# Another split relay question



## whitevanwoman (Jun 22, 2013)

Yesterday I swopped over leisure batteries as the one I've been using seems to be losing charge whilst standing even without powering anything - for example, it was showing 12.7 v when parking up but by the following morning it was down to 12.3 even though I hadn't used it as I was monitoring the rate of discharge. 

So first question is this normal? I have a car stereo wired directly to the leisure battery, not via split relay and even though it was switched off, I've been told that it will still draw from the leisure battery, so would it use that much overnight whilst switched off? The only other thing that was drawing power was a single 12v socket with a digital voltage meter plugged into it. 

Whilst switching over the batteries and the leisure battery was disconnected, I accidentally switched the stereo on but didn't expect it to work as the leisure battery wasn't connected. But it did work, and so it seems to me that the leisure battery wiring is somehow drawing power from the starter battery, otherwise how else would the stereo work if the leisure battery was disconnected? 

Second question - does this mean that my split relay isn't working properly? As I understand it, the split relay should stop any power being drawn from the starter battery. Or have I got that wrong?

Having swopped the leisure battery for a fully charged one last night, it was showing 12.9 volts last night, today it's dropped again to about 12.5, again without powering anything overnight apart from the volt meter. So the same thing is happening with 2 different batteries, and I know the second one is ok as I've had it in the house on charge and then monitored the standing discharge from it and it only dropped about 0.2 volts over a week. 

So therefore I know that there is some problem with my elecs but not sure if it's the split relay which isn't working properly (it's charging fine, showing 14v when engine running) or whether I have a faulty earth or other wiring fault which could be the cause of the leisure battery standing discharge when connected into the system.

I'm guessing now that perhaps the discharge in the leisure battery might be because it is effectively recharging the starter battery?

I do suspect there may be some wiring fault with my starter battery, as the connector to the live terminal was very loose and I've had to bang a nail inside the circular connector which fits over the terminal to take up the slack so to speak, to ensure a constant connection. That bodge job repair does seem to have made a big difference - I know it's not ideal but I'm planning to turn up at the Fix It meet armed with new terminal clips, a job lot of wire, various batteries, connectors, fuse box, fuses, isolator switch etc so that I can sort out my elecs properly (it's like spaghetti, and I do need to add an extra 12v socket into the system to reach to next to my head in bed, on the other side of the van) when I'll have the time and space to empty some stuff out of the van to get to the elecs and hopefully there'll be plenty of knowledge and advice to help me. 

In the meantime any suggestions / advice welcome.


----------



## oldish hippy (Jun 22, 2013)

The spilt charge relay is a electric switch in plain terms that switches the power from the main battery to lesuire battery when the engine is running {powering the alternator} so you should have a live wire from alternator  NUMBER 3 {engine} to one of the contact on split relay and a earth connection NUMBER 2 {nuetral, negative } on other side, then there should be a live wire NUMBER 4 from main battery to one side of the switch and a live wire NUMBER1 from other side of the switch to lesuire

   link to site here  splitcharge


----------



## whitevanwoman (Jun 22, 2013)

The split relay isn't wired to the alternator, there is simply a wire from each terminal on the starter battery to each terminal on the leisure battery with the split relay wired into the red wire (+) between the 2 and also a fuse. 

It's charging fine but there seems to be a two-way draw in between batteries, which means that the split relay isn't working properly as it shouldn't allow a backwards draw from the leisure battery, it should only be a one way draw from starter battery to leisure battery. I think. Or have I misunderstood the function of the split relay. It's a smartcom btw.


----------



## oldish hippy (Jun 22, 2013)

well it not a split relay system as such not sure on how smartcom work think it works on voltage so if voltage is above a set voltage  then it feeds it to lesuire battery which from what you have said ithink it is doing hence radio works

Just found this Avoids discharge of car battery when running a caravan ‘fridge and charging the leisure battery. Relay switches on at 13.5 and off at 13.2 volts and features heavy duty terminal blocks so voltage on van battery must be above 13.2


----------



## Tow Itch (Jun 22, 2013)

Your Smartcom looks like this?









