Hi guys, it's just a bit of clarification as i'm doubting myself. Leisure battery runs everything bar van electrics so Radio,Fridge,Heater etc etc....I have a C-TEK to charge it up and run as a "slave" whilst on site, and I fitted a relay off the alternator wire as per Jokers diagram on the old site to top it up as we drive along, went out in the van on Tuesday and the radio didn't work so i thought blown fuse i'll sort it at the weekend, fuses ok but took me a while to decide to check battery voltage, anyway it's as flat as a witches tit 3.8 volts so i've put it on charge, the Main battery is showing a healthy 12.69 volts without the engine running and it's been sat since Tuesday and i ran about with lights on etc so clearly it's charging and holding charge. Now i've waffled i just want to know this. Does the Alternator give priority to the Main battery while driving and that's maybe why it hasn't been topping up the Leisure?. If the Leisure was very flat (maybe i left the radio on?) would it not accept charge from the relay? (the radio didn't work whilst driving the other day but as soon as i connected mains this morning and tried it, it worked, this suggests to me that whilst the engine is running the Leisure battery isn't getting charge because normally once the Alternator is spinning even a dead battery will show power to the radio etc as it's now just being fed by the Alternator), but clearly the Alternator is working as my Main battery is charged. To cut to the chase once the Leisure is charged off the C-TEK how can i test if the Alternator is topping it up?, if i put a volt meter on it should it show charge being taken or will it not give charge until the Main battery is full?, i don't really know the ratio of how the relay decides to share the Alternators output, also is there a test to see if the relay is doing whatever it should? note it's not one of them intelligent switching relays just a bog standard one. Cheers Rick.
The alternator doesn't give priority to either battery once the engine is idling . If anything it's determined by the state of the battery, so the LB should be the one that's taking the charge if it's low. The thing to test is if the relay is delivering a voltage to the leisure battery with engine running. You should have it wired up so that as soon as the charging light on the dash goes out, the switching circuit (termnals 85 and 86) allows power from the alternator (terminal 30) to go to the LB (terminal 87). If the relay is faulty this won't happen, but it's very cheap to replace. Of course if the battery is knackered you'll need to swap it but the relay check is the first thing. In my case a worn out relay killed the battery. It was charging but only just. I took the relay apart and found that the contacts were burned out.
it's a brand new leisure battery so i would guess the relay may not be working, if i pull the feed to the leisure off the relay and put a meter on that with the engine running that will check the relay yes?
Stick a multi meter on the 12 volt feed from the relay to the leisure battery you should have over 13 volts with the engine running
With just a normal relay the alternator should charge both at the same time A intelligent split charge system will feed the charge to where its needed most
ok cool, i'm gonna leave it charging all night and then tomorrow i'll get my multi meter out, if it's charging i'll assume i must have left the radio on to flatten it, but that still doesn't explain how the radio wouldn't power up with the engine running.......
the main battery is sound, i may be just creating debate for the sake of it....the leisure has been charging all yesterday and overnight so ill test the relay later i'm guessing it's at fault and hasn't been opening to let the current through to top the leisure up, this is the only explaination i can think of as to why it discharged and then wouldn't power the radio with the engine running because as i mentioned before even a dead battery will power a radio once the engine is running because it uses the alternator then, therefore i can only assume the battery went flat and it's probably never been topping itself up. i'll report back in a bit.
with the engine running the voltage did not change on the leisure battery so i am assuming the relay is not switching to let the charge over to it....i also put a meter on the wire that came off the relay to feed the leisure battery and it shows no voltage when running so i think the relay is dud, during the diagnosis i found a leaking fuel line so i have abandonned worrying about the relay for now and i'll sort it once i replace a fuel pipe.
Your relay should be connected to both batteries an earth & the relay on the RHS of the engine bay:- http://www.sevenkay.com/stoem/splitcharge/
http://www.google.co.uk/imgres?q=split+charge+wiring&hl=en&sa=X&rlz=1C1GGGE_en-gbGB426GB426&biw=1280&bih=923&tbm=isch&prmd=ivnsfd&tbnid=hynUE3BZ6T_LXM:&imgrefurl=http://www.keithandsylvia.co.uk/tech%2520pages/splitcharge.htm&docid=UqWuBN47AhkhgM&w=600&h=385&ei=o3tuTs_tE8nu-gbUl4zeBA&zoom=1&iact=hc&vpx=439&vpy=108&dur=71&hovh=180&hovw=280&tx=159&ty=88&page=1&tbnh=121&tbnw=188&start=0&ndsp=28&ved=1t:429,r:2,s:0
it is wired right just obviously not letting the charge over to the leisure, i've abandonned it for now as i found the petrol leak while checking, i'll fit a new relay and see if it sorts it.
You should have 12V at terminal 30 at all times when the engine is running you should have 12V at terminal 87. Terminal 30 goes to your driving battery Terminal 87 goes to your leisure battery. Basically if you put a wire from 1 +ve terminal to the other the +ve terminal both batteries will charge at all times, but they will also flatten the same time the relay interrupts the circuit. Terminal 86 is earthed When terminal 85 is fed with 12V it allows the relay to connect the 2 batteries together. when the engine is running 30 87 & 85 should all be 12V Your problem is either the loss of feed to the 85 terminal, a loss of earth at the 86 terminal or a dodgy relay.
