Installing second battery where 3rd row seat was

[Mundy55]

Thanks, Nev. I'll look for it tomorrow

[Mundy55]

Some people raise stupid children. My only excuse is that it was a long day yesterday. Somehow I wasn't using the mulitmeter probes correctly because, contrary to what I said yesterday the most of fuses in the under bonnet fuse box have power connected, albeit permanently. In the passenger compartment, the situation is the same with many of the fuses connected to items which operate independently of the ignition eg fog lights, so they, too, have power permanently connected.

However, I found an unallocated fuse 21 under bonnet and fuse 10 in the passenger compartment which are ignition switched. Fuse 2 in passenger box is also theoretically usable but the 'make a fuse' connector I have is oriented such that it can't be plugged in as it interferes with the relays above it.

We continue, 3 steps forward, 2 steps back.

[Mike DiD]

I've tested the voltage drop from the bodywork at the Right Rear 3rd Seat Bracket to the Battery Negative terminal - it's the same as running a 6B&S cable.

All non-engine electricals - including 10 amp loads like the Rear Demister - have their earth return via the body, so I see no need to do it differently.

[Mike DiD]

The NW and NX now reduce the Alternator voltage when the battery is full to avoid overcharge and to reduce energy wastage, by sensing the current flowing through the battery.

You can see the sensor in the Ground Lead near the Negative Terminal of the Battery.

It's easy to ensure that the voltage does not drop until the Auxiliary Battery is charged, by connecting the Negative of the Auxiliary to the Negative Terminal of the Starting Battery, instead of to Ground. This means Auxiliary charging current will flow through the current sensor.

If you are using a DC-DC charger, this isn't needed.

[pauld]

My NX has the 2nd battery to the body and I monitor the alternator voltage, it very rarely drops.

[cprand]

I have a volt meter on the main and second battery on my NX and the voltage varies from 14.4 down to 13.8 depending on whether you are on the accelerator or not. Its a good idea about the earth wire.

[Mundy55]

I thought it worth making a point about using a "make a fuse". The MAF has a common positive leg for the 2 fuses it holds and it's important to orient it correctly so that the common leg of the fuse goes into the positive side of the fuse holder. If the MAF is oriented the other way, the current flows through both fuses to the new device, which could cause the original fuse to blow. The way to check is to initially install the MAF with only the new fuse in place without the original fuse. If you aren't getting power then its the wrong way around.

[KPJero]

Just a quick dumb question, if (and when) I get a second battery in the bonnet, is there any issue with running some cables with anderson plugs to the rear of my pajero? The idea would be that I can either connect a fridge (when and if) I ever get one or power other accessories.

[Dicko1]

Just a quick dumb question, if (and when) I get a second battery in the bonnet, is there any issue with running some cables with anderson plugs to the rear of my pajero? The idea would be that I can either connect a fridge (when and if) I ever get one or power other accessories.

None. Just ensure you get good size cable...say 6B&S and put an appropriate fuse..say 50amp near to the battery on the positive wire. If you want to run wire internally to use a fridge you can get away with just running one length of 6b&s POSITIVE and use the body for an earth near the anderson plug. I have my setup like this and it runs 2 dc/dc chargers and several sockets in the rear

[KPJero]

None. Just ensure you get good size cable...say 6B&S and put an appropriate fuse..say 50amp near to the battery on the positive wire. If you want to run wire internally to use a fridge you can get away with just running one length of 6b&s POSITIVE and use the body for an earth near the anderson plug. I have my setup like this and it runs 2 dc/dc chargers and several sockets in the rear

Thank you.
Too many projects in my brain and not enough money!

[Old Paj]

Second Battery

I have been running a second battery (AGM) under the bonnet now for nearly 3 years (fitted less than 1 month after purchase).

Have and currently continue to have an Anderson plug run to the rear (for camper trailer fridge) and have a duel port merit connection in the rear of the Paj to run an Engel on an MSA drop slide.

All giving, and continuing to give excellent service.

[Detonator]

Ctek 250s

The Ctek you need is a Ctek 250SA.
The SA denotes smart alternator.
If you already have a Ctek 250S you can still use it but it needs a relay added to the circuit.
See attachment for details