I have searched the internet for a supplier but without much success, can anyone help please?
I ordered a self-switching combination relay from Towsure a couple of weeks ago quoting their ref. H78. What finally turned up however, was a device consisting of a circuit board rattling about in a short section of electrical conduit and bearing a sticker saying it was a 'Smartcom'. This would appear to serve a similar purpose but is not up to specification or build quality of the one advertised. (It has the appearance of being made from a kit of parts although I couldn't find it on the Maplin site)
As Towsure haven't got round to answering my email yet, I was wondering if anyone knew of an alternative supplier for the advertised item (or a reasonable alternative) before I send this one back where it came from?
Thanks,
Alan
Self-switching combination relay
Moderators: Doone, westonwarrior
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Barnet Al
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alang4kuf
Self switching combi relay
Hi Alan,
I don't know whether my experience is relevant as I don't know what you are using it to drive (towing socket or a second battery in the vehicle). In my case, it was for a second (leisure) battery under the bonnet only a couple of feet away (and that is relevant). Mine was originally fitted with a very similar relay, the TF1170-2 Smart Combi Relay from Ryder, supposedly rated at 20A. The relay cuts in when the main battery is at or above 13.65V and drops out at 13.46V. The problem I had was that with a flat leisure battery, the peak charging current over such a short cable was around 30A, blew a fuse and melted the combi relay! I was not unhappy with the skeleton way the Ryder relay is built so repaired it but now use it to drive the coil of a much more pokey Lucas 33RA split charge relay with contacts rated at 60A. It has worked fine for a year.
Alan
I don't know whether my experience is relevant as I don't know what you are using it to drive (towing socket or a second battery in the vehicle). In my case, it was for a second (leisure) battery under the bonnet only a couple of feet away (and that is relevant). Mine was originally fitted with a very similar relay, the TF1170-2 Smart Combi Relay from Ryder, supposedly rated at 20A. The relay cuts in when the main battery is at or above 13.65V and drops out at 13.46V. The problem I had was that with a flat leisure battery, the peak charging current over such a short cable was around 30A, blew a fuse and melted the combi relay! I was not unhappy with the skeleton way the Ryder relay is built so repaired it but now use it to drive the coil of a much more pokey Lucas 33RA split charge relay with contacts rated at 60A. It has worked fine for a year.
Alan
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Barnet Al
Self-switching combination relay
Hi Alan
Thanks for your reply, I have an identical set-up, and apart from concerns over the quality of the relay they sent me , had suspected the relay contacts might not be up to the job. The fact that the thing is easy to get into may therefore prove an advantager.
A quick web search suggests that the Lucas relay you mentioned is readily available so I will proceed with what they have sent me and upgrade when things go wrong.
Thanks for your help.
Alan
Thanks for your reply, I have an identical set-up, and apart from concerns over the quality of the relay they sent me , had suspected the relay contacts might not be up to the job. The fact that the thing is easy to get into may therefore prove an advantager.
A quick web search suggests that the Lucas relay you mentioned is readily available so I will proceed with what they have sent me and upgrade when things go wrong.
Thanks for your help.
Alan
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Harpo
i have found this little device very easy to wire in and works well. However you are quite right when you suspect that the relay is not up to the job. The first one i had melted the PCB and the relay. Towsure customer service were very helpful when i phoned, said that this occasionally happened and sent me a replacement at no cost which arrived next day. I also have now used this device to drive another relay rated at 20amps so far with good success. If I were you i would only use it to drive another relay. It may also be of interest to you that there is a small variable resistor on the circuit board that is accessable thro one end of the case, turning this will alter the voltage that the relay cuts in and out.
Jonathan
Jonathan
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Barnet Al
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gmcnaugh
Re: Self switching combi relay
Alan,alang4kuf wrote:Hi Alan,
I don't know whether my experience is relevant as I don't know what you are using it to drive (towing socket or a second battery in the vehicle). In my case, it was for a second (leisure) battery under the bonnet only a couple of feet away (and that is relevant). Mine was originally fitted with a very similar relay, the TF1170-2 Smart Combi Relay from Ryder, supposedly rated at 20A. The relay cuts in when the main battery is at or above 13.65V and drops out at 13.46V. The problem I had was that with a flat leisure battery, the peak charging current over such a short cable was around 30A, blew a fuse and melted the combi relay! I was not unhappy with the skeleton way the Ryder relay is built so repaired it but now use it to drive the coil of a much more pokey Lucas 33RA split charge relay with contacts rated at 60A. It has worked fine for a year.
