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Geedublya
11th June 2019, 06:41 PM
Has anyone got an iTech120 (https://itechworld.com.au/collections/lithium-batteries/products/100ah-12-volt-1000-cca-lithium-battery)? The specs look good and it has in-built battery management so it should be ok hooked up to the Traxide SC-80.

Don't bother telling me I should just get a lead acid as I understand the differences. I want the light weight and the increased capacity.

drivesafe
11th June 2019, 07:32 PM
Hi Geedublya, unfortunately, you can not use a Lithium battery with a VSR isolator, mine or any other brand.

VSR isolators will not turn off because of the higher constant voltage of a lithium, and even if you keep the batteries connected, you will only be draw current from the lithium battery until it is down to around 20% SoC. Only ten will you be drawing off the cranking battery.

The only way to set up to use a lithium battery as an auxiliary battery is to disconnect the batteries when the motor is turned off.

In other words, an ignition switched type isolator.

Because you can not use the cranking battery while camping, a 120Ah Lithium battery only gives you a very small increase in capacity, and the weight saving is not much better either.

Geedublya
11th June 2019, 07:49 PM
Thanks Tim, it still may be useful as a house battery in the caravan and then I could put the 150AH AGM from the caravan into the car,

austastar
11th June 2019, 09:44 PM
Hi,
Interesting that it claims to be "drop in". So did my Fusion 200 AH. But the charging profiles on the tech sheets, if I am reading them correctly, would indicate that a lead acid charging profile is not ideal.
I am still using an SC80 Traxide isolator, but it feeds a dc2dc / MPPT solar charger. This saved me a bit of wiring, and is backward compatible if I ever go back,
Is there a noticible difference between the lead vs lithium?
Well I cobbled the wiring together for a trip last weekend.
Charged the battery to float on a mains lithium charger and left.
Camped for 2 nights (fridge, lights, diesel heater) and the voltage barely moved.
Coming home, the battery was back to float after about 30 minutes driving.
No way would I see that with the old battery.
Cheers

John_D4
12th June 2019, 12:22 PM
Hi Geedublya, unfortunately, you can not use a Lithium battery with a VSR isolator, mine or any other brand.

VSR isolators will not turn off because of the higher constant voltage of a lithium, and even if you keep the batteries connected, you will only be draw current from the lithium battery until it is down to around 20% SoC. Only ten will you be drawing off the cranking battery.

The only way to set up to use a lithium battery as an auxiliary battery is to disconnect the batteries when the motor is turned off.

In other words, an ignition switched type isolator.

Because you can not use the cranking battery while camping, a 120Ah Lithium battery only gives you a very small increase in capacity, and the weight saving is not much better either.

Same deal using the USI160 controller?

drivesafe
12th June 2019, 12:47 PM
Same deal using the USI160 controller?
Unfortunately, yes.

The only way to charge and maintain lithium batteries properly, is by using a DC/DC device.

I have been helping people setup caravans with lithium house batteries for nearly 7 years now.

While I originally set up a good friends D4, as an experiment, with one of my isolators. The setup was quickly converted to a DC/DC charging system, using Sterling gear.

I still help customers set up with the same Sterling gear, and these same setups are idea for Lead Crystal house batteries as well.

John_D4
12th June 2019, 12:48 PM
Bummer. Thanks

Eevo
12th June 2019, 03:08 PM
The only way to charge and maintain lithium batteries properly, is by using a DC/DC device.




help me out if, if an alternator puts out 14.6 volts
and a lithum battery charges at 14.6 volts, why is a DC/DC charger needed?

drivesafe
12th June 2019, 04:22 PM
Hi Eevo, 14.6v is the absolute maximum charge voltage most lithium batteries can safely tolerate.

Once a lithium battery reaches a fully charged state, the voltage should be lowered to no more than 13.8v, 13.6v is preferable.

austastar
12th June 2019, 04:26 PM
Hi,
there is a bit of info here.

Lithium Vs Lead Acid >> Marsen (https://marsen.com.au/lithium-explained/lithium-vs-lead-acid/)

Cheers

oka374
12th June 2019, 04:36 PM
There are two reasons to use a DC to DC charger to charge lithiums from a vehicle, one is to get the voltage correct, personally I won't charge my lithium to anything higher than 14.2 and the bigger reason is to prevent alternator meltdown.
As you probably know a lead acid battery's internal resistance rises as it approaches "full", from about 75-80% state of charge it rises quite steeply which in turn limits the amount of charge amps it can accept and which the alternator supplies.
Lithiums have a very low internal resistance and will accept whatever the charging source can supply so in the event the alternator is rated at 100 amps then the lithium battery will accept that until full.
Most alternators cannot handle running at full output for any length of time without internal temperature rising which in turn limits the output current if it is fitted with thermal protection or if not can sometimes lead to total alternator failure.
Many 240v chargers also suffer the same problem when used to charge lithiums especially larger capacity banks.

Pedro_The_Swift
12th June 2019, 05:23 PM
Lithium Vs Lead Acid >> Marsen (https://marsen.com.au/lithium-explained/lithium-vs-lead-acid/)

well that ^^^ has convinced me,, [thumbsupbig]
not sure I'll implement it in this van though...

LRD414
12th June 2019, 10:07 PM
The sales blurb for the lithium battery linked in OP indicates it has a built-in BMS of some sort, enabling it to be directly replacing an AGM unlike a typical lithium battery by itself.

Scott

drivesafe
12th June 2019, 10:25 PM
Hi Scott, just about all lithiums these days, come with their own builtin BMS.

It is the quality of the BMS that can make a difference as to what battery is better than another.