Trickle charger - Page 3 - Boxster/Cayman - PistonHeads UK

If….. I get delivery of the new GT4 at some point, a recent change of circumstances means I’m not gonna have access to a garage. I do have access to an outside power source so can anyone advise if there’s a way of having a trickle charger connected whilst still leaving the car all locked up and secure. Cheers

I have a CTEK c harger. They come with a lead with a waterproof socket attached which can be left permanently connected to the battery with the socket threaded through the interior boot trim coming out at top of bonnet. The charger is then connected to that socket when needed - simples !!

Or just close the door on the cable.

If I were doing this outside, I'd have to add a fuse near the battery.

It's easy enough as you can shut the door with the cable in it. I used to set it up like this: Extension cord plugged into outdoor socket End of extension cord sits in driver footwell Charger plugged into extension cord within driver footwell Charger plugged into passenger footwell socket. This way the only bit exposed to the weather is the (waterproof) extension cord.

SlimJim16v said: If I were doing this outside, I'd have to add a fuse near the battery. +1 on this, CTEK should supply this as std. For now I’m using the socket in passenger footwell, but as I’m away from home for extended periods I’m going change my set up to go directly to battery with an inline fuse. Also going to put a -ve connection post close to the battery (there is empty threaded hole on n/s suspension mount area) as the one on drivers side is too far for a neat install.

CTEK do a connector with traffic lights so you can quickly see the state of the battery. This has an inline fuse as std. I have the MX5 and use on an older 911 and modern one. I feed both charger wires through the top of the bonnet and then have the extension cables under the front wheel. CTEK also sell a long extension lug in for the charger.

If you want to keep an eye on the state of your battery you can use a victron Bluetooth smartbatterysenss for around £30 https://lowenergysupermarket.com/product/smart-bat... Put it on your battery and you can get a remote battery voltage reading from the house Edited by elan362 on Monday 14th March 16:29

I've yet to get a trickle charger for my 981 gt4. How long can they be left before the battery starts getting into trouble?

edc said: Or just close the door on the cable. This, I do it on all of my cars which were kept outside

What about a solar charger that would sit on the dash inside the car? Then there are no cables to worry about.

bosshog said: I've yet to get a trickle charger for my 981 gt4. How long can they be left before the battery starts getting into trouble? If the battery is in decent shape to begin, more or less indefinitely. I’ve left cars for 10+ months on a CTEK with no issue.

braddo said: What about a solar charger that would sit on the dash inside the car? Then there are no cables to worry about. The footwell 12v socket shuts down if there is a current drain detected after a period of engine off. It stays live if there is a positive inflow of current into the car (eg via external charger. Solar panel would have nil current in at night so the 12v socket would shut down.

elan362 said: braddo said: What about a solar charger that would sit on the dash inside the car? Then there are no cables to worry about. The footwell 12v socket shuts down if there is a current drain detected after a period of engine off. It stays live if there is a positive inflow of current into the car (eg via external charger. Solar panel would have nil current in at night so the 12v socket would shut down. I use a Ctek plugged into the ciggie lighter and shut the door on the cable. I house the Ctek in a waterproof cable box and run just the charger cables through the door. The car and charger will happily sit like that throughout the winter months without a problem.

braddo said: What about a solar charger that would sit on the dash inside the car? Then there are no cables to worry about. Unfortunately a solar charger won't work plugged into the socket in a 718. This is because the socket only stays live as long as power is connected; fine for a mains powered charger (assuming no power cuts) but no good for solar charger. I used a solar charger for seven years in my 987.2, but on getting a 718 had to get a CTek. Closing the door on the cable works fine

This is for a 981...but I have the connection direct to the battery, the cteck charger I use will fit under the hood with it closed no problem

Royal Jelly said: If the battery is in decent shape to begin, more or less indefinitely. I’ve left cars for 10+ months on a CTEK with no issue. I meant without a charger? 3-4 weeks?

