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By Stefan Fischer | ALLOFFROAD

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This one stings. I don’t say that lightly, and I don’t say it for effect. After three years of testing dual 100Ah DCS lithium batteries under the bonnet of my Land Cruiser, I’ve made the decision to pull them out. It’s not a decision I wanted to make — there was a lot to like about this setup — but the results speak for themselves, and I owe you an honest account.

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What I Loved About the Setup

Let me be clear: there were genuine advantages to running lithium under the bonnet. The super-fast charging, the high charge and discharge currents — these made a real difference on the road. The weight and space savings were significant too, freeing up room in the back of the Cruiser where every square centimetre counts.

I also managed to prove a few sceptics wrong along the way. Starting off a lithium battery? No problem. Winching off it? Done that too, and it worked.

But there was always one question mark hanging over the whole experiment — longevity. LiFePO4 chemistry is not particularly well-suited to sustained high-heat environments, and under the bonnet in the Australian outback is about as harsh as it gets.

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The Capacity Test That Changed Everything

A capacity test was long overdue, and I teamed up with Joe from JS Autoelectrics to get it done properly. The results were, frankly, shocking.

• Battery 1: 80% capacity loss
• Battery 2: 50% capacity loss

These figures far exceed the promised annual degradation of just 5%, as claimed by DCS. For batteries that are supposed to deliver reliable power in remote areas, that kind of loss is unacceptable.

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A History of Issues

To put this in context, here’s the timeline:

• November 2019: Joe installed the initial set of DCS 100Ah marine batteries. They performed well at first, but the Bluetooth functionality had persistent bugs that were never properly resolved.
• After approximately one year: A capacity test revealed significant issues. The culprit turned out to be outdated passive balance technology.
• DCS response: They assured me their new active balance batteries would solve the problems. However, the dual 130Ah system proved impractical due to size constraints under the bonnet.
• February 2021: Joe installed the latest version of the 100Ah marine batteries.
• Shortly after: A BMS firmware recall affected performance. DCS sent replacement batteries with updated firmware in November 2021.
• Present day (2023): After several trips, I noticed a noticeable drop in capacity. Joe ran a proper test — one battery was sitting at a mere 50% capacity, the other below 80%

When you tour remote Australia the way I do, a battery failure in the middle of nowhere isn’t just inconvenient — it’s a serious problem.

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Joe’s Experience Tells the Same Story

It’s worth noting that Joe’s own experience mirrors mine. He ran a 75Ah DCS marine battery in his Prado — low current draw, not charged by the alternator — and still saw a 30% capacity loss in under two years**.

JS Autoelectrics has since completely stopped using DCS batteries in their installations. That says something.

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## DCS’s Response

I reached out to DCS with the test results. The response was, in my view, far from satisfactory.

First, they suggested **moisture ingress** as the cause. When we opened the battery with 50% capacity loss, we found **no evidence of moisture ingress whatsoever**.

Then came the real surprise: DCS told me that my 30,000 kilometres of driving over 16 months had subjected the batteries to **six times the expected punishment**. Apparently, DCS measures battery lifespan in kilometres — which, if true, doesn’t bode well for anyone who actually drives and tours extensively.

Both batteries were sent back to DCS. At the time of writing, I’m yet to hear back. DCS also had no replacement batteries to offer, which left me without power and a major trip just four weeks away.

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What I’m Doing Now

Thanks to Joe’s help, I’m switching back to **lead-acid under the bonnet** and adding a **different lithium battery in the rear** of the Land Cruiser. It’s a setup I trust, and one that should serve me well for the long haul. I’ll be documenting the new configuration in an upcoming piece.

For the record, I don’t have any issues continuing to use my 150Ah DCS battery in the camper trailer (lost 9% capacity within 19 month) —  The two 130Ah DCS batteries in the back of my Hilux will also stay in service, but critically, they’re not subjected to engine bay heat. That may well make the difference.

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My Verdict

After three years of real-world testing, my conclusion is this: **lithium under the bonnet can work for certain applications, but the accelerated capacity loss in high-heat environments makes it a poor long-term investment.**

If you’re willing to replace your batteries every three years and have the budget for it, that’s your call. But based on my experience — and Joe’s — it’s not a worthwhile proposition for serious touring.

It’s genuinely disappointing, because I loved so much about having lithium under the bonnet. But you never know until you try, and that’s exactly what I did.

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A Word of Advice

If you’re currently running DCS batteries under the bonnet, I strongly urge you to get a proper capacity test done. Don’t rely on the state of charge displayed in the app — that won’t give you the full picture. Have the batteries tested by a qualified auto electrician, or look into standalone capacity testers available from reliable sources.

Simply saying “the batteries are working fine” isn’t enough. You need data.

And if your experience differs from mine, I genuinely want to hear about it. But back it up with a proper test.

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This review is based entirely on my personal experience and that of JS Autoelectrics. I don’t do paid reviews, and this channel is mainly self-funded. If you found this useful — or if it saved you from a costly mistake — consider supporting independent content creation through Patreon or Buy Me a Coffee. Every contribution helps me stay honest and keep producing unbiased content.*

See you out on the tracks.

— Stefan

Update: DCS Took Me to Court — And Lost

Since publishing my original review, things took a turn I didn’t expect. In May 2024, Deep Cycle Systems filed a defamation lawsuit against me in the District Court of Queensland (Proceeding Number 1169 of 24), claiming my videos and commentary caused them financial harm.

I won’t pretend that wasn’t stressful. Being taken to court by a manufacturer for sharing honest test results and real-world experience is not something any independent reviewer wants to deal with. But I stood by my findings, because they were factual, tested, and documented.

On 11 March 2025, the court dismissed the case. The judge ruled that DCS is not an excluded corporation under Queensland defamation law — meaning it has more than ten employees and is therefore not entitled to bring a defamation claim. Only excluded corporations (those with fewer than ten employees and not related to another corporation) have standing to sue for defamation. DCS didn’t meet that threshold. The court also identified inconsistencies in testimony from DCS’s side, which did not help their credibility.

The 30-day appeal window has since expired. We are now awaiting the settlement of costs.

I want to be clear: I didn’t go looking for a fight. I tested a product, reported my findings honestly, and the court confirmed I was within my rights to do so. Independent testing by the Australian Renewable Energy Agency (ARENA) also confirmed performance issues consistent with what I reported — so this wasn’t just my word against theirs.

This case has been described by some in the legal and media space as a potential landmark for the rights of independent product reviewers. Whether or not that label sticks, my hope is simple: that honest reviewers can continue to share their real-world experiences without fear of legal intimidation.

I’ll keep doing what I’ve always done — testing gear properly, reporting the results truthfully, and letting you make your own informed decisions.