AUX BATTERY

[k10klub]

I am kicking around the idea of putting a second battery in my ochre truck to run some accessories in the camper and not drain my starting battery. I have done a little research on the topic, but all of the results seem to be setup so they can jumpstart the primary battery, not to mention expensive, and I am not currently trying to go that route.

From what I remember remember reading on Optima's website, a battery typically needs something like 10 amps or less to charge (more amps won't charge it any faster, better, or fuller) so I would run an appropriate gauge wire for the length to the location, my assumption is that the relay as shown in my sketch supplies current to the battery when the engine is running, and disconnects when the engine is off.

Thoughts?

Thanks,
Ben

View attachment 357195

 

[k10klub]

sketch

 

[Kain]

i used one from this guy, was easy just had to shorten the wires

http://12voltguy.net/

 

[ktmoutfront]

That design will work. Needs to be on an OFF circuit while cranking. If not, if the starting battery is low, it will feed the starter and fry that wire.

 

[Wes Harden]

sure power 1314 solenoid. it is smart and will close when main batt has 13.5 volts. On my old hippie van I use a Cole heresy normally open constant duty solenoid, on a toggle switch.

Update your alt as well. I went with https://www.speedwaymotors.com/Powermaster-7294-GM-12SI-100-Amp-Alternator-Natural,98638.html

But I think I'm going to change it this https://www.speedwaymotors.com/Tuff...lternator-140-AMP-V-Groove-Pulley,278157.html.
I have dual AGM, front and rear ac, to aux fans for a/c and trans cooler, Warn winch, small center consul cooler. No stereo amp. Overdrive trans, thou cruise is @2500 rpm so I should be getting full charge at that rpm. If you were idling around on trails all day, might not be enough to charge aux batt after a night of use.

 

[skunked]

But I think I'm going to change it this https://www.speedwaymotors.com/Tuff...lternator-140-AMP-V-Groove-Pulley,278157.html.
I have dual AGM, front and rear ac, to aux fans for a/c and trans cooler, Warn winch, small center consul cooler. No stereo amp. Overdrive trans, thou cruise is @2500 rpm so I should be getting full charge at that rpm. If you were idling around on trails all day, might not be enough to charge aux batt after a night of use.

just installed that alternator on a friends truck a couple weeks ago.

 

[k10klub]

Installed a Powermaster unit about 2-3 years ago

 

[ZooMad75]

150 amp continuous duty solenoid instead of the relay. Have the aux battery tied to the other battery via the positive cable with the solenoid in-between. Use a 3 position rocker or toggle switch so that one side provides power to the solenoid with the key on. When the key is off it will automatically disconnect the batteries from each other. Key on and switch on it will charge the aux battery. The other side of the switch is a circuit direct from the aux battery and then to the solenoid so if the main battery is dead you can flip the switch to the other side and "jump start" from the aux battery.

My aux battery has been set up this way for 4 years and works perfectly.

 

[Wes Harden]

just installed that alternator on a friends truck a couple weeks ago.

just use the 1 wire or 3 ?