 This is a self sensing relay it senses the change in voltage and then charges the leisure battery. If things are exactly as you say then there is no ground wire to the Smartcom so I fail to see how it detects a change in voltage. N.B. Is yours slightly different to the picture and does bolting the body of the Smartcom down allow it to connect to ground?

 As you conducted a test on your second battery by checking it's a known good battery. The reading of 12.9V was probably obtained just after charging and it showed a surface charge. Batteries should be left at least 4 hours before reading off a voltage. Though 12.7 V at the end of the week is excellent as 12.65 is fully charged. If you had not conducted this test i would have suggested checking the batteries disconnected from the camper. 

 As you have a multimeter I would try reading the resistance across the 12V input and the 12V output wires when the ignition is not switched on. One guess is that the pins on the relay have welded together. These relays are built to a cost and while one solution to split charging is to just take a feed that is live only when the ignition is on and to feed it to a much larger relay self switching relays wired to heavy duty relays for the leisure battery and fridge are also used. Obviously if the pins have welded the split charger is junk.



> Whilst switching over the batteries and the leisure battery was disconnected, I accidentally switched the stereo on but didn't expect it to work as the leisure battery wasn't connected. But it did work, and so it seems to me that the leisure battery wiring is somehow drawing power from the starter battery, otherwise how else would the stereo work if the leisure battery was disconnected?


 OK this unit is how the leisure battery is charged but how does it power the leisure circuits? You had disconnected the battery to circuit connection not just the charger from the battery? If you had disconnected the leisure battery from the leisure circuit then without you having any other change over switches I'm left to believe that the radio is powered by the starter battery. This is as it would be normally did you get the radio changed over?

 Your fridge how is this powered on the move?

 One other test is to leave the battery disconnected from the leisure circuit and connect to the charger with the ignition off. This is just coppying the first test and you are looking for a voltage drop on connection.

 Likewise switch everything off and connect the leisure circuit up again looking for a voltage drop as you connect. 

 If you detect a voltage drop on connection then you can consider using the ammeter function to test the rate of loss. I am cautious to suggest ammeter tests though as if you misjudge and the amps are too high it is easy to burn out the multimeter. 

 Split charge relays when functioning always suffer from the alternator reducing it's output as the engine bay warms as it assumes by that point that the starter battery has charged. Additional controls can be used but that is beyond the scope of today maybe someone can explain at the fix up meeting.

This is a nice explanation of how things work and a nice diagram (The small battery icon is the charge light.) It comes from here but I have quoted the text as the full page might confuse. http://highfields-arc.co.uk/vehicles/files/auxchg4.png



> Voltage Sensing Relay
> 
> 
> 
> ...


----------



## whitevanwoman (Jun 22, 2013)

Tow Itch said:


> Your Smartcom looks like this?  yes
> 
> 
> 
> ...




Thanks for this excellent reply, I've made some points above in red.


----------



## whitevanwoman (Jun 22, 2013)

Diagram of my wiring system - drew it wrong initially so the amendment to it is how it is. 

http://i704.photobucket.com/albums/...s/Big White Van BWV/DSC_01651_zps494bb1ad.jpg


----------



## oldish hippy (Jun 22, 2013)

on a side note you can take a feed from the permant live feed to the radio memory feed so the radio remembers the stations that you have tuned in


----------



## whitevanwoman (Jun 22, 2013)

oldish hippy said:


> on a side note you can take a feed from the permant live feed to the radio memory feed so the radio remembers the stations that you have tuned in



Memory feed is taped up as there's no aerial off it, another job to do at the Fix it meet


----------



## Tow Itch (Jun 22, 2013)

WVW I am more than willing to help you I just lost the next 40 minutes of this post trying to type an Omega symbol (Ohms) I cant help tomorrow or Monday but if you get no help before then then Tuesday we will do electrics 101. I know I'd not broached your replies but there were places to go to first. Or I think that there are.



