Data Field not writing to fit and/or showing chart in connect?

I wrote a quick datafield keeping track of the battery level and discharge rate, first intention was to just display but thought 'ah well, why not write to fit as well to display it in a chart on connect'. I am finding that out now...

What I have done (showing for 1 field):

1. Added 'Fit Contributor' permission to the manifest

2. I added a 'fitcontributions.xml' file in a 'fitcontributions' subfolder of the resources folder (tried a raw fit.xml file in resources before as well) containing the following:

<resources>
<fitContributions>
<fitField id="0" displayInChart="true" sortOrder = "0" precision="2"
chartTitle="@Strings.LevelChartTitle" dataLabel="@Strings.LevelLabel"
unitLabel="@Strings.LevelUnit" fillColor="#FF0000" />
</fitContributions>
</resources>


3. Added relevant entries to the strings.xml

<string id="LevelChartTitle">Battery Level</string>
<string id="LevelLabel">battery_level</string>
<string id="LevelUnit">%</string>


4. Added the following code to the View.mc sourcefile

Added global
using Toybox.FitContributor as Fit;
using Toybox.System as Sys;

and inside the class (extending UI.DataField):
var batField;
const BATTERY_FIELD_ID = 0;

Then in 'function initialize()':
batField = createFieId( "battery_level",
BATTERY_FIELD_ID,
Fit.DATA_TYPE_FLOAT,
{:mesgType=>Fit.MESG_TYPE_RECORD, :units=>"%"}
);



In 'function compute(info)':
var battery = Sys.getSystemStats().battery;
batField.setData(battery);


The battery value is also shown in the field and is visible, it's a float...

Am I missing something? The chart doesn't pop up on connect, when I load the .fit file in monkeygraph nothing happens either... No errors, no messages, nothing.

Anyone a clue?