Hi I know this topic has been covered before. Which type of relay is suitable for new vans and can they be fitted easily by someone with basic wiring skills?
I'm going to add to Cleanclears reply. The important issue is that some vans that have stop start technology may still work with a split charge relay or a voltage sensitive relay.
But if your van has regeneratve braking then you got to have a B2B charger.
Can they be fitted with someone with basic electrical skills? Yes.
https://www.ebay.co.uk/itm/Sterling-Power-12v-30amp-Battery-to-Battery-Charger-BB1230/252410937461?hash=item3ac4dd4075:g:iUoAAOSwyltZTR4-
If you contact this chap (I think his name is Mike) who runs simply split charge on Ebay he will help you. He isn't just a supplier that buys and sells what he thinks he can make money on. I've conversed with him and, in my opinion, he knows his product.
You can buy a kit and there will be full fitting instructions.
The only 'issue' is that you may have to identify a positive power source from the ignition that switches off with the key.
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To add to Spruce comments, You will also need to check if the vehicle has the latest Euro 6 engine emission standards. This will only really effect very new registrations 2017 onward. A VSR (variable split relay) will not work with Euro 6 standard. As I understand with Euro 6 the alternator will supply 14V + for only 20 seconds from ignition after 20 seconds the alternator output will fall below 11V a VSR will not operate at such low voltages. With Euro it would have to be a B2B
Also note that if self fitting onto a new vehicle the manufacturers warranty may be affected.
The manufacturers aren't very forth coming when it comes to how vehicles achieve these new emission standards. They don't seem to advertise if a van has regenerative braking or not. They will just say that their vans/vehicles meet Euro whatever.
The best way is to either phone the technical support dept of the motor manufacturer or buy one of the plug in digital volt meters - the ones that plug into the cigarette lighter. (I don't have too much faith in the manufacturers technical depts tbh. I phoned Citroens one in Coventry and asked if the new generation Citroen Relay vans after 2007 are galvanised . The person answering needed a reg or chassis number. I had a reg number from a van on Ebay and gave it to him. He looked and looked and then replied that he could see no mention in the specs of galvanising being fitted to that van. I rang off as I realised that it was pointless carrying on a conversation with an idiot. Actually, this was the second communication. I originally emailed the question; are Citroen Relays from 2007 galvanised dipped. We need a chassis number or reg number. After I provided that the answer came back that Citroen Relays did not have galvanised dipsticks.
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If the volt meter reads a steady 14 + volts if driving any distance then a SCR or VSR will probably work. But if the voltage drops as you have detailed and then jumps up when going downhill with your foot off the gas and in gear then that vehicle is fitted with regen braking and needs a B2B charger.
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