Tony

curious...i leave my car parked at the airport for 4 days at a time...any input on these solar battery maintainers. Or do they rank up with bulb grease, muffler bearings and blinker fluid.

oh..and my last Duralast 48 lasted exactly 2 years to the day i bought it...got a freebe from auto zone last week. I didnt tell them that it has seen pure hell over the last few months dealign with my hot start issues. It failed the test on their machine and i walked out with a new one...

danglerb

This little solar panel is $10 when its on sale at HF.
http://www.harborfreight.com/cpi/cta...emnumber=44768

About the size overall of a keyboard, rated at 1.5 watt, which at about 13v would mean 0.1 amp, and that for "maybe" the 6 hours a day when the sun is closest to overhead and clouds aren't in the way. In theory as long as your parasitic loss was less than 25ma, it just might work. OTOH if your loss is that small you likely don't have any problems anyway.

VehiGAZ

Nice thread, guys! And good charging ideas!

Solar chargers with a maintainer circuit ARE effective - I have a 5W (peak) panel with maintainer circuit on our sailboat, and it was able to charge the batteries from almost-fully discharged (too weak to turn the starter) to mostly fully-charged (starter turns and starts the engine) in a week. They say they are not designed to recharge a fully-discharged battery, but they can come close apparently.

Now, for long-term battery charging, I know it is very important to have a maintainer circuit to cycle charging on and off. But for short-term applications (like Tony's 4 days at the airport) would the solar panel without a maintainer circuit pose any threats to the battery life?

I have another 5W panel (without a maintainer) that I was going to use when the shark goes into winter hibernation, but without the maintainer, I am hesitant to try for fear of starting a fire from over-charging the battery. Is this concern valid or am I being overly cautious?

dr bob

As cool and green as solar chargers seem to be, I still believe in pulling the batteries from stored vehicles and maintaining them separately. For one, it 'forces' me to do all the cleaning, inspection, terminal and wiring maintenance. After that, the batteries go in a rack in the garage where they can be at least visually monitored. For folks who live in a really cold climate where battery freezing is a possibilty, putting a battery in a warmer place seems to make the charging much more effective. Lots of boat owners are using solar these days, but the systems are a little more sophisticated than the H-F panel attached to the battery with a diode. Serious solar chargers for boats are 'smart', similar to the better car battery maintainers. They exercise the battery some with cyclical charging routines, dramatically extending their life.

Good News for me though is that the only battteries I've needed to maintain longer-term are boat batteries. Our non-boating season is about four months from Thanksgiving to early April, when the afternoon temps just barely make it to the sixties. I no longer have boats since K gets seasick (even on cruise ships...) but do enjoy crewing for friends these days when I have the time. So no more bottom cleaning duty.

borland

I just replaced my 5 year old Duralast 48-DL with a new Duralast Gold H6-DLG. This is on my 1990 S4. The new battery sure looks like the Porsche battery shown on 928 Specialist's web site... It's got the same fold in handles and cell screw caps.



The new battery weighs 42 lbs, compared to the old at 37 lbs. Seems to have more cranking power too.

auzivision

Just checked out the prices on Autozone for the Duralast Batteries. The Golds are $165 with 3 year full replacement and the rest prorated. The standards are $105 with two years free replacement.

I know I've been out of the battery market for a while, but it sure seems like the prices have spiked. Four years ago the top of the line diehard where only $100 and change with free 3 year replacement and 100 months prorated. I guess I'll see how much they take off for my dead battery.

So is there any consensus out there as to best value replacement. Go cheap and replace more often and go big and hope for the best. Duralast vs. Diehard vs. Interstate vs ????

Ironically, the cheaper Duralast has more CCA. Also, both state “Battery is vented to outside of vehicle”. How does that work when they are in the hatch?

