a winch, a big inverter ect OR an alt gives up, using the same switch above to join the batteries (when the engine isnt running, close the switch,start the car) you can split the load accros both alts and both batteries or use it as a very basic split charge when 1 gives up. I run twin 65 amp alts on my 110 and there more than ample. I don't know why I hadn't clicked before, but putting the 2nd pattery in parallel with the starter battery and putting an isolator in would do just what I want, not quite as flexible, but thats fine. With regard to a 2nd alternator, its a solution, but the problem i have is a location for the alternator as I now have the air box mounted on the redundant AC pump mounts (disco 200tdi) and it took me a while to find that as a suitable position so don't really want to move it. Also I don't really expect my power needs really to exceed the output of one alternator, but I may be wrong. Thanks chaps for your input, went out today and bought another key isolater for battery no2, and a isolater with a toggle type switch for the starter back-up change over part of the circuit... now the easy bit to fit it all up... not... Quote Link to comment Share on other sites More sharing options...
muddy Posted November 26, 2011 Share Posted November 26, 2011 Just out of interest doeas no one fit one big battery? 663 or similar, what sort of current loads/duration are you expecting to run? Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted November 26, 2011 Share Posted November 26, 2011 Just out of interest doeas no one fit one big battery? 663 or similar, what sort of current loads/duration are you expecting to run? The idea of 2 batteries is that you can run anything you like off the leasure battery while camping etc and still have a decent battery to start the car up the next day, 1 big battery still doesn't allow this. Quote Link to comment Share on other sites More sharing options...
Maverik Posted November 27, 2011 Author Share Posted November 27, 2011 Just out of interest doeas no one fit one big battery? 663 or similar, what sort of current loads/duration are you expecting to run? Yeah like VB says, the idea of 2 batteries is to allow you to maintain one battery as the primary starter batter and thats what it stays, powering more demanding equipment of the 2nd battery allowing you to always have enough juice to start the engine. I've as yet not calculated what the approximate current draw off the 2nd battery will be. Quote Link to comment Share on other sites More sharing options...
finnarne Posted November 27, 2011 Share Posted November 27, 2011 Another thing is that it's harder for an alternator to fully charge a large battery. That's also the reason why I have 2 alternators. Two smaller batteries are easier to fully charge with 2 alternators. 2 batteries on one alternator is something like one large battery on one alternator, but a splitt-charge solution somewhat makes it better than if you just connect them together. edit: I think Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted November 27, 2011 Share Posted November 27, 2011 Another thing is that it's harder for an alternator to fully charge a large battery. That's also the reason why I have 2 alternators. Two smaller batteries are easier to fully charge with 2 alternators. 2 batteries on one alternator is something like one large battery on one alternator, but a splitt-charge solution somewhat makes it better than if you just connect them together. edit: I think An alternator will never ever fully charge a battery, no matter what size alternator or battery. Quote Link to comment Share on other sites More sharing options...
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