Battery Charging Questions - General

Hey guys, Ok i'm doing some battery science recently, here's what it's about: I've got two batteries, Number 1 is from the battery-disposal at work. Specs: 12V 60Ah 380A CCA IEC. It was pretty much dead when i got it, 8volts and the digital tester measured merely 0 Amps CCA. I charged it for nearly 2 weeks at around 15.5 Volts. I know, that's way too much, but the charger at work was malfunctioning and i didn't notice. After 2 weeks it was back to normal voltage, fully charged and had a CCA of at least 300Amps, rising by a few amps each day. After that I took it home and let it hang on a steady 13.8Volts 100mA Current. Now it's back in service and working like a charm. What the hell was going on? I don't understand this, i thought it was dead. Anyways, battery Number 2: 12V 18Ah, Sealed battery from a starter pack. It was deeply discharged like the other, i was charging it for 2 days at 14.4Volts and 2.5Amps. It all seemed good, the clamp voltage of the battery got higher each day. At one point it got very warm and then the clamp voltage fell below 9 volts. It was dead. What happened to it? I am asking because i'm now having another battery, 12V 55Ah 300CCA IEC, which is doing the same thing. Was charging at 14.4V 2.5A for the night and now it's warm and i stopped charging because i'm worried the same thing might be happening again.

So I've been working at my dad's mechanic shop for a year now... We get batteries coming in all the time that are dead. from what i understand your charger shouldn't be charging it more that 13V + or - Also, we either charge ours at 12V 40A or 12V 10A (Industrial Charger) You want to keep checking on it to make sure that it doesn't get warm, all i know is its really bad for the battery >.< It sounds like you have a trickle charger, am I right? Sorry for the TINY amount of info, I'm still learning :P

Heh thanks for your answer but part of it isn't true. You can charge a battery at up to 14.4-14.6 volts, depending on the type. Float charge is 13.8 Volts. Current shouldn't be over 10% of the capacity of the battery. There is also a type of charge called an equalization charge at 15.5ish volts, to remove sulphation from the cells. But yeah i was using a trickle charger. I have no idea why we have such a cheap and bad piece of equipment in our Workshop. Heat isn't directly bad for a battery, only if it gets too hot. Modern batteries have ways of recovering cooked out electrolyte up to a level. I'm still confused with my situation though as the battery i charged last night, last one i mentioned in the OP, keeps emitting heat, even though i stopped charging it hours ago.

Told ya im still learning :D Your battery shouldnt be doing that :/ Is it inside or outside? [editline]16th October 2011[/editline] So one thing that caught my eye.... why such a low CCA battery?

Well it's not low by other standards, it's just the IEC measurement cycle that only indicated 300A CCA. Maybe that's not much for American Standards, but here in germany that's a pretty normal size. The only in my car is almost half that big. Man, those culture differences, even in batteries! :D

No kidding... some of the Mercedes and higher end fanciness here require like 1000cca D:

[QUOTE=Verto26;32812741]No kidding... some of the Mercedes and higher end fanciness here require like 1000cca D:[/QUOTE] Wow by which standard? IEC, EN, EN2?

Bahaha no clue... >.< Doubt this will help but we end up putting these in some of our cars [url]http://www.interstatebatteries.com/cs_eStore/Products/RT/PID-MTP-93%28Automotive+Truck%29.aspx?dsNavigation=Ntk%7eSearchGroup%7cmtp%252f-93%7c3%7c%2cNy%7eTrue%2cNtpc%7eDisabled%2cNs%7eproduct+Type%7c101%7c1%7c&Title=Mega-Tron+Plus+93+Automotive+Battery+++85+months+++850+CCA[/url]

Haha that's a weird site, there's no capacity rating anywhere to be seen.