Brilliant new device from CTEK
 

Just saw this on the CTEK website:
CTEK CTX Battery Sense

Brilliant for those like me, who don't drive daily (and are data freaks), and want to keep the battery in good condition.

Cheap and great peace of mind! I'm going to get one.

...ORDERED... delivery next week

Got it today and installed it on my big lump of a battery in the boot of my XC90.

As I am an engineer by trade, and have seen cable loom damage through chaffing and even cable loom fires, I added extra wire wrap tubing to the positive wires for extra protection against chaffing and accidents. It does have a 1A inline fuse about 4 inches from the battery terminal. And those 4 inches are now also double insulated.

The CTEK Battery Sense is cable tied to the positive distribution box by the left hand side of the battery, and the whole lot sits neatly under the plastic battery cover.
Watch that sharp edge on the battery distribution box mounting bracket! That's exactly what can cause chaffing.

Bluetooth connection didn't connect first time - for whatever reason - but 2nd time it did.
Now upstairs at my desk I can see that it logs battery voltage every 5 minutes.
I see that I connected the Battery Sense at 14 Mar 19:10.
I can view the voltage graph and overall battery state (I'm at 91%, in the green) when away from the car.

When at the car I can see battery volts and ambient temperature, which was 12°C, and 12.72V.

I walked back down to the car after an hour and as I approached the vehicle with the app open, it updated itself with the latest data. Cool!

The battery was now at 93%, which shows how it recovers charge once power drain has stopped.

No more mucking about with multimeters!

Now I'll be able to determine how often I should recharge my battery to keep it on peak condition, as my car often sits for a week without being used.

I'll take some screenshots after this weekends driving to show you what it looks like over time.

So I've been monitoring this over the last few days, through a short 10km drive on Saturday around time, then a 30km drive on Saturday evening to visit a friend.

When I first connected it, it had no history, and used the battery voltage to determine that the battery was 91% charged.

Yesterday, in the morning, the battery had gone up to 93%. Over the course of the day it went up to 95% following driving. But what happens when driving? The battery is at 14.4V for 30 minutes, and the CTEK doesn't measure current, only voltage. So how does it know what the battery state during the charging period?
Today, after having been parked for 24 hours, the battery is showing 98%, higher than it was when I stopped the engine yesterday.
So what is happening here?

The CTEK app must using the Ah size of the battery (mine is 90Ah) plus the length of time charging, and then the resting voltage of the battery to help calculate the state of charge in percent.

So it will take a few days of driving cycles for the CTECK Battery Sense to fully report the correct values, as it notes how long the battery is charging and what the resting voltage of the battery is.

I'm interested to learn how much the battery charge degrades over time when the vehicle is not being used, as this will be the most useful understanding for fellow Volvo owners.

I'll keep you posted.

Well, I just thought I'd do a google and I found CTEK document that states:

1. When connecting for the first time, the initial % is a loosely accurate number which shown more to let the user know that the unit is connected and beginning its "triage" of your battery.

2. The % you will see over the next days is an accumulation of charge and discharge factors gathered over time (among other secret calculations) that reports a percentage representing the true state of charge of your battery but not the immediately measured OCV (open circuit voltage) as OCV is not usually the true state of charge of a battery.

3. Accuracy will improve as more data about your battery is accumulated over time.

Which is exactly what I have observed :)

Hello Swiss, your op mentioned "cheap and great peace of mind"

Is it really a got to have gizmo, or actually useful?

Plus .... I don't know what the pricing is in your neck of the mountains, but UK its seems to be circa £50 .... I admit to having very short arms and very deep pockets (as do most Scots) but is it proving to be worth it?

:regular_smile:

I paid the equivalent of GBP 59.

I haven't had it a week yet, but I want to avoid the situations where I have run my battery down to the Low Battery warning level (happened a few times).

I connect a charger every now and then to top up my battery, but I'd rather connect it when I need to, instead of guessing.

The app helps me to stop guessing.

And I'm a database administrator and I love data....

Must have? No. But very helpful.
So for me, yes worth it.