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Post by Deleted on Jan 19, 2014 2:00:15 GMT
Situation = brand new vehicle battery last month, my leisure battery is good and holding charge well, it's wired up using Smartcom split charge relay, have had various problems with wires falling out of smartcom (thick wires between vehicle battery and smartcom and the screw sockets for the wires are too small, have tried all sorts in the past, posted loads of queries on t'other forum, in desperation resorted to supergluing the wires in, which seems to have worked and they've not come out since).
Have been doing loads of work in the van over the past week, redoing insulation as by chance I had to lift some and discovered condensation between metal and silver bubble wrap so have completely redone in, using several cans of spray glue, more camping mats, expanding foam etc etc, anyway I digress from the battery issue...
Was working out there this evening and because I'd run the engine for half an hour yesterday I knew the vehicle battery was good (and anyway it's only a month old), and so I switched on the florescent light in the back of the van which is wired off the vehicle battery (it came like that, I put the leisure battery in it). I've got a digital voltmeter wired off the leisure battery via the smartcom, which in theory should show the leisure battery voltage.
But after half an hour with the light on I noticed that the volts on the leisure battery had dropped from 12.5 to 12.2. The leisure battery was not powering anything other than the voltmeter and over the past week, the voltmeter has gone from 12.5 to 12.3 over at least a week. So something was taking power out of the leisure battery but the only thing switched on was the florescent light which is powered by the vehicle battery.
I switched the light off and the voltmeter went immediately back up to 12.5.
I've got plans to overhaul my elecs in the next month or 2 when the weather is better and I can park up and empty van contents outside for the day and sort out my elecs - I've got a fusebox, isolator switch, various rocker switches for various different things (fridge, cig socket, digi voltmeter etc), I need to wire my stereo back in, and run an extension cable from the smart com to a cig socket close to my bed, fit various in line fuses etc etc, so that will be the time to sort out the problems with the Smartcom once and for all - either replace it with a new Smartcom, in case the superglue has buggered it up inside, or preferably to find another voltage sensing split relay which has better wire connection fittings than the smartcom.
But I'm trying to figure out exactly what is happening with the elecs at the moment.
Any comments, suggestions, explanations, advice?
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Post by n brown on Jan 19, 2014 8:57:16 GMT
first,the digital voltmeter does take a small amount of power if left on.secondly I don't know if your set up is van battery to smartcom to leisure battery with a 6mm wire,but a much better set up is to use the smartcom relay with 2.5mm wires to operate a 100amp relay,which connects the 2 batteries with much thicker ,jump-lead size,wires
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Post by Deleted on Jan 19, 2014 13:38:07 GMT
thanks for the reply. The digi voltmeter reads about 0.1v lower than the actual voltage, I'm assuming this is voltage drop and I only have it connected permanently when at home so I can monitor the battery discharge. Last week it took over a week for the voltage to drop from 12.5 to 12.3, which is why I knew something was wrong yesterday when it went from 12.5 to 12.2 in half an hour, when using the florescent light connected to the vehicle battery.
Not sure what size the wire is, Firefox got the right wire for me, but it's 35amp doubled, I think, so 2 strands to twist together which is why it wouldn't stay in the smartcom.
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Post by Firefox on Jan 19, 2014 15:34:33 GMT
They were about 7mm2 cables. Two 3.5mm2 connected in parallel. 3.5mm2 would have done, but put in bigger ones to reduce voltage drop when charging and one can fit a bigger fuse too which has less chance of blowing. Also gives room for second leisure battery. Put on crimp connectors with cut down folded spades which jammed in the smartcom sockets.
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Post by Deleted on Jan 19, 2014 16:42:33 GMT
They fell out too Vern.
But any idea why the leisure battery is powering the florescent light which is only connected to the vehicle battery? How else to explain the voltage drop and rise again when the florescent light was on and then switched off?
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Post by Firefox on Jan 19, 2014 18:42:59 GMT
Only two explanations
1. The relay is stuck on and the leisure battery is permanently connected to the van battery. (Assuming it is wired up right)
2. The voltmeter is connected to the van battery (Input)terminal of the relay and is actually measuring the van battery voltage.
To eliminate number two connect the voltmeter directly across the two terminals on the top of the leisure battery. Switch the light off and on and see what happens. If there is a change in voltage, you'll know it is number one.
