Most batteries are pro rated.

 

Interesting in that the circuit logics of many battery chargers will not recognize a completely dead battery.....the logics of these chargers think they are seeing an open circuit.....so they don't do anything. The impedance of a completely dead lead acid battery is very high. Parallel a completely dead lead acid battery with another fully charged battery. Wait a few minutes or so. Connect a battery charger to the dead battery and then remove the healthy fully charged battery.......this should be enough for the battery charger to start working charging the dead battery. I've done this.

BTW. The internal impedance of a partially discharged lead acid battery is very low. Connect a fully charged lead acid battery to it will result in sparks and a large inrush current.

Also.....just my opinion. Once a lead acid battery has gone completely dead...."flat" as they say in England/Austalia....plan on getting rid of it. They are never the same. Unfortunately, with today's environment regulations, lead acid batteries have become pretty expensive....~$150, Used to be about $80.

I know almost nothing about lithium batteries.....I think occassionally discharging them to 0 is not harmful.

 

Not true at all. if it's short term like overnight, it has little impact on the life. I've received several 'free' batteries when our work van GPS units would deplete a battery over the weekend (the company would just buy new batteries rather than wait to charge up a dead battery), and they'd last me many years. I'm still using some. I had two that were frozen SOLID from sitting dead in sub-zero temps all weekend. Thawed them out, charged up, they work great to this day ...7 years later. I have one in my snow plow truck in fact where you need a battery you can trust.

But if they sit dead for a long period, yeah, probably going to have a shortened life battery.

 

That is commom. Either use an analog charger or use a set of jumper cables connected from a charged battery to your dead battery with your new charger attached and activated. Id give it a half hour or so then remove the jumper cables as the the dead battery will have enough voltage to allow the digital charger to work. It takes 5 to 7 kills to ruin a lead acid on a farly new battery.

 

If you have a battery that is "flat" or "dead" it is possible to recover most of the capacity IF you act quickly. The longer it is left flat the worse the damage will be to the battery. The plates will oxidize and that will affect your overall capacity.

When you have a battery that just got pulled down to less than 6 volts connect it to another good battery in parallel. Try this for a few minutes and then attach a charger to the dead battery and see if it starts working normally charging like it is supposed to.

The longer the battery is left discharged the more capacity will be lost. Never try to add new electrolyte to an old battery either, it will damage the battery's plates if you do this.

If a battery is internally shorted DO not put another battery in parallel or it will discharge the good battery into the short. Shorts make heat and the hydrogen inside a battery can make it blow up. I have witnessed a battery in a Dodge Van exploding one day. It developed an internal short and went dead in hours. When the Van was Jump Started the next morning the alternator tried to charge a shorted out battery which then exploded sending acid and plate material everywhere in side the engine compartment. They were very lucky it was contained in the engine bay. Battery electrolyte will blind you if it gets in your eyes.

When I handle a battery used in a Car after it has been in service for a while I always carry it "flat". You don't want the lead that has fallen off the plates to short out the bottom of the plates. If the lead moves and shorts the battery it could easily rupture or explode after it gets really HOT. Most automotive batteries don't have a lot of room beneath the plates so shorting them is fairly easy to do on a used battery.

Batteries Cost more today because the consumer is now expected to pay part of the cost of recycling the materials after the battery is worn out. Recycling is expensive and the manufacturers thought you should pay more of the costs since you are using the battery...

 

Thanks for all the help! I was able to get a replacement for free since the battery was so new