Mrmerlin

for the battery vent they usually come with a vent tube attached to the side of the battery in a plastic bag.
This is connected to the battery vent and then routed forward in the battery box to the holes in the box push the tube through one of the holes

auzivision

Looks like I'm sticking with Sears. $80.40 out the door with prorated warranty. For 4.5 years, that's a little under the $20/year average.

It worked flawlessly until recently. I left the park lights on one day. Had to jump started the car, let it run and drove it for a while… worked fine that night.

Recharged using a automatic battery charger over night everything was good in the AM. A few weeks later put on the trickle charger overnight, everything green. Then two weeks later dead as a door nail and won't hold a charge.

I did notice one of the caps was slightly crooked... I wonder if that's a clue. Maybe it needs some water?

dr bob

The at-least-annual maintenance includes checking fluid level and adding distilled water when needed. An experience-driven rule of thumb is that every time a battery is drained below 10 volts, a percentage of the remaining life is sacrificed. When a battery is dropped to almost dead by leaving lights on, it takes a bigger bite. Plus, it takes longer to charge and offgasses a lot more in a short time. So it's important to check the fluid levels in the cells before serious recharging, and again after that charging. Letting fluid levels drop too low changes the concentration of the battery fluid and increases the risk of sulfation in the bottom of the battery. Charging the battery at a high rate also increases heating and outgassing, and therefore the risk of losing water from the battery fluid mix.

There are simple testers for specific gravity of the battery fluid. They range from little floating colored ***** in a glorified eyedropper, to a calibrated float in a glass turkey-baster. Results are the same though-- you get to see the battery capacity in a heartbeat. It's a great way to discover a near-failing battery before it strands you.

karl ruiter

I have been reading up on this a bit, and it seems our batteries probably fail because of sulfation. Lead sulfate crystials (which are non conductive) build up on the electrodes. Apparently there is a way to slow and/or reverse this process called (strangly enough) desulfation or pulse conditioning. Desulfator modules are available from several vendors and many types are available on ebay.

Anybody have experience with this? I had a stock of non working batteries, and was thinking about getting one of these and a load tester to see if I could really bring some of them back, but I decided I did not have time to mess with it right now so I just got new batteries and dropped off the non working ones.

borland

Good comments Bob. The problem is, the battery is buried under the spare tire. Personally, I'd rather replace it early than try to keep it up.

The Gold Duralast I bought at Autozone was not provided with a vent tube. Where there the vent tube adapter is shown in the Porsche battery photo above, on the Gold Duralast there was a plastic plug installed. Since I never installed a vent tube on the prior Duralast batteries and experienced no corrosion, I installed the new one the same way (no vent tube). The battery box does have vent openings on one side for which a vent tube could be routed.

borland

Currently, you can buy a Desulfator for about $25 with shipping that handles our 72Ah battery. None of these units are guaranteed to last the normal life of the battery.

Batteries fail for other reasons besides sulfates building on the plates, so it may be more trouble than it's worth.

shadowknight

I have had some experience with the Durlast gold series. In the truck the first one lasted two years it was under warranty and was replaced with no issues. The replacement battery has been working for the past two years and still seems strong. The 928 has had two new batteries in the 3 years I have owned it a Duralast lasted two years and a Die Hard it remains to be seen how long that one will perform. I have heard that the heat down here in Florida is a real problem for batteries causing them to have short life spans. I don't know if thats true or not but I do know when I lived in more temperate climates my batteries ran up to 4 or 5 years with no problems.

nsantolick

I am about to throw in an Optima redtop. I bought a few last year and noticed at our local stores, there seem to be several choices with redtops, beyond the orientation and type of terminals. Some have significantly higher ratings than the others. Does anyone know what PARTICULAR Optima Redtop currently is the best choice for my 1989 S4?







Nick - Hazleton, Pa - 89S4 Auto

karl ruiter

My batteries fail because I don't use them enough. There are indeed other ways batteries can fail, which have to do with head and shock but, from what I understand, the type of failure I have is caused by sulfation. I just wonder if the desulfators work or if they are like the gadgets that are supposed to keep mosquitos away.