bosshog said: Royal Jelly said: If the battery is in decent shape to begin, more or less indefinitely. I’ve left cars for 10+ months on a CTEK with no issue. I meant without a charger? 3-4 weeks? My 987.1 will last just over three weeks without a charge and the battery is about two years old. After that the starter turns over noticeably slower. I’d not leave mine any longer than four weeks, otherwise I’d have to faff around plugging a spare battery into the fuse box to open the bonnet. I recently bought one of these: https://www.ctek.com/uk/cs-free-portable-charger-a... It’s a Ctek cable-free battery conditioner and charger. You can charge it at home and plug it into a dead battery and it will charge your battery enough to get it started in fifteen minutes. You can also use it to condition your battery once a week to bring the charge level back up. I’ve used one to keep my Boxster topped up throughout the winter as I have no power supply where it’s stored. It’s expensive (approximately £200) but a great bit of kit. It’ll hold a charge for up to a year.

bosshog said: Royal Jelly said: If the battery is in decent shape to begin, more or less indefinitely. I’ve left cars for 10+ months on a CTEK with no issue. I meant without a charger? 3-4 weeks? With a new battery, 6 weeks would be fine. Have you considered a lithium battery?

Chubbyross said: I recently bought one of these: https://www.ctek.com/uk/cs-free-portable-charger-a... It’s a Ctek cable-free battery conditioner and charger. You can charge it at home and plug it into a dead battery and it will charge your battery enough to get it started in fifteen minutes. You can also use it to condition your battery once a week to bring the charge level back up. I’ve used one to keep my Boxster topped up throughout the winter as I have no power supply where it’s stored. It’s expensive (approximately £200) but a great bit of kit. It’ll hold a charge for up to a year. Why not buy a bog standard battery power pack thingy? £40 to £80? No? Wjy not?

The Mad Monk said: Why not buy a bog standard battery power pack thingy? £40 to £80? No? Wjy not? That's what I did. Very compact and gets a car started very quickly.

bosshog said: I meant without a charger? 3-4 weeks? Sorry, misunderstood you.. If the battery is new, then a month or more - but it doesn’t do it any favours. You’re looking at ending up with a serviceable but damaged battery though, which is problematic with Porsches.

I flattened the battery on one of the cars by parking and leaving the headlights on. The breakdown man turned up with something the size of a packet of cigarettes, connected it, said ok, try that, and away we went. I regret not asking him what make and model it was - one of these perhaps? https://www.autoexpress.co.uk/product-group-tests/...

The Mad Monk said: I flattened the battery on one of the cars by parking and leaving the headlights on. The breakdown man turned up with something the size of a packet of cigarettes, connected it, said ok, try that, and away we went. I regret not asking him what make and model it was - one of these perhaps? https://www.autoexpress.co.uk/product-group-tests/... Yeah, these have come a long way in recent years. We used to have a jump starter the size of a massive toaster and very heavy, and now have the Halfords one in that article, so you can keep one in the glove tray. And there are alterrnatives to Ctek, got a couple of Noco Genius smart chargers and they seem to do the job just fine.

Royal Jelly said: Sorry, misunderstood you.. If the battery is new, then a month or more - but it doesn’t do it any favours. You’re looking at ending up with a serviceable but damaged battery though, which is problematic with Porsches. This is true. And not just for Porsches. My Cayman has been fine left for 3 or 4 weeks but after watching a Car SOS recently they explained why batteries do degrade much faster the less they are charged and drop below a minimum voltage, so I will usually hook it up to the charger if I'm not intending to use it for more than a week.

For any future googlers... on my 981 GT4 only the cigarette lighter outlet in the centre console / ashtray bit stays live after locking. Footwell is live for ~30 mints then turns off, so trickle charger needs to go on the ashtray one.

If you get a jump pack, don't leave it in the car and do keep it charged up. If the main car battery is totally flat and so is your jump pack then it won't matter that you can't unlock the car then.

braddo said: The Mad Monk said: Why not buy a bog standard battery power pack thingy? £40 to £80? No? Wjy not? That's what I did. Very compact and gets a car started very quickly. I didn’t want a jump starter. I wanted something that would condition and charge the battery throughout the winter. I wanted to avoid the battery running down. The Ctek unit keeps it topped up for months.

