{"id":28636,"date":"2025-05-23T11:52:35","date_gmt":"2025-05-23T09:52:35","guid":{"rendered":"https:\/\/www.victronenergy.com\/blog\/?p=28636"},"modified":"2025-06-22T10:46:21","modified_gmt":"2025-06-22T08:46:21","slug":"paralleled-bmses-for-reliable-power","status":"publish","type":"post","link":"https:\/\/www.victronenergy.com\/blog\/2025\/05\/23\/paralleled-bmses-for-reliable-power\/","title":{"rendered":"Paralleled BMSs for reliable power"},"content":{"rendered":"

We recently introduced a major upgrade to our Lynx BMS range: the ability to connect multiple BMSs in parallel. This feature not only expands the power storage capacity but also adds redundancy for a more reliable system.<\/p>\n

While redundancy is valuable in any system, it becomes essential when your entire vessel relies on electricity to cover 695 nautical miles across open water\u2014like Nazca, the first yacht to compete in the legendary Fastnet Race powered only by renewable energy.<\/p>\n

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Nazca is a 1984 Contessa 34 and has already sailed over 5,000 nautical miles without burning a drop of fossil fuel or using biocides. Her mission is to \u201csail for the ocean, without leaving a trace\u201d, and the Fastnet race will put her to the test.<\/p>\n

She is powered by an Oceanvolt ServoProp 10kW electric saildrive, which also works as a hydrogenerator under sail\u2014recharging the batteries with up to 1000W. Additional power comes from a 400Wp solar array mounted on the rear arch, feeding into a 48V, 20.4kWh Victron NG LFP<\/a> battery bank, managed by two Lynx Smart BMS NG<\/a> connected in parallel.<\/p>\n

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Why paralleling matters offshore<\/h4>\n

It is well known that paralleling battery banks allows the system to handle higher currents. But even more importantly, it adds redundancy. And for a fully electric race yacht aiming to leave no trace in one of the world\u2019s most demanding offshore sailing races, reliability isn\u2019t optional.<\/p>\n

\u201cA paralleled LFP system aboard a pure electric yacht is a key evolution,\u201d explains Wayne Peters, Nazca\u2019s captain and the ‘mad scientist’ behind her electrical system. \u201cWhen the only energy source is the LFP battery, and when historically if one battery in the system fails, it all fails, being able now with two BMSs to have the ‘spare’ to get you home, should the worst happen, is very reassuring.\u201d<\/p><\/blockquote>\n

Traditionally, if a lithium battery bank encountered an error, the entire system could shut down. This is a common drawback compared to lead-acid systems.<\/p>\n

Now, with paralleled BMSs, if one battery bank or its BMS experiences a low cell voltage, its BMS will disconnect that bank to protect it, while the other battery banks continue operating normally. When the bank is ready to reconnect, the BMS checks the voltage difference before closing the contactor, and once the levels are within a safe range, the battery bank reconnects automatically.<\/p>\n

With this paralleling feature, you can also connect existing Lynx Smart BMSs with the new Lynx Smart BMS NGs, making it possible to use Lithium Battery Smart<\/a> and Lithium NG<\/a> batteries in the same system \u2014 as long as the BMSs have the same current rating. Something to keep in mind if you’re thinking about going fully electric in the future.<\/p>\n

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Monitoring onboard Nazca<\/h4>\n

Just as important as the power generation and storage is how everything communicates on board.<\/p>\n

\u201cWith Nazca, integration is key,\u201d says Wayne. \u201cWe know the three CANbus systems work together reliably \u2014 Oceanvolt, B&G, and Victron Energy.\u201d<\/p><\/blockquote>\n

At the centre of this integration is the Cerbo GX, which ties everything together and gives the crew a clear view of what\u2019s happening in real time.<\/p>\n

When multiple Lynx BMSs are connected to the same VE.Can network, they are treated as if they\u2019re connected to the same DC bus. These BMSs will then form a ‘virtual’ battery bank, which appears as a single battery bank in the GX device list, making monitoring easier. This virtual battery bank works just like a standard one, showing the overall system status, but with the option to also view each individual BMS, including which battery banks are connected or disconnected.<\/p>\n

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Where you can learn more<\/h4>\n

The Fastnet will be the first proper offshore test for Nazca\u2019s fully electric system, and we\u2019re excited to follow their journey throughout the race. We\u2019ll be back with a follow-up blog after the race, with a closer look at how everything performed when it mattered most.<\/p>\n

If you\u2019d like to follow along Nazca\u2019s journey and support them as they write the next pages of green offshore racing, check out their website<\/a>, where they share regular updates.<\/p>\n

And to learn more about the new paralleling feature, you can find everything, including system drawings, in the Lynx Smart BMS manual.<\/a><\/p>\n

We are proud to support Team Nazca, not only because they are committed to pushing boundaries, but because they will not compromise on what matters most while doing so. We wish them the best of luck for the Fastnet Race in July 2025.<\/p>\n\n\n