BMS: Battery Management System – What is a BMS and what safety measures does it provide?
Lithium batteries are at a clear advantage over old-school lead-acid batteries: they charge more quickly, are much lighter weight, last exponentially longer, and are more efficient in almost every way. With that technological advancement comes some sensitivities that their counterparts don’t face. Not to worry, though, as that is where your BMS comes in – and our batteries come with their own BMS!
A Brief Overview
Your Battery Management System is the brain of the entire operation that keeps you and your battery safe. This set of electronics monitors your battery and, most importantly, shuts down operation if variables are found to be outside set safety margins. Your battery can be damaged by:
- Overcharging occurs when excess voltage continues to flow into the battery after it has reached full charge. This causes premature aging, and the excess heat becomes a fire risk.
- Over discharging
- To fully discharge a lithium battery down under 2.5v per cell (or close) can degrade the life cycle of your battery because some of the copper current collectors begin to dissolve into the electrolyte.
- Temperature extremes
- The ideal operating temperature of your battery is easy to remember – room temperature! When temperatures get below freezing or above ~95°F (0°-40°C), it can start to cause damage to the integrity of your battery.
- Loose connections or shorts in wiring
- Thermal runaway can occur with faulty wiring. This can damage your battery and other parts of your electrical system. It also poses dangers to you when handling or possible fire risk.
- Imbalanced charging between individual battery cells
- A balancing of the cells is required for any lithium battery and is integral to their preservation and function. An imbalance between them, even if minuscule, can lead to them being prone to overcharging or over discharging.
If any of these unsafe conditions are detected by your BMS, it shuts your battery down. This saves your battery’s lithium-ion cells, you and any other users, as well as your electrical system as a whole. It also saves you money by preserving the life of your battery. Talk about peace of mind!
What exactly is a Battery Management System comprised of? That can depend slightly based on the battery in question, as each system is created for each individual battery’s purpose. We supply everything from small batteries to power your camper, to enormous systems for large machinery and household usage. While each of these applications will require varying levels of complexity and performance, there are always the same three main goals of the BMS:
- Protect the battery and its cells from damage
- Prolong the lifespan of the battery
- Maintain the battery’s state which allows it to continue functioning appropriately
The Battery Management Systems are able to do this by constant monitoring of temperature, voltage, coolant flow, and current (in and out of the battery). This data is calculated, authenticated, reported to the control panel(s), and balances or cut off as needed to keep the battery functioning. A proper BMS is paramount in many applications.
Who is best suited for batteries with BMS systems?
In short, there are few that won’t benefit from the safety, security, and saving that a Battery Management System provides.
- Seasonal, off-grid housing applications – If you have a property without fulltime residents, your BMS ensures your batteries are safe even if inclement conditions keep you from maintaining your electric system.
- RVs, campervans, or marine applications – Whether it is high tide or rough roads, systems that get shaken around can occasionally have pieces toggle loose. In the event of a wire shortage, your BMS is always keeping your battery protected.
- Industrial Equipment – Heavy machinery equipped with battery management systems are protected from overheating or short-circuiting ensuring maximum safety, reliability, and peak vehicle performance at all times
- Golf Carts – BMS-equipped batteries go longer between charges, are more cost-effective long term, and are the safest (yet most powerful) alternative on the market. They are ideal for golf cart owners looking for more mileage between charges while also giving the financial security of being a sound investment.
The Benefits of your BMS
The Battery Management System is the ideal long-term solution for those that are safety-minded, as it will be with you for the life of your battery. These highly precise measurements and advanced algorithmic monitoring ensure nothing but the best:
- Shortened charging time, maximizing your efficiency
- Maximum battery life for each component, saving you time and money
- Improved range for each charge, extending your usage
- Efficient balancing, this happening quickly ensures safety for your cells
- Functionally safe, allowing you to navigate maintenance with confidence
Most Common Issues
In an ideal scenario, the function of your BMS that causes an automatic shut off would never come into play for your system. However, from time to time, there are environmental stressors that will negatively impact your battery. In these cases, your Battery Management System will take over by shutting processes down. The most common causes for this are:
- Temperature fluctuations – Be sure that the housing for your batteries adequately protects them from extreme temperatures. Once the components drop below freezing, it becomes much more challenging for your battery to charge or function because of the degree to which chemical reactions slow. Likewise, extreme heat (on average above 90 degrees Fahrenheit) can also be dangerous. Ambient room/area temperature isn’t the only way heat can rise; this can also happen during fast charging if systems are not properly maintained.
- Overcharging – Lithium ion cells are quite sensitive and don’t take well to overcharging. This could be due to user error via possibilities such as a miscalculation of appropriate solar array. In situations like this, the individual cells within the battery can become unbalanced due to varying self-discharge rates. This is one of the greatest ways your BMS shows its value, by preventing these errors from taking over.
- Voltage management – Your Battery Management System ensures that your voltage never overcharges, and just as importantly, ensures that voltage doesn’t drop too low. Occasionally, your power supply (be it shore power, solar, or otherwise) may be inadequate for your usage or become incidentally incapacitated altogether. In these scenarios, your BMS will ensure your battery shuts off safely before any long-term damage is done.