Testing your Lithium Ion battery system

Check what version of the firmware your Victron equipment has and write it down.  If there is a later version available consider updating the device.  If you have a Color Control GX connected to the internet, not only can you update its own firmware at the touch of a button, but you can also update the firmware of anything connected to it.  The batteries themselves and any Bluetooth devices have firmware that can be updated through Bluetooth.  To do that make sure you have the latest version of the Victron Connect App and then connect to the device in question and follow the prompts. When you are done write down all the firmware and software versions in a log book and keep it updated. Why do we need to do this?  All this is new technology, there are always improvements and bug fixes. 

Are all the devices programmed to do what you want to do?  Did you keep a copy of the program or the settings?  The Battery Protects in the drawing above need to be programmed for program "C", external control.  The Charge Controller needs to be programmed for Lithium batteries and the MultiPlus needs to be programmed with the VE Bus BMS Assistant as well as having its charge and inverter settings tweaked for Lithium batteries.  I have written a separate Blog Post about Assistants Programming.

In the drawing above its possible to test that the system is measuring things correctly because there is more than one device measuring the same thing.  For example if you have a solar panel in operation and everything else turned off, you should be able to see on the Bluetooth App how much power your panel is generating, what voltage the panel is producing, and then how many amps are flowing in to the battery and what the battery voltage is.  If you do your math using the formula Watts = Volts x Amps you should be able to see that a bit less power is flowing out of the Charge controller than is going in, and that represents its self consumption.  You should then be able to read on the BMV battery monitor the same amount of amps going in to the battery.  Depending on your system design there may be other ways to cross check that everything is being measured correctly.  It would be a help to document your typical readings so if anything is misbehaving you can spot it more easily.

The example system is designed to shut off the solar charge when the battery is full. There are two ways that this is achieved.  The charge controller has a voltage limit at which it should stop and also the BMS turns off the battery protect between the Solar Charge Controller and the battery.   I dont have an actual solar panel here to be able to test the former so I will have to get someone to help me out with that part.  You can put your comments in the box below.  To test the operation of the Battery Protect unplug its control wire and make sure it switches off the charge to the battery. Make a note of what the Victron Connnect App screen for the charge controller looks like when the Battery Protect has been turned off.  When you plug it back in there is a time delay, take a note of how long it is.  Check to see that the charge has resumed fully.

In the example system the multiplus has two ways that it would stop charging when the battery is full.  See if you can test both ways!   When it reaches the voltage that you have programmed into the multi it should switch to absorption and continue to charge for the length of time that you programmed.  Then it should go to float.  Make sure it does what you programmed.  Then it should also stop charging if the BMS says the battery is full.  To test that you can just unplug the VE Bus cable from the BMS.  The Multi should turn off. Plug the cable back in and it should start up again.

In this demo system the Battery Protect serving the DC Loads should shut off when the BMS says the battery is low.  To test this disconnect the control cable going to the Battery Protect.  The MultiPlus has two ways that would stop it inverting as the battery gets low.  If you programmed in a low voltage shutoff of somewhere around 12 volts you can test that out by running your battery down to that level.  That level should be somwhere above totally empty.  Make a note of how much capacity your battery has when this happens.  You can program an alarm to go off sometime before.  Can you test it?   The inverter should also stop on the command of the BMS and we have already tested unplugging the VE Bus cable

You can test the operation of the BMS by disconnecting the cables between it and the batteries.  You should then be able to see how the whole system behaves with a low voltage shutdown.  You will also discover what you need to do to get it restarted. After you reconnect the data cables to the batteries you will find that the MultiPlus wont self restart until it detects AC voltage on its input terminals.  The Battery Protects will restart after a time delay.

After you have tested each individual part of the system you have to test the whole lot together.  That means you have to charge the battery up to full and make sure everything stops as designed.  Then you have to run it down to empty and do the same.  While you are doing this you can monitor and record readings on the various devices you have connected.  How many amp hours did you get from the battery.  What was the battery voltage when you got to the rated amp hours, how much more power, if any was there actually available.  You need to take it to the limits and really understand how it all works so that when it happens out in the ocean you know what to expect.  

Connecting a system to the Victron VRM Portal is a very good way to get detailed operating statistics.  You need an internet connection and a Venus GX or Color Control GX in your system. Opening a VRM account is free.  The data generated is great for giving your system a full test and the exercise is well worth while even if you don't plan on keeping the system online after the test phase.  Take a look here at some sample data.

Im suggesting that you document all this.  In a years time you will have forgotten half the stuff and being able to refer back is the best way to get reacquainted in the event you make system changes or have a problem.  Make an "as built" wiring diagram and a list of all components with part numbers and serial numbers and then put in in a Dropbox folder that you can share if necessary.