What I'm worried about. You obviously don't do electric it is not what you understand. After seeing what I have said and what you have said I'm concerned that I could say something that was correct but you could interpret it in a different way and it it could do harm to your motorhome or more importantly you.

 Having said that I've seen the way you have responded to my points and the way you constructed your circuit diagram. You are no fool. Sorry that is not meant to be either condescending or patronising but an observation. I don't know what I would have said if it were the opposite way around. Just because someone doesn't know what they need to know isn't a problem if a realistic prospect of them learning doesn't exist there is a problem.

 If you don't like what I say check it out. I have no electrical or electronic qualifications but in trying to find suitable tuition for you and on a previous occasion for a friend I have used "educational" videos on you tube. I have shat myself both in laughter and in fear at the mistakes from the slight to the howling. If you don't like what I say ask me to check what I said ask others at any point. The last thing I ask is for you to trust me.

 It's not just 12v. 12v will not electrocute you but a fully charged battery is really good at starting fires. Most people are not left handed this is how left handed DIY people cook their finger:

 [video=youtube;ZfFViY1-zYw]http://www.youtube.com/watch?v=ZfFViY1-zYw[/video]


----------



## whitevanwoman (Jun 23, 2013)

Tow Itch said:


> WVW I am more than willing to help you I just lost the next 40 minutes of this post trying to type an Omega symbol (Ohms) I cant help tomorrow or Monday but if you get no help before then then Tuesday we will do electrics 101. I know I'd not broached your replies but there were places to go to first. Or I think that there are.
> 
> 
> 
> ...



Very right, I don't really do electrics :scared:

I managed to wire in the smartcom but it was really Firefox who bought the right wire and basically just told me where to cut it and where to connect it. I do sort of understand the basics but you got to bear in mind that the last time I had any formal training in elecs was in 3rd year in high school physics lessons (mid 1980's) and all I can remember is how to wire a plug and something to do with standing on a rubber mat and making your hair stand on end. So if you assume my knowledge and understanding level to be approx age 12 you will need to instruct and advise me accordingly.

And as my diagram demonstrates, I'm perhaps more of an artist than a scientist. My brain responds best to pictures and I have always struggled with anything to do with numbers, maths, science, physics etc. I am what you could call a conscious incompetent with regards to elecs ie, I am aware that there is much I don't know which is an improvement on being an unconscious competent and totally unaware, as it does mean that I will question and check if I'm not sure about something and I do tend to err on the side of caution. Perhaps too much so sometimes, and have a tendancy to do belt and braces. And the van's been wired over a year now and nothing's gone up in smoke....  yet...

PS. So what's wrong with my diagram then? :lol-053:  Apart from getting it wrong initially, I was quite pleased with it and it's helped me to understand the system a bit better.

PPS. Impressive video though I don't understand the reference to left handers. Lucky I don't usually wear rings very often, and not usually when working, and I always put wellies on when working with power tools


----------



## Firefox (Jun 24, 2013)

Your stereo should not be working if the leisure battery is disconnected. It may work if you had wired it into the permanent live output you marked with a X. But you don't appear to be using this terminal. It does suggest the relay is allowing connection even when the alternator is not on. 

One way to test this would be to charge both batteries up on a run. Wait two or three  hours till the batteries settle and the relay opens. Measure the voltage across both batteries. Now switch on the radio full volume, fridge, lights and as many other accessories off the leisure as you can manage. Measure the voltage across the leisure battery and you should observe a drop of 0.5v or more as you have put the loads on the battery. Now go to measure the voltage across the starter battery. You should not see a voltage drop on this battery. It should be the same reading as you took a few mins ago before you switched on the accessories. If the voltage has dropped, you know the relay is not working as intended. Either the relay is fried or you could try the adjustment screw on the smartcom.

