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Discussion Starter #1
There have been a few threads here about how newer cars don't fully charge the battery while driving. During normal driving ours switches back and forth between charging and letting the battery power everything. Most of the time, after the journey (long or short) and the car is parked, the voltage is 12.2v or lower (i.e. 50-60% charged). We've had the Crosstrek over a year now and it has always had enough power to start but I don't think the normal resting voltage has ever been over 12.2v.

Besides being bad for the long term life of the battery, I've just discovered a new problem with this charging philosophy. How to power a dash cam in parking mode?

I just installed a new dash cam and the power monitor had a default minimum voltage of 12.5v, so it wouldn't work. The only other setting is 12.0v and that worked for a while but the voltage dropped to 11.9v overnight.

So, my question is, how can I modify the battery charging so that it always charges the battery while the car is being driven, without overcharging/overheating it?
 

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You can't. Keep your battery charged by driving regularly and on longer trips, or top it off with a charger from time to time. I have had to do that once already with my Crosstrek.

Not sure why you want to keep your dash cam running while you are parked (overnight?). But it shouldn't take that much power, I would think. And not sure why it has to cut out at 12.5V (90% charge, 12.7 is 100%)). Maybe you can change that on your camera. Or start looking for another camera.
 

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Discussion Starter #3
You can't. Keep your battery charged by driving regularly and on longer trips, or top it off with a charger from time to time. I have had to do that once already with my Crosstrek.

Not sure why you want to keep your dash cam running while you are parked (overnight?). But it shouldn't take that much power, I would think. And not sure why it has to cut out at 12.5V (90% charge, 12.7 is 100%)). Maybe you can change that on your camera. Or start looking for another camera.
>You can't.<

Why not? Maybe it would require too many hardware and software changes to be worthwhile but I don't accept, "You can't" as an answer. Until recently, my cars' alternators would power the electrical system and charge the battery all the time I was driving.

>Keep your battery charged by driving regularly and on longer trips, or top it off with a charger from time to time. I have had to do that once already with my Crosstrek.<

I don't want to have to top up the battery when it should be being charged while we're driving it, and it's not. I've ran tests, and posted the results here, that show that the battery is often not being charged while driving.

>Not sure why you want to keep your dash cam running while you are parked (overnight?).<

Are you serious? The point of a parking mode cam is to have some evidence (for insurance, the police, etc.) if something happens to your car while it's parked.

>But it shouldn't take that much power, I would think. And not sure why it has to cut out at 12.5V (90% charge, 12.7 is 100%)). Maybe you can change that on your camera. Or start looking for another camera.<

If you had read my post you would know that the default minimum voltage on the power saver, supplied with the camera, is 12.5v and I changed it to 12.0v. But that's not the point of this thread. I'm looking for useful suggestions how to get the Crosstrek to charge the battery while it's being driven...
 

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Well, it is your car, time and money... And just so you know car batteries not staying fully charged is a pretty old problem. My 2004 Avalanche was not driven frequently, and I had to charge it every 3 months or so in the winter. And it had a giant alternator and battery. Needed that for its 8.1L engine.

Good luck with your quest...
 

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Also, curious why do you need to provide evidence to the police or your insurance if you have a break-in?

And just how many times with all your past cars, have you had situations where a dash-cam capture vid would have saved you money?
 

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Discussion Starter #6
Also, curious why do you need to provide evidence to the police or your insurance if you have a break-in?

And just how many times with all your past cars, have you had situations where a dash-cam capture vid would have saved you money?
This is your second post, after you wrote, "Good luck with your quest..."

Why does it bother you so much when I challenge your opinions?

Lots of people I know like the idea that a dash cam can provide evidence. If someone damages our car while it's parked, maybe the dash cam will find out who it is and then their insurance company will have to pay for it, not ours (and they may get charged with a hit and run). Just a few days ago I was in a supermarket parking lot and a lady was upset because someone had scraped her car while she was shopping.

The extra money for a dash cam with a parking mode is peanuts compared to several years of insurance premiums.

