12V Guru – How much should I spend on a Lithium battery?

Question to 12V Guru

I am considering buying a new BMPRO lithium charger and 2 x 100A 12V lithium batteries as I find our current single 120A AGM caravan battery just keeps running our if power on cloudy days. I am confused by the price of lithium batteries as a single 100A lithium can range from $500 to $2000, why? How much should I spend on a Lithium battery to meet my needs of performance, safety and reliability?

David Sajfar, Keilor VIC

12V Guru answers:

Hi David,

This is a great question and extremely topical now, especially as we are seeing more and more discussion in regard to the use of lithium batteries.  Lithium batteries are a hot topic with the likes of Tesla propping up the SA power grid and domestic power storage becoming a more prevalent option. 

The RV industry is now seeing a surge in the use of lithium batteries with RVers keen to be able to expand how far they can roam without 240V power.  A good solar setup and a reliable DC AUX supply from your car’s alternator gives you the ability to generate a vast amount of energy and this needs to be stored within a reliable energy storage system.  Lithium batteries provide this!

Performance, safety and reliability of lithium batteries

However, the key to any great system is exactly the three points which you raise in your question. Performance, safety and reliability! Without these factors any battery is not going to be a quality investment.  In many ways it is like most things you invest in – do your homework. 

One of the most important factors to look at in purchasing these latest technology batteries is to do your research on the brand and also the quality certifications or testing of the battery and its manufacturer. 

Only buy from a trusted source.  You may pay a higher price for these branded batteries, but you can be guaranteed that they have the quality systems implemented through the manufacturing process which will ensure the longevity of such an investment in batteries. 

Power Management System (BMS) of 12V lithium batteries

As the inside of a 12V lithium batteries contains multiple cells it is therefore even more important to buy only quality as across the top of all these cells is a set of electronics called a Power Management System (BMS). The BMS, which is also internal to the battery, controls the input and output voltage and current of each the internal cell and keeps these cells balanced to ensure the battery charges and discharges properly. 

Like everything in this world, cheaper batteries will not have invested in quality technology and manufacturing process for the BMS or the individual cells and therefore will be more likely to malfunction, especially in tough Australian conditions.  These companies won’t be around in the longer term and then if there is a problem you will have no-where to go to have your warranty honoured. 

You get what you pay for

Recently I phoned a company that advertised lithium batteries for the RV industry and asked them what testing they had done on the batteries, what certifications did the factory have etc and the response was “I have been told they have them but NO, I haven’t seen them myself” – really can you trust a source such as this. Especially with such an $ investment and potentially dangerous source of stored energy.  EBay or a fancy online website with images of melting polar icecaps is not a recommendation as a high-quality source of reliable lithium batteries.

Batteries, such as the BMPRO Invicta range, are in fact not just certified at individual cell level but also as a complete assembled battery offering an even higher level of guaranteed quality. Also check if the batteries can be connected in parallel – quality batteries offer this option.

At BMPRO headquarters we have tested extensively a range of lithium batteries across a range of price points and manufacturers. Generally, those batteries which were slight above the average price point performed exceptionally and as per the manufacturers claims.  Whilst lithium prices are falling as they become more accepted in the market, we would expect that a battery priced between $1000 and $1400 will represent great value for money for a 100Ahr setup.  If you feel the price is too high, better to either wait for the price to ease back or save a bit longer.

Be warned – don’t buy cheap lithium. You’ll get what you pay for!

Happy travels – 12V Guru

The article first appeared in Caravan World Magazine

For more information on 12V lithium batteries, check our blog posts:

Advantages of Lithium batteries for caravans

12V Guru on how to connect lithium batteries in parallel

Interview with Ryan Hammond and David Bayliss on the future of lithium in the RV Industry