Hi, sprinter , nomad, 2017, how is the solenoid between starter battery and house battery energised, the low voltage relay drops at 10.5v my fridge gets no power etc while traveling ,the solenoid under the passengers seat must either cut out or the contacts need cleaning up, Anybody have a schematic diagram?
Possum3 said
08:47 PM Jan 15, 2023
Welcome to the Forum Glenn, Electrics/electronics not my area of expertise - there are many in GN's that will help I'm sure.
valiant81 said
09:13 AM Jan 16, 2023
Hi all; Most 4x4 that have a 2 battery set up ( one for the car and one for all of the extras including a fridge or caravan main power feed ) have a relay that would sence the accesory feed so that when the motor is running the relay between the two positive terminals of the batteries are connected and allow the auxiliary battery to be charged. This is a old school way and has been around for years. Most installs of the day just used a 30 Amp or higher headlight relay.
The other way is what is called a VSR ( voltage sence relay ) and it sences the main battery voltage and once this battery has reached a certain voltage the relay will "pull in" and allow current to flow into the auxillary battery to charge. Turn off the engine and the main battery voltage would drop a little and the VSR would automatically "drop out" These relays are also very easy to install. Just 3 connections are needed, the positive wire from the main starter battery, a main wire going to the positive terminal to the auxiliary battery ( both these wires have to be able to carry a high current charge ) and the third wire is the ground wire, this connects to the cassie of your 4x4 etc. I payed a few years ago around $60.00 for my VSR relay at the time. My 4x4 is now getting on to around 28 years old, so old school electronics and has a basic alternator, a bit of caution is needed if your 4x4 is fitted with a computer controlled alternator as you could damage the computer.
Inverter said
11:13 AM Jan 16, 2023
Hi thanks for that, that solenoid is wired as u described, car, so if it energised via the starter battery/alternator, I'm assuming when the car is not running there's is 12.6v at the relay when the motor starts after a few seconds the relay senses 14.5v from alternator being higher then energised,....something to think about why sometimes it might drop out. Thanks
The other way is what is called a VSR ( voltage sence relay ) and it sences the main battery voltage and once this battery has reached a certain voltage the relay will "pull in" and allow current to flow into the auxillary battery to charge. Turn off the engine and the main battery voltage would drop a little and the VSR would automatically "drop out" These relays are also very easy to install. Just 3 connections are needed, the positive wire from the main starter battery, a main wire going to the positive terminal to the auxiliary battery ( both these wires have to be able to carry a high current charge ) and the third wire is the ground wire, this connects to the cassie of your 4x4 etc. I payed a few years ago around $60.00 for my VSR relay at the time. My 4x4 is now getting on to around 28 years old, so old school electronics and has a basic alternator, a bit of caution is needed if your 4x4 is fitted with a computer controlled alternator as you could damage the computer.