Trickle charger never changes to green (full charge)

Should I leave my Porsche brand trickle charger plugged in? After my wife drained a 5 year old battery by leaving the lights on....my trickle charger just keeps running but never turns green to indicate a full charge. I'M guessing i need new battery but I'm booked for next two weeks, is it safe to let a trickle charger just keep running. It turns green for a minute-or-two each day...but then goes right back to orange (meaning that it's charging again). Thanks

If the battery was completely drained then a trickle charger won't bring it fully back to life. It needs to be put onto a proper battery charger to determine if it's ok or not.

The battery is toast, sorry. If the battery was ok then the trickle charger would go green given enough time. An old battery that was taken to flat status is likely internally damaged now.

I'm sure the battery will never be the same, I'm just wondering if it's safe to leave trickle charger on for next two weeks until I can get some time to buy a new battery . Car will start, but trickle charger has to run 23.5 hours a day. Worried about adverse effects of letting trickle charger work so hard on a wounded battery . ( stuff always breaks during the worst time... I will be traveling over next two weeks, but wife still uses car).

Yea, the battery is history. While you may be able to start the car, it's not going to keep its charge for long and you may not be able restart if you go somewhere. With the trickle charger, I would take it off line and you are right about it burning it out due too over use. As recommended use a battery charger set to fast charge if you need to take it somewhere. Personally, I always bail out when a battery starts having problems, modern electronics are sometimes not tolerant of battery issues.

If its the charge-o-mat, its old rebranded CTEK without the current tech. While a 5 year old battery is old, I would get a modern CTEK and used the recondition mode. I know from experience it works. For how long? I don't know. See below. Besides, if you ever get an AGM battery you need the new ones anyway as the old CTEKs cannot properly charge at 14.7v required by the AGM batteries.

+1 on the Ctek chargers... highly recommended and the only brand I will connect to my vehicle's battery . I have a couple of them now as I have a two Porsches and a truck that sometimes sit for a few weeks at a time, since going to this brand nearly 10 years ago I have never had to replace a battery , I have a MULTI US 3300 for general maintenance and a MUS 4.3 TEST&CHARGE, both handle AGM batteries used in the Porsche with the added benefit of the MUS 4.3 being able to test a few parameters in the charging system if you think you have a problem there. Check them out here: Battery Chargers - CTEK Battery Chargers

It only takes a few minutes at AutoZone, Advanced Auto, OReilley,.... You can even order it online and then get it installed at a close-by B&M store. They'll pop a new one in and dispose of the old one. Much easier and quicker than finding a new charger and the problem is solved. However, to answer your question - before leaving the battery connected to the maintainer, top-up all the cells with distilled water. That might solve your problem. But if its 5 yrs old, you'll need a new battery soon anyway. BTW, you just missed a bunch of July 4th sales. Advanced Auto had 20% off thru yesterday.

If it'ss the modern CTEK / Porsche rebranded maintainer, the longer it runs, the better the chance u have of bringing it back to life. Make sure it is switched to the Winter (Snowflake) mode. The battery may be toast, but try these tips to make sure. And it won't hurt it to drive it either, assuming it starts reliably. If so, go ahead and get it tested at a shop or auto parts store of ur choice.

You didn't mention what kind of battery this is, there are many types and some need to be maintained differently, voltages, charge rates and electrolytes differ... As for long term connected chargers, only if you are sure that the unit you are connecting is suitable for the battery type and can detect the level of charge in the battery and reduce the current flow to prevent an over charge condition. Be careful as all chargers are not created equal, as I posted earlier a modern tender/maintainer is recommended. Regarding the bolded statement, AFAIK this is only for regular lead acid batteries, modern maintenance free and AGM batteries are sealed, you cannot add water, the OP didn't specify what type of battery he was working with.

Mark is a local so I know he has a a 2012 GR 987-2 Cayman. So, assuming his post was regarding his Cayman (not another car), his 5-yr old battery would have been the Porsche OEM flooded cell batteries just like mine. They have caps to check/add water. AGMs weren't used until 2013(981).