My ISF sort of became my weekend car these days. I am afraid I don't drive it currently enough to keep the battery fully charged.
I have OPTIMA YELLOW in my ISF, I know many guys charge these. I have this Schumacher charger, never used it.



Questions:
Anyone in the same situation, charging the battery regularly?

What would be the desired setting for the charger to just maintain the battery, as my battery is not dead.
(I believe 2AMPs for maintenance charging, there are three more setting there MANUAL and 2 AUTO settings)

Can I charge my battery while hooked to my car?

Any informed advice would be greatly appreciated.

 

Isn't there a maintenance setting on the charger? you would select the low amperage setting and leave it on. and yes you can charge it while still in the car. A battery Tender is what the correct item would be.

 

My car is weekend only and I (every month or so) hook it up to trickle charger overnight to keep the battery fully topped off.

This is the one I have. https://www.zoro.com/battery-tender-battery-charger-12vdc-125a-021-0156/i/G3739933/?gclid=CjwKEAjw5M3GBRCTvpK4osqj4X4SJAABRJNC8yh8g9yLlwEmY1bLClenkEvmCj0w2jCqJWoHm0S5eRoC_bHw_wcB&gclsrc=aw.ds

Works great - you connect it and forget it - auto shutoff once battery is topped off and auto restart if it starts losing power.

 

+1. Have the same one, only drive the car 4,000 miles a year. Works great

 

Sounds complicated. I have a cheap Wal-Mart charger set to 2 amps with a timer that runs for 2 hours daily connected to my Supra with a yellow top Optima. Works like magic.

Supra has less than 3000 miles in the last 10 years.

 

Thank you for all the replies. I found the manual for the charger.

Yes, it seems pretty straightforward. I will set it at 2AMPs.
There is an auto mode for deep cycle battery. The charger will automatically switch off when battery reaches approximately 14volts.
The charging will be discontinued until the battery voltage drops below 13 volts again.

I will connect it tomorrow. Cool I don't have to disconnect the battery. Little scary to be honest, but I heard about that before.

Thank you!!!

 

Is your Supra modded (heavily) or no? Just wondering, lol.

V.

 

i got the walmart battery charger, its 2 and 8 amp and works well. got for 30 on clearance. well vatozone tested my battery and says it's good. i was going to use it on my gs350, but put die hard back in and going to pep boys to pick battery for the F.

 

Only a little. Still has all OEM cats, so it's not a power monster even with the wastegate disabled and the FCD working.

 

I don't drive the F in the winter. I use a Battery Tender maintenance charger, works great.

 

+2

I have a Battery Tender harness hard wired into my F, one of my Ford F trucks, my Jeep, etc. All of my vehicles that I don't daily have the harness hard wired, just plug it in and forget it. Have used them for 20+ years on motorcycles and boats during their respective off seasons. Batteries live forever comparatively with very low sulfating issues.

 

Just wanted to weigh in on a weekend ISF. I had issues with my battery draining quite quickly when off a CTEK charger. I took a parasitic load measurement and its a huge 140mA when the car is fully locked. (Normally <50mA is acceptable). A quick calculation would mean a 140RC battery would be drained flat in 15-16 days. I'm not sure if its just my own car but it may explain why people have battery drain troubles with a non-daily ISF....

Addit - so I found out my trunk was open the whole time! Despite the fact that the trunk lamp was switched off.... Seems to me if the trunk is open, a (?security) subsystem doesn't go to sleep. So now what I've observed is that it drains 140mA for about 15 minutes when the car is first switched off and then it drops to 25mA after that.

 

I have these for the weekend cars since I only drive them about once a week. You just plug them in and they regulate it themselves. I got them on amazon for about $50ish. I had to get their extension cord also since it was a little short. Don't cheap out when buying a battery tender; you want one that doesn't warm up because that might be a sign that they'll catch on fire.

https://no.co/g3500

 

ISF is my weekend car, but I don't drive it much in the winter due to snow and salt. So in the winter I use a battery tender, this one specifically.

 

Thanks for posting a real number. It is the first I've seen after looking for a while.

25mA is still a pretty good draw but way less than 140mA.
At 25mA that puts it at 18Amps a month which is going to take a serious toll on any battery. From what I have read systems begin shutting down in 15 day increments. So after idle for 15, 30, and at 45 days it has all non-essential loads terminated...

What meter did you use?