It may be also worth getting a brand new leisure battery at some stage, because as far as I know, you have been using second hand ones or cast offs up to now. These are fine up to a point, but you never know exactly how they have been treated or how much life is left in them. Even a good 12V lead acid battery can be ruined by leaving it off charge for 2 or 3 months. It may charge up OK, but it will have a fraction of its original capacity, and you'll effectively have a 5 Ah or 10Ah battery even though it says 75 Ah on the label.


----------



## oldish hippy (Jun 24, 2013)

The ohm symbol is alt then on number pad 234 Ω hold down alt then type 234 on NUMBER pad Ω


http://www.wikihow.com/Type-Symbols-Using-the-ALT-Key


----------



## whitevanwoman (Jun 24, 2013)

Firefox said:


> Your stereo should not be working if the leisure battery is disconnected. It may work if you had wired it into the permanent live output you marked with a X. But you don't appear to be using this terminal. It does suggest the relay is allowing connection even when the alternator is not on.
> 
> One way to test this would be to charge both batteries up on a run. Wait two or three  hours till the batteries settle and the relay opens. Measure the voltage across both batteries. Now switch on the radio full volume, fridge, lights and as many other accessories off the leisure as you can manage. Measure the voltage across the leisure battery and you should observe a drop of 0.5v or more as you have put the loads on the battery. Now go to measure the voltage across the starter battery. You should not see a voltage drop on this battery. It should be the same reading as you took a few mins ago before you switched on the accessories. If the voltage has dropped, you know the relay is not working as intended. Either the relay is fried or you could try the adjustment screw on the smartcom.
> 
> It may be also worth getting a brand new leisure battery at some stage, because as far as I know, you have been using second hand ones or cast offs up to now. These are fine up to a point, but you never know exactly how they have been treated or how much life is left in them. Even a good 12V lead acid battery can be ruined by leaving it off charge for 2 or 3 months. It may charge up OK, but it will have a fraction of its original capacity, and you'll effectively have a 5 Ah or 10Ah battery even though it says 75 Ah on the label.



There's a voltage drop of 0.1 on the leisure battery when the mobile is plugged in to charge off it, haven't tried checking for voltage drop on the starter battery, will do, but I'm pretty convinced that the Smartcom isn't working (properly) - I seem to have been having odd elec probs for ages now, and I think it's either fried or the superglue has had some effect on it functioning. It's quite possible it got shorted ages ago due to the wires coming out and may well have been kaputt before I superglued the wires in. 

For the price of another split charger, I'm going to get a new one - any suggestions as to a model that works the same way as the Smartcom (ie doesn't need wiring into the alternator)? Or should I get another Smartcom, but wire the 2 strands of wire from each terminal on the starter battery together into a connector thing which will fit into the Smarcom sockets better without falling out? 

The 2 newest secondhand batteries I've got are both good, I've had them on charge in the house and then let them stand for a couple of weeks each to check them, and even after about 3 weeks, one had only dropped to 12.7 (although it was probably more like 12.65 but rounded up), and the other was at 12.5. When both of them have been connected into the van system they have dropped from full charge to 12.0 within 24 hours without powering anything. Then they seem to settle around that level and only discharge further very much slower or if powering something.

My guess (based on gut instinct rather than any proper electrical knowledge) is that the Smartcom is knackered but still allowing the leisure battery to be charged whilst driving, and that the starter battery is dying and so it's discharging quickly and because the Smartcom isn't doing what it should, the leisure battery is effectively recharging the starter battery when standing. Once the starter battery is fully charged, the leisure battery is then discharging more slowly and it is effectively trickle charging the starter battery. Would this make sense? I did think over the winter that my starter battery wasn't good, but then once I got new glow plugs it seemed ok. But maybe it's just because it's been charging off the leisure battery all this time.


----------



## Ems (Jun 24, 2013)

I fitted my smartcom and the weekend, it took quite a bit of tweaking with the adjuster, when I first fitted it, it basically connected both batteries together meaning both were reading more or less the same, I knew my leisure battery was below 12 volts.  This would mean the leisure battery would drain the starting battery and anything used on the leisure battery circuit would also pull some power off the starter battery (I think).  

