gjpearce

I have posted this same info on the TT forum. I have a 2001 TT. I just bought it 6 months ago. Twice i have stupidly let the battery run down- once i left the lights on all day, once i left the key in the ignition. I have re-charged car and and it runs. I am worried I may be running on a half dead battery which will burn out my alternator. What is the best way to assess battery health- I could go to the local service shop every week for a free battery check where the man comes over to your car with a handheld computer, I could use my old battery load tester which gets super hot, I could hook up those $10 NOCO leads that have LED indicators- any advice- a 2year old battery that has already run down completely twice in the last 2 months makes me worry.
Gary Pearce

Slakker

Use a multimeter to test the voltage. It will give you a sign of battery health.

Ahsai

After a long drive or over night charging, use your load tester to test it. It the voltage can hold above x volt for y seconds, your battery is ok for now. X and y should be specified in the manual of the tester. Y is usually tens of seconds and x about 9 to 10.

DBJoe996

What's your time worth? Spending hours checking your battery, load testing and voltage checking, recharging, etc. Generally automotive batteries do not recover well from deep cycling. What's your peace of mind worth? Coming out from a long work day and not being able to start up and drive home totally sucks. Or being stranded somewhere. Buy a new battery and rehearse your exit procedures, ie, quit doing stupid stuff. Drive on!

extanker

for some every day is a challenge

wwest

Deep Cycling of itself is not the problem, RECOVERY RATE IS.

Automotive systems regulate VOLTAGE, they will supply an UNLIMITED rate of current flow which will often result in overheating, boiling off the electrolyte, plate warping often results.

Most often a problem in RVs and MHs. Dual 6 volt deep cycle batterys that are often deeply discharged and then recharged with a very ROBUST, HIGH current alternator/VR common to the venue.

Often only takes a single outing to destroy a set of 6 bolt deep cycle batterys. RV/MH workaround is to use a >400W 12 volt DC to AC inverter to power the onboard converter-charger once underway.

Hurdigurdiman

I have never had a failed battery. I always completely lock the car (even inside the garage). Push the remote only one time and should NOT hear a horn beep when completely secured. If you hit the remote twice you WILL hear a horn beep to tell you that the inside motion detector is disarmed. That's if you leave a dog loose in the car when shopping. So lock the car EVERYTIME you are not inside it. Locking the car takes less from your battery than leaving it unlocked. That's a fact.