[DrewM]

Hello, planing on replacing my battery. The positive terminal connector is pretty crap with a lot of corrosion, metal plating coming off,etc. I would rather just replace it then try and clean it up. Is there something aftermarket that I could replace the connector with (highlighted in red box in pic)?

Or would I have to replace the entire distribution block?
Or maybe there is something better than the distro block I don't know about, where you would take it out altogether?

 

[bman400]

DO NOT go aftermarket, as you've battery sensing hardware that is part of the connector. Best to get a proper connector from the dealer.

You might try mixing some baking soda with water and cleaning the battery surface and connector to see if you can salvage the connector. I do this on an annual basis with my 2013 Nissan Leaf as it as the same Flooded Lead Acid battery and creates the same acid stain in your picture on the battery surface.

You're also using a Subaru factory battery that is a Flooded Lead Acid battery that during recharge cycles, likes to spew up acidic fluid hence that wonderful white fuzz. Long term best to pay extra for a AGM battery as they DO NOT create that wonderful white fuzz!

I used to have that same white fuzz when I used Flooded Lead Acid batteries, identified by the "Danger..." Cap. Those caps are meant to be popped off for you to top-up the battery with distilled water. The battery needs topping up because all the fluid get's evaporated during the recharge cycle and creates that white fuzz.

Since switching to AGM battery I never have the white fuzz.

 

[ForesterBill]

It will be a lot easier to just clean the connector. Just wet some baking soda with water and use an old toothbrush to apply it to the battery clamp and flush the residue away with water. To prevent that acid buildup from happening again, consider installing an AGM-type battery which does not gas. If you end up installing another flooded battery, these may help: Felt Battery terminal Protectors

 

[DrewM]

You're also using a Subaru factory battery that is a Flooded Lead Acid battery that during recharge cycles, likes to spew

I know, I got talked into replacing it at the dealer and knew I shouldn't have but convenience factor.
Ok, sounds like I am just gonna clean it up.
Any AGM you would recommend? And what to put on terminals during AGM install?

...also, there is some speculation out there that the 2015 alternator doesn't provide enough current to recharge AGM batteries. Is this a thing?

 

[ForesterBill]

I bought an Interstate group 35 AGM battery from Costco because it was the least expensive AGM battery I could find. My local Costco just started stocking them again after a long pandemic-related absence:

 

[bman400]

COSTCO sells a Group 35 AGM, Batteries Plus sells Group 35 AGM. Not sure what you mean by "...put on terminals during AGM install?", can you clarify.

Below are pictures for my 2001, so it does not have the sensor part. The battery in the picture is from Batteries Plus, their X2 battery. Lasted 5 years in TX heat, which I consider awesome. I probably could have stretched it to 6 years.

 

[ForesterBill]

And what to put on terminals during AGM install?

Nothing other than reinstalling the red plastic terminal cap that came with the car.

...also, there is some speculation out there that the 2015 alternator doesn't provide enough current to recharge AGM batteries. Is this a thing?

No problem keeping my AGM charged after 9 months.

 

[DrewM]

Not sure what you mean by "...put on terminals during AGM install?", can you clarify.

Oh, I meant what to put on terminal to prevent corrosion. The metal plating is coming off off the terminal connector, so maybe grease AND felt pads would be good choice?

 

[OutbackJon]

Doubtful. At worst, if the alternator is a lower amperage than other models (which is highly doubtful) it would just take longer to charge. Unless you're doing an awful lot of really short trips, that shouldn't be an issue.

 

[bman400]

...also, there is some speculation out there that the 2015 alternator doesn't provide enough current to recharge AGM batteries. Is this a thing?

AGM needs to see 14.7+ voltage to recharge properly anything less will long term weaken the battery. I cannot speak towards the 2015 alternator. I recently added a special "fuse" to the my 2001 and the alternator now recharges.the battery at 14.7+ volts. I have done battery test and so far so good.

 

[bman400]

Subaru AGM Battery Alternator MOD: ('03-'05) - Alex's PBP '03 X +AVO...

 

[DrewM]

Unless you're doing an awful lot of really short trips

THIS...

Subaru AGM Battery Alternator MOD: ('03-'05) - Alex's PBP '03 X +AVO...

Thanks, but not interested in doing any mods.

 

[bman400]

Your 2015 may not need the MOD for the alternator since it has the sensor module on the POS connector and may take into account the battery. My older 2001 has what I call "dumb alternator".

 

[DrewM]

AGM needs to see 14.7+ voltage to recharge properly anything less will long term weaken the battery. I cannot speak towards the 2015 alternator.

Is this gonna be a problem for 2015? I have read a few threads about the load being short, maybe that's just with OEM battery or alternator/etc related?

 

[bman400]

Oh, I meant what to put on terminal to prevent corrosion. The metal plating is coming off off the terminal connector, so maybe grease AND felt pads would be good choice?

Since AGM's do not create/leak out any acid on their surface, there is no corrosion to be concerned about. The pictures I posted are after 5 years of usage with NO maintenance, no felt and no grease.

 

[bman400]

Is this gonna be a problem for 2015? I have read a few threads about the load being short, maybe that's just with OEM battery or alternator/etc related?

I don't think it will be an issue. But @ForesterBill has a 2018 and can speak better to how the newer models handle the AGM better than my 2001.

 

[donkpow]

...also, there is some speculation out there that the 2015 alternator doesn't provide enough current to recharge AGM batteries. Is this a thing?

AGM batteries are very responsive. They take and release a charge quickly. I had not heard that any alternators are having trouble charging them.

 

[OutbackJon]

The SJ Foresters have a really crappy charging algorithm built into their circuitry. In an effort to squeeze a bit more MPG out of the cars, they often don't charge on a short trip, or allow the voltage to go too low. Mine was so bad that I was regularly seeing voltages in the 11.5V range while driving. It would often cause my dashcam or my AccessPort to shut down, because they thought the voltage was too low. This would even happen during long drives. Cobb even reprogrammed their AccessPorts to account for this issue.

This mod is easy and 100% reversible. And well worth the time in my opinion. Now I see the voltages that a car is supposed to operate at.

 

[Oldguy2]

Oh, I meant what to put on terminal to prevent corrosion. The metal plating is coming off off the terminal connector, so maybe grease AND felt pads would be good choice?

Yes to both. You've gotten lots of decent suggestions, but I've also had good luck thru the years with these simple (and cheap) pads preventing the corrosion build up like you originally experienced. battery terminal protectors I also put a light coating of regular old Vaseline on the terminals, although you can buy specially made battery protectant spray fairly inexpensively that does the same thing ... probably even better than Vaseline.

My son put an AGM battery in his '14 Outback 2 years ago and its worked fine ever since for him.

 

[DrewM]

Now I see the voltages that a car is supposed to operate at.

Is the voltage you are getting after this mod enough to run the AGM batteries at 14.7?

---""AGM needs to see 14.7+ voltage to recharge properly anything less will long term weaken the battery""