Chrisatronic said: For any future googlers... on my 981 GT4 only the cigarette lighter outlet in the centre console / ashtray bit stays live after locking. Footwell is live for ~30 mints then turns off, so trickle charger needs to go on the ashtray one. In a similar vein - my CGTS 4.0 footwell lighter socket stays live - as long as you plug the trickle charger in fairly swiftly after turning the ignition off - don’t quote me but I think the time limit is 10mins. If you miss the deadline then as quoted the socket switches off after 30 mins or so.

My original q is how can i get the extension lead cable in the car safely. I dont think just slamming the door on it will work adequately

You don't need to have the extension cable in the car though. The cable on the ctek is long enough to place the unit outside the car and it is IP rated waterproof. You could if you wanted buy and outdoor extension cable too. I have a 15+ metre one but for Xmas decorarions!

SpyderMatt said: My original q is how can i get the extension lead cable in the car safely. I dont think just slamming the door on it will work adequately As has been said above. Just buy one of these: Masterplug WBXBFG10B-MP Weatherproof Electric Box for Outdoors with Four Socket 10 Metre Extension Lead, 351 x 220 x 126.5 mm, Dark Grey https://www.amazon.co.uk/dp/B0062GTL42/ref=cm_sw_r... Run the cable from your mains into the extension bar, placed in the weatherproof box, with the Ctek plugged in, also stored safely in the box. Then run the Ctek charge cable through the bottom of the car door. You can even tuck the weatherproof box under the car to keep it out of the way. I’ve done this safely for years through the winter months.

Perfect, cheers 😎

paddy1970 said: bosshog said: Royal Jelly said: If the battery is in decent shape to begin, more or less indefinitely. I’ve left cars for 10+ months on a CTEK with no issue. I meant without a charger? 3-4 weeks? With a new battery, 6 weeks would be fine. Have you considered a lithium battery? I'm currently trying a LiFePo4 battery on my 986. It works fine but it has gone flat a couple of times on me. The last time was this morning because I'd left the side lights on so my fault really. The good news is it is seriously light. I've temporarily just zip tied it to some pipes - coolant for the heater I'd guess. This means I could also remove the original battery tray which is a bit of a heavy lump too. The bad news is you're meant to use a specific LiFePo4 compatible charger which I don't have. So if I really need to top it up I just use a regular charger. As I don't really know when it needs topping up this add yet a further problem. I believe ctek now sell LiFePo4 compatible chargers. As you might expect if I use the car regularly then its fine. If you're planning to lay the car up for a while you'll need to consider it's smaller capacity.

LiFePO4 batteries should not (under any circumstances) be charged below 0C. In fact, if it has a BMS, It almost certainly will prevent charging below 0C. A proper lithium charging profile would have a temperature sensor to the battery negative terminal to measure battery temperature and not charge if <0C There are LiFePO4 batteries that have an "Arctic" constr that essentially comprises heating elements around the LiFePO4 cells, and the BMS sends charging current to the heating element to warm the battery sufficiency rather charge it in sub zero temps https://www.ksenergy.co.uk/lithium-battery-product... the standard KS-Energy batteries say Low temperature charge protection (charge current disconnects at zero <0oC) Operating temperature range: -20oC to +50oC, storage temperature range: -20oC to +30oC the heated "Arctic" version says BMS integral protection: Low temperature cell heating: (charge current diverted to internal heating elements <0C) Operating temperature range: -30oC to +60oC so it says the charge current is diverted to heating below 0C in the Arctic version Even Tesla lithium batteries won't charge <OC - they rely on precondition (heating) by diverting charging current cell warmers to warm them above 0C before they can accept charge Edited by elan362 on Wednesday 23 March 03:20

I have a LiFePo4 battery on one of my motorbikes. One of the more interesting features is its seemingly complete inability to go flat. It holds charge when the bike is laid up so much better than lead acid batteries its not quite believable. I bought one of the specific CTEK chargers for it when I got the bike, and I pop it on charge every year to 18 months just so I feel a bit better about having bought the charger. Every time it has been fully charged within about 30 minutes, and I don't doubt the bike would have just fired up without me even putting the charger on it. It is so light and tiny that I just remove it from the bike and bring indoors to charge if its cold out. Never left unattended while on charge, and always on hard surface and away from anything flammable. They don't often go wrong, but can be pretty spectacular when they do. Liam

