Just swapped over my Aux battery

[Numb Thumbs]

I have had an AGM 120 Ah battery as an Auxiliary battery for a while, running the 40 litre Waeco and the tyre compressor on trips. I take it out when I do not need it as it is in a plastic battery box.

I thought there must be a better solution than a lead based battery.

I got a 125 Ah Lithium battery from Sentry.

As a comparison:

Weight:
AGM 38 kg
Lithium 15 kg

Size:
Comparable, the Lithium is slightly smaller, but only slightly. It fits easily in the same battery box with a little room to spare.

Usable Capacity:
AGM 60 Ah, 12.2 Volts 50% SOC, significantly less under load
Lithium 100 Ah 12.8 Volts at 80% SOC, regardless of load

Expected Life:
AGM Maybe 8 years, looked after carefully
Lithium Over 20 years expected

The Lithium battery has a Bluetooth setup which allows me to monitor Voltage, SOC, temperature, charging rate, discharging rate, etc. on my phone.

So, 40% the weight, 65% more useable capacity, over twice the life expectancy AND it maintains a constant, useful Voltage right down to at least 20% SOC. It is so much easier to get in and out of the car and has given me back 23 kg of payload.

I am charging it with a Ctek D250S Dual DC-DC and Solar Controller, as per the suppliers instructions - the exact same one I was using for the AGM.

I'm a happy camper!

Cheers
Numb Thumbs

[Troutman]

What is the cost comparison?

[Numb Thumbs]

A quality AGM - around $700 to $800?
Lithium 125 Ah around $1700

So, a bit over double?

To me, well worth it for the life expectancy alone, but add in the lack of Voltage sag, constant Voltage and major weight reduction, and it is no comparison.

Most people seem to forget the Voltage side of things - no fridge turning on and off, compressor working properly, etc.

Cheers
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[crdv6]

Just out of curiosity, where have located your auxiliary battery?

[JnK]

Im interested in how you came to decide on the brand???
I have a similar setup with an 80a AGM in a battery box behind the Engel and struggle to lift it in and out nowadays.
With lithium batteries of 100a priced from your Sentry price and and Enerdrive BTec (with a similar phone monitoring app) at $1695, down through all the way to $695 Satplus own branded battery.
All with varying but similar weights of around 13kg.
I'm aware there will be quality and construction differences and the max discharge rate specs for the range available show huge differences.
Confuses me as I don't know a lot about the technology.
There is a possibility of replacing the 2x100 AGM in the caravan as well so it could turn into a major purchase.
The weight saving and the potential available capacity is a compelling argument.
So while I don't need to be convinced about the advantages I'm still faffing about and can't bite the bullet.
Thanks
John

[Numb Thumbs]

crdv6

As I said, I do not leave the battery in the GC all the time, only when I need it. Originally I made up a lightweight 19 mm ply replacement floor over the spare wheel to which I bolted a long fridge slide. I put that in for trips when I was taking the Waeco fridge. I would then strap the battery box to the end of the fridge slide and then strap the fridge to the end closest to the tailgate. It worked really well, but then O started thinking about how heavy the whole thing was - a trip to a weighbridge will do that I find...

I stopped using the fridge slide - I found I could actually access the fridge quite well without it. That save a lot of weight - 26 kg in fact, I just weighed it.

I now simply put the battery box hard up against the rear seat back on the passenger side and strap it to the child seat restraint anchors. I then put the fridge in and push it up against the battery box. It is a perfect fit.

JnK

Five years ago I decided to go Lithium in our camper trailer hybrid - a VistaRV Crossover XL. Lithium wasn't an option so I made up my own batteries out of Winston Cells, four cells to a battery. It was actually easier than I expected and I fitted battery management modules to protect the cells from under or over charging. Those two 100 Ah batteries have worked flawlessly. The 200 Ah in two batteries plus management modules, connectors, solid state relays, etc cost me around $1400.

Since then, VistaRV have made Lithium a (very popular) option and they use the Sentry batteries. They have had no problems with them that I am aware of so I decided to go with the devil I knew as they say and use one of the Sentry 125 Ah batteries as my auxiliary battery in the GC.

There is a lot of misinformation around about Lithium batteries and initially there were some real cowboys flogging some poor quality batteries at extortionate prices. It seems to have settled down a lot now. Some batteries seem to be over priced, and I am nervous of the real cheapies - remember, your 4WD and van batteries have to withstand a lot of vibration and banging around.

The weight difference is amazing, especially noticeable in the battery box. It is so much easier to lift in and out of the car.

Hope this helps. PM me if you want more information.

Cheers
Numb Thumbs

[JnK]

Originally Posted by Numb Thumbs

JnK

Five years ago I decided to go Lithium in our camper trailer hybrid - a VistaRV Crossover XL. Lithium wasn't an option so I made up my own batteries out of Winston Cells, four cells to a battery. It was actually easier than I expected and I fitted battery management modules to protect the cells from under or over charging. Those two 100 Ah batteries have worked flawlessly. The 200 Ah in two batteries plus management modules, connectors, solid state relays, etc cost me around $1400.

Since then, VistaRV have made Lithium a (very popular) option and they use the Sentry batteries. They have had no problems with them that I am aware of so I decided to go with the devil I knew as they say and use one of the Sentry 125 Ah batteries as my auxiliary battery in the GC.

There is a lot of misinformation around about Lithium batteries and initially there were some real cowboys flogging some poor quality batteries at extortionate prices. It seems to have settled down a lot now. Some batteries seem to be over priced, and I am nervous of the real cheapies - remember, your 4WD and van batteries have to withstand a lot of vibration and banging around.

The weight difference is amazing, especially noticeable in the battery box. It is so much easier to lift in and out of the car.

Hope this helps. PM me if you want more information.

Cheers
Numb Thumbs

Hmmm can't see the 'like" button....
Thanks for the quick reply.......I'll continue to research.....
I've got 6 years on the van batteries and 4 on the Jeep aux so time is ticking.
J