Traxide and Lithium

[ytt105]

Here's my setup.

Disco 4 2010 TDV6. AGM starting battery, Traxide 80 to a second AGM in the rear footwell. Then an anderson plug to my caravan which has a 200a lithium battery.

I don't have a DCtoDC charger, I'm assuming/hoping that my solar will do the heavy work of keeping the battery charged. I don't actually have a large load on my system, no fridge connection, mainly the odd coffee machine operation.

So the question is, can I use the the direct from alternator charge to give the battery a quick base charge if it gets very low sometime.

Regards
Trevor

[drivesafe]

Hi Trevor and unfortunately, no you can not charge your lithium battery directly off your D4’s alternator while driving.

This has nothing to do with your Traxide setup, it is to do with the way your SMART alternator operates in your D4.

If your D4 AGM batteries were low at the start of a drive, you would actually FAST charge the lithium battery if it was not fully charged.

This would be fine because the Traxide isolator’s operation causes the alternator to run at high voltages. Up to 14.7v, which would be safe for your lithium battery, way back in your caravan.

But when ever your two AGM batteries in the D4 are fully charged or near fully charged, the SMART alternator function will cause the alternator voltage to drop as low as 12.2v, but normally as low as 12.5v, but both of these voltages are way too low for lithium battery use.

The problem is that lithium batteries have a settled voltage level of 13.2v to 13.3v and this will be for 80% of the discharge cycle of any lithium battery.

What this means is when ever the SMART alternator voltage drops below 13.2v, your D4’s electrics will be running on the power coming from the lithium battery not from your alternator.

This is a problem common to these Drop-In Lithium battery setups. People can leave home with fully charged Drop-In Lithium batteries and get to their camp site, set up and go to bed.

When they wake up, the next morning, their fridge has stopped running because their lithium batteries were near flat by the time they reached their camp site, and the fridge finished them off over night.

The only way you can charge your lithium battery in your caravan off the alternator, while driving, is with a DC/DC device.

To help charge your lithium battery quicker, as I take it, you have solar on the roof of your caravan, make sure the solar is connected to the lithium battery via a seperate solar regulator and not through any DC/DC device.


PLEASE Note, all this info applies to D4s, but NOT to D3s. D3s have a different type of SMART alternator operation which will allow you to charge lithium batteries directly from your alternator.

[ytt105]

Thanks Tim. Its good to know how these things work.

I didn't intend to charge via alternator as a matter of course. I would only need to charge direct when the caravan battery is very low, and only enough to tide me over till the sun comes out.

So, as I understand it, in an emergency, an hour or so on the alternator wouldn't do any harm to the car. True?

Regards
Trevor

[drivesafe]

So, as I understand it, in an emergency, an hour or so on the alternator wouldn't do any harm to the car. True?
This would be of no harm what so ever to your alternator, but if your two D4 batteries are fully charged or near fully charged, idling your motor will just further DISCHARGE your lithium battery..

My suggestion for this type of event is to have a about a 500w 12v to 230vac inverter and a 5 amp 240vac battery charger,

You could then connect up to the Anderson plug at the rear of your D4, and power the inverter.

The inverter could then power up the 5 amp battery charger and you could then slowly charge the lithium battery properly, from your D4, without running your D4.

Regardless of how long you run this setup, a short drive in the D4 will replace most of the used battery energy, ready to do it again the next night if need be.

[ytt105]

What a great idea Tim!

I just happen to have a 300w inverter running my 3 way fridge when I drive. For the odd time I might need a little battery help I could forgo running the fridge for the morning drive.

Thanks
Trev

[ytt105]

Tim, your a wealth of info.

I've got another scenario. When stopped and setup, I often connect my car to the van and let the van solar help with running the car fridge.

After reading your message, I'm wondering if this be a problem with the van battery being lithium and the car one AGM.

Regards

[drivesafe]

Tim, your a wealth of info.

I've got another scenario. When stopped and setup, I often connect my car to the van and let the van solar help with running the car fridge.

After reading your message, I'm wondering if this be a problem with the van battery being lithium and the car one AGM.

Regards
Hi Trev and sorry for the delay in replying, I had two days off and was out of phone and internet range.

If your lithium battery is connected directly to your two D4 AGMs with or without the solar, the two D4 batteries will be kept topped up.

With no solar connected to the lithium battery, the lithium will S-L-O-W-L-Y discharger while topping up your D4 AGMs and discharge further while running your fridge.

When the solar is connected and if it is big enough to run the fridge and charge the lithium, then all your batteries will benefit from the solar.

NOTE, in the above scenarios, none of your batteries will be put in harms way.

[ramrod]

PLEASE Note, all this info applies to D4s, but NOT to D3s. D3s have a different type of SMART alternator operation which will allow you to charge lithium batteries directly from your alternator.

Hi Tim, I was about to ask the very same question except I have a 2.7 D4 and the D3-DS Traxide set up. Will I need a DCDC charger to power lithium in a caravan or can I run it straight from the rear Anderson plug
Cheers

[drivesafe]

Hi Tim, I was about to ask the very same question except I have a 2.7 D4 and the D3-DS Traxide set up. Will I need a DCDC charger to power lithium in a caravan or can I run it straight from the rear Anderson plug
Cheers
Hi ramrod and being as the D4 2.7 has the same SMART alternator operation as a D3, you should be able to charge directly from the alternator.

Just make sure you have 6B&S cable in your caravan.

If you have voltage monitoring in your Disco, check that it does not run any lower than 13.5v