DBK
LIFE MEMBER
I've just fitted a Sterling BB1260 B2B charger. Things didn't go quite to plan but it is working now so here is a short account of what I did just in case anyone is thinking of doing the same.
For those unfamiliar with them B2B chargers replace the usual split charging system fitted in MHs. A split charger basically just connects the leisure batteries to the vehicle alternator once the engine is running. A consequence of this is the vehicle and leisure batteries are exposed to the same voltage. Now if your leisure batteries are fairly well discharged they need a lengthy charge at a high voltage - typically 14.4 volts for sealed lead acid batteries. The problem with this is the vehicle battery is exposed to the same voltage and could be over charged. Modern vehicle electrics are aware of this so what tends to happen is the voltage is reduced and the time to re-charge the leisure batteries will be extended. This won't generally be a problem if you are driving a good distance every day but on our trip down the Mosel late last year we were struggling on battery power. It was a combination of low sun, a power hungry diesel heater and the short distance between stelplatz!
A B2B can charge the leisure batteries at a higher voltage than the vehicle battery. It does this by placing a load on the alternator to maximise its output and then boosting this voltage and using this to charge the leisure batteries.
They are not cheap but Sterling have a small number of reconditioned units and a 60A model cost me £159 which is about half the price of a new one.
To fit the B2B requires positive and negative connections to both the vehicle and leisure batteries. Sterling recommend for maximum efficiency you don't use the vehicle body as the return.
On the model I chose no connection to the alternator is required. The cables have to be chosen to match the current and lengths of cable run. On my installation this dictated 25mm cables which I ordered from Electrical Car Services who I've used before and are excellent. https://www.electricalcarservices.com/battery-leads-made-to-order/c-p-0-0-535
Because every installation will be different I won't describe in detail where all the cables went but the front part will be common to most Fiat based MHs so I'll describe this.
Here is a shot of the vehicle battery.
The cables to the B2B are the two disappearing under the bottom of the dash at the top. The positive is fused. From here they run under the carpet just below the pedals. They are out of the way of my feet and do not interfere with the pedals.
To get to the rear of the vehicle I used the space behind the trim below the door.
Removing this and the part in front of it reveals this.
The two cables can be seen running front to back. There were even two unused cables clips I could take advantage of.
I had to run the cables on top of the carpet for about 6" before taking them through holes into the space behind the seat/bed where the leisure batteries are. The cables are out of the way here and do not interfere with the handbrake although it might look as if they do.
The negative cable is connected to the negative terminal of one of the leisure batteries. From these negative terminals I had already run a 35mm cable to the inverter and this I'm doubling up as the return from the B2B. The red cable runs all the way to the B2B which is fitted behind the panel shown below with wires coming out of it for the TV and WiFi booster. You might just be able to see the four mounting bolts.
This photo shows the other side.
The wires and cables coming out of the bottom are from left to right the wires for the leisure battery temperature sensor, the cable from the vehicle battery and a smaller wire connected to the same terminal from the BatteryMaster which I had to re-connect as it was originally wired through the split charging relay which I disconnected by removing the fuse to the relay. The next cable is the black common negative which runs a short distance to the negative terminal on the inverter to join up with the 35mm cable mentioned earlier. The final red cable is connected to the battery side terminal of the inverter isolating switch, making use of the heavy cable running from there to the leisure batteries through a fuse.
The leisure battery temperature sensor is the yellow thing visible below.
It is not essential to fit this but if you do the unit will alter the charging voltages, reducing it when it is hot and increasing it when cold. So without the sensor fitted it will charge sealed lead acid batteries at 14.4 volts but when fitted and in the current cold weather it is doing this at 14.6 volts. All charging voltages can be altered during setup to match your type of battery including lithium.
So what went wrong?
The first problem is when the B2B arrived I couldn't get it to work! I returned it and Sterling tested it and said they could find no fault but would replace it anyway. When this unit arrived I connected it and it worked perfectly! Most curious.
The B2B comes set up to operate automatically when the vehicle battery voltage rises above 13.6 volts. As mentioned in another thread I was a little concerned how this would get on with the BatteryMaster when the sun was shining. My worry was the vehicle battery voltage could be raised above 13.6 volts by the trickle charger from the BatteryMaster and the B2B tricked into starting. I raised this with Sterling who advised this wouldn't be a problem but to be sure I decided to set the unit up so it would only start when the engine was running. To do this you have to connect a terminal on the unit to an ignition feed which is only live when the alternator is running.
And this is where I hit a problem. The unit would start but not turn off properly when I switched the engine off. It just repeatedly went through a cycle of flashing LEDs, beeps and re-booting itself. I spoke to Charles Sterling and sent him a video of it happening. His answer was he couldn't explain what was happening, never having seen it before and could offer no solution!
I couldn't be bothered to return this one so I've switched it to automatic operation, which it does perfectly and see how it gets on in the summer when the sun is shining strongly. In the worst case I could just disconnect the BatteryMaster or fit an isolating switch.