Alan
I too have been having probs with the relay fuse blowing with a flat LB. Just to clarify, are you using the output of the split charge relay to drive the coil of the 2nd beefier relay? And has this stopped the fuse blowing with an empty LB? If this works for me then I owe you a pint the next time I see you.
Glen
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Barnet Al
Hi Glen,
I had not, at the time of my original post, used the smartcom so had not experienced any problem using it on its own.
Following Harpo's advice, I have now installed it using it to control a 70 amp relay. I suspect this will not be adequate for a really flat LB but do not anticipate long stays on site without using the Bongo and recharging the battery. So far I have not put it to the test but will do so in the next few days.
A slight concern was that on setting it up I found the relay was not dropping out when the engine was stopped. Adjustment of the resistor mentioned by Harpo resolved this but the setup is a bit sensative and could leave you with a flat battery. A dashboard LED would let you know the state of the relay and I must remember to look into this when I have time.
(Being a lazy git and knowing a trip to Halfords would be a waste of time, I got the relay, cable and hefty fuses mail order from Vehicle Wiring Products Ltd.)
Alan
I had not, at the time of my original post, used the smartcom so had not experienced any problem using it on its own.
Following Harpo's advice, I have now installed it using it to control a 70 amp relay. I suspect this will not be adequate for a really flat LB but do not anticipate long stays on site without using the Bongo and recharging the battery. So far I have not put it to the test but will do so in the next few days.
A slight concern was that on setting it up I found the relay was not dropping out when the engine was stopped. Adjustment of the resistor mentioned by Harpo resolved this but the setup is a bit sensative and could leave you with a flat battery. A dashboard LED would let you know the state of the relay and I must remember to look into this when I have time.
(Being a lazy git and knowing a trip to Halfords would be a waste of time, I got the relay, cable and hefty fuses mail order from Vehicle Wiring Products Ltd.)
Alan
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gmcnaugh
Alan,
Thanks for that. I think that I will definitely go down the route of adding the beefier relay in series. I take it you used heavier cable between the two relays.
Also, I contacted Towsure about this problem (this is after I too burnt out the tracks of the SmartCom predecessor) who said that they were unaware of this problem. I suggested that they may want to have a look on this forum just to see how big the problem is!
What sort of current do you think an empty LB will pull initially?
Regards,
Glen
Thanks for that. I think that I will definitely go down the route of adding the beefier relay in series. I take it you used heavier cable between the two relays.
Also, I contacted Towsure about this problem (this is after I too burnt out the tracks of the SmartCom predecessor) who said that they were unaware of this problem. I suggested that they may want to have a look on this forum just to see how big the problem is!
What sort of current do you think an empty LB will pull initially?
Regards,
Glen
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Barnet Al
Glen
What follows should not be taken as advise but simply an account of how I approached the problem, others may have done things differently and no doubt Pippin may offer advice.
My setup is a bit of a compromise, as I said, I do not expect my battery to reach a totally discharged state.
I believe the alternator will put out around 90 amps to a fully discharged battery so a relay and cable to handle this might be considered ideal.
However, I have used a 70 amp relay with 60 amp cable (120/.03) and protected it with 50 amp fuses. I am hoping this will be adequate as it is 2.5 times the capacity of the Smartcom on its own, and if not should simply blow a fuse.
AS the Smartcom output is only used to trigger the HD relay the wire from it to the relay does not need to be anything special, its the cable switched by the HD relay that needs to take the current.
As I say, I have not yet tested this out on a camping trip but will do so in the next few days.
Good luck
Alan
What follows should not be taken as advise but simply an account of how I approached the problem, others may have done things differently and no doubt Pippin may offer advice.
My setup is a bit of a compromise, as I said, I do not expect my battery to reach a totally discharged state.
I believe the alternator will put out around 90 amps to a fully discharged battery so a relay and cable to handle this might be considered ideal.
However, I have used a 70 amp relay with 60 amp cable (120/.03) and protected it with 50 amp fuses. I am hoping this will be adequate as it is 2.5 times the capacity of the Smartcom on its own, and if not should simply blow a fuse.
AS the Smartcom output is only used to trigger the HD relay the wire from it to the relay does not need to be anything special, its the cable switched by the HD relay that needs to take the current.
As I say, I have not yet tested this out on a camping trip but will do so in the next few days.
Good luck
Alan