Batteries designed to fail?

[Witchword]

Well, I had a shower thinking I would have to sleep through beeps, and it has stopped now. Weird.

[ditchcrawler]

Well, I had a shower thinking I would have to sleep through beeps, and it has stopped now. Weird.

What do you do about charging your batteries?

[Witchword]

Nothing, I ran the engine for an antisocial hour and then thought I had to just leave it. It has beeped a couple of times this morning but not constantly. The monitor is mad, it is saying 0% charge but also maximum time to discharge fully.

[Tony Brooks]

 

Nothing, I ran the engine for an antisocial hour and then thought I had to just leave it. It has beeped a couple of times this morning but not constantly. The monitor is mad, it is saying 0% charge but also maximum time to discharge fully.

 

And what sort of monitor would that be?

 

Without studying all the posts - a gas detector may well react to the fumes given off by a faulty cell when being charged. Maybe it took time for them to reach the detector an d then time for them to disperse.

 

How do the rested voltage readings and hydrometer state of charge readings compare? I have a feeling w emay be looking at sulphated batteries if not downright faulty ones.

[Witchword]

Well, it was the alternator, coupled with some dodgy DIY. According to the battery centre guy who looked today. The batteries may have been fine but they are likely now dead (8V lead acid), but they weren't charging because the alternator wasn't connected to the circuit. Something to do with a diode. Someone suggested the alternator- who was it!? Greenie for them.

[mayalld]

The plan is to investigate further just as a matter of interest. Each battery is holding a charge of 10.9 ish which suggests that one of the cells is disconnected. On a equalisation charge 5 of the cells are fizzing away merrily the 6th is lifeless.

 

OK, take a step back, and think about the internal construction of a 12v Lead Acid Battery.

 

It is made of six 2v cells in series.

 

A fusible link that fails in around the right time just wouldn't have the effect you describe, because if one link fails, then the whole thing goes open circuit, and no current flows, not even to the other 5 cells.

 

To make this work there would need to be something that CONNECTED at a certain age, so as to miss one of the cells out of the chain.

 

It is possible that they have designed things so that there is a very predictable amount of plate shedding, which with a known amount of space below the plates would lead to a very predictable failure point.

[spadefoot]

Spot on Mr Mayall, I was about to post the same thing. (well, not quite so well put)