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Post by Deleted on Jan 19, 2014 21:05:11 GMT
Only two explanations 1. The relay is stuck on and the leisure battery is permanently connected to the van battery. (Assuming it is wired up right) 2. The voltmeter is connected to the van battery (Input)terminal of the relay and is actually measuring the van battery voltage. To eliminate number two connect the voltmeter directly across the two terminals on the top of the leisure battery. Switch the light off and on and see what happens. If there is a change in voltage, you'll know it is number one. Ty for this - I'll test it tomorrow and will report back. I'll check the wirings too, and will report back on what is wired up to what / where, iykwim. Option 1 is distinctly possible due to the superglue, or else perhaps the smart com is blown due to all the messing around with it. But then Option 2 is quite possible too. I have wired a 12v plug onto the voltmeter so that it's easy to switch off and to use with the vehicle battery if required, so I will connect a 12v socket direct to leisure battery with croc clips to test the leisure battery voltage. I'll do the same with the vehicle battery and see what results I get. I've wired a 12v cig socket through the smartcom which is what the voltmeter is presently plugged into.
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Post by Etienne Le Croq on Jan 19, 2014 21:32:49 GMT
I've been reading this thread with great interest ,as my own electrical knowledge is very limited.Yes I've completely wired my van from scratch! I'm very good at following diagrams and tutorial advice though! My split charge system has been copied from a well tried and tested system on the SBMCC.Theres a copy diagram on my blog (March 2012). It's much the same as yours WVW,but uses a 100amp relay( 4 post),as well as the smartcom. The cable used for the smartcom part is 1mm2 cable and from battery to battery is 16mm2 flexible welding cable.There was a fault on my system where the smartcom wasn't switching off after the engine stopped.This was rectified by turning the small screw in the smartcom.There should be a loud click a few seconds after the engine has stopped. Hope this maybe of help? If you want I can email you a more clearer diagram of the system that I have.If I can follow it and it works at the end ,then anyone can!!
Stephen.
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Post by Etienne Le Croq on Jan 19, 2014 21:42:59 GMT
I forgot to say! I found that when I disconnected the leisure batt ,everything in the rear of the van was still working,it was drawing power from the starter battery as the smartcom wasn't switching off.Does this make sense? As my van is quite modern and has canbus wiring,everything that's in the rear of the van is wired off the leisure batteries,via two fuse boxes.
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Post by Firefox on Jan 19, 2014 22:07:54 GMT
The super glue should not affect the smartcom provided it only went in the terminal holes and not inside the case. But everyone knows my views about relays. They are continually going wrong and/or need replacing. I just have a manual switch. I do have to remember to throw it when I want a charge off the engine but I never seem to forget. And I can do other stuff like charge the van battery off the hook up or solar panels. It's very versatile. I'd swap 1000 relays for my manual switch
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Post by Deleted on Jan 20, 2014 3:34:24 GMT
I forgot to say! I found that when I disconnected the leisure batt ,everything in the rear of the van was still working,it was drawing power from the starter battery as the smartcom wasn't switching off.Does this make sense? Yes yes yes (think Meg Ryan, When Harry Met Sally) ;D That's exactly what was happening before when the stereo was wired in, and before I got a new vehicle battery and I was convinced that something was drawing power from the vehicle battery as it was going flat every few days if not used daily. But I also thought the vehicle battery was dying so wasn't sure what the problem was. So disconnected leisure battery and pulled the fuse out of the wiring but the stereo in the back was still working so disconnected that too and checked leisure battery discharge manually over a week and it was normal, virtually no discharge. So then at least I knew that was ok. Then I got new vehicle battery so I knew that both batteries were good, and could eliminate failing batteries as a cause of the problems. Then I reconnected the leisure battery via the smartcom as per printed instructions, (during which more wires came out of the smartcom). The only thing connected to the leisure battery via the smartcom at the moment is a 12v cig socket into which is plugged the digital voltmeter. So I'm gradually eliminating causes but my gut feeling (don't know why and can't explain it) is that the smartcom is not working properly. But I still find electrics very confusing and difficult to understand so I could be completely wrong. I do remember fiddling with the screw and getting the click but wasn't sure which side of the click it should be, so maybe it's as simple as adjusting it the other side of the click. I'll try that tomorrow with the voltmeter plugged in so I can see if there's any change in the voltage on the other side of the click - am I right in thinking that the voltage of the leisure battery should be slightly lower than the vehicle battery after standing overnight as the voltmeter will have used a little power?