For me the sweet spot with a lithium battery is they charge very quickly. A Lead Acid battery takes a long time to get to fully charged so that's why they take hours and hours to charge and modern chargers have this form of final topping up mode. Then when you add in how Lead Acid go off when left only partially charged it seems an easy win for lithium. So if you have an occasional use car which lives outside away from a charger or maintainer and use a lithium battery then even a small little trip in the car can get it back up to fully charged. However the bad news is the smaller ones store less overall. So even though they have the oomph to start a car it's electrical systems will drain it much quicker than the massive Lead Acid version. Most modern LiFePo4 batteries have a system inside which cuts them off when the charge gets low to protect them ss they dont like being or going flat. So it can seemingly have loads of power - they don't lose power as they lose charge - but then it will just switch itself off. That's why I'm now thinking about one of these Bluetooth monitors so I can keep tabs on the charge. Although I'm confused how they can know for sure how much is in the battery if the voltage stays high even as it is draining down. Also the thought of a Bluetooth device connected to my battery seems counter intuitive as it will also drain the battery.

I charge directly to the positive battery contact and the negative charge post on the chassis (as recommended in the 981 handbook) ... the cover over the battery is easily removed and the cable comes out from the rear edge of the bonnet. I generally top-up the battery every 2 to 3 weeks if not used and put the C-Tek on top of a thin plank of wood with a glass bowl over the top. This gives ventilation for the charger whilst protecting from moisture. It also uses what I have Lithium batteries may be less susceptible to auto-discharge, but if any drain reduces the voltage too far, they cease to be batteries and to resurrect them the cells have to be reformed. We developed a system to resurrect deep discharged batteries in the photographic lighting market ... it worked well but required each battery to contain a micro-processor which worked with the charger to manage the battery, but it did also present some residual load ... Edited by ChrisW. on Saturday 26th March 09:49

ATM said: . That's why I'm now thinking about one of these Bluetooth monitors so I can keep tabs on the charge. Although I'm confused how they can know for sure how much is in the battery if the voltage stays high even as it is draining down. Also the thought of a Bluetooth device connected to my battery seems counter intuitive as it will also drain the battery. im my MH, I have a Victron BMV-700 bluetooth battery monitor (that has an external display) -https://www.12voltplanet.co.uk/battery-monitoring.html to monitor the State of Charge of my leisure battery (nut one could equally put iy onto the starter Battery the latest versions are the BMV712 IIRC, but , but nowadays, if you are happy using the Victron App, you can use a Victron 500A Smartshunt - https://www.12voltplanet.co.uk/victron-smartshunt-... that works without a display and relies on the phone app for the display. one puts a single cable from the battery to the input side, and connects all ground connections to the ground side of the shunt. you configure the smart shunt with your battery details etc and then the smart shunt essentially counts out all the energy out of the battery in coulombs - it monitors the battery voltage under charge - the battery voltage rises some 13.3 v static to eventually a charged voltage of 14.4v (or whatever you set the full charge voltage at, so it knows when to reset the SOC to 100%. so the Smartshunt essentially keeps count of energy in vs energy out. in terms of power drain, the data sheet https://www.12voltplanet.co.uk/user/downloads/Data... says it draws <1mA

Car is currently on trickle charge, not been run out for several months and now going on holiday for a week before getting it out as soon as home. I am planning on taking it off charge (as have a vision of house going up in flames) , interested on opinion of others on leaving a car on trickle charge for a week when not at home. OK or really stupid........ Edited by tighnamara on Sunday 27th March 21:47

tighnamara said: Car is currently on trickle charge, not been run out for several months and now going on holiday for a week before getting it out as soon as home. I am planning on taking it off charge (as have a vision of house going up in flames) , interested on opinion of others on leaving a car on trickle charge for a week when not at home. OK or really stupid........ Edited by tighnamara on Sunday 27th March 21:47 I'd have no qualms about doing this with a CTEK charger (assuming this is a lead-acid battery, not lithium polymer/LiFePO4). Pretty much any other charger and I would be less confident, but I certainly wouldn't say stupid unless it was a really cheap and nasty charger being used. Liam

