Battery trickle charger question

[Frrair]

Evening All

I am heading away on hols soon and also won’t be using my new Porsche 911 for longer periods when winter sets in so decided to buy a trickle charger to have no issues when the opportunity arises.

I have had Accumate trickle chargers before and purchased another one, attached the battery cables as photos and plugged in. The charging unit confirms the polarity is correct, it’s registering it’s charging but it never gets full and steps down to a maintaining trickle.

I have put the new charging unit on the Boxster Spyder which is wired the same way and that charged up to full then stepped down so its not the charging unit so it must be the way I have connected to the battery, but it looks ok to me can someone tell me what I have done wrong here please?

Thanks in anticipation
Ed

[Frrair]

[Frrair]

[smudger911]

How long have you left the 991.2 GTS charging before deciding things aren't working out properly?

Sounds like yours is charging aok then going into 'float mode' to maintain charge.

fwiw i also have a 991.2 GTS, if left off the charger for a few of weeks it only takes a couple of hours with a 800mha charger to hit float mode - a range between 13.2v and 13.4v

[ras62]

This generally means the Battery is not in top condition. If left the charger will continue charging and this will kill the battery completely. There is often a warning of what happes if the trickle state is not reached in the user manual.

[Frrair]

smudger911 said:

How long have you left the 991.2 GTS charging before deciding things aren't working out properly?

Sounds like yours is charging aok then going into 'float mode' to maintain charge.

fwiw i also have a 991.2 GTS, if left off the charger for a few of weeks it only takes a couple of hours with a 800mha charger to hit float mode - a range between 13.2v and 13.4v

Hi Smudger

Thanks for taking the time to respond.

Because I have used the car recently on a decent run without too much electrical load being drawn when driving I expected it to be simply topped up in a couple of hours, just like the Spyder does. To answer your questions because I was a bit nervous about leaving it on when I expected it to be showing full I have put it on a few times then turned it off probably three times from 3 hours up to a max time of about 6 hours.

It has a light to show it’s stepped down to float mode which hasn’t come on when connected to the 911 but the charger does when it connected to the other.

[Frrair]

ras62 said:

This generally means the Battery is not in top condition. If left the charger will continue charging and this will kill the battery completely. There is often a warning of what happes if the trickle state is not reached in the user manual.

Hi ras62

Thanks for taking the time to respond.

The car was brand new in March and has been used between weekly and fortnightly. I am surprised if it’s the battery but could get that checked but as I go away this weekend it’s not going to possible before I go so it will go unused or plugged in for nearly four weeks. This is what i was trying to avoid.

This is the same model of charger I have had twice before, one left with a car long sold that worked perfectly for 5.5 years and I have had the Boxster Spyder one for a couple of years now and that been perfect too.

The fact both chargers step down on the Spyder into float mode probably supports the view it’s the battery.

The booklet with the charger says it would fully charge a 56 to 75 Amp-hours battery from flat in 27 to 37 hours but I am not sure it would be wise to just to go for it and leave it on all that time or I might kill the battery all together.

I did 65 mile commute in it today so it should be pretty much full so I will plug it in tomorrow evening for about four hours to se if that tops it up...

Very curious

[elisered]

There is a long thread on here if you search around - you should not attach the -ve directly to the battery or it bypasses the battery ‘brain’ and prevents a complete charge. There are a couple of places to attach directly to the chassis depending on the car - see your handbook for details.

[gtsralph]

As above, battery conditioner + to battery + post, battery conditioner - to earth point.

[Frrair]

Hi there elisered and gtsralph

Really good info, thanks.

My battery charger is wired to the car the same way as yours Ralph, I have just plugged in the charging unit and I will see how we go but feel assured it will now work.

Thanks for taking the time out to help, it’s much appreciated.

Cheers
Ed

[Bobtherallyfan]

So how does it work when you use a CTEK direct into the cigarette lighter? That happily goes to float mode.

[smudger911]

Bobtherallyfan said:

So how does it work when you use a CTEK direct into the cigarette lighter? That happily goes to float mode.

At a guess it is wired to allow charging correctly, but also when the car is locked / alarmed.

Centre console lighter socket is a LOT less hassle than removing all the up front plastic covers tooooo

[elisered]

smudger911 said:

At a guess it is wired to allow charging correctly, but also when the car is locked / alarmed.

Centre console lighter socket is a LOT less hassle than removing all the up front plastic covers tooooo

Later 981s have a configuration change that means the lighter sockets will not stay live unfortunately.

Once a connecter is hard wired correctly, feed it through the handle hole in the plastic cover and you don't need to remove it again to charge or disconnect.

[smudger911]

elisered said:

smudger911 said:

At a guess it is wired to allow charging correctly, but also when the car is locked / alarmed.

Centre console lighter socket is a LOT less hassle than removing all the up front plastic covers tooooo

Later 981s have a configuration change that means the lighter sockets will not stay live unfortunately.

Once a connecter is hard wired correctly, feed it through the handle hole in the plastic cover and you don't need to remove it again to charge or disconnect.

Yep. Tho' the OP is talking about his 991.2 GTS, a different machine and electrical system.
re the 981's - appears some work, other claim if you switch the charger on within the 30 mins cut off window it will continue charging aok.

[DJMC]

smudger911 said:

Yep. Tho' the OP is talking about his 991.2 GTS, a different machine and electrical system.
re the 981's - appears some work, other claim if you switch the charger on within the 30 mins cut off window it will continue charging aok.

My 2014 981 will charge only via the centre console 12v socket. This will still cut out, as will the under dash one, after around 30mins if an accessory is plugged in outputting power. But CTEK charger input keeps going indefinitely.

[Frrair]

In answer to the question did it work then, err no.

I wired just like the photo gtsralph posted (thanks ralph) connected the charger, put the bonnet down and locked the car.
As I used the day before for a decent run I thought it might go into float after an hour or two, came back after 4 hours just before bedtime and... no. I didn’t want to leave it charging over night so put it on about 4pm until 10.30pm the following night and still no.

I have gone on hols now and I will see when i get back, I will need to sort before winter but I was trying to get sorted before leaving dormant 3 weeks.

[elisered]

Does your charger have a mode for AGM? That’s what you should be using - would assume so if you’ve just purchased. Battery technology seems to have advanced since the good old unsealed lead acid ones😉

[nw942]

In the past I have had to wait over 24 hours for my CTEK to get to the final float stage so I would keep it on overnight when you return.

FYI I was also running my charger for a few hours every day as I didn't want it switched on overnight. But after a few months of this it got the battery into a state where it did not hold charge. I had to use a 'dumb' charger to charge it to a point that the CTEK would then accept it. So I would fully charge the battery or just keep the charger on all of the time.