parodielin

I bought a new CTEK 3300 trickle charger and hook it up with my E350 main battery. It's been charging for 20 hours and still charging. Is that normal? It's longer than I have expected. What is the average time for a full charge?

KEY08

Ctek is my preferred brand of charger/maintainer. Good choice.
Depending on how far depleted the battery was it could be 2-3 days for that light to glow green. Just be patient.

parodielin

When I use Battery Tender Plus, it's showing 80% completed after 20 hours. I assume CTEK 3300 is the same speed but who knows which one is correct. How long would the main battery last?


Do you use trickle charger on the aux battery in the trunk?

KEY08

It's a 3 amp charger, so it is not a rapid charger, but they work extremely well. You are probably close to full charge and I bet it goes green in a few hours. I do not have the ECO battery in my car, so I cannot comment on whether trickle charging that battery is recommended.

parodielin

So it is still charging after 24 hours. It been 2 days. I am guessing the pre-safe limited function was due to low charge. Would dealer be able to check how well the battery is?

KEY08

Absolutely, or take it by a Pep Boys, Autozone, O'Reilly's, etc

parodielin

So what's funny is I remove the connectors and put them back in. Now it's showing green light.

KEY08

Okay, that's weird. When you start it right now, the starter should spin up like a mad man. These cars are designed to not fully charge the battery in order to save the environment,I guess.
You will notice a difference in how the car starts for the next cycle or two.

parodielin

It is. I don't have issue with the battery except the one pre-safe msg - which I suspect somehow the battery wasn't enough. I just do this as a best practice. I don't know if the battery has ever been charged in the last two years. Based on the car needs tire balancing, I guess not.

So I want to charge it to full as a baseline.

I changed my BMW's battery yesterday. The shop I went asked me do you want a better quality or average quality. I said better (I trust the mechanic). So he ordered the battery for me and put it in. During the process, I saw the BMW battery was made in Italy. The battery he put in was Made in Germany (World SourceOne). And it costs $240 labor / programming included w/ two year no-question replacement and roadside warranty. I never heard of World SourceOne but "Made in Germany" was a surprise. Given the cost, battery replacement probably not a big deal.

CEB

Did the shop "register" the battery with your car so that the charging system will not overcharge the battery?

If not, then your BMW battery will die a very quick death.

parodielin

That's the programming part - although I think you will be fine without programming. There has been many discussions in this. The reality is BMW charging sucks. The original battery started having issue within the first year b/c of all short drives. The replacement (still BMW battery w/ dealer programming) lives longer because I used Battery Tender. So I believe even if I don't do programming, it won't live any longer without a battery tender. If it dies in two years, it has free replacement anyway.

I don't mind it overcharging. The problem is it undercharges even with programming.

thefisch

I've got the CTEK 4.3 and on average it takes about 12-14 hours for the charging process to fully complete (to step 7) on my E. On my wife's Honda it takes about half that time. As Key08 mentioned, MB keeps these batteries at a low SOC. But if mine was taking 24 hours, I would cycle power and try again.

cadbob

I have the Ctek Polar, works awesome