Split charger for 2nd battery

[blackbird]

Has anyone set up a split charger to run a second battery ?

I notice things like pajeros have 2 batterys

Sent from my SM-G960F using Tapatalk

 

[don simon]

Has anyone set up a split charger to run a second battery ?

I notice things like pajeros have 2 batrerys

Sent from my SM-G960F using Tapatalk

I found these guys very useful, https://www.12voltplanet.co.uk/split-charging.html
I probably bought from here too.

 

[panelbeater]

funny that my 140a vs relay full kit came yesterday,5mtr red and 1mtr black,all you need is in it cost 58 from the bay.
i run a spare 180a battery in rear footwell behind the front passanger seat with a 1500w pure sine wave as i need to charge my buggy up in rear also to plug in caravan if i get a bit low on power not on mains.
i had looked into putting a solar panel on terrys roof as well as i have a spare 100w.

 

[blackbird]

Can you also have a switch to help the engine bay battery. Or are they to be kept separate.

I was going to fit the additional battery in the boot.

Sent from my SM-G960F using Tapatalk

 

[don simon]

Not sure I understand the question, but the starter battery will always work as the starter battery, nothinng changes there. The relay for the charger kit allows the 2nd battery to charge from the alternator through the starter battery, but prevents the second battery taking charge from the starter battery when ignition is not switched on.
You don't want to be using the starter battery to run camping kit, or whatever.
My second battery is in the boot as it's an AGM battery and I understand they don't like being in the engine bay. They don't give off any noxious gasses either, so sleeping next to it isn't going to be a problem.

 

[Lazy-Ferret]

The safe way to have a permanently easy way to re-connect the second battery to the first, to actively jump start the car from it, would be to use one of the old-fashioned starter solenoids as your split charge relay. You need something that can pass 600-800 amps when jump starting, and normal relays are not up to this. If you look back through Uncle Rustics posts on here, you will see that was exactly what he did on his Maverick.

I found it was cheaper to use a 200amp relay for the split charge, and easier just to carry a jump lead that would reach from the positive of one battery to the positive of the other should I ever need to jump start myself. You don't need to do the earths (negatives) as they are already connected via the car body. For mine, I have the batteries on opposite sides of the engine bay, so only need about 4 foot.

 

[blackbird]

Thanks for the info

Sent from my SM-G960F using Tapatalk

 

[elty001]

have a look at the last couple of pages of my project thread as iv'e recently fitted a split charge kit and second battery.
http://www.nissan4x4ownersclub.com/forum/showthread.php?t=25940&page=21

 

[panelbeater]

the wiring for my kit is very straight forward but yes you can use the second battery to start but the main wiring must be upgraded to starting size and where the relay is an exrta high amp switch is needed to bypass the vs relay so in effect it will be like jump leads then switch the bypass off so vs relay is back in line.

 

[Fez_uk]

I always liked the T-max split charge system. 180a capacity maybe a bit over the top but great if you had a winch or needed to start from the 2nd battery. Had voltage display for both batteries too.

 

[kitchenman]

On my motor bike I use a 40A diode between the two + poles so juice won't flow from the spare battery to the main
The diode is a sorta one way valve,
Both - poles are linked together, works a treat

 

[Lazy-Ferret]

On my motor bike I use a 40A diode between the two + poles so juice won't flow from the spare battery to the main
The diode is a sorta one way valve,
Both - poles are linked together, works a treat

The downside to using a Diode, is they have a volt drop over them, usually up to about 0.7v which means the second battery will never get enough volts to fully charge. Lead acid batteries charge on voltage, rather than just current, so 0.7v is a lot to them.

 

[solarman216]

Most car systems are limited to 14.2 to 14.8 but this is not the voltage for a fully charged wet cell lead acid battery, it is more like 15.2 + depending on the actual lead composition, the reason for the lower voltage is due to the fact most batteries are in the engine compartment, and will be subject to relatively high temperatures with the engine running, so to limit gassing and water loss around 14.2 is chosen, however I am seeing more and more motors with batteries in hidden places other than the engine bay and with the introduction of smart alternators this may change, if you want to know about batteries, talk me I run on them, currently around 1.2 tonnes of them, I fast charge and consume around 5 ltrs battery water a week, Rick

 

[Goatmaster]

if you want to know about batteries, talk me I run on them, currently around 1.2 tonnes of them, I fast charge and consume around 5 ltrs battery water a week, Rick

WOW!!! I am seriously impressed.

 

[panelbeater]

he mixes it with gin.:lol