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Post by Firefox on Jan 20, 2014 4:07:48 GMT
It should be lower if there is something drawing power off it, and provided the relay has isolated the leisure battery. But the voltmeter should use very little. I'm surprised the voltmeter stays on for so long (I think mine has an auto-power off. Good luck with it anyway
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Post by stonedaddy on Jan 20, 2014 11:35:48 GMT
Jess keep an eye on the weather, batteries can drop in voltage if it turns very cold and then rise a bit when it gets warmer. Good luck with your fault finding. .... Tom ....
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Post by Deleted on Jan 22, 2014 13:22:27 GMT
Thanks to everyone who replied, just a quick update...
I used my yellow voltage meter (not the digi voltmeter which is wired through the smartcom) to test both batteries yesterday morning - vehicle battery 12.5v, leisure battery 12.4v (vehicle had been used the previous teatime).
On checking the leisure battery voltage I discovered that the earth connection was disconnected - the blue plastic quick release had jumped off the terminal somehow. So I've reconnected that.
The digi voltmeter wired through the smartcom was showing 12.5v. All connections to the smartcom seemed ok, all other connections seemed ok, fuse ok, and am pretty sure the smartcom is wired up right.
So then I tried turning the little screw. It was as far one way as it would go, so I slowly turned it the other way and after a couple of turns, I heard the click and the digi voltmeter wired through the smartcom went from 12.5 to 12.4
I tested this again a couple of times to make sure that this small voltage drop was indeed being caused by the click in the smartcom screw and it definitely was.
So now, I think (if I'm right and please advise me if I'm not) that the digi voltmeter is now being powered by the leisure battery as will be anything else wired through the smartcom. I intend to wire in a fuse box from the 12v live output on the Smartcom which is what the digi voltmeter is currently plugged into via a 120amp cigarette socket. From the fusebox I can then wire the digi voltmeter, stereo, some led lights and an extension cable with cig socket to next to my bed (across the van and at the back so a long extension as it will have to go up one side, across the roof, and down the other side).
If / when I put my little 12v mini fridge back in the van (the type you can fit 4 cans of beer in with a fan and a switch for hot / cold, and a 12v/240v switch) that will be wired up direct to the fridge socket as it was when Firefox first helped me wire in the Smartcom last year.
When it was first wired in, the fridge would stay on for a while after parking up (maybe a couple of hours) and would then start switching off and on intermittently until it finally switched off and stayed off (this is the voltage in the leisure battery dropping down to the "cut off level" so I knew the smartcom was working and at what voltage it was kicking in). So then after a while when I realised how annoying that was, especially when trying to get to sleep, I turned the screw in the smartcom gradually until the fridge switched off and stayed off as soon as I switched the ignition off.
So everything was working perfectly until wires started coming out of the smartcom, and I started having problems starting the van if left longer than a couple of days.
And so now, fingers crossed, after a new vehicle battery, comprehensive testing of the leisure battery, (which was a brand new one which someone had taken out of a brand new vehicle and replaced it with a larger one so it had had virtually no use and had been kept on trickle charge till I bought it for £20,) a tube of superglue, several rolls of insulation tape, much cursing and swearing, I think the set up is now working as it should do.
Just some switches, fusebox, stereo etc all to wire in now... but that can wait till I get to a meet and can pick the brains of someone who knows more about elecs than me!
(So much for a "quick" update!!!)
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Post by Firefox on Jan 23, 2014 1:08:55 GMT
Glad it seems to be working! Cig lighter socket would not be 120Amp... more like 10 or 12Amp? Usual way of setting the smartcom would be run the engine so leisure battery is at fully charged. Switch off ignition and then turn the screw so the relay clicks off when the ignition is off which I think was what you were doing. Then make sure it clicks on when the engine starts again and the alternator kicks in. Great to get it all fixed yourself. Sorry the smartcom relay has been such a pain!... nearly two years since you put it in now, doesn't time fly
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Post by Deleted on Jan 23, 2014 1:57:51 GMT
I still don't know my amps from my watts, the cig socket is 120W.
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Post by Firefox on Jan 23, 2014 2:27:46 GMT
^ Makes perfect sense, 10 Amps x 12 Volts = 120 Watts
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Post by kernowjon on Oct 25, 2016 19:20:30 GMT
Hi I have the same problem with a Smartcom. Jammed on when switched off. The solution I am adopting is to use the old fashioned electro mechanical relay 30amp and operate it using the voltage sensative switch for DLRs. Oh yes my van - a home converted LDV Convoy with 2.5 naturally aspirated Bananna engine. Originally a disability minibus it is a 2 seater with a fixed double bed at the rear with large load area under. The water tank, gas and leisure battery are all in this load area.
Jon
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