My battery went flat (458). Will the battery tender recharge it to allow the car to start again?
Welcome - no - it only maintains not recharges - you might get away with a full charge from a proper charger but most likely a new battery will be better
Batteries are too cheap to think about recharging an almost dead one. (Killed the airbag controller of my DD when driving with a dead battery. Parked my car for three weeks, battery went flat, taxy driver gave me a jump start, motor was running, but after some miles: air bag lights) If in doubt, through away.
You can try it. It cannot hurt. If the battery is still good, it will just take a few days for the battery tender to recharge it. If the maintainer indicates a full charge and the car starts, you can have the battery tested to see if it is still in good condition.
My experience as well. A battery tender can recharge a dead battery, but it can take a few days, instead of a few hours. But definitely have it loaded tested once charge. Even a single deep discharge can greatly reduce the capacity of a battery, sometimes enough to render it useless. Once in a while you can get lucky.
I put an AGM-teknologi (Absorbent Glass Mat) in my 360. It is said to have three times better cycling sustainability, you should also be able to charge a totally disharged battery and get it back to full power. Also there is no lose acid as all acid is contained in glas wool micro fiber. That feels good to know when you have the battery inside the coupe in case of an accident no accid can leak out,
Just make sure to use a tender that is designed for AGM. To the OP: you could try a better class of tender to bring the battery back to life. I like the CTek 7002 (if you are in the US) - a few hours on this should help. If your battery is 3+ years old, you might want to consider replacing it anyway. But, in my case I had an OEM battery go dead because the stock tender died. I used the 7002 to bring it back to life- this was 10 years ago- and that OEM battery gave me good service for several more years. The 7002 is way better than what they include with the car. And it has an AGM mode if you decide to go with an AGM battery. Just make sure to use it. (on the CTek it looks like a star or snowflake and has a picture of an AGM battery beneath it).
