Increased Battery Discharge issue

Hi Thunder Dump, sorry just saw your message. What is Smart Top?

Hi Beha, yes last month I sent my car in for a check. They took a few hours to fully charge my battery. They claimed it was 53% charged when I drove in. I really appreciate your suggestion and trying to help thanks!

Hi Thunder! I just googled it, no. This car is not modified in any way

Originally Posted by ctuna

so about 3 of these would = one of those if the sun was shinning at a optimum value.

The sun only shines at optimum in SoCal Everywhere else you will need at least 5 panels, just kidding.

Here's the problem (these are best guesses), if the battery discharges around 50 mA while in sleep mode and is a 90 Ah battery, theoretically at 99% SOC to 50% SOC you can get ~5 wks before the battery is no longer happy . Additionally if for example it takes 180 amps to starting that would be ~.25Ah of capacity gone. So to stay charged you need to replace what you use for starting and sleeping based on the alternator can handle loads while driving at a net gain of ~1.25Ah based on 15 min at 5 amps charging of driving per day. Figure a couple starts and a constant drain ~50mA works out to be ~1.7ish Ah/day net loss. About 26 days of this driving cycle the battery will be pissed off. But the good news is you just need to replace about 2Ah/day. So two 12V, 5 watt panels gives ~800mA *.8 sun eff yields 640mA*3.125hrs = 2000mAh or 2Ah. So charging your battery to 90% SOC, use a total of 10 watts of solar, find 3 hrs/day of sunlight and your power budget should be slightly net positive. Or this can be all crap.

It sounds like this might be worth a shot in the southern latitudes of the US if you leave your car outside while at work.
The panel would have to put out more than 12.5 Volts to be effective . I wonder if it comes with a regulator?

http://www.amazon.com/BMW-Solar-Batt.../dp/B004QDAPOI

http://compare.ebay.com/like/2206313...=sbar&_lwgsi=y

The panel on this one looks like it would closer to the right size but its pricey.

Or buy a house.

Hi yikes98 & Ctuna, you both are talking about physics here. Let me go study what you said first. Thanks for the input


Ctuna: buying a house just for a car? Not sure about that

Btw I m heading out to "charge my batt" = burn some gas = burn some money, by hitting the highway. Wish me luck

After driving about 20miles on the highway this morning, hope the car battery is charged reasonably well. Will take a look at the last 2 posts. Thanks!

Btw saw another panel at amazon with 15watts, would that be better?

http://www.amazon.com/Sunforce-50033...2954641&sr=8-3

The thing is you probably want one with a regulator and a way to hook it up.
Looking at some of the ones in the amazon link and ebay it looks like some can be hooked
in via the OBD 2 port . That's a connector that normally is used for smogging and car
diagnostics its on the drivers side next to the kick panel right below the dash.
That is a standard diagnostic port for all cars so any one of those panels that's for cars and has that type of connector
would probably work. I would get one that is just for a car though if your not into
physics or somebody doesn't come up with another solution.
The BMW one is pretty expensive but its probably certified.

This one plugs into the OBD2 port but I would prefer more power from a bigger panel

http://www.ebay.com/itm/BMW-VW-Audi-...0777%26ps%3D54

Its pretty cheap though.
That ebay link has a bunch of them.
I assume you take your car to work and it spends a few hours in the sun during the week.

Originally Posted by terri_atl

Btw saw another panel at amazon with 15watts, would that be better?

http://www.amazon.com/Sunforce-50033...2954641&sr=8-3

Bigger is usually better but sometime its get awkward to put on the dash. Try this and have someone with some electronic knowledge to install it. Would recommend getting the extension cable to run the connections directly from the battery in the trunk. It's only 18 x 18 inches so it fits on the dash, can be stowed in the back and has a built in controller.

http://www.amazon.com/Battery-Tender.../dp/B004Q86JJ8

Hi ctuna: So you think the one in the ebay is good? Yes, physics gives me a headache. I tried to read the reviews on amazon of those solar panels. I would read them twice and still no idea what they were saying with those numbers. I intend to study them because I should really know more about this since I am the only one with this problem. OBD2 port? I don't think I have seen it but since like you said, it should be there. I will sure try to look for it tomorrow. It is winter and I don't even see that much sun here this week. Gloomy like in London. I am thinking during winter, I may just have to burn off some gas and get the battery charged every weekend. But of cos I will want to get the battery maintained during the day as much as possible. We get alot of sun during the spring, summer and early fall here in Atlanta.

Unfortunately my car stays in the deck or covered parking most of the time during the day. But if the sun is plentiful, I can get my car parked in front of the building with a pass, max 3 hours. Is that good enough? So should this solar panel will only be up when the car is parked?

Hi yikes98, the battery is not in my trunk. You did refer to the battery located at the back right? No, the battery for mine is in the front.

What you said is very true, it is indeed awkward to put a huge panel on the dash.

