John_T Posted December 21, 2005 Share Posted December 21, 2005 Cobblers!!....just fried my split charge system causing the second battery to go flat! My winch is hydraulic so it wasn't that, maybe it doesn't like the amperage the TD5 alternator pushes out. I have just ordered a proper spilt charge kit from X-Eng but it won't be here till after Xmas....must remember to shut the manual isolator switch off in the meantime. My next plan is to fit a voltmeter to let me know if the second battery is getting a charge. I run things like the coolbox and kettle off the second battery. Is it best to use a small relay fired up by an ignition circuit to get it working or is there a better way bearing in mind I don't want it "live" all the time? When the system is charging and the batteries are linked what will the gauge tell me about the main battery? If I have got this idea round my neck has anyone a better idea of how to monitor the charge to auxiliary battery? Thanks Quote Link to comment Share on other sites More sharing options...
rtbarton Posted December 21, 2005 Share Posted December 21, 2005 If I have got this idea round my neck has anyone a better idea of how to monitor the charge to auxiliary battery? If your split charge connects the two batteries together, the voltage accross each will be the same, so a voltmeter won't tell you much about the charge of the 2nd battery. You could connect a voltmeter to the 2nd battery via a "Push On" momentary contact switch, pushing the button with the split charge switched off will give you some idea of the charge of the 2nd battery. Quote Link to comment Share on other sites More sharing options...
western Posted December 21, 2005 Share Posted December 21, 2005 To monitor my 2nd battery, I fitted a voltmeter [or battery condition gauge, genuine LR part PRC7315] wired through a ignition controlled relay, to shut the gauge down when the vehicle/engine is switched off, connected like this [4 terminal on/off relay] Quote Link to comment Share on other sites More sharing options...
rtbarton Posted December 22, 2005 Share Posted December 22, 2005 The point is you should only measure the voltage across the 2nd battery when it is disconnected from the main battery. Quote Link to comment Share on other sites More sharing options...
simonr Posted December 22, 2005 Share Posted December 22, 2005 Better than that! If you can find a Land Rover VSS (Voltage Sensitive Switch) which is fitted in series with the rear de-mist on 90/110s and probably others as well. It is a yellow box, bit like a relay with four terminals and VSS on the side. They are about £90 new, but you can pick them up easily as sodbury & the like from people selling old relays for 50p It monitors the voltage of a battery on two of the terminals and if the voltage drops below about 11v, it opens the contacts of a built in relay. Connect one of the relay contacts to battery positive and the other one to your fridge etc and forget about it. If the battery gets too low - it will switch the fridge off. A gauge is fine - but it won't help you if you leave it on over night (unless you've taken to sleeping in the driver seat and waking up often). Personally, I wouldn't bother! I have a VSS in a plastic box with a pair of lighter sockets and use this to power my cool box etc. Never a flat battery have I! Si P.S. Cheers for the order! Quote Link to comment Share on other sites More sharing options...
John_T Posted December 22, 2005 Author Share Posted December 22, 2005 Thanks guys. All points taken on board and a plan is hatching. Quote Link to comment Share on other sites More sharing options...
02GF74 Posted December 22, 2005 Share Posted December 22, 2005 Better than that!If you can find a Land Rover VSS (Voltage Sensitive Switch) which is fitted in series with the rear de-mist on 90/110s and probably others as well. It is a yellow box, bit like a relay with four terminals and VSS on the side. They are about £90 new, but you can pick them up easily as sodbury & the like from people selling old relays for 50p hmm, I reckon it is possible to make something that will work in the same way using a relay, a zener, transistor and a resitor for less then £4.... but if you wanna pay me £90, I can may 2 for ya (might even be possible to squeeze it iinside therelay casing) as an aside, I have been looking at gutting a maplin £4 voltmeter use as a small panel LCD voltmeter thingie... Quote Link to comment Share on other sites More sharing options...
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