UdderlyOffroad Posted July 19, 2011 Share Posted July 19, 2011 Sooo, split charging. My truck will eventually have a winch, and Anderson jump sockets front and rear. I’m in the “preserve the starting battery for starting” camp, I.e. winch off battery no 2. But, I’d also like to run a fridge/worklights when camping; so is there a battery that is a reasonable compromise between deep-cycling leisure jobbie and a mahoosive truck battery that will fulfil both roles? I’m not a fan of Christmas-tree light split chargers on the dash, nor do I like voltage sensitive relays, mainly because (apparently) it’s easy to accidentally cook them, and ones rated to a suitable current are mega-£££. So an old-fashioned, aux-circuit switched high-current relay it is, with a battery isolator switch to allow for self-jump-starting. A switch on the dash will allow me to manually turnoff the split-charge should I deem it necessary. So far so conventional. But I have seen one of these: The idea is to connect the winch and jump sockets to the output, so that I can select either battery 1, 2, or both to power these. In ‘both’ mode I can self-jumpstart. Does anyone forsee a problem with this? In particular, this solution involves ‘commoning’ up all the negatives onto one busbar, I have read (somewhere) that it could cause problems? Can’t for the life of me find the link though. If it does, should I run dedicated negatives for all the fridge/lights/aux circuits etc run off the 2nd battery? These circuits will not be switched via the isolater but connected directly to battery 2 via a suitable fusebox. Final question: when winching, should the split charge remain connected? I.e. would it cause funny effects such as attempting to drain battery 1 (assuming I’m winching off battery 2, engine running). I don’t believe it should, provided battery 2 is healthy. Note: The winch will not be for competition use, it will be a recovery/self-recovery only unit. Anyway, apologies for the slight rambling, please let me know your thoughts. Matt Quote Link to comment Share on other sites More sharing options...
rtbarton Posted July 19, 2011 Share Posted July 19, 2011 Numax & Lucas do dual purpose starting and deep cycle batteries, not sure of the quality though. Edit - Spelling - should be Numax not Namax!! Quote Link to comment Share on other sites More sharing options...
Eightpot Posted July 19, 2011 Share Posted July 19, 2011 I've used Numax and found them excellent - can be used as a starter or deep cycle. Ideally use two, one for starting, the second for aux stuff, and that way they are matched in terms of output, charging and can be swapped over. Think you can buy them on the x-eng shop? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 19, 2011 Share Posted July 19, 2011 Tayna.co.uk for Numax CVX-X 100MCA Quote Link to comment Share on other sites More sharing options...
Guest Posted July 19, 2011 Share Posted July 19, 2011 Matt, If I understand you correctly, as far as I am aware there is no technical issue in doing what you want I think the issues are more down to practicality and a common earth would be the way to go otherwise you would have the potential of making a circuit 24v I would see your practical issues as follows: You would have remember to switch and isolate the batteries otherwise the second one wouldn't charge/over time damage each other Drawing loads of power (ie CCA) from a deep cycle battery is not good for its longevity so using the jump start option is not good The charge between the two would not be controlled so when you flicked the switch the batteries would try to equalise potentially causing damage to the batteries If one battery went faulty it would likely take down both. Without a charge indicator how would you know the state of the second battery Personally I would use a split charge as it's pretty much fit and forget you could go for a simple set up with no Christmas tree display and either buy a more complicated kit our make one yourself, starter Solenoid relays are less than £15 (Linky) and would do the job for that money you could buy a second one you could also add a Battery Monitor to your seat base so you could keep an eye on the batteries. Jason. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted July 19, 2011 Share Posted July 19, 2011 Edit: Ignore me...Didn't read the first post properly. Quote Link to comment Share on other sites More sharing options...
