928 battery charger/maintainer
08-28-2012, 07:07 PM
#16
Nordschleife Master
I recently upgraded my Ctek 3600 to a new Ctek MXS7 to gain the additional "recondition mode" and "power supply mode" where it puts out 13.8V and can be used to power things (like front seat motors when they're on the bench
Amusingly, two days after I got it one of the neighbours knocked on my door as she'd left her lights on overnight and had a flat battery.
08-28-2012, 07:46 PM
#18
Rennlist Member
I have a maintainer like the Schumacher above, but I connect to a socket under the rear license plate. Thats connected direct to the battery poles via a 10A fuse - this allows you to disconnect the ground lead to work on stuff, but keep the battery topped up. The plug is a 'positive' + connection type (rather than a rubbing contact), as might be used in 4x4 trucks. Dont have to open anything. Rear is easiest for me as the nose is right up to the end wall of the garage. And its obvious that the lead needs disconnection when you go to use the car.
So far the current battery is 5+ years old, and the previous was older when it died.
Not sure why Dr Bob says cycling is bad for the battery - I was always told cycling was good, or at least better than no use at all. Maybe its not draining enough?
jp 83 Euro S AT 54k
So far the current battery is 5+ years old, and the previous was older when it died.
Not sure why Dr Bob says cycling is bad for the battery - I was always told cycling was good, or at least better than no use at all. Maybe its not draining enough?
jp 83 Euro S AT 54k
08-29-2012, 12:27 AM
#20
Rennlist Member
I think as a charger OK, but too big and maybe too dumb as a maintainer. My maintainer is 1.6A, and smart enough to stop when the battery is full. Dumb chargers can ultimately fry the battery.
jp 83 Euro S AT 54k
jp 83 Euro S AT 54k
08-29-2012, 02:41 AM
#21
Chronic Tool Dropper
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they are typically constant voltage supplies, and the battery 'resting' voltage is about 12.4V. Ultimately that charger will boil the water out of your battery.
The standard maintainer charges until terminal voltage is around 14V, stops until it drops below about 13V, repeats. Fancier variations provide higher initial charging current, calculate drain and load based on charge/discharge times, and provide just enough current to 'float' the battery for a while. Then cycle again. More fancier units charge with a square wave "pulse" charge when adding current, to deal with sulphation issues on flooded cell batteries.
The Schumacher maintainer is typically available at high-tech places like Wal-Mart. The much fancier Ctek units come directly from Ctek or from Amazon. There are other hi-tech chargers with the Bosch name on them too. I havemnt decided yet whether it makes sense to use a $100 maintainer on a $70 battery.
The standard maintainer charges until terminal voltage is around 14V, stops until it drops below about 13V, repeats. Fancier variations provide higher initial charging current, calculate drain and load based on charge/discharge times, and provide just enough current to 'float' the battery for a while. Then cycle again. More fancier units charge with a square wave "pulse" charge when adding current, to deal with sulphation issues on flooded cell batteries.
The Schumacher maintainer is typically available at high-tech places like Wal-Mart. The much fancier Ctek units come directly from Ctek or from Amazon. There are other hi-tech chargers with the Bosch name on them too. I havemnt decided yet whether it makes sense to use a $100 maintainer on a $70 battery.
08-29-2012, 03:53 AM
#22
Nordschleife Master
08-29-2012, 01:32 PM
#24
Chronic Tool Dropper
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My Duralasts seem to puke regularly at a point in warranty life where the used-life cost is about $70. Face it, we just "rent" batteries anyway once we get into the warranty-life cycle. I can pay more up front and less later, thanks to a "longer" warranty, or less now and more later. Either way, the "rental" rate seems to be about the same.
Wal-Mart sells a Group 48 for under $100 last I looked. It is identical case design and weighs the same as the $130-new Duralast I have in there now. My local Costco will order a group 48 for me for a similar low price to the Wal-Mart offering, but that means I have to 'order' a replacement in advance of failure.
Disconnecting the battery while I'm away seems to extend the life of the battery. I -may- plug the maintainer in to the battery overnight when I return and before I start the car. Last but not least, replacing the tired ground strap at the battery lets it charge more completely from the alternator. That's made a big difference in apparent battery performance.
Wal-Mart sells a Group 48 for under $100 last I looked. It is identical case design and weighs the same as the $130-new Duralast I have in there now. My local Costco will order a group 48 for me for a similar low price to the Wal-Mart offering, but that means I have to 'order' a replacement in advance of failure.
Disconnecting the battery while I'm away seems to extend the life of the battery. I -may- plug the maintainer in to the battery overnight when I return and before I start the car. Last but not least, replacing the tired ground strap at the battery lets it charge more completely from the alternator. That's made a big difference in apparent battery performance.
08-29-2012, 02:29 PM
#25
Rennlist Member
You can hold the battery at 13.8 indefinitely without causing harm. Anything over 13.8 will boil electrolyte and harm the battery.
