LA very high percentage of Lithium batteries are incredibly safe.
This article is not to dissuade you from using Lithium but to point out best practices to be 100% safe.
On the right is a forum article from a user who put his own Lithium battery and BMS together.
The BMS is a reasonable quality unit.
· Safiery does NOT assemble it’s own lithium batteries and hook up a third party BMS as you read in the article above. However, there are several suppliers in Australia who do. We make no criticism of them, they may have the investment needed to test correctly.
· When you see the extensive testing in a Lithium battery factory, it is just a huge investment to do it correctly.
· Lithium batteries are made up of cells or pouches. No two cells of pouches are exactly the same, although they may be very close.
· A quality Lithium battery manufacturer looks for the cell voltage ranges when charging and discharging. If the individual cell ranges are not compatible, they set aside the out of range cells. They may be compatible in a different grouping.
· The batteries are then completely discharged and charged several times watching cell voltage ranges and temperature.
· In these lithium battery factories, there are thousands of test wires and computer data connections dropping down from the ceiling. You may not be able to see to the end of the hall for wires. These are plugged into the batteries being tested on the floor.
· It’s a massive IT job of computer testing and adds significant cost to the battery.
In the article above, .
In the forum article above, the user describes the white smoke. That is the 3rd stage of a Lithium battery fire. The battery may not START the process, it is always electrical abuse. This can come from either a short circuit that is not properly fused or the wrong charging voltage at a solar charge controller, an inverter charger or a DC DC. Any of these can start the process in the picture below. This can occur even though the batteries may have approval certificates. You see it is not the approved battery that starts the process, it will be something else.
However, don’t be alarmed with the lithium systems Safiery supply.
The pre-cautionary steps which prevent an electrical abuse from occurring are these:
· The high power 12V and all 48V Lithium Batteries have a CANbus BMS.
· The CANbus BMS in the battery dictates to the Victron system and Scotty, the charge current limit for all collective charging devices. When a battery is close to being fully charge at say 98%, it is most vulnerable to electrical abuse. The Charge Current Limit reduces in value from a high number progressively to zero. Victron share this to all connected devices (including Scotty if it is on CANbus) and this stops charging abuse.
· Victron add another layer of protection by allowing the installer to set an overall voltage charge limit independently to the BMS. There are some tricks to how this is done, and Safiery have mastered these values.
· The short circuit prevention requires careful design of cable sizes and fuses. For 48V systems, the mega fuses have to be certified at 48V. Most only go to 32V. The fuse is designed to protect the wire from melting and to prevent electrical abuse of the battery. The short circuit design values are very important to understand.
· The installation team at Safiery are well trained in selecting cable and fuse size. There can be applications where selecting a larger cable may not be the correct choice.
A simple check on the quality of the installer or supplier is to ask if their Products and Public Liability Certificate of Currency specifically includes Lithium batteries. Insurance companies are now extremely careful on due diligence with the companies installing or supplying lithium. Typically, one strike or hint of a problem and you are not renewed.
· Safiery carries Certificate of Currency for Lithium installations in RV’s and Marine to $50 million with a global insurance company.
How Good’s That!
These are the stages leading to fire with Lithium Iron Phosphate Batteries in a mobile application. The cause for the fire may not be the lithium battery. It may be electrical abuse caused by inadequate installation to prevent this.