Dual Battery

[discojools]

Would like to hear from people who have fitted a lithium dual battery system under the rear floor. Have heard stories that vibration and heat are a problem.

[W&KO]

There are probably not too many har have fitted lithium to the new defender…….

Although I have an older defer my lithium is in a tight compartment with cupboards surrounding it. There is ventilation via the gap around the cupboard door.

I regularly check the temp of the battery and it’s always been in the green zone, even on hot days. My thoughts are if it’s insulated with stuff over the top and there is a bit of ventilation than all should be good.

Re vibration, you’d be running air all round, I don’t reckon vibration with be an issue. I run half air suspension and half springs for the three years mine has been installed with no issues to date.

In my install the biggest heat generator would probably be the DC-DC……this is mounted above the battery in a cabinet with more ventilation.

[grey_ghost]

I haven't fitted one to my Defender.

However I was told that these guys (In Victoria) have to a 110:

Piranha Off Road | Battery Trays | Dual Battery | 4WD Accessories

Cheers,
GG.

[JessicaTam]

I fitted a 100W lithium on a custom timber and steel tray in the back. I have just finished a pretty rugged week in western Tassie with no issues. I will dig out some pics of the install.

[one_iota]

This is relevant for D300 owners:

Dual Battery Wiring Landrover Defender D300 MY22 - YouTube

[Summiitt]

This is relevant for D300 owners:

Dual Battery Wiring Landrover Defender D300 MY22 - YouTube

Thanks for sharing, that's a very interesting vid

[one_iota]

Thanks for sharing, that's a very interesting vid

It's worth reading his replies to the comments: particularly that he rewired the 12v accessory plug that he used as the trigger to an ignition-on circuit to prevent draining the starter battery.

[VillaDazzler]

I fitted an aux lithium setup in November '21, so far has worked very well for powering fridge, lights, wifi router, etc. Mind you, I also carry a projecta 1500a lithium jump starter after a dead starting battery event that wouldn't turn over with their 1200e, but that is another unrelated story. If you have an MHEV it is relatively easy to fit a slimline lithium 100Ah and a lithium suitable dc/dc charger into the tray. Make sure you get an inline fuse, (40-50 amp) and wire the positive red cable to the 12v side of the connector block on the stock dc/dc charger under the floor. Get a multimeter to verify. Use 6AWG red wire minimum, mount the fuse close to the terminal, then wrap the red wire in conduit and cable tie to existing cable run on the left side, around to the back of the seat until you can come out through the foam (or over) to your new lithium dc/dc charger the powertech 20A fits very nicely in the right side section. Don't skimp on wire and make sure you earth everything to the chassis, not the battery. There is a good earth point behind rear seat driver side which you can get to by dropping the seat. Everything should fit nicely in the foam box including a slimline VoltX 100Ah battery with a decent bms. Follow the instructions on the dcdc charger and you should end up with a very efficient auxiliary battery system that will only charge the battery when the vehicle is running and isolate it from the starter battery otherwise.