Installing DC/DC Charger

Hi John. Might be worth asking Redarc if they have something suitable.
My van has a large fuse on the positive side of the battery that has a blade fuse in it. Haven't looked at it for a while but the amperage would have to be 50. Will take a photo over the weekend. Cheers,Bob

John,

I used a 50A circuit breaker from ABR Sidewinder with my 30A dc-dc charger.

Something worth noting - to deliver 40A, the charger draws a fair bit more than that from its supply. In normal operation it may well be pushing towards 50A - this can be hard on a 50A fuse, and especially on a 50A alternator. I fitted a 70A alternator to handle this.

Cheers

John

John,
As suggested good to use circuit breakers then you don't need to carry spares. One thing is that it is best to NOT use the auto resetting type in your application. If they blow then there is a problem that needs to be fixed before resetting.

cheers

I am also a fan of the ABR Circuit Breaker / Trip Switch as the charger device is easily isolated as a switch as well as offering fuse protection.

ABR switch

Greg N

When we do BCDC installations we use Maxi fuses rated at 50amps and solder the fuse holders into the input and output wires..... we also wire rap the connections before soldering and heat shrinking using dual wall adhesive heat shrink.

You can use circuit breakers if you want but you also have to find a spot to mount them whereby maxi fuses are in line...... we find over time the cheapy metal or plastic can type circuit breakers fail due to water and corrosion entering them or the spot weld holding the bimetal strip in place breaking.

If done right a fuse should not blow, we mostly find fuses blowing due to shonky workmanship or under rated fuses and fuse holders.

You have to also install a 70amp 5 pin change over relay and relay socket triggered by an ignition feed if you want to use solar inputs.....

We also recommend using minimum 8B&S cable for input, output and earth wires, 6mm for solar inputs and all the rest 3 or 4mm wire..... connect all earths to one location only (battery - or dedicated body earth point.

Spray all connections including the relay with a quality silicon electrical spray grease... this also includes the heat shrinked joints after shrinking.

We also try and mount the BCDC in front of the radiator for maximum airflow to help with heat dissipation.

Hopefully this may help you.

I have the BCDC 1240 and have found the 50A fuse too small for the power in side. Its a long cable run from the vehicle battery to the van and at peak output mine draws some 55A. Also, as the engine bay gets quite warm, it results in the breaker tripping a bit earlier than the the rated 50A, hence two reasons for the change to a larger breaker.

The 1240 is a great bit of kit, the MPPT solar controller also works well on my 160W panels, very happy with the Redarc. And make sure you use decent size cables.

Cheers

Captain

Reading the replies above, I am rather supprised that the Redarc BCDC1240 is installed at the beginning of the circuit run rather than the end.

I would have thought the whole idea is to have the DC/DC charger as close as possible to the remote battery end to overcome voltage drop issues, etc.

This is the way I have installed my CTEK D250s Dual DC/DC Charger.
Dual input for alternator and/or solar panel inputs and the charger is mounted at the service (auxiliary) battery end.

Excellent info guys, all very helpful.
Thank you all any further comments etc appreciated.

John
As you have the welding cable running to the batteries, you could use a insulted battery stud to step down in cable size by using the appropriate cable lug per cable. I also agree with Richard and would use Narva Mazi fuse holder and 60 amp fuse at both batteries. The maxi fuse and cable is about 300mm long so should be able to mount the stud at batteries. I think narva also make the insulated battery stud which you could buy at Bursons.
Just another suggestion
Murray