Again, not sure why you're trying to tell me I'm wrong here, in a thread I started, asking how to keep the Crosstrek's battery charged fully...
 

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Just trying to save you some time and money...

Just thinking about your dash cam kicking out at 12.5 or 12V. On 2nd thought, that is actually a good feature to prevent you from running down a battery when parked.
 

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Discussion Starter #8
Just trying to save you some time and money...

Just thinking about your dash cam kicking out at 12.5 or 12V. On 2nd thought, that is actually a good feature to prevent you from running down a battery when parked.
Exactly, that's why I bought the power saver/monitor with it...
 

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Before the discussion gets too animated (and for once it's not about OIL!!), everyone is right to a certain extent! What we have here is really a failure to communicate!

R P is right that cars have never been able to FULLY charge a car battery, as I've explained in previous threads, due to cost, the time needed, and generally a reason to. With the eco-charging system, as AstroKats pointed out (and I believe I have a thread on that somewhere as well), the existing system leaves a lot of charging that isn't done (ie the battery stays in the 50 to 60% region for SOC) especially when compared to older cars without an eco-charging system.

So, is there a way to defeat the eco-charging system? And what would you know, I have a thread on that as well... it seems WRX owners experienced the issue first as the low voltage would shut down their Cobb devices during drives. One WRX owner found out that by removing ONE wire from the engine fuse box, you can defeat the eco-charging system and the battery would charge all of the time just like previous generations of cars! Another method is installing a specialized fuse which supposedly addresses the issue as well.

Will that FULLY charge a car battery? NO! However, it's a whole lot better than 50 to 60%!

Here's that thread - https://www.subaruxvforum.com/forum/lighting-electrical/152466-crosstreks-intelligent-charging-leading-poorly-charged-batteries.html. In that thread is a link to another forum's thread on the subject as well as a link to a Youtube video on it. As far as I know, no one has done either on a Crosstrek so it would be interesting to see what happens.
 

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Anytime a battery thread comes up, my solution is always ditch the factory battery. Subaru batteries are junk IMO. I usually have an argument with someone who does not think they are that bad and the thread ends. However, in this case even if you do not agree Subaru batteries are junk, I think the argument can be made for ditching the factory battery for a higher capacity battery.

My logic:
- Higher capacity battery will hold voltage longer... with the right battery it should be long enough to maintain your dash cam until the next time the vehicle is driven unless you take a long break from driving.
- Higher capacity battery will present need to be charged longer to the vehicle without you modifying the charging system at all.

Potential drawbacks:
- Price; Good batteries are not cheap.
- Additional alternator wear; Likely minimal and I think the solution you are looking for would do the same thing anyway.
- May still not fully solve your problem depending on your driving habits. Ultimately you are presenting a load to the vehicle that the car does not expect to be present. Leave it sitting long enough and the battery will drain.

Ultimate reason to do it... The Subaru OEM batteries are junk and there is a good chance it will need replacement way sooner than it should :smileyvault-stirthe. New battery gets that out of the way now and could solve your problem.
 

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Anytime a battery thread comes up, my solution is always ditch the factory battery. Subaru batteries are junk IMO. I usually have an argument with someone who does not think they are that bad and the thread ends. However, in this case even if you do not agree Subaru batteries are junk, I think the argument can be made for ditching the factory battery for a higher capacity battery.

My logic:
- Higher capacity battery will hold voltage longer... with the right battery it should be long enough to maintain your dash cam until the next time the vehicle is driven unless you take a long break from driving.
- Higher capacity battery will present need to be charged longer to the vehicle without you modifying the charging system at all.

Potential drawbacks:
- Price; Good batteries are not cheap.
- Additional alternator wear; Likely minimal and I think the solution you are looking for would do the same thing anyway.
- May still not fully solve your problem depending on your driving habits. Ultimately you are presenting a load to the vehicle that the car does not expect to be present. Leave it sitting long enough and the battery will drain.

