My CHARGE-O-MAT experience.

I thought I would post a little summary of my CHARGE-O-MAT experience. My battery died in just 3 cold months without starting the car So I decided that the best fix would be to order the Porsche CHARGE-O-MAT which works through the cigarette lighter. You can get the same unit without the cigarette lighter plug on eBay for around $65 but I paid $125 to my door in Canada from Don Rosen Imports (a very helpful dealer when it comes to internet business). I went out to my garage and plugged the charger into the "power socket" in the center armrest, rather than the cigarette lighter itself, since I read that this was a better approach. I then ran the cord out through the (ajar) door and down to my wall socket. When I plugged in the unit, nothing happened: I needed to set the mode. There are two modes, "motorcycle" and "car". I selected Car. Let this be a warning to you - don't start this process with your door ajar! What happened to me is that the door ajar lights inside the car immediately began to flash on and off as the battery charger cycled. This was pretty scary, so I shut it off until I could figure out what was wrong. A better approach is to run the cord out the window!!! Then you can close the door completely. I then turned on the Charge-O-Mat and set it to Car again and it began to charge quietly. Unfortunately, its been around 26 hours and it does not indicate a full charge yet, even though the manual said it would take around 18-23 hours. I'll update this when the car starts (hopefully tomorrow). Overall its a very nice product, it feels small and easy to use and I'll likely keep it in a little pouch in the trunk or in the glove box for emergency use! -Kris

$125 to trickle charge a dead batt seems a little steep to me . . . oh yeah, it's a Porsche product. Seriously though does it have to take that long to charge? Can't you just jump start it, run it for a while to charge the batt and then use the charger to keep it full?

charge o mat I'm not 100% sure, but I don't think a trickle charger will bring a dead battery back to life. I used a Battery Tender on my cycles for years and they keep a charged battery in great shape for years but in their brochure they stated that it WILL NOT bring a dead battery up to a usable state. But good luck. Seeing that you paid $125 and it's from Porsche, it will probobly work.

These battery maintainers are NOT trickle chargers. Trickle chargers can boil a battery dry if left on. Modern maintainers know when to shut off! Their charging rate is very low, as their purpose is to maintain a charge, not to charge a dead battery . A so-called smart charger is the right thing to use if you frequently run a battery pretty far down (as we boaters do with our 'house' batteries). Marty

Depends on the amount of charge you start with but once the battery is dead it is dead. I've used this model for years to maintain batteries with no problems. There is a sequence described in the charger's owner's manual for plugging and unplugging it into the wall/car. Make sure you follow that (if anyone ever reads manuals that is).

According to the manual of the CHARGE O MAT it actually has two modes, and switches automatically from being a battery CHARGER that can charge a drained battery , to being a battery MAINTAINER. It uses a totally different amperage/voltage/cycle for the two modes. So I don't think its just a tender! Should bring the battery back. I could jump start the car although I thought I would try this first since I don't have easy access to the battery or another car or jumper cables etc. So, we'll see. $125 is not bad, my local store would have been nearly as much if I had bought a local brand plus also bought the cigarrette adapter. Sadly electronics are generally more expensive in Canada. I don't really care as this is pretty cheap and I will use it for a number of years to come, and it looks nice and not like some big ugly box

The manual says it cannot be used to restore a fully worn out battery and if the charger doesn't go to maintenance charge after three days the battery is most likely worn out and needs to be replaced. After 3 months of not driving the car, what's a couple of more days to wait and see what happens. Get a Deka if you need a new battery .

My understanding is that completely discharging a battery significantly shortens its life. I hated my 03 M3 so much that I was often several weeks without using it. After approximately 5 complete discharges, my battery was dead and had to be replaced. A trickle charger is cheap insurance. Edit: I should have said battery maintainer instead of trickle charger

Yeah it does shorten the life... the charge o mat is supposed to blink if it decides the battery is too dead to recharge. In my experience you need to REALLY drain it for this to happen, I'm pretty sure its not that far gone after only 3 months with the car off. If it starts blinking then yeah I'll get something new and lightweight.

By Kor's description, the Charge-O-Mat IS a smart charger. And Denis54 is also quite correct in that fully discharging a battery significantly reduces its useful life. Try to keep the discharge to less than 50%. Marty

Gotta Ask... Maybe stupid question but here it goes, Kor, if you were dead to the water, no juice, how'd ya get the window down to run the cord thru? just asking cuz I know I'm going to be using the same thing next fall, hopefully it won't die on me, thanks.......

Good question, as soon as I plugged in the charger through the open door, the window actually rolled down a crack, because of the auto-rolldown feature? There was enough power as the lights were blinking on and off...

You may need to reset the windows...look in your manual regarding dead battery and windows.

So I guees that's how you'll have to run the power cord in the future b4 it dies, crack the window and plug it in?

I normally leave my doors ajar (latched, but not fully closed) in winter to prevent the door seals from flattening out. I did this with my '01 Boxster , and also do it with my Dinos and '04 SL 500. However, unlike the Boxster and the SL, with the Cayman I was unable to set the interior lights so they would not go on, and also had to leave the window open a bit (I do so anyway, for air circulation, and to avoid mildew) and run the power cord over the window. Hope that your battery comes back to life, Kor. 987f

First I don't even own a Boxster or Cayman , hopefully that will change soon. In doing all my research I thought I remember the door molding having a cutout for the cord to go through. I looked and can't find any info so I'm probally wrong.

i use the porsche battery tender --about $65-$80 depending on where you buy it--i plug it into the cigerette lighter after every drive since i do not drive the car much--the cigertette lighter is in a much more convient location than the power outlets--so far after 12 months--no problems--longest time i left the car undriven was about 2 months--just so you know the cable on the battery tender is very small so closing the door on it is no problem

a trickle charger may end up overcharging your battery--get the tender--or a smart trickle charger

C-Tek sell the same unit in England from £40-£200 !!!!

I just charged my sisters MB that has been in my garage for six months. Even though the battery was good enough to start the car it still took 46 hours to get a green light with a battery tender . So be patient...

Kor, With the identical unit you displayed, it took me 2 days to get the green light after letting it sit for 3 weeks this winter. The battery has maintained well every since. I just put the charger on it yesterday evening after driving it for a month (probably 10 miles a day, 3-4 times a week) as it took me 1½ hours to get the green light.

I have the CTEK unit, purchased it for my SLK350 which use to drain its battery while sitting in the garage. Now I use it on my CS, its a great little product and does exactly what it says on the box.

The charger has now been on the car for around 54 hours. Its still not fully charged. But the car started without a problem today I'm going to just leave it on there, can't hurt it. The manual actually says in a different place that 72 hours is as long as you should wait. I'm a good ways off that so I'll leave it 1 more day and if its still not at max, I'll just drive it until I feel like putting in a new battery , or see if driving it helps.

A battery is like a loaf of bread. Take a slice out of it every time you discharge it. The deeper the discharge the thicker the slice of bread. When a battery is new and drains down you can still recover it to a point (take a thick slice out). Charging a battery only puts back a thinner slice than what was taken out. Eventuality you end up with only the crust and it’s time to change the battery . If maintained properly a typical car battery should last from five to seven years. What is happening as you leave the Charge O Mat on is that only a few milliamps are being given to the battery over a long period of time instead of a large amount of amps over a shorter period of time like a regular battery charger. Give it sometime and it will recover. As always driving is the best way to charge the battery . Sorry to be so long winded, I do batteries for a living.

Turn it off, then turn it back on (using the button on the unit). It might flick on to green (or not).