UdderlyOffroad Posted July 19, 2011 Author Share Posted July 19, 2011 Thanks for the responses guys, seems I’ve got some thinking to do re batteries. Jason, I think I might have added to the confusion by not drawing a diagram of the circuit, will try and knock something up on Autocad during my lunchbreak at work tomorrow but in the meantime, let me try and explain myself better... Drawing loads of power (ie CCA) from a deep cycle battery is not good for its longevity so using the jump start option is not good Agreed. starter Solenoid relays are less than £15 (Linky) That's exactly the kind of relay I was going to use as the basis of my system. You would have remember to switch and isolate the batteries otherwise the second one wouldn't charge/over time damage each other There would be an indicator light on the split charge switch (N/C) to indicate split charge was on, as well as a warning light (one of the spare ones on the instrument binnacle warning cluster) to indicate that the winch/andersons are live. To be clear, the battery switch would be wired 'in parallel' to the split charge, and would only come into play during winching, jump-starting or self-jump-starting. Again, a decent diagram will help here! The charge between the two would not be controlled so when you flicked the switch the batteries would try to equalise potentially causing damage to the batteries But surely this is the same with all 'dumb relay' type split charge systems (inc those factory fitted by land rover)? It seems to work ok for other folk? As long as the 2 batteries are healthy, that is. Without a charge indicator how would you know the state of the second battery I forgot to mention that there would be Voltmeter on the dash, selectable between batteries 1 and 2, so would enable me to keep an eye on the various voltage levels. I just don't like these lights that illuminate red, green or amber when they think the battery has reached a certain voltage level; far better to know. I think perhaps it would help to know my requirements/wish list for a split charge system: Winch driven off battery 2 (isolatable) Aux circuits driven off battery 2 Jump sockets driven off Battery 1 (Isolatable) Self-Jump-Start-ability No need to access the battery box for any of these operations, as the standard Land Rover seats have been replaced with something more comfortable... The awkward part about this setup is though that it would require 3 battery isolators! The beauty of one of these 'Marine' style battery master switches is that I can use one switch to control them all.. Quote Link to comment Share on other sites More sharing options...
roguevogue Posted July 19, 2011 Share Posted July 19, 2011 Innitially I thought you were suggesting running your winch through the isolator switch but i've re-read it and see that's not it. I was going to point out that the 300amp bit is likely to be the momentary limit rather than the constant limit and therefore not sufficient for winching. However, for what you are thinking of I think your plan is sound. In terms of batteries, I agree with a couple of the other posts that the Numax battery is excellent value for money. I have a pair of Numax and have abused them mercilessly in competitions for more than two years with great results. I think that forum members get a discount too! Quote Link to comment Share on other sites More sharing options...
UdderlyOffroad Posted July 28, 2011 Author Share Posted July 28, 2011 Here it is, took slightly longer than my lunch break to do, but it was a good exercise, made me think about all the connections, what gets connected to where, etc! The schematic isn’t complete yet, I still need to add cable sizes, lengths, etc… The numbers in ovals are usually Durite part numbers, catalogue available here (PDF, large!). Switch part numbers are Carlings Conturas, from Dun-bri. Cable-wise, I’ve tried to follow the Land-Rover diagram convention, as well as the BS-standard wiring colours. As you can see, the isolator switch is placed where one would normally expect to find it, I.e. linking the two batteries to allow for self-jump-starting, but with the winch and jump-sockets connected to the ‘output’. I have tried to draw the isolator switch electrically as I think it should be, hopefully it makes sense. The split charge relay itself is designed such that it should allow me remove it and drop in a ‘proper’ intelligent split charge controller should I feel the need to. The dash-mounted switch might be a little complicated to follow. To save dash space it serves two functions To turn the split charge on and off To select which battery the voltmeter is ‘seeing’ With split charge on, in sees battery 1 – which of course is linked to battery 2, thus the voltmeter should read ‘system voltage’. With split charge off, it sees battery 1 on its own (as long as the ignition is on). Position 2 energises the voltmeter change over relay and the voltmeter sees battery 2. The idea being to enable me to keep any eye on battery 2 level without the ignition switched on, e.g. when camping. Of course, because of the way the switch is wired, it will also engage the split charge, but only with the ignition on. The sparkies and engineers amongst you will point out that I have managed to create some bar-steward-hybrid between a single-line-diagram and a ‘proper’ electrical schematic. This is of course true, but it means I think about how many cables I have running between each ‘area’ (battery box, dash, rear, etc) Anyway, have a look people, let me know you think… Matt Edited to add: Sorry, just realised those p/n balloons are totally illegible in yellow, as well as some of the cables (line thicknesses) have got thinner, something to do with the DWG->PDF process, will try and fix later Schematic First Stab.pdf Quote Link to comment Share on other sites More sharing options...
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