"BIG FOOT 25"

or 

2004_12_17

or

"Battery System"

 

Because there isn’t that much progress with the further building of the camper and of various requests I suggested to give some more detailed information about some older stuff.

 

As you may remember I don’t need anything except water and diesel. The cabin is equipped with an Eberspächer diesel warm-air heating. Warm water will be achieved by an Eberspächer warm-water heating, alternatively by connection to the cooling circuit of the engine (and as third but never used facility by a 230V heater in the hot water tank). Everything else is handled by 12V or 24V DC directly or by transforming 24V DC into 230V AC. This installation I had described previously. But I didn’t get into detail about the batteries.

 

The dynamo or a charger either charges the batteries. The original dynamo was replaced by a more powerful with 24V and 100A.

The original controller of the dynamo was replaced by Agtar by a special HPR-controller. This manages that the batteries are charged to the maximum. Normal controllers stop the charging much earlier to prevent heavy steaming of the battery.

If there is a local power supply the batteries can be charged by a Victron charger with 50A and 24V.

As well you see the shunt (with the two powerful fuses required if both transformers are working at maximum power), necessary for the battery control system.

 

 

When batteries are charged they start steaming which sets free oxyhydrogen plus the fluid level in the cells drops. To fill the batteries it would be necessary to remove the bottom plate, open 7 x 6 screw lids and than try to carefully fill the cells without wasting water. To prevent all this action I have installed a battery filling system.

This consists of a small tank from a normal car windscreen-washing unit with integrated electronic pump, which I had mounted in the small seat in the front of the cabin.

 

 

After having filled the tank with distilled water I just push the small, black button on the photo. The pump starts to run and as long as water is flowing the red mill in the window turns.

 

 

The water access the first cell through the special screw lids from BFS. These smart screw lids have a float, which closes the valve if the first cell is filled to its maximum and passes the water to an exit. The filling status is visible by a white notch from the top. This first screw lid is connected to the entry of the next screw lid . So the story continues for 7 x 6 = 42 cells to the very last one. The exit of the last one has a dead-end stubby tube. So if all cells a properly filled no more water is flowing and the mill from above stops running – time to release the finger from the button.

 

 

These battery

 

 

For the 12V circuit I have a 7th battery (on the very left and top, only half of it can be seen), which is kept charged by a DC / DC converter (on the picture on the very top). Of course this system is connected as well to the BFS-System.

Here you see all 7 batteries in their compartment.

 

 

The next job will be a fixation for the batteries so that they don’t jump up when driving in heavy terrain.