Trying to recharge a 12V Jump starter. Been on charge almost 6 days constant and still not fully charged. Any idea what might be wrong as surely it should not take this long.
You've probably left it too long between recharges. If you do that it becomes impossible to charge it again and it's only fit for the tip. (That's why mine packed up and I've been told that the vast majority of such jump-starter units go to an early grave because people forget that they need to be periodically recharged).
Yep - agree with Chris - I had a 'big yellow starter' that I ignored & it just wouldn't charge when I remembered it.
The replacement gets topped up every couple of weeks & it's still going strong after many years.
[ I'm assuming that we're talking about on of the old-school heavyweight starters here - the more modern, small size, Li-ion ones are much more forgiving of neglect and should be capable of being recharged at any time ]
Any re-chargeable battery, lead acid particularly, will meet an early death if not charged up on a regular basis. Lap top batteries are another example. Many people, run them from the mains without either discharging or indeed checking if they are capable of being charged. Result when you need it to work off the battery it wont.
In lithium-based batteries this is in fact a myth, it only applies to older Nickle-based batteries. So fully discharging and charging the battery is completely useless and even harmful.
The modern lithium battery can be charged regardless of its current percentage, given that it has absolutely no negative effect in its performance.
Working for me Ivor. My previous laptop battery failed, fairly soon after warranty. My current lappie is going strong after 4 years. I do regularly use it off mains unlike the early one. I could not put it down to advances in battery technology because my daughter had hers fail in similar circumstances only 4 months ago. Mains use for months then a battery fail when she needed it. Plus there are fairly strict guidelines issued by the suppliers of EVs regarding charging protocol, if you don't want to forfeit warranty. Lithium Ion Batteries.