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Discussion Starter #1
Is using a solar battery tender/charger (what is it really called) a viable long term option for a car that suffers from parasitic drains? If so:

1. It's there any long term damage to the battery, or would getting a unit with "overcharge protection" take care of any dangers?

2. I assume getting a 12 volt?

3. What wattage? I see 5W, 15W, 30W etc....

4. Do you still need a voltage regulator if using a unit that's 15W or less? Or should I just get one with the VR built in?

5. Is getting the one that plugs into your cigarette lighter ok? I heard for some cars that can cause problems

6. If the above is ok, I have a splitter in my cigarette lighter... I'm assuming this should not be used with a splitter, so I need to remove the splitter and plug it in every day I exit the car?

7. Will this void the battery warranty?

8. Are certain brands better than others, or have you used one that works well that you can post the model #

Thanks!

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Discussion Starter #3
Why not just find and fix the parasitic drain?
Sure, solar battery tenders work well. jfoj touted them years ago, but solve the problem instead of bandaiding it.
Well right now I don't know if there is one... The old one I took care of it by unplugging that fuse, it's only for interior/glove box lights and trunk release, all of which I can do without spending more time and hundreds fixing it. With this new issue, I just don't feel like going through that whole process again, not that most fun thing to do, and that's why I ask if there's no long term damage, I rather use the solar charger that will take care of several issues all at once, since it seemed most of you were saying I simply have to drive the car more but that's not really something I can just schedule in every day when a simple charger would take care of that as well.

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Why don't you at least do a parasitic draw test? That may at least tell you if you have a rogue current draw, and if so then how much it is.

Even if you don't fix it (and assuming it doesn't get worse or cause a fire) ... at least you would have a amp number to work with in terms of figuring out how big a solar tender you would need to keep up ... How else could one determine how much solar output you need to balance the power consumption?

Parasitic draw tests are not difficult or even that time consuming and you also might find that you can fix it by pulling another fuse or that it's something potentially serious like the final stage resistor that should be dealt with.
 

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Discussion Starter #5
Why don't you at least do a parasitic draw test? That may at least tell you if you have a rogue current draw, and if so then how much it is.

Even if you don't fix it (and assuming it doesn't get worse or cause a fire) ... at least you would have a amp number to work with in terms of figuring out how big a solar tender you would need to keep up ... How else could one determine how much solar output you need to balance the power consumption?

Parasitic draw tests are not difficult or even that time consuming and you also might find that you can fix it by pulling another fuse or that it's something potentially serious like the final stage resistor that should be dealt with.
I was actually thinking that and yea the test isn't hard, just annoying AF because the last multimeter I had, the wire was only like a yard long, meaning for every fuse pulled, I had to go and check, and then go back, etc., and I'm not that flexible anymore so that fuse box location is horrible to deal with for 70 reps.

But I might have to bite the bullet and set aside a couple of hours and maybe find a meter with a longer cord so at least I can park myself somehow at the fuse box. Because ya I was thinking of doing it to figure out how much draw is happening as you said, to get the correct charger.

Thanks for that

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Discussion Starter #6
Why not just find and fix the parasitic drain?
Sure, solar battery tenders work well. jfoj touted them years ago, but solve the problem instead of bandaiding it.
And I want to say, I appreciate your input a always and I don't mean to disagree with you, you have valid points always... It's just a lot of different things going on and I'm ashamed to say that yes, in this case I'm hoping a bandaid would work (normally NOT how I like to do and teach things to others)... But I might have to do it the right way anyways.

Thanks again.

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What about a normal parasitic draw test with dmm in series with battery to see the total current draw once car is asleep. Then instead of pulling fuses to ID the bad circuit, you can test for voltage drop across each fuse and use a chart to extrapolate what the current draw is on that circuit and avoid the back and forth.