The last battery I bought was about $125.00 US.
I do not use a tender.
I have never check parasitic drain on either of my cars but must not have a problem as they can sit for MONTHS and still start.
The last battery I bought was about $125.00 US.
I do not use a tender.
I have never check parasitic drain on either of my cars but must not have a problem as they can sit for MONTHS and still start.
08-29-2012, 02:31 PM
#26
Burning Brakes
Hi,
I'm very happy with my Ctek MXS 5.0, it's really connect it and forget it!
It comes with the crocodile clips for a fast connection and also another cable for a more "permanent" connection.
Besides being a charger they say it's also a battery conditioner.
Regards
I'm very happy with my Ctek MXS 5.0, it's really connect it and forget it!
It comes with the crocodile clips for a fast connection and also another cable for a more "permanent" connection.
Besides being a charger they say it's also a battery conditioner.
Regards
08-29-2012, 02:40 PM
#27
Rennlist Member
Hmmmm. I can let my car sit for about 2 weeks then it is dead. I have the Schumacher tender on the battery and I am going on over 4 years on the battery and it works great still. I have killed it a couple times leaving the lights on or something but it keeps on keeping on. I think I have a Bosch battery.
08-29-2012, 07:32 PM
#28
Rennlist Member
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"I have never check parasitic drain on either of my cars but must not have a problem as they can sit for MONTHS and still start. "
Extremely rare 928s...
Extremely rare 928s...
08-29-2012, 08:41 PM
#29
Burning Brakes
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Hey!
I just bought my first Porsche, an '88 928S4 a few weeks ago. I've loving it! i am also learning very valuable German lessons nearly every time i touch it. recently i discovered (As i travel for work) that it misses me when i am gone for 2 weeks and wont start when i come home. The batt was fully flat. i have a high current battery conditioner and maintainer which brought the battery back to life, and to charge it i followed the 928 owner's manual's suggestion and removed the battery completely.
which leads me to my question: i want to use a very small battery maintainer (not my jumbo one, but a 1.5 or 2A model) and wire in leads etc. This may seem obvious but i want to know explicitly: is it ok/recommended/correct to attach the maintainer to the boost points under the hood? i read the whole battery charging FAQ and there's lots of opinion on frying the electronics/losing the injection memory etc etc and lots of recommendations to take the battery out to charge it etc as well as contrary opinions, but no where does anyone just say "yes hook up the battery maintainer to the boost points under the hood, that will be ok."
so, ya. long post for a simple question. can i put a trickle charger on this thing without having to pull the battery every time i am leaving for a few weeks?
I just bought my first Porsche, an '88 928S4 a few weeks ago. I've loving it! i am also learning very valuable German lessons nearly every time i touch it. recently i discovered (As i travel for work) that it misses me when i am gone for 2 weeks and wont start when i come home. The batt was fully flat. i have a high current battery conditioner and maintainer which brought the battery back to life, and to charge it i followed the 928 owner's manual's suggestion and removed the battery completely.
which leads me to my question: i want to use a very small battery maintainer (not my jumbo one, but a 1.5 or 2A model) and wire in leads etc. This may seem obvious but i want to know explicitly: is it ok/recommended/correct to attach the maintainer to the boost points under the hood? i read the whole battery charging FAQ and there's lots of opinion on frying the electronics/losing the injection memory etc etc and lots of recommendations to take the battery out to charge it etc as well as contrary opinions, but no where does anyone just say "yes hook up the battery maintainer to the boost points under the hood, that will be ok."
so, ya. long post for a simple question. can i put a trickle charger on this thing without having to pull the battery every time i am leaving for a few weeks?
I know I tried it and would have to leave the key in the on position for it to work.Who wants to store their car with keys in it and in the on position with other accesories on?
So went and bought a unit at a place like Auto Zone to mount seperate for a plug that goes direct to the battery.
This way its not going thru the whole wiring system either.
Took the ground strap off located under the tool kit.When in use just undue the tool kit and plug the trickle charger in.Stored for long periods of time it keeps the battery up which will help with battery life.
Its a quick install and nice to hide when not in use.
Mounted it in behind tool kit on angle allows to put the tool kit in place when not in use.Hot wire goes to positive side of battery used with inline fuse.
The body of the unit mounts right with the ground strap which provides a very good ground.
Last edited by inactiveuser1; 10-06-2013 at 10:23 PM.
08-29-2012, 08:53 PM
#30
Rennlist Member
Have never had a battery fail in warranty period....latest one was a local Century 660CCA for A$161 for Suby, 3 yr warranty. Bought a genuine German Varta in Saudi when i got the car, died in 3 months, no warranty. Saudi joint venture battery (with a 12m warranty) lasted 6 years. 928 has a chinese battery, now 6 yrs old, but its on a maintainer most of the time.
jp 83 Euro S AT 54k
jp 83 Euro S AT 54k