DIY: 5lb Shorai Battery Install

[new2subaru]

Originally Posted by frs23

Not sure if this question has been asked but for the Shorai, about how long does it take to recharge battery from car alternator after one or two crank start attempts? I am asking this question to see if I get this setup, then if I have a few short drives will it need to recharge from a wall battery charger / tender.

It behaves just like the stock battery IMO. I forget it there most of the time.

The only thing that I do is pull the negative terminal if it's going to be sitting for a long time but I did that with the stock battery too. This car seems to have a lot of draw when sitting. You can charge it will a regular charger, just follow the Shorai instructions.

[ZDan]

Originally Posted by frs23

Not sure if this question has been asked but for the Shorai, about how long does it take to recharge battery from car alternator after one or two crank start attempts? I am asking this question to see if I get this setup, then if I have a few short drives will it need to recharge from a wall battery charger / tender.

In my experience running the Shorai in my daily-driven and tracked '17 from 2020 up to Spring '23 when I got new BRZ, continuously through all seasons in Providence RI/SE Mass, it never failed to start the car. In fact it started the car more eagerly than the massive stock battery did. Only reason I haven't swapped it into the new car is that I already have to add ballast to meet my weight limit for T50 class time-trialing with COMSCC...

[frs23]

Thanks for the replies. With my Lead acid if I have to many local short drives (few miles for 5-10min) then it never charges well and shortens the life of the battery (only 1-2 years life). This happened to all my cars and not just he FR-S. Related to my question here, when the Led acid battery is good or good enough condition I am to start. with your replies then it sounds like the Shorai should have a chance to start all the time then. Thanks both!

[cmiovino]

I saw this thread pop up with activity and it caught my interest moving to STX next year for autocross... and having a battery from 2019 right now. Looks like the stock battery in my 2017 was replaced in 2019 by Subaru right before I got it. Subaru's batteries have gone downhill since the mid-2000's when I regularly saw the Panasonic ones they used last 10 years.

I will give my experience with the Braille 22lb battery. Had it my WRX when that one needed a battery. ~$200 at the time back in 2018. I was skeptical going from a 40lb stock battery to this 22lb one would be reliable in the winter, but sure enough it started the car reliably at even 10 degrees F. I'd probably go with a 5-10lb version from Shorai or other manufacturer this time. Nothing against Braille though.

For anyone looking at these lightweight batteries, don't think you're giving up much if anything. A lot of the CCAs these are rated at around 550, which is right in line with the stock battery. Not sure I'd run a 5lb mini battery in the dead of winter, but you'd more or less fine down to about freezing I'd assume.