lets talk batt maintainer for p car newbie
 

i did some searching and found lots of info on maintainers, but no clear info on why.

so


can someone give me a couple of short answers to a couple of questions?

1a, how long (new fully charged battery) can i park a boxster before the voltage drops too low?

1b, WHY? i have owned cars,trucks,boats. bikes you simply pull the battery at the end of season, charge it and put it under the bench till next season. no tender needed.

2 a,does any body know what the actual amp draw is while sitting?
2b, again WHY? this is supposed to be a quality vehicle, even lada's didn't come with or require battery tenders.

3 if i put a new battery in my boxster and drive it every weekend will i need a battery maintainer?

thanks in advance.

You can get by with just driving the car on the weekend and not need any battery tender. I've done that, and have also just left it sit for weeks at a time without use or battery tender, and it started up fine. My experience with that, however, is that the battery tends to only last normal time frames (eg. 4 yrs), which is ok, but since using the battery maintainer (I have the old Porsche branded one), my last battery lasted 7 years (and was still good when I replaced it just for peace of mind). One thing I did do was turn off that red LED blink that is usually set to on in the factory CDR 220 radio, however, as I see no need for it. You can turn that off in the settings on the radio, so it doesn't blink when the car is off.

There is no single value or answer. Like most things in life, it depends! It depends on the condition of the battery, the level of charge in the battery, and the residual or parasitic draw on the battery while the car is parked.

I'm not trying to be evasive, so please keep reading and I'll explain how to figure this out...

This approach should work as you describe as the key element is removing the battery from the car to eliminate the parasitic draw. A fully charged battery in good condition will still lose some charge over time but it should be very small and the battery should still have enough charge to start the car at the beginning of next season.

But many owners don't want to deal with what they perceive as the hassle of removal/installation of the battery and messing around with re-setting the clock, re-authorizing the radio, etc. Thus, the battery tender comes into play with its "plug and play" minimal hassle approach.

There are various estimates of the parasitic draw on the internet. However, the actual value can vary significantly from car to car depending on the year and the options.

Thus, the best way to find this value is to measure it. Its fairly easy and quick to measure and I describe how I did so in the link. This link also describes how to calculate how long the battery can sit (without a tender) and still be able to start the car: http://986forum.com/forums/507715-post642.html

I did this because my Boxster is a race car which can sit for up to 60 days in between races and I needed to know if I needed a battery tender or if I could just let it sit and still have confidence that it would start.

Not sure what to say here. I've tried to address your questions as best I can.

No. A battery in good condition should have more then enough capacity to maintain charge between weekends (and probably for much longer).

The quick answer is to use a Ctek MUS 4.3 with the full accessory kit.That is what Porsche (& many other OEMs) do.You can plug it in to the cigarette lighter socket.It will not overcharge the battery (& destroy it like the cheapie trickle chargers do) and it will reduce/remove sulphation -unlike most cheap ones.
https://www.amazon.com/CTEK-56-864-Automatic-Battery-Charger/dp/B006G14FK8

The battery is perhaps the most important electrical component on the car, and due to its design and nature, is perhaps one of the most troublesome. As mentioned above, it depends on a few variables. Battery tenders are good for those that have vehicles that sit for long extended periods of time. If you're taking it on a drive a few times a week, you should be fine. If it is going to sit, the battery tenders can help prolong the battery life. I have a vehicle that is currently sitting for a few weeks at a time. I don't have any issues starting it right up, but recently purchased a maintainer for ease of mind.

We do have some info in our tech article and in the comments below the figures (read paragraph above figure 1): Porsche Boxster Battery Disconnect Switch / Battery Buddy Installation - 986 / 987 (1997-08) - Pelican Parts Technical Article

The tender I use is this one: Porsche Boxster (1997-2004) - Miscellaneous - Page 10

Speaking of batteries, please stay away from Walmarts Everstart Maxx H6 which is the correct one for our Boxsters. I have had nothing but bad experience with these. Last Aug my battery died on a drive. Got one from Walmart and by years end did not take a charge. Not one cell would charge. Yesterday, I got a replacement and when I hooked up to a slow charger one out of six cells would not charge. The only good side to these batteries is that they are warranted for 5 years with a free replacement for first 3 years. I will probably drive it for awhile till it downgrades then take it in for another replacement. At every exchange the new 3 year replacement clock resets so I guess I'll never have to buy a new one again! Yeah right! At some point it will be discontinued cause of its reputation. Am I the only one going through this?

My Ctek is 9 years old. Its worked well.

My parents went through that with their cars down in Florida.

I guess the good news, like you said, is that Walmart will replace it for the first three years...

How it works: You bring the battery to their customer service counter with your receipt, they take the battery from you without testing it, refund your original purchase price, and you then go over to the automotive department and buy a new one. The new one comes with a new warranty, effectively resetting your warranty.

It got so bad, that after the 3rd battery (in two different vehicles) my father just began swapping them out every 2 years for new ones, whether they were bad or not. You do need to hang on to your receipt, and you'll have to pay any difference if the price has gone up since you bought the last one.

Not sure what is in my Boxster - it was a brand new battery that the dealer (non-Porsche, a Maserati dealer) put in when I bought the car. It's held up well (3 years) - I use the Porsche (branded CTEK) battery charger/conditioner to keep it topped off over the winter if I won't be driving it for over a month.

- Pulling the battery is fine but a PITA; tender will keep it in top condition
- Max amp draw for cars (so I've heard) should be less than 30 milliamps; some cars are notorious for high amp draw when parked
- you don't need a charger if you drive it every weekend. I only use the charger (sometimes) during winter heated storage (4-6 mos)
- I use a negative terminal disconnect on some vehicles

With credit to the original poster:

disraeli posted this on Porsche Pete's Boxster Board (*)

"The factory technical manual (Section 97-07 page 2) has the following table of total electrical load after the car has been shut off (ModelYear 02):

(electrical current is worst case, i.e. car loaded w/all options...)

FROM TO mA

0 min 5 min up to approx. 950

6 min 15 min up to approx. 900

16 min 20 min up to approx. 750

21 min 60 min up to approx. 50

61 min until the battery is empty up to approx. 30

1000mA equals, of course, one amp.

If the car had no options whatsoever, the load after 60 min would be 17mA instead of 30mA.

thanks for the info .