Drop in Lithium Battery replacement

[Outback Pilgrim]

Hi Team Bushtracker,
I wonder if anyone give some feedback or advice on the above topic.
I have been readin Caravan World and have been noticing a lot of ads from iTechWorld advertising a direct battery replacement for Gel batteries without the need to upgrade the van's existing charging or management system.
I have a 2006 BT with 3 solar panels, a bushtracker BC190 50a charger, a Xantrex prosine 1800w inverter with 2 gel batteries.
My batteries will be requiring replacement in the near future and I was wondering if these iTech batteries may be an easy replacement. I gave iTechWorld a call and was assured that the batteries would work fine in the application.
I have been reading some ot the posting on the forum and it appears that a lot of equipment requires change out to take lithium batteries.
I live out in Cobar, which is pretty remote with very few or no-one with experience in Lithium upgrades.
Would I need 2 X 120amp new batteries and will there be enough solar panels to charge them?
Can anyone help me with this or has anyone have any experience with this battery as a direct replacement?
Any assistance would be much appreciated. Thank you.

[WayneBB]

I think 2x 120 iTechWorld lithium batteries is a bit too little. I'd use 3 or better 2x 200Ah lithium batteries. With these lithium batteries you can't accurately determine state of charge without a shunt. I recommend a Victron Bmv-712 Smart shunt. The shunt can be installed when the batteries are installed very easily. At a later date you can make other upgrades to slowly migrate to a more optimized lithium architecture.
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This image might assist -
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[Outback Pilgrim]

Hi WayneBB,

Thank you for your response. Sorry for my ignorance but what is a Smart Shunt. I was looking online and did not quite understand what it does. Is it a battery management system? I saw some photos on line with the smart shunt connected to AGM batteries.
You also recommended that I get 2x200 Ah batteries. As mentioned above I have 3 old solar panels which I believe are original, not sure what the wattage of these panels are, but will these panels be enough to keep these 2 batteries charged?
What lithium batteries would you recommend. I noticed that Itechworld advertises a lot in Caravan World and there are a few ads for Century Batteries and if you look online there are a lot of batteries to choose from. Someone on the forum suggested EV Power and if you go to their website they have a Bushtracker conversion to Lithium.
You also mentioned I can make other upgrades later. What would I have to replace on my existing system?

Thank you again for your help
Kind Regards,
Outback Pilgrim

[WayneBB]

Thank you for your response. Sorry for my ignorance but what is a Smart Shunt. I was looking online and did not quite understand what it does. Is it a battery management system?

AGM batteries have a noticeable drop in terminal voltage when not under load or only very lightly loaded. Some people have a voltage chart for these batteries to give the SOC (state of charge) usually in percent. A lithium battery has a very consistent terminal voltage over most of it's state of charge making it very difficult to determine if it is 80% charged or 30% charged. A Smart Shunt measures the energy going out and coming into the battery enabling more accurate monitoring of the battery SOC even when it's under moderate load. I recommend the Victron BMV-712 Smart Shunt which I use in my vehicle and caravan.

You asked about Itechworld 120 batteries and that's why I suggested 2x 200A batteries. I believe you may find them a little low in capacity both stored energy and maximum current availability. I have an Itechworld 120 lithium battery in my vehicle to power an Engel fridge, my UHF, USB points and various chargers. I've found it works quite well in this role being charged by a DCDC charger while the vehicle is being driven during the day.

[Outback Pilgrim]

Hi WayneBB,

Thank you for your explaination. Really appreciate the assistance.

Cheers,
Outback Pilgrim

[shallowal]

Most of these 12V "lead replacement batteries", such as those mentioned can be operated with your existing Lead/AGM equipment, so no need to do a "big" upgrade to change over from lead to Lithium. The Battery Management electronics in the battery housing will take care of charging and discharging regardless of what the external charger thinks it is dealing with.
However, you might consider upgrading your solar charger to an MPPT design rather than the original PWM charger installed by bushtracker. These chargers can increase the charging performance of your solar panels significantly (I see around 25% improvement on mine) regardless of the battery technology.
Also have a look at Solarking batteries. They seem very reliable and perform at the nameplate capacity even after 3 years in my case.