Ultimate reason to do it... The Subaru OEM batteries are junk and there is a good chance it will need replacement way sooner than it should :smileyvault-stirthe. New battery gets that out of the way now and could solve your problem.
What battery do you recommend?
 

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What battery do you recommend?
Well, for my cars, and how I monitor and maintain a good charge, my batteries last a long time, 5+ years. So I just use a cheap but good brand, whatever my local battery shop recommends when I do have to buy one. But for my airplanes, this is the battery I use. Airplanes are not always flown frequently, and the firewall forward in an airplane is a very harsh environment, high vibration and high heat.
ODYSSEY Battery - Official Manufacturer's Site
These have many advantages incl withstanding deeper discharges without damage, hold their charge for a long time, high cranking amps in a small lighter weight package, etc, etc. They were originally designed for the military, so have very high spec standards. So if you really want the best, this is it.
 

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I typically buy Odyssey Extreme AGM batteries (35-PC1400T for first Gen Crosstrek). Not sure if the latest Crosstrek is using the same size battery or not; what I can find by part number appears to indicate it is a group 35 battery (meaning the one I mention should work). However, I am also not standing in front of a 2018 to check.

I will note that while I typically use Odyssey, I did not use one on my Crosstrek. I went with one from my local auto parts store when mine failed, because I wanted the battery that day. I only have one local (1 hr away) place that stocks Odyssey and they did not have the correct size in stock when I replaced.
 

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I installed an Optima battery in my truck 6 years ago & it is still good. Although I've noticed a little bit of weakness lately. This truck gets intermittent use. https://www.optimabatteries.com/en-us

I do think its important to intermittently use a battery charger on any vehicle not driven on longer trips.
 

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Discussion Starter #15
Before the discussion gets too animated (and for once it's not about OIL!!), everyone is right to a certain extent! What we have here is really a failure to communicate!

R P is right that cars have never been able to FULLY charge a car battery, as I've explained in previous threads, due to cost, the time needed, and generally a reason to. With the eco-charging system, as AstroKats pointed out (and I believe I have a thread on that somewhere as well), the existing system leaves a lot of charging that isn't done (ie the battery stays in the 50 to 60% region for SOC) especially when compared to older cars without an eco-charging system.

So, is there a way to defeat the eco-charging system? And what would you know, I have a thread on that as well... it seems WRX owners experienced the issue first as the low voltage would shut down their Cobb devices during drives. One WRX owner found out that by removing ONE wire from the engine fuse box, you can defeat the eco-charging system and the battery would charge all of the time just like previous generations of cars! Another method is installing a specialized fuse which supposedly addresses the issue as well.

Will that FULLY charge a car battery? NO! However, it's a whole lot better than 50 to 60%!

Here's that thread - https://www.subaruxvforum.com/forum/lighting-electrical/152466-crosstreks-intelligent-charging-leading-poorly-charged-batteries.html. In that thread is a link to another forum's thread on the subject as well as a link to a Youtube video on it. As far as I know, no one has done either on a Crosstrek so it would be interesting to see what happens.
Thanks rlouie, I had remembered that thread (I even posted in it, almost a year ago, LOL) but either forgot or never read the part about the charging mod. That's exactly what I was looking for and seems super easy and no cost.

I shouldn't have referred to "fully charged" - what I really meant was more fully charged than it is now. Since I got a USB cig port adaptor with a voltage readout I've noticed the voltage drop, sometimes quite significantly, for extended periods while driving around town. So if this mod really does mean that the alternator is always putting out over 14v then hopefully it will solve the problem with the parking mode for the dash cam, and may even extend the life of the battery, as I know it's not good to leave lead acid batteries at a low charge for long periods.

OAK has the car now so I can't check if the fusebox wire is exactly the same as in the video but I'll try it over the weekend and report back. If anyone has a service manual and can confirm, that would be great.
 

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Both Odessey and Optima sites list size 35 (35-PC1400T and Redtop 35 respectively) for 2017 Crosstrek. Yet both indicate they don’t have a battery that will fit 2018 Crosstrek. Not sure I believe that. Wonder if they simply haven’t updated their listings to include the new Crosstrek?
 

