Thread: Lithium Aux Battery?

Originally Posted by John_D4

What’s MLI?

Multi layer insulation

Originally Posted by John_D4

What’s MLI?

Lots of layers of a thin insulator, each insulator rejects say 90% of the heat, very little gets through. On a large scale the James Webb Space Telescope, I think the heat shield on that is the size of a tennis court.
Works better if the layers do not touch or have minmal touching.

Oh right. That makes perfect sense. Just need to find time to made the box. Thanks

John you are still going to get a lot of heat soak when parked up, even with a heat shield / box.

May pay to get a wireless temp sensor/gauge to see what sort of under bonnet temps you will be dealing with.

Originally Posted by drivesafe

Hi John and first off, your Traxide isolator is NOT the limiting factor when trying to charge lithium batteries directly from a D4 alternator.

The D4 comes with a SMART alternator operation and will stop charging a lithium battery and the BMS in a D4 will actually cause the D4 to run its electric off the lithium battery while your are driving.

In D3s and the original defenders, you can charge lithium batteries directly off the alternator through a Traxide isolator.

Next, your idea of an aluminium battery box is far superior to a thermal blanket, because any heat that will get to the battery, particularly on long drives, will keep in battery hot, long after the motor has stopped.

An aluminium box, fitted no closer to the battery than 10mm, will reflect the radiated heat coming from the motor but will allow any heat in the battery to quickly vent off once the motor stops.

Drivesafe - can you confirm that you can use a LiFePO4 aux battery with a traxide system. I have a SC80 i am looking at migrating from my D4 and would like to use a lithium for this.