I know it's not strictly cars but I think there are a few on here who know their stuff.
I'm fitting a 20amp Sterling B2B charger in the boot of my car, to charge leisure batteries in caravan while towing and recharge same leisure batteries in car while out and about on holiday. All cables are massive and connection between car and caravan will be Anderson connectors.
I was going to install seperate heavy duty cable from car boot (via VSR) to caravan fridge (I don't have 7S wiring in car but understand it doesn't really work anyway), but I'm starting to wonder whether this is necessary - I'm thinking I could just run cable from caravan battery to VSR just before fridge, this would power fridge, I guess from a combination of caravan battery and supply from B2B. The VSR cuts off at 12.9v so should cut power when engine switched off, so fridge doesn't try to run off battery.
Questions -
the Sterling B2B is a 3 stage smart charger so the voltage varies, but is always above the 12.9v VSR cut off, I'm pretty sure the fridge will accept whatever voltage it gets, but will the battery charging be affected by the current drawn from the fridge, or is it the voltage that determines how the charger works?
surface charge - obviously I want the fridge to shut off as soon as I switch the engine off, but if the battery has just had 20-30 amps pushed into it and the surface charge is giving a voltage in excess of 12.9v the relay will carry on supplying current to the fridge - from my freshly charged battery! Hopefully I'm worrying unnecessarily and either the voltage won't be above 12.9, or if it is it will drop very quickly.
Any advice appreciated, but please bear in mind that I'm a labourer, not a physicist!
I'm fitting a 20amp Sterling B2B charger in the boot of my car, to charge leisure batteries in caravan while towing and recharge same leisure batteries in car while out and about on holiday. All cables are massive and connection between car and caravan will be Anderson connectors.
I was going to install seperate heavy duty cable from car boot (via VSR) to caravan fridge (I don't have 7S wiring in car but understand it doesn't really work anyway), but I'm starting to wonder whether this is necessary - I'm thinking I could just run cable from caravan battery to VSR just before fridge, this would power fridge, I guess from a combination of caravan battery and supply from B2B. The VSR cuts off at 12.9v so should cut power when engine switched off, so fridge doesn't try to run off battery.
Questions -
the Sterling B2B is a 3 stage smart charger so the voltage varies, but is always above the 12.9v VSR cut off, I'm pretty sure the fridge will accept whatever voltage it gets, but will the battery charging be affected by the current drawn from the fridge, or is it the voltage that determines how the charger works?
surface charge - obviously I want the fridge to shut off as soon as I switch the engine off, but if the battery has just had 20-30 amps pushed into it and the surface charge is giving a voltage in excess of 12.9v the relay will carry on supplying current to the fridge - from my freshly charged battery! Hopefully I'm worrying unnecessarily and either the voltage won't be above 12.9, or if it is it will drop very quickly.
Any advice appreciated, but please bear in mind that I'm a labourer, not a physicist!