LiamH66 said: I'd have no qualms about doing this with a CTEK charger (assuming this is a lead-acid battery, not lithium polymer/LiFePO4). Pretty much any other charger and I would be less confident, but I certainly wouldn't say stupid unless it was a really cheap and nasty charger being used. Liam Thanks Liam It is a CTEK charger and lead - acid battery.

if the battery in your car is an AGM then you need to be careful with a solar panel... These is pretty basic and not equipped with a charge control then you could in theory quickly toast your battery. trickle charge a battery is basically to... take care of the standby state of the car, all cars will consume some current. take care of the battery self discharge. now doing that with a trickle charger will take care of that. However you need to get power out to the charger - usually at mains potential. that has some safeguarding issues that need to be taken care of. the cable should be weather ;proof and able to cope with where it is being run. you need to really be sure of this. Also running a cable out to a car... you need to consider the fact that your taking a supply out to the car. and if there is an earth cable in that flex then you have a raised issue to consider with that earth. Id be making sure that the socket is not metal and that there is nothing earthed to the mains earth that can be touched, All double insulated please. the supply should also be protected by a 30mA RCD just to be safe. Id then be looking at the battery, that ctek or what ever charger your using id be putting in an inline fuse between the + terminal of the battery and charger as close as possible to the battery. that battery can pump out the amps if shorted. so that fuese should give you some protection. Its doable, but if your looking at doing this long term then make sure its done right

tighnamara said: LiamH66 said: I'd have no qualms about doing this with a CTEK charger (assuming this is a lead-acid battery, not lithium polymer/LiFePO4). Pretty much any other charger and I would be less confident, but I certainly wouldn't say stupid unless it was a really cheap and nasty charger being used. Liam Thanks Liam It is a CTEK charger and lead - acid battery. You can leave a car for months at a time with a Ctek conditioner. I’ve been doing it for years throughout the winter months with no issues.

Chubbyross said: You can leave a car for months at a time with a Ctek conditioner. I’ve been doing it for years throughout the winter months with no issues. Another vote in favour of leaving it trickle charging with a ctek. Let's face it - we all go out to work or whatever during the period we leave our cars trickle charging for relatively lengthy periods, so what's the difference in going away for a week. You're not going to pop outside and check on it every half an hour if you're at home either so you may as well not be there.

Probably best to keep an eye on it occasionally if left charging... https://www.pistonheads.com/gassing/topic.asp?h=0&...

Lexington59 said: Probably best to keep an eye on it occasionally if left charging... https://www.pistonheads.com/gassing/topic.asp?h=0&... I remember that, the problem was it didn't step down to trickle, but stayed on full charge.

Chubbyross said: You can leave a car for months at a time with a Ctek conditioner. I’ve been doing it for years throughout the winter months with no issues. Me too, GT4 over-winters with one permanently connected. I use an MXS 5.0 (in fact 2 of them, most of the time on various vehicle batteries). Only advice I can give that might save issues is: 1. If it takes more than 3 goes to get through the reconditioning cycle, buy a new battery as soon as you can; make sure the charge programme is appropriate to the battery you are charging. I have a couple of vehicles that have needed replacement batteries for years, but I have used the CTEKs to keep them operational beyond what I might have considered their natural life. If one of those blows up, it won't be CTEK's fault. I know those batteries are beyond their years and I really ought to replace. 2. Don't use the "motorbike battery" setting for car batteries. The CTEK will get confused between recovery, bulk charge and maintenance trickle charge. It's possible that might have been one of the issues for someone back in 2017. 3. Check if you have an AGM battery. Shouldn't be safety critical, but standard lead-acid will possibly suffer slight shorter life if charged using AGM settings. I've got it wrong the other way around in the past, but the difference is at worst trivial in terms of charge life. Liam