After much twiddling and working out which way to turn the adjuster I managed to stop this, I'm guessing it just needs to be set at the right voltage, when the alternator kicks in and increases the voltage the smartcom switches over.  They are quite difficult to set as there is nothing in the instructions and no markers by the adjuster so I kept loosing where I was!

Lots of superglue could interfere with the connections as it won't conduct.  My wires haven't fallen out yet!  Fingers crossed!  If you are confident enough I'd take readings of both batteries disconnected then connect it all up and take readings again to see if they change, this might indicate if the smartcom has linked them together without the engine running?  This is what I did to understand what the smartcom was doing, as I knew the voltage of both batteries before connecting I knew the smartcom had connected them together (with the engine off) as they went from very different readings (starter reading 12.9 ish and leisure reading 11.5 ish when disconnected) to both reading and fluctuating slightly around 12.7 volts when connected back up so I adjusted the smartcom until they went back to the original readings I took (12.9v and 11.5v).  I've probably confused you even more now!  Might be worth a try though!  If moving the adjuster doesn't work then the smartcom is probably knackered!

No guarantees with the above, this is just my first experience of the smartcom at the weekend and I may be heading completely along the wrong lines but thought it was worth mentioning!!


----------



## whitevanwoman (Jun 24, 2013)

Ems said:


> I fitted my smartcom and the weekend, it took quite a bit of tweaking with the adjuster, when I first fitted it, it basically connected both batteries together meaning both were reading more or less the same, I knew my leisure battery was below 12 volts.  This would mean the leisure battery would drain the starting battery and anything used on the leisure battery circuit would also pull some power off the starter battery (I think).
> 
> After much twiddling and working out which way to turn the adjuster I managed to stop this, I'm guessing it just needs to be set at the right voltage, when the alternator kicks in and increases the voltage the smartcom switches over.  They are quite difficult to set as there is nothing in the instructions and no markers by the adjuster so I kept loosing where I was!
> 
> ...



Thanks Ems, I think this was what Firefox was suggesting I do, although your explanation is more suited to my level of understanding 

Is the adjuster the little round circle in the white plastic with a small slit notch in it on one side of the Smartcom? Can you remember which way you turned it? How did you know when you'd reached the exact right spot on the adjuster? Or is it a case of adjust it, then test batteries, then adjust more, then test batteries again etc?


If you've only used single wire you should be ok with your Smartcom, the problem of the wires coming out was because I have got double wires (to reduce voltage drop I think?! Not sure why exactly but Firefox explained to me why double wires were better and it sounded good and I believed him!) and so when twisted together, the 2 wires were effectively too big to fit inside the smarkcom sockets. Hopefully this can be resolved by using connectors on the wires in future.


----------



## whitevanwoman (Jun 24, 2013)

I was out in the van this afternoon, got back a couple of hours ago, so just took some readings off batteries now...

With system connected, starter battery 12.58v, leisure battery 12.60 v

With leisure battery disconnected from the system, starter battery 12.53v, leisure battery 12.61v

I'll leave it a few hours and will take some more readings, which I think will show that the leisure battery will remain about the same level but the starter battery will have discharged further (if my theory is correct).

If that's the case then it's either that the Smartcom is bust or else it needs adjusting. Edit - and I need a new starter battery :sad:

I think


----------



## Ems (Jun 24, 2013)

whitevanwoman said:


> Thanks Ems, I think this was what Firefox was suggesting I do, although your explanation is more suited to my level of understanding
> 
> Is the adjuster the little round circle in the white plastic with a small slit notch in it on one side of the Smartcom? Can you remember which way you turned it? How did you know when you'd reached the exact right spot on the adjuster? Or is it a case of adjust it, then test batteries, then adjust more, then test batteries again etc?
> 
> ...



