[Spruce]

I know that this is an old thread, but my 7 year old TEC2 alternator triggered SCR packed up last week. I was shocked to find that this SCR is only a 15 amp relay as I thought it was a 30 amp one like the 2 Brocott SCR's fitted to the boy's vans - the same unit I recommended to other wfpers.

I ordered and received an Altec 140 amp VSR which is very similar to the Durite VSR's that a couple of you recommend. Fitted with 70 amp cable, this unit does appear to charge the leisure battery at a much higher rate than old unit did. The supplier told me that it was probably due to the size of the cable more than anything - less resistance.

However, I have a problem with this unit that I don't have with the smaller Brocott units. I identified that this Altec VSR is bi - directional. The issue with this is that the battery has to be disconnected from the system if you want to give it a supplementary charge. I purposely tucked my battery out of the way as it isn't something I to attend to often as I have a flylead in the back of the van that I plug my charger into when needed. I also don't want to disconnect the battery each time as I have to digital controller attached to my Airtronic diesel heater and don't want to mess on setting the date and time and programs each time the power goes down.

If you don't disconnect it then you have the charge triggering the relay and your starter battery is being charged as well. The trouble is that the charge state of the starter battery seems to not be transmitted back to the charger which means it will charge the batteries forever.

I'm waiting for the supplier to get back to me with a solution which will probably be to put an on/off switch on the earth wire from the VSR. I would imagine that switching that off will prevent the VSR from triggering.

I was wondering if any of you had similar issues with your self switching relays with regard to battery charging in situ.

[martinw]

you will need battery isolator switch or clamp that goes on negative terminal.
http://www.ebay.co.uk/itm/Universal-Car-Heavy-Duty-Battery-Disconnect-Switch-Isolator-Cut-off-Switch-W066-/370699015960?pt=LH_DefaultDomain_3&hash=item564f621718

forgot to mention that i fitted ctek charger leads with a quick connect plug.

[Spruce]

you will need battery isolator switch or clamp that goes on negative terminal.
http://www.ebay.co.uk/itm/Universal-Car-Heavy-Duty-Battery-Disconnect-Switch-Isolator-Cut-off-Switch-W066-/370699015960?pt=LH_DefaultDomain_3&hash=item564f621718

forgot to mention that i fitted ctek charger leads with a quick connect plug.

Doing this has saved a few chargers for me as I would connect the terminals up incorrectly sometime down the line.

Battery terminal isolator is a good idea - I've never seen one before TBH. But the problem is that I have an Eberspacher digital programmer powered by the leisure battery which is a pain to reprogram, especially as I boost charge my leisure battery every second day.

We have just found that the Durite VSR is also bi-directional. So if anyone has one of either of these VSR's then they need to remove a battery terminal or remove the battery completely from the van to supplementary charge it.

With further experimentation this morning early, I have found that the VSR sensor is deactivated by removing the VSR earth flylead. So I'm going to order a splashproof rocker switch and fit it to this flylead and switch it off (open the circuit) when charging my leisure battery in situ.

I also found that with the leisure battery isolated, my charger kicked out after 10 minutes to tell me that the leisure battery was fully charged.

I then put the same charger on my van battery and it kicked out in 30 minutes to tell me that it was fully charged. I then connected up the VSR and switched the charger back on to charge the van battery and a charging voltage was also registering across the leisure battery. But my charger registered that my van battery was only 75% charged and nothing changed after the charger was on for an hour. Who can explain that?

[martinw]

assuming that you have a smart charger after bulk charging, absorption phase can take hours to complete as current goes down.