Using Solar Charger for Battery Maintain/Parasitic Drain

[Dathaeus]

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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[DeathTrap]

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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It's viable, but it's not the right option. Parasitic drains are typically low current. I used 2 Siemens solar panels wired in parallel back when I was experimenting with this idea. I think it was a total of 10 watts.

1. Lead acid batteries are rugged, I don't believe you would need any overcharge protection as the panels would naturally lower the current as the battery voltage increases. Keep an eye on the battery voltage and you can gauge where it starts to equalize.

2. You would need higher than 12v. I believe the open circuit voltage on my panels are 22 volts. As soon as a load is put on them, that voltage falls drastically. Also ANY amount of shading will cause the voltage to drop. I'll get some numbers for you as I still have the panels and a spare battery.

3. Depends on the severity of your parasitic draw. I would try to measure that first.

4. See answer 1.

5. The E46 cigarette lighter is only connected to the battery when the key is in ACC or IGN (can't remember the German equivalent name lol) so that wouldn't work. You'd have to connect it to an always hot circuit.

6. See 5.

7. As long as you don't overcharge it, it won't.

8. I personally go with name brands, as I trust them more than the generic panels.

Hope this helps!

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[Dathaeus]

It's viable, but it's not the right option. Parasitic drains are typically low current. I used 2 Siemens solar panels wired in parallel back when I was experimenting with this idea. I think it was a total of 10 watts.

1. Lead acid batteries are rugged, I don't believe you would need any overcharge protection as the panels would naturally lower the current as the battery voltage increases. Keep an eye on the battery voltage and you can gauge where it starts to equalize.

2. You would need higher than 12v. I believe the open circuit voltage on my panels are 22 volts. As soon as a load is put on them, that voltage falls drastically. Also ANY amount of shading will cause the voltage to drop. I'll get some numbers for you as I still have the panels and a spare battery.

3. Depends on the severity of your parasitic draw. I would try to measure that first.

4. See answer 1.

5. The E46 cigarette lighter is only connected to the battery when the key is in ACC or IGN (can't remember the German equivalent name lol) so that wouldn't work. You'd have to connect it to an always hot circuit.

6. See 5.

7. As long as you don't overcharge it, it won't.

8. I personally go with name brands, as I trust them more than the generic panels.

Hope this helps!

Sent from my Pixel 2 XL using TapatalkThat's awesome man, thanks so much.... Direct connecting to my battery might be too much work ugh!

And this whole issue is needed because I don't drive a lot so it'll be pointless to use the cigarette lighter port.

Back to square 1 [emoji31][emoji37][emoji34]

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[t.er]

How bad is your drain, are you concerned more for long-term storage, or if your don't drive your car for a few days? When I store my car every winter I disconnect the battery so there isn't any drain at all. There's basically no voltage drop in the 6 months it sits. This method is good for long-term but if we're speaking in terms of a few days, that could get pretty draining (.....haha)

[bandwagn]

I wired in a 15w Solar Battery Tender in my X6 (notorious for eating batteries) and it works pretty well. Have it wired directly to the batery with the quick detach connector, so I can plug it in to AC as well. Also, it’s a name brand (Deltran), so I trust it a bit more than some no-name gadget.

They make a few different sizes - it was easy to attach the large one to the parcel shelf in the SAV, but may be a bit different in the ZHP.

https://www.xbimmers.com/forums/attachment.php?attachmentid=1608412&stc=1&d=1492469206

https://www.batterytender.com/solar-panels

[sillieidiot]

5. The E46 cigarette lighter is only connected to the battery when the key is in ACC or IGN (can't remember the German equivalent name lol) so that wouldn't work. You'd have to connect it to an always hot circuit.


The E46 cigarette lighter isn't switched. It's always on. So he should be able to use the cig lighter. Although, I would still prefer to connect it directly to the battery.

[das boots]

The E46 cigarette lighter isn't switched. It's always on. So he should be able to use the cig lighter. Although, I would still prefer to connect it directly to the battery.

FYI. My E30 M3 is being on constant trickle charge by using the cigarette lighter. It works that way.

[Dathaeus]

How bad is your drain, are you concerned more for long-term storage, or if your don't drive your car for a few days? When I store my car every winter I disconnect the battery so there isn't any drain at all. There's basically no voltage drop in the 6 months it sits. This method is good for long-term but if we're speaking in terms of a few days, that could get pretty draining (.....haha)Ya the issue is my primary job is about 1000 yards away....who woulda thought setting up life convenience would screw up my car life???

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[sillieidiot]

Ya the issue is my primary job is about 1000 yards away....who woulda thought setting up life convenience would screw up my car life???

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iono, I used to WFH before the whole pandemic thing and I would just go drive and push my car around just for the hell of it. Then get a weeks worth of groceries otw back. Then it sat there until next week and I did the whole routine again lol Didn't need a tender. Mine only dies though if I let it sit for about 2.5 weeks.

But yeah, a solar charger connected to the cig lighter should work fine. Unless this parasitic drain you have draws more than the charger can provide lol

[Dathaeus]

iono, I used to WFH before the whole pandemic thing and I would just go drive and push my car around just for the hell of it. Then get a weeks worth of groceries otw back. Then it sat there until next week and I did the whole routine again lol Didn't need a tender. Mine only dies though if I let it sit for about 2.5 weeks.

But yeah, a solar charger connected to the cig lighter should work fine. Unless this parasitic drain you have draws more than the charger can provide lolYa true that but I found out the e46 you need to him it up directly to the battery... So to be that's fubar... I'll need to find time to get my hands real dirty now...

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[sillieidiot]

Ya true that but I found out the e46 you need to him it up directly to the battery... So to be that's fubar... I'll need to find time to get my hands real dirty now...

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I responded to that in the other thread.