As to whether fitting this device is going to help only time will tell. We may have to revisit the Mosel in the autumn.
For those unfamiliar with them B2B chargers replace the usual split charging system fitted in MHs. A split charger basically just connects the leisure batteries to the vehicle alternator once the engine is running. A consequence of this is the vehicle and leisure batteries are exposed to the same voltage. Now if your leisure batteries are fairly well discharged they need a lengthy charge at a high voltage - typically 14.4 volts for sealed lead acid batteries. The problem with this is the vehicle battery is exposed to the same voltage and could be over charged. Modern vehicle electrics are aware of this so what tends to happen is the voltage is reduced and the time to re-charge the leisure batteries will be extended. This won't generally be a problem if you are driving a good distance every day but on our trip down the Mosel late last year we were struggling on battery power. It was a combination of low sun, a power hungry diesel heater and the short distance between stelplatz!
A B2B can charge the leisure batteries at a higher voltage than the vehicle battery. It does this by placing a load on the alternator to maximise its output and then boosting this voltage and using this to charge the leisure batteries.
They are not cheap but Sterling have a small number of reconditioned units and a 60A model cost me £159 which is about half the price of a new one.
To fit the B2B requires positive and negative connections to both the vehicle and leisure batteries. Sterling recommend for maximum efficiency you don't use the vehicle body as the return.
On the model I chose no connection to the alternator is required. The cables have to be chosen to match the current and lengths of cable run. On my installation this dictated 25mm cables which I ordered from Electrical Car Services who I've used before and are excellent. https://www.electricalcarservices.com/battery-leads-made-to-order/c-p-0-0-535
Because every installation will be different I won't describe in detail where all the cables went but the front part will be common to most Fiat based MHs so I'll describe this.
Here is a shot of the vehicle battery.
The cables to the B2B are the two disappearing under the bottom of the dash at the top. The positive is fused. From here they run under the carpet just below the pedals. They are out of the way of my feet and do not interfere with the pedals.
To get to the rear of the vehicle I used the space behind the trim below the door.
Removing this and the part in front of it reveals this.
The two cables can be seen running front to back. There were even two unused cables clips I could take advantage of.
I had to run the cables on top of the carpet for about 6" before taking them through holes into the space behind the seat/bed where the leisure batteries are. The cables are out of the way here and do not interfere with the handbrake although it might look as if they do.
The negative cable is connected to the negative terminal of one of the leisure batteries. From these negative terminals I had already run a 35mm cable to the inverter and this I'm doubling up as the return from the B2B. The red cable runs all the way to the B2B which is fitted behind the panel shown below with wires coming out of it for the TV and WiFi booster. You might just be able to see the four mounting bolts.
This photo shows the other side.
The wires and cables coming out of the bottom are from left to right the wires for the leisure battery temperature sensor, the cable from the vehicle battery and a smaller wire connected to the same terminal from the BatteryMaster which I had to re-connect as it was originally wired through the split charging relay which I disconnected by removing the fuse to the relay. The next cable is the black common negative which runs a short distance to the negative terminal on the inverter to join up with the 35mm cable mentioned earlier. The final red cable is connected to the battery side terminal of the inverter isolating switch, making use of the heavy cable running from there to the leisure batteries through a fuse.
The leisure battery temperature sensor is the yellow thing visible below.
It is not essential to fit this but if you do the unit will alter the charging voltages, reducing it when it is hot and increasing it when cold. So without the sensor fitted it will charge sealed lead acid batteries at 14.4 volts but when fitted and in the current cold weather it is doing this at 14.6 volts. All charging voltages can be altered during setup to match your type of battery including lithium.
So what went wrong?
The first problem is when the B2B arrived I couldn't get it to work! I returned it and Sterling tested it and said they could find no fault but would replace it anyway. When this unit arrived I connected it and it worked perfectly! Most curious.
The B2B comes set up to operate automatically when the vehicle battery voltage rises above 13.6 volts. As mentioned in another thread I was a little concerned how this would get on with the BatteryMaster when the sun was shining. My worry was the vehicle battery voltage could be raised above 13.6 volts by the trickle charger from the BatteryMaster and the B2B tricked into starting. I raised this with Sterling who advised this wouldn't be a problem but to be sure I decided to set the unit up so it would only start when the engine was running. To do this you have to connect a terminal on the unit to an ignition feed which is only live when the alternator is running.
And this is where I hit a problem. The unit would start but not turn off properly when I switched the engine off. It just repeatedly went through a cycle of flashing LEDs, beeps and re-booting itself. I spoke to Charles Sterling and sent him a video of it happening. His answer was he couldn't explain what was happening, never having seen it before and could offer no solution!
I couldn't be bothered to return this one so I've switched it to automatic operation, which it does perfectly and see how it gets on in the summer when the sun is shining strongly. In the worst case I could just disconnect the BatteryMaster or fit an isolating switch.
As to whether fitting this device is going to help only time will tell. We may have to revisit the Mosel in the autumn.