 

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Discussion Starter #8
What about a normal parasitic draw test with dmm in series with battery to see the total current draw once car is asleep. Then instead of pulling fuses to ID the bad circuit, you can test for voltage drop across each fuse and use a chart to extrapolate what the current draw is on that circuit and avoid the back and forth.

Hmmm I didn't know about that, I'll try it but not sure how much my body can handle that at once, might have to just do like ten at a time before resting... Thanks again

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I'd agree with the need to find out why your battery is going dead. However I'll take a stab at trying to answer your question.

We have a great customer with a 99 528iT A. She's got a bazillion miles on it and often goes away for business for a week or two. Upon her return sometimes the car is fine, other times the battery is completely flat-nothing. We have tried every draw test, voltage checking, even testing here in my shop (car locked, meter on and left for 4 days.) we CAN'T replicate the condition when the mystery draw happens to even begin to diagnose. Not wanting to just toss parts at the car but have with some of the common ones of aux. fan, ignition switch, hood (alarm) switch, final stage resistor etc.
None have solved the issue and leaves me extremely frustrated to say the least.
We both have acquiesced and we bought her a solar charger. After a year and a half it seems to be minding the battery. I just I could find the root cause!!

 

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2003 330cic, 2003 325iT
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Why not just find and fix the parasitic drain?
Sure, solar battery tenders work well. jfoj touted them years ago, but solve the problem instead of bandaiding it.
Solar tenders have one fantastic purpose - keeping your battery topped up when your car is not a DD. If you are driving regularly, you should not need one, and you should heed BaliDawg's advice.
 

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Discussion Starter #11
I'd agree with the need to find out why your battery is going dead. However I'll take a stab at trying to answer your question.

We have a great customer with a 99 528iT A. She's got a bazillion miles on it and often goes away for business for a week or two. Upon her return sometimes the car is fine, other times the battery is completely flat-nothing. We have tried every draw test, voltage checking, even testing here in my shop (car locked, meter on and left for 4 days.) we CAN'T replicate the condition when the mystery draw happens to even begin to diagnose. Not wanting to just toss parts at the car but have with some of the common ones of aux. fan, ignition switch, hood (alarm) switch, final stage resistor etc.
None have solved the issue and leaves me extremely frustrated to say the least.
We both have acquiesced and we bought her a solar charger. After a year and a half it seems to be minding the battery. I just I could find the root cause!!

Thanks

Does a ODB scan tool not help at all with battery/current issues? I'm thinking there has to be a model that detects such things easily, no?

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Discussion Starter #12
Solar tenders have one fantastic purpose - keeping your battery topped up when your car is not a DD. If you are driving regularly, you should not need one, and you should heed BaliDawg's advice.
Dd?

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Thanks

Does a ODB scan tool not help at all with battery/current issues? I'm thinking there has to be a model that detects such things easily, no?

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No it doesn't. Only the later cars with "Closed Current Monitoring" can see issues with current draw flagged as a fault and "Forced Shut Down" as a result.

Too much to go through and explain on e46 that doesn't have such.
 

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No it doesn't. Only the later cars with "Closed Current Monitoring" can see issues with current draw flagged as a fault and "Forced Shut Down" as a result.

Too much to go through and explain on e46 that doesn't have such.
DANG... That would have been really nice... Been looking to get a better OCD tool so was hoping to kill two birds...

Looks like it's time to get on my knees again....

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DANG... That would have been really nice... Been looking to get a better OCD tool so was hoping to kill two birds...

Looks like it's time to get on my knees again....

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I want an OCD tool to match my mental disorder!
 

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Discussion Starter #18
I want an OCD tool to match my mental disorder!
I'm actually right about here, I have one I me Amazon cart.... $170

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You can make the test leads as long as you want- just use more wire!

I like the 'current' method, too. Alternators and other unfused components
can do it. I dislike very much having to wait for the last 'step' where the body
electronics finally shut down.

We've been logging current usage at work, and I'd be tempted to fabricate
a homebrew logger if I had a truly intermittent draw...

t
IS an OCD tool...
 
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