Buying a 12V Lithium Battery; what should you look at?

12V lithium batteries have become far more common in the 4WDing, camping and Caravanning world over the last few years, and there’s plenty of reasons why. Historically they’ve been very expensive and uncommon, but today they are becoming extremely economical and are getting installed all the time.

Whether you are looking for a camping setup, or something to run your winch and compressor off, many  lithium batteries will handle it with ease, with a number of other benefits along the way.

Before we get too far into the Lithium Battery Buyers Guide, I want to point out that I’m here purely to pass on what we’ve learnt, and to cut through some of the marketing rubbish that goes on.

I’ll mention a few brand names, but please do your own research and get something that you are comfortable with.

I’m not here to promote a particular brand of battery; there’s enough people doing that already (and often without the actual data to back their claims up).

These are my opinions only, and whilst I do my best to be completely honest please do your own research too.

What’s the benefits of a lithium battery?

Lithium batteries have changed the caravan, camping and 4WD world, and are leaps and bounds in front of your traditional lead acid (or AGM) deep cycle batteries, because of the following:

Much lighter and compact

The energy density of lithium batteries is nothing short of astounding. A 120 amp hour lithium battery is roughly the same as a 200 amp hour AGM or lead acid battery in terms of its usable capacity.

That 200aH AGM is going to weigh in at around 58kg, whereas a 120aH lithium is only about 13kg, and half the size.

The weight and space savings are huge, and allow for you to run a larger lithium setup with a big inverter, and still to save weight.

In our Dmax for example, we went from a 150aH AGM to a 230aH lithium battery, gaining some 2.5 time more usable capacity for less than 50% of the weight, and a very similar size. We literally went from a 43kg battery, to an 18kg one.

Far higher discharge ratings

If you want to be able to run power hungry appliances, like coffee machines, induction cooktops, air conditioners, kettles, toasters and so forth, you need a battery that is capable of delivering the power.

Most lead acid batteries will not be rated for these sort of loads (unless you have several together, and even then it can be sketchy), and you end up damaging the batteries by discharging them too fast.

A lot of lithium batteries today are good for 150 – 200 amps being discharged, which is equivalent to 1900 – 2600W, and will run most of your appliances at home.

Much longer lifespans

If you get 5 years out of a traditional lead acid battery, you’re probably doing pretty well. Yes, some will do 7, but many only do 3.

Lithium batteries often have a rating of 2000 – 3000 cycles, meaning a minimum of 5.5 years discharging all, or most of the battery every single day, and more likely much longer than this.

If you only discharge them 50%, you can be looking at 14 years of life before you need to consider swapping them out!

You pay a fair bit more for lithium batteries, but over their lifespan they can comfortably be more economical than replacing lead acid ones each time.

What should you look for in a 12V lithium battery?

If you are going to purchase a lithium battery, here’s the minimum checks you should do to ensure the battery you buy is going to do what you want it to, at a reasonable cost and for a decent duration.

Usable capacity

The most sensible place to start is the usable capacity. Lithium batteries prefer to be run between 10% and 90%, giving you 80% of ‘usable capacity’. Yes, you can run them outside of this, but that’s their preferred range. With that in mind, a 100 amp hour lithium battery has 80 usable amp hours of capacity. 

If you are replacing lead acid batteries with lithium’s, you can get away with a much smaller lithium battery setup than AGM. For example, 200 aH of AGM batteries is equivalent to about 120aH of lithium.

When you are looking up usable capacity, make sure you don’t confuse it with the battery name, or the total capacity.

A popular lithium battery seller for example, are misleading in the way they advertise their batteries.

Their most common battery (advertised as 120aH) is actually not a 120 amp hour battery, despite what so many people think when they buy it. In a recent Lithium Battery test, they came in at only 93 odd amp hours!

To get a bit deeper, the usable capacity is rated at a certain discharge current, and not all lithium battery companies will use the same discharge rate, which can skew the results. Look into the C rating and compare apples for apples. A C20 rating is not the same as a C5 rating!

Weight

The weight of a lithium battery should reflect the battery build. Often you can find out who’s telling porkies quickly, simply by looking at the battery weight. A 100aH lithium battery should be no less than 13kg.

If it is less than this, there’s a good chance that the battery isn’t actually 100aH, and the seller is telling porkies.

Type of cells

12V lithium batteries can be made from a number of different cells, and they have their own benefits and downsides.

Prismatic cells are rectangular blocks, and these are supposed to be the best for mobile applications, especially where vibrations and movement is likely to happen. 

From there, you have pouch cells, which are lots of little pouches stacked together. 

Lastly, you have cylindrical cells, which use lots of small, cylinder battery cells connected together. These take up more space, and have a lot more failure points, but this is what Tesla run in their vehicles.

In the 12V market you’ll find companies selling all 3 types, with no clear evidence as to what is actually best.

Prismatic are usually touted as the best, but there’s some high end 12V lithium batteries running pouch cells, and we’ll see long term how they all go.

