Had my car in storage for approx. 4 months, but wasn't worried because I had installed a CTEK trickle charger.

It may be in the manual somewhere, but I don't remember seeing it; If the unit loses power, it must be manually turned back on. Sometime during the winter, there was a power interruption, so the CTEK turned off and stayed off, and I had a dead battery when I got home.

Given the purpose of this charger, I would think it would default to the "On" position, to avoid this problem.

 

^^ That's bad for sure. I know that the Battery Tender Plus will restart after a power outage, cycle through it's charge/trickle mode and get back to full green light once the battery is back to 100%.

 

Good to know. I may pick one up.

 

I've had mine since 2009, and still going strong. I keep mine plugged in from Nov 1-April 1 each and every year during the winter hibernation period.
I use it to recharge my electronic Golf Cart during the summer months.

It's a little more money, but well worth it for sure.

 

I have a CTEK 7002 and never had that happen. It starts back where it was after power is restored.

 

Most of them won't restart after a power interuption.

 

Most of them you have to manually hit the mode button to get them working again. That is bad if you have a car in storage that is not close by.

 

I had my tender for about 5 years. I leave it on all year. I moved to Florida and I still leave it on all year .

 

I've had my Deltran Battery Tender for 10+ years and pretty much always leave it plugged in using the lighter socket.

I lose power fairly often but it always comes back on. I do have a surge suppressor as well, but don't know if surges and/or brown outs have any affect on the Tender.

The power-cycle-reset appears to be another feature to check for when purchasing one.

 

My CTEK MUS 4.3 restarts automatically & so does my older 3300.

 

Just checked my Battery Tender Plus and it came back on automatically after I cut the power.

 

Then there's at least 3 dif. models of Ctek 3300: the Corvette-supplied one which does not turn back on, the one listed above that turns back on, and mine which does not turn back on once power is interrupted (not to mention the fellow who posted that his 3300 was not working, and didn't know HIS was one that turned off after power off).

 

I have 5 Ctek 3300 units used on 4 seasonal cars and a truck that sit for long periods in the shop over the winter. There are several power interruptions over the winter and all have restarted correctly.

The procedure I use is when putting the charger on the car is:

1) Connect the charger to the car. Charger will indicate proper connection made or incorrect reversed polarity attempt.
2) Set the mode, usually pushing the mode button twice
3) Plug the charger into 120 vac

When the power is interrupted, the mode that was set continues to be lit on the charger, just as it was before step 3 above. Once power is restored, the charger resumes operation just as though step 3 was completed.

IMO, the charger draws some current from the battery after it is connected but before being connected to AC, as the charger senses the voltage of the battery and must have some way to power its indicator lights. My belief is that during a prolonged power interruption, the battery drains due to charger draw, and perhaps cold temps or parasitic draw from the car itself. Once the battery is drained down far enough, the charger 'loses' its mode, and once power is restored will not start or start in the desired mode.

I haven't seen one of these fail to start properly while on the car, but I have put one on a battery on the bench that was so dead it wouldn't light the mode light on the charger, and the charger just wouldn't start. Hence my supposition about starting after a prolonged interruption.

All just my .02

 

Easy to test, but it would be a dealbreaker for me...

 

It's my understanding that if you lose power and your battery has not drained completely once power has been restored it will continue to maintain your battery if power was off for an extended amount of time and battery drained down it will have to be reset

 

Same with mine.

 

I have the one that sells with the car from GM, I think it had $120 on the window sticker for the charger....mine does NOT have any mode buttons or nothing like that at all, simple plug in the rear cigar outlet, plug into wall, mine shut off sometime during the winter and the absence caused my battery to drop very low and IF it tried to come back on, it never did....I don't think these are worth the money....a lot of others are on the market at 1/2 the price and more reliable than the CTEK....called the CTEK factory and they couldn't help me and didn't know why mine died...they said take it up with GM, it is under warranty from the factory for 2 years...I understand that these are only battery maintainers, not really chargers or replenishers !! they maintain BUT if it drops so far down, it then doesn't work at all, this is poor quality especially when car people want a battery tender that works all the time. and many people put their car to "sleep" for 4 -5 months at a time !!!!! My $.02

 

Have had mine for awhile as well. Shortly after getting it, had it hooked up when the power went out due to a storm. Power was off for several hours; when it came back on one of the things I checked was the charger, it was on & charging

 

Same thing happened to me few years back. I found out that CTEK 3300 does not revert back to the charging stage after an power failure, short or long. I could not have that. I traded it for the CTEK MUS 4.3 that does. I reported that here in the forum many times on each battery tender thread. Lot of people do not pay attention to it. Now I can go away in peace.