Calibre DC to DC charger

[Farmer Joe]

I have bought a DC to DC charger with the intention of topping
my second battery, which is a deep cycle calcium, to 15.4 volts,
which is the recomended voltage for that type of battery.

My question is What is the correct way to wire it up?

I have a SBI 12 redarc isolator, do I just cut the wire between
isolator on second battery and wire it in or is it more difficult?

Thanks for any advice.

Cheers fj

 

[bods]

If you're using one of those chargers you can remove the sbi12 altogether. The DC charger will only run when it gets a certain voltage input from the main battery, ie, the alternator is charging it. Then it will charge the second battery until you turn the car off, then when the voltage drops again it will stop charging the battery

 

[Tappet]

Using a Calibre DC-DC charger here straight to the main bat. and it does the job but have noticed that when you turn the engine off somtimes the votage of the main battery is enough to keep the charger alive. So it turns on, voltage drops a little, then turns off, then back on and so on. There probably is some kind internal adjustment so you can change the set point of the voltage to it to when it livens up. Obviously that needs to raised just havn't got around to it.
For best results mount the charger as close to the Aux bat as possible.

 

[Farmer Joe]

Cheers guys.......... I'll wire it up on the week end.

Thanks for your help.

fj

 

[Farmer Joe]

Using a Calibre DC-DC charger here straight to the main bat. and it does the job but have noticed that when you turn the engine off somtimes the votage of the main battery is enough to keep the charger alive. So it turns on, voltage drops a little, then turns off, then back on and so on. There probably is some kind internal adjustment so you can change the set point of the voltage to it to when it livens up. Obviously that needs to raised just havn't got around to it.
For best results mount the charger as close to the Aux bat as possible.

Yeah Tappet I had the same thing happening so I wired up a relay that turns it off with the key so now when the ignition is off the DC to DC charger is off. Works a treat..
fj

 

[Tappet]

Yeah Tappet I had the same thing happening so I wired up a relay that turns it off with the key so now when the ignition is off the DC to DC charger is off. Works a treat..
fj

Ok! Rather than fooling around with it ended up doing just the same thing.

 

[Navd22yd25cr]

Im thinking of doing a second battery in my tub, with the dc to dc charger do u still need to run thick cable to the back or is that only when running a redarc type set up?

Sorry if its a stupid question...

 

[sparra04]

Im thinking of doing a second battery in my tub, with the dc to dc charger do u still need to run thick cable to the back or is that only when running a redarc type set up?

Sorry if its a stupid question...

the dcdc will need good cabling to combat voltage drop
do you plan on fitting charger in tray or under hood?

 

[Old.Tony]

Always use heavy cable to transfer DC power over long distances.

 

[Tappet]

and for best results mount the charger as close as possible to the battery.

As for cable, I used 30 amp. The Calibre charger has only an output of 10 amps so you would get away with 25 or even less but best to use something heavier to avoid a voltage drop.

Also run a negative to the DC-DC charger. Don't rely on the vehicle ground/earth.