Yes, the adjuster is the little white bit.  I think right increased the voltage that the smartcom switched over at and left reduced it.  I put it full right, tested the battery readings and then full left to establish if had kicked in or not.  If I've got it the right way round I then started with it all the way to the left (lower) and turned it a little bit, tested the battery readings then tried again, and again!  Eventually the batteries went from reading the same to reading there actual voltage readings.  I then turned it to the right a bit more in case it was very close to the 12.9v of the starter battery.  Then start the engine and check that both are getting charge, if they are not you've turned it too far to the right (I think) so turn it back a little!  Its just trial and error really, lots of messing about with the multimeter.  I might have got it the wrong way round.  If its not working I think you'll get the same readings no matter where the adjuster is!


----------



## whitevanwoman (Jun 24, 2013)

Ems said:


> Yes, the adjuster is the little white bit.  I think right increased the voltage that the smartcom switched over at and left reduced it.  I put it full right, tested the battery readings and then full left to establish if had kicked in or not.  If I've got it the right way round I then started with it all the way to the left (lower) and turned it a little bit, tested the battery readings then tried again, and again!  Eventually the batteries went from reading the same to reading there actual voltage readings.  I then turned it to the right a bit more in case it was very close to the 12.9v of the starter battery.  Then start the engine and check that both are getting charge, if they are not you've turned it too far to the right (I think) so turn it back a little!  Its just trial and error really, lots of messing about with the multimeter.  I might have got it the wrong way round.  If its not working I think you'll get the same readings no matter where the adjuster is!



Thanks v much, this is the kind of language I understand  

So I need to reconnect the system, adjust the Smartcom and then test both batteries with both connected in the system, until I get as close as possible to the readings I've taken from each battery when system is disconnected (ie, each battery's true charge).


----------



## Ems (Jun 24, 2013)

whitevanwoman said:


> Thanks v much, this is the kind of language I understand
> 
> So I need to reconnect the system, adjust the Smartcom and then test both batteries with both connected in the system, until I get as close as possible to the readings I've taken from each battery when system is disconnected (ie, each battery's true charge).



Yes, that's what I did but my battery charge levels were very different so it was easy to see.  It might be harder to do it this way if your batteries charge levels are very similar.  Don't forget to check that the relay then charges the leisure battery when the engine is running!


----------



## The Grand Wanderer (Jun 26, 2013)

I find that soldering two wires together help them to fit into smaller contacts, much better than super glue.


----------



## whitevanwoman (Jun 26, 2013)

The Grand Wanderer said:


> I find that soldering two wires together help them to fit into smaller contacts, much better than super glue.



I've now got a 12v soldering iron and also a gas soldering iron (I also use them for pyrography) for in the van, and got a supply of solder and flux. 

Just need to find someone to teach me how to solder now... :raofl:

Another job for the Fix it meet hopefully. 

Definitely can't recommend superglue :sad:


----------



## FULL TIMER (Jun 26, 2013)

If you don't have much joy with the smartcom  which I find totally unsuitable, ie connectors not suitable for correct size wiring etc,  never seemed reliable either you might find one of these Durite ones better and very easy to fit Durite voltage sensing split charge relay 140 amp. they are very reliable and robust we have used them on many occasions and I've never had one back yet, one wire from vehicle battery to unit, one from unit to aux battery with suitable fuse at both battery connections and a small wire to connect to earthing point / negative job done,


----------



## Tow Itch (Jun 26, 2013)

Hello WVW got here a bit later than intended and was going to do things in a different way. I will try to jump on to site when you are about. It might be quicker if you have your multimeter and a pad to hand and I run through the checks over the phone. It should be easy you need to learn x,y and z  and tell you to watch these films on youtube. I have to watch each film and several others first as there are so many plausible people who talk complete rot on youtube. I will catch you.


----------



## Tow Itch (Jul 2, 2013)

Apologies I have let you down on this. I was trying to find time to write stuff up and every day the time has evaporated. Trying to pack at the moment for a fortnights holiday with no laptop. Thought I better come on here and confess my sins first. Sorry WVW I've let myself down as well as you. Hope it gets sorted if you are still stuffed when I get back we will see what can be done. Sorry once again.


----------