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Anytime a battery thread comes up, my solution is always ditch the factory battery. Subaru batteries are junk IMO. I usually have an argument with someone who does not think they are that bad and the thread ends. However, in this case even if you do not agree Subaru batteries are junk, I think the argument can be made for ditching the factory battery for a higher capacity battery.

My logic:
- Higher capacity battery will hold voltage longer... with the right battery it should be long enough to maintain your dash cam until the next time the vehicle is driven unless you take a long break from driving.
- Higher capacity battery will present need to be charged longer to the vehicle without you modifying the charging system at all.

Potential drawbacks:
- Price; Good batteries are not cheap.
- Additional alternator wear; Likely minimal and I think the solution you are looking for would do the same thing anyway.
- May still not fully solve your problem depending on your driving habits. Ultimately you are presenting a load to the vehicle that the car does not expect to be present. Leave it sitting long enough and the battery will drain.

Ultimate reason to do it... The Subaru OEM batteries are junk and there is a good chance it will need replacement way sooner than it should :smileyvault-stirthe. New battery gets that out of the way now and could solve your problem.
If the charging system is under charging the battery (as with all smart/eco charging systems), it won't make much of a difference if it's a big battery or a small one as eventually, the under charging will catch up to the battery. You are just kicking the can down the road until the failure happens. One of the other Subaru forums discussed this very issue of putting in a large high cap battery to 'fix' the battery issue as they too believed a larger battery will fix everything... as it turns out, that same person (who put in a high performance battery) posted in that thread a year later stating that the issue of under charging the battery returned.
 

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If the charging system is under charging the battery (as with all smart/eco charging systems), it won't make much of a difference if it's a big battery or a small one as eventually, the under charging will catch up to the battery. You are just kicking the can down the road until the failure happens. One of the other Subaru forums discussed this very issue of putting in a large high cap battery to 'fix' the battery issue as they too believed a larger battery will fix everything... as it turns out, that same person (who put in a high performance battery) posted in that thread a year later stating that the issue of under charging the battery returned.
Well, one thing about these Odysseys, is they accept a charge fast, and will utilize the amps available to charge up very quickly. This is especially important with my floatplane, as many flights are often quite short (when alpine lake hopping). This could be very good with the Crosstrek, too, so that when it is able to charge hard (not in Eco mode) it should charge the Odyssey up faster.
 

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Discussion Starter #19
If the charging system is under charging the battery (as with all smart/eco charging systems), it won't make much of a difference if it's a big battery or a small one as eventually, the under charging will catch up to the battery. You are just kicking the can down the road until the failure happens. One of the other Subaru forums discussed this very issue of putting in a large high cap battery to 'fix' the battery issue as they too believed a larger battery will fix everything... as it turns out, that same person (who put in a high performance battery) posted in that thread a year later stating that the issue of under charging the battery returned.
As 13ST14XV wrote, it may not (i.e. probably won't) solve our problem as OAK's commute is only 5 miles, in traffic. Interestingly, the parking mode held up last night but she went to her book club across town so drove a lot more in the evening, and probably at speed on the freeway as she came home late, after the bad traffic. It's definitely a combination of driving habits and the eco charging, and there's only one of those I have any influence over... :D

My only concern is that the constant charging may have some other undesirable effects on the battery but I can't imagine it's any worse than it being constantly left at 50% charge.
 

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In this case his drain is coming from an additional outflow on the battery. Having additional capacity on the battery buys extra time for the accessories (dash came in this case) assuming the car has time to charge to equivalent voltage. Hopefully the other workaround fixes it, but more capacity is more capacity when charged to an equivalent voltage. I get that it does not address the undercharging issue. Real issue here is running out of charge to power dash cam. Can be solved by fixing under charing. Can be solved by additional capacity. That said, I get and agree with your point of undercharging eventually catching up to the battery.
 
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