Vicl

Just want to share my experience with my new battery charger CTECK MUS 4.3

That is the only charger I found with exact description of the charge algorithm. As you may recall I have Schumacher Speed Charge SC-1000A (see my prior post => https://www.audiworld.com/forums/a8-...arger-2942858/).

I’ve used CTECK 2 times and validated they algorithm of charging is exactly what they claim. Also, it is in agreement with my understanding how the battery should be charged.

Here is what it does:

1. Desulphation . 15.8V spikes. I have not seen it was engaged yet.

2. Soft Start. 4.3 A until 12.6V. Mine is already 12.6V, so I have not observed that stage

3. Bulk. Increasing voltage to 14.4V and 4.3A. Observed very slow increase to 14.41V and precisely 4.3 A

4. Absorption. Declining current, 14.4V. Observed slow current declining from 4.3A to 0.8A while holding 14.41V

5. Analyse. Just waits to see if voltage will drop. That stage is 3 min.

6. Recondition. CTECK 4.3 allows to engage recondition mode. I have not used it yet and I do not think I will ever use it. The mode will elevate voltage to 15.8V and will hold it with 1.5A 30 min to 4 hours depending from the battery voltage.

7. Float. 13.6V and to 4.3A. I have not observed it doing. In my case as soon as it is on stage 7 (green battery indicator) – CTECK 4.3 does not supply any current. Documentation indicates it will stay in stage 7 for 10 days. Maybe at some point it does supply the voltage and current, but I turning it off as the battery is fully charged at that stage.

8. Pulse. After 10 days the CTECK 4.3 goes to pulse mode 12.7V to 14.4V with current between 4.3A to 2A. I do not plan to use it.


The 110 Ah battery accepts the charge without bubbling (unlike the charge from the Schumacher even on the small current 2A or 6A with 16.98V always produces the bubbling noise).

The only negative feedback the CTECK MUS 4.3 is getting warm on the stages 3 and 4.


I hope it will help someone to preserve the Audi A8 electronics and extend the battery life.

Schumacher Speed Charge SC-1000A is definitely not the choice for any battery (in my humble opinion).


with best regards,
Victor

richard-tx

Here is the problem I have with those pocket sized chargers. They take a long time to fully charge a battery. Given that the charger you like is a 4.3 amp unit, it will take 25 hours for a fully dead battery to charge. The way that batteries are supposed to be charged is first determine the state of charge. This is usually done with a hydrometer. Batteries are now sealed which makes that method unavailable. The other but less reliable way is with a voltmeter. Once the state of charge is determined, then simple math is required to determine how much and for how long charging is required. THe problem is that it is usually a sliding scale as most chargers are of the constant voltage type.

Vicl

Thanks for the feedback!

I guess it will depend from the charger purpose. In my case I want to "top up" the battery.
I do not believe in restoration of Fully Dead battery. Once it became dead - it will be dead the next time very soon.
But to keep the health of the battery it is important to keep it charged.
The "fast charge" never can charge the battery to it is max capacity, the slow charge with low amperage does it.

I used to do it "manually" on my other Audi's and I managed to run on the same battery 10-15 years.

Abusing it with "fast charge" as Schumacher did - just killed the battery in no time.

SS_RTR

I've also gotten a few over charges with the Schumacher charger. It seems like it happens when there is additional draw maybe when I open the doors or switch to car on/not started causing 10-15 amps to be drawn. I have an AGM battery but I do use the AGM mode on the Schumacher.