Maximum discharge current

One of the major benefits of 12V lithium batteries is that they are able to discharge quickly, allowing you to run some pretty incredible appliances. However, they are not all the same, and a good indication of quality is the rated discharge current. 

Some of the cheaper batteries are limited to 50 amps maximum discharge, whilst the more expensive ones can be all the way up to 200 amps.

This may affect you, and it may not, but there’s a big difference. For example, 50 amps is roughly 640W, which is not enough to run many coffee machines, most induction cooktops, a toaster or anything else that draws high current. 

Make sure you don’t get a battery that has the capacity to run large appliances, but not the rated discharge current.

Maximum charge current

On the flip side of the coin, lithium batteries will have a limit to how much current you can charge them with.

Unless you have a crazy big solar array, or an AC charger that can do huge rates this is generally less important, but you should still check it out. 

Number of cycles

Every lithium battery will come with a rating for the number of cycles its good to do. Many are around the 2500 cycles at 100% depth of discharge, and there are plenty that are less than this.

To give you an idea, 2500 cycles is just under 7 years of discharging the battery completely, every single day. 

If you only used a portion of the battery (say 50 – 60% depth of discharge) it’s going to do far more cycles, and that’s pretty amazing.

Warranty information

Lithium batteries aren’t cheap, and what ever you buy, you want to know that if it all goes wrong you’ll be able to get your money back, or a replacement unit.

Some lithium battery companies offer a pro-rated warranty arrangement, where you’d only get a portion of your money back (or credit) depending on how long you’ve had it for.

One would hope not to use the warranty, but generally the amount and conditions speak volumes about the battery quality.

Lithium battery sizes

A lot of the lithium batteries are similar sized, but you can get some interesting shape and sized units if you look around.

The Renogy 170aH lithium battery is a good example of this, which is marginally taller than a normal 120aH battery.

You can also get slim line batteries which can be mounted in some pretty unique spots (in a false floor, or behind the rear seats of a dual cab) and I’ve seen some very clever installations over the years.

Building your own lithium battery

If you like the idea of a little project, its entirely possible (and fairly straight forward) to buy the components, and to build your own lithium battery.

There are more tutorials and information online than you can poke a stick at, and anyone can get one made without too much trouble at all. We’ve done this, and go into more detail in another post (Building a lithium Battery).

Essentially you need lithium cells, a BMS, cell balancer, bus bars and wiring to hook it all together. 

You can buy components from a number of places, with Ian at FPV power highly recommended by many. Our DIY battery was built using cells from a reputable seller on Alibaba. 

Who sells 12V lithium batteries?

There’s more companies out there selling 12V lithium batteries than you can poke a stick at, and some are significantly better quality than others.

Like other guides, I’m going to list them in a rough order of price/quality, in our opinion. Yes, this is a generalisation and its very much dependant on what you are chasing. Please buy what suits you; this is purely to explain where you can get them from.

Kings, Voltx, Jaycar, Itech, Renogy, Custom Lithium, ATG, Power Paul, Baintech, Enerdrive, Redarc, DCS, Invicta, Victron and All Spark 

What do we run?

We’ve got 3 lithium batteries. In our Reconn R2 we have two Renogy 170aH lithium batteries, which supply our freezer, water pumps, lights, a 3000W inverter and a few other random bits and pieces.

We use the induction cooktop to cook when we have plenty of power available, and swap to gas when we don’t. We also have a toaster, and a toasted sandwich press that gets a bit of a work out.

In our Isuzu Dmax, we’ve got a 230aH DIY lithium battery, that I built with the help of a good mate. This runs through a 150 amp Daly BMS, and supplies power to our Bushman Upright Fridge, 2000W inverter, lights, water pump and camera batteries.

The inverter in our vehicle is used for charging camera batteries, running the induction cooktop on 12V, toaster or toasted sandwich machine, and occasionally for moving power across to our camper, as needed.

Now, it wouldn’t be fair to rave about either setup just yet as they are quite new, but we have given the Renogy batteries a fair bit of punishment already and they are going just fine.

If that changes, you’ll know about it here.

Do you need lithium batteries?

Absolutely not. AGM or lead acid batteries have been working for decades, and if you are comfortable with them and they work well, there’s no need to change.

That said, if you don’t at least explore the option I reckon you should; you might find its actually more economical to swap and you get a much better system in doing so. 

You need to ensure that your charger is suitable for lithium (there’s no such thing as ‘drop in lithium batteries’) and the rest of the system suits them, but some times there is very little that actually needs replacing.

On our Reconn R2 for example, all I had to do was change the Enerdrive DC2DC from AGM to the lithium profile, and swap the batteries out with lithium ones.

Yes, we did a lot more than that because I wanted a big inverter, solar array and dedicated solar charger, but you don’t have to go down that path.

Lithium batteries offer a lot of advantages, and whilst they are not necessary, they can be a good idea.

Are you running 12V lithium batteries? What do you think of them?

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