The Mad Monk said: I flattened the battery on one of the cars by parking and leaving the headlights on. The breakdown man turned up with something the size of a packet of cigarettes, connected it, said ok, try that, and away we went. I regret not asking him what make and model it was - one of these perhaps? https://www.autoexpress.co.uk/product-group-tests/... I have a council garage with no mains at all, and can't really use a CTEK (unless I hang the mains cable out of my first floor flat window), which leads to my question. Will these jump start units charge a battery if you leave them attached or they only useful for jump starting?

tonyg58 said: I have a council garage with no mains at all, and can't really use a CTEK (unless I hang the mains cable out of my first floor flat window), which leads to my question. Will these jump start units charge a battery if you leave them attached or they only useful for jump starting? the jump starters are only good for jumping. they need to be charged and when you connect to your battery they will discharge. you would end up with two flat batteries. keep it charged in the house and use it to jump your car when required. dont let the car get to a discharged state and leave it in that state for a while as that will toast your battery.

tonyg58 said: The Mad Monk said: I flattened the battery on one of the cars by parking and leaving the headlights on. The breakdown man turned up with something the size of a packet of cigarettes, connected it, said ok, try that, and away we went. I regret not asking him what make and model it was - one of these perhaps? https://www.autoexpress.co.uk/product-group-tests/... I have a council garage with no mains at all, and can't really use a CTEK (unless I hang the mains cable out of my first floor flat window), which leads to my question. Will these jump start units charge a battery if you leave them attached or they only useful for jump starting? These jump start units are just LiFePo4 type batteries. These have a lot more oomph for their size compared to a traditional battery. But they don't have more capacity. So a small LiFePo4 can start a car but it will keep it's charge for a short period of time if connected to a car which is leaching power constantly. These LiFePo4 batteries will maintain they're power almost indefinitely if not being drained so not connected to a car. Therefore to answer your question - no it will provide a bit of power and that might add some charge to your battery but it will still go flat quickly. A traditional battery charges slowly so you can't charge them quickly. That's why we charge them overnight at least. I'd suggest you switch the main battery to a smaller LiFePo4 battery - like I have - which you will then disconnect from the car when you leave it in the garage. Then when you need to use it just reconnect it and it will be fine and away you go.

Ocho said: Chubbyross said: You can leave a car for months at a time with a Ctek conditioner. I’ve been doing it for years throughout the winter months with no issues. Another vote in favour of leaving it trickle charging with a ctek. Let's face it - we all go out to work or whatever during the period we leave our cars trickle charging for relatively lengthy periods, so what's the difference in going away for a week. You're not going to pop outside and check on it every half an hour if you're at home either so you may as well not be there. Thanks, all is well, came back to a fully standing house and running car

ruggedscotty said: the jump starters are only good for jumping. they need to be charged and when you connect to your battery they will discharge. you would end up with two flat batteries. keep it charged in the house and use it to jump your car when required. dont let the car get to a discharged state and leave it in that state for a while as that will toast your battery. Thanks, I'll just have to keep driving it then. It's a 2011 911 and it sometimes does some strange things when the battery gets low.

tonyg58 said: Thanks, I'll just have to keep driving it then. It's a 2011 911 and it sometimes does some strange things when the battery gets low. It really depends on your usage. If you use it occasionally for short trips then the battery will be suffering. You could just accept that and change it for new regularly. The other option is have a 2nd battery in the house always on trickle. Then every 2 or 3 or 4 weeks swap them over. There are various options. If you have access to the roof you could try a cheap little solar panel type charger too. You could go mad and buy some massive deep cycle type motorhome batteries, leave these in the garage and then run a charger off them to the car. I'm sure there is an option that works.

Hi everyone. Following this thread closely as I store my 2015 GTS during the Canadian winter in a faciliity with no mains power source. Perhaps I am misreading some of the posts, but it seems that some folks are plugging the CTEK into the footwell and then connecting the conditioner/charger to the battery. How does this function if the footwell power is supplied by the car battery and the CTEK is drawing-down the car battery via the footwell -- seems to me that both the battery and the CTEK will go flat and/or that CTEK has a way to overrule known, to me, laws of physics. Please help me, the non electrician, understand as I would like to believe this works. Many thanks in advance.

From the car it needs to connect to a mains power supply.

Thanks. I was afraid I was going to have to lie down and reconstruct my world view.