Let me go research more on the solar panels at amazon & ebay. Thanks for being so patient with me

You need one with an OBD 2 connector and regulator you do have to have some
time in the sun . I don't know if garage lights would do anything . You only have it
in place while charging you take it off when you drive the car.

you guys are assuming the OBDII is 'active' when the car is a sleep, and has contact with the battery to charge it. Most things, like the aux power ports are completely switched off. it wouldnt surprise me that the OBD is turned off? im just going off the top of my head here...

also, and i know people do otherwise... but it states, clearly, in the book that any charging or battery maintenance to the battery must be done by means of the under hood posts.
pg 237

Originally Posted by terri_atl

Hi yikes98, the battery is not in my trunk. You did refer to the battery located at the back right? No, the battery for mine is in the front.What you said is very true, it is indeed awkward to put a huge panel on the dash.

Terri,

Yes, your car's battery really is in the trunk (part of the BMW 50/50 weight distribution), but it is hidden under/behind the interior liner. What is in the front is just a set of hookups or jumperpoints. I have an '09 cabrio that doesn't get a lot of road time. It's a daily driver but it only takes me 15 or so minutes to get to and from work. However, we really do our best to take it out on the weekends and run it. In 18 months of ownership I've not had any battery issues. When we go out of town I lock the car to insure it has gone to sleep. If you live in a condo and don't have a private garage I cannot imagine why your car is behaving so badly unless it really never is driven for more than 5 minutes at a time. Pull out your owner's manual. It will show you the true location of your battery - not just the "jump points" under the hood.

Good luck but I think your car is just begging to be driven more-- much more.

They sell these things at BMW parts places so they must work some how.

http://bmwpartsunlimited.com/partloc...subcat1=165843

and the OBD 2 port is the most likely candidate.

Also think driving for hours to charge not distance.

Heck, you bought a BMW, get out there and have some fun! You could have bought a '92 Honda if you wanted to drive 5 minutes a day.

Originally Posted by B-737

but it states, clearly, in the book that any charging or battery maintenance to the battery must be done by means of the under hood posts.
pg 237

Agree but I don't see much of a difference attaching it at G6430 or i01121 or x1369. All of which I've used to hookup a battery charger at some point during module coding or just charging the battery. It's effectively all the same electrically.

You hooked up a battery charger during coding was it one that had a power supply
function ? Did you register the battery or install any stuff like the ipod interface or alarm that required you to process the car or mess with the VO?

Originally Posted by Nordic_Kat

Terri,

Yes, your car's battery really is in the trunk (part of the BMW 50/50 weight distribution), but it is hidden under/behind the interior liner. What is in the front is just a set of hookups or jumperpoints. I have an '09 cabrio that doesn't get a lot of road time. It's a daily driver but it only takes me 15 or so minutes to get to and from work. However, we really do our best to take it out on the weekends and run it. In 18 months of ownership I've not had any battery issues. When we go out of town I lock the car to insure it has gone to sleep. If you live in a condo and don't have a private garage I cannot imagine why your car is behaving so badly unless it really never is driven for more than 5 minutes at a time. Pull out your owner's manual. It will show you the true location of your battery - not just the "jump points" under the hood.

Good luck but I think your car is just begging to be driven more-- much more.

This has been my experience too. Given the recommended driving patterns suggested by BMW I am a battery abuser. My 2006 330xi saw a total of 3,000 miles over the 18 months I owned it. Half of which were a trip to North Dakota. Much of the time it sat in my garage, often not being started / driven for months at a time. And the times I did drive it were primarily short trips. I did replace the battery but I suspect that was due to it being an original battery who's time had come. Other than that I had no issues with the battery in this vehicle.

The same can be said of my 1999 328i which saw a lot of garage time too. In the eleven years I owned it I replaced the battery once...after about six years. Granted the 328i didn't have nearly the electronics of the E9x vehicles.

Then there's the X5...my 2001 received the bulk of my driving but much of it around town. I did replace the battery in it but again it could have been time for a new battery (it did have 108K miles when I bought it). This vehicle sat outside and experienced cold weather (-20 degrees one day) and kept on trucking.

It's still too early for me to comment about my new X5 and battery life. I've only had it sightly more than a month but it sees daily six mile commutes to the office.

In the end I don't do the type of driving BMW recommends to keep the battery well maintained and I haven't had the battery issues I've read about here. This is not to say there isn't a problem...more curious as to why I haven't experienced the problem.

Hi Nordic_Kat thank you for letting me know. I guess I really have zero knowledge about cars. When the technician opened the hood and pointed at that, I thought that was the battery. My bad!

My car is a daily driver too. I drive 5-10miles at a go. Weekends may be abit more but now I force myself to wander on the highways on a weekend like what I did yesterday. I do enjoy driving my car alot.

Yes, I live in a condominium when there should no issue with the key in very close proximity to the car.

Tuna and yikes, I figured as such, good points all around
That is a great schematic btw!

ctuna: got it!! I saw that link you posted, it didn't state any compatible models for 2011 models. Yes, it's on the more expensive side, but since I am not sure this will solve my problem and today is another gloomy day in Atlanta, I am not willing to purchase that for now. But I am open to buying one less than $100 to experiment on it. I need one that helps me maintain the battery.

The spot I park daily is always located by the side of the deck. So there's a little sunlight shining in. But if solar panel helps, I can get a pass to park it outside. I can't wait for spring to come!