Another one for you electricians❓

[nortada]

It is well known that a duff battery in a parallel wired battery bank can/will ‘take down’ a serviceable battery in the same bank but if (as in a 24v system) 12v batteries are wired in series will a duff battery take down a healthy battery in the same series chain

I appreciate that the bus bar, loads may not see the correct 24v supply but can’t see this would impact on the batteries.

 

[jakew009]

It is well known that a duff battery in a parallel wired battery bank can/will ‘take down’ a serviceable battery in the same bank but if (as in a 24v system) 12v batteries are wired in series will a duff battery take down a healthy battery in the same series chain

I appreciate that the bus bar, loads may not see the correct 24v supply but can’t see this would impact on the batteries.

You hypothesis is correct to an extent but generally if one battery in a bank is dead the others are also ready for replacement too.

 

[nortada]

You hypothesis is correct to an extent but generally if one battery in a bank is dead the others are also ready for replacement too.

They are all new batteries. The duff one fails to hold it’s charge.

Fortunately, still covered by warranty.

 

[jakew009]

They are all new batteries. The duff one fails to hold it’s charge.

Fortunately, still covered by warranty.

Should be fine to swap it then

 

[nortada]

Should be fine to swap it then

My concern is what, if any, impact will the duff battery have had on the other serviceable one and should I suggest that this one also needs replacing

 

[PaulRainbow]

My concern is what if any impact will the duff battery have had in the other serviceable one and should I suggest that this one also needs replacing

If it will not hold it's charge it's unlikely to have done any harm to any other batteries in the bank. Worse case scenario, the bank may not have entered float, but that shouldn't do harm in the short term.

Another failure mode is a shorted cell, where the battery then becomes a circa 10v battery, which will boil and gas excessively. This can, and often does, destroy the other batteries.

 

[nortada]

If it will not hold it's charge it's unlikely to have done any harm to any other batteries in the bank. Worse case scenario, the bank may not have entered float, but that shouldn't do harm in the short term.

Another failure mode is a shorted cell, where the battery then becomes a circa 10v battery, which will boil and gas excessively. This can, and often does, destroy the other batteries.

The bank consists of 2x12v batteries in series.

Boiling and gassing - no evidence of this.

 

[billskip]

Boiling and gassing - no evidence of this.

In series it is unlikely as the resistance is increased, you will get reduced voltage if one is lower,but unlikely to cause damage.

 

[PaulRainbow]

The bank consists of 2x12v batteries in series.

Boiling and gassing - no evidence of this.

I'd say you are OK

 

[jrudge]

They are all new batteries. The duff one fails to hold it’s charge.

Fortunately, still covered by warranty.

Has anyone in the history of the world had a battery replaced under warranty ?

 

[billskip]

Has anyone in the history of the world had a battery replaced under warranty ?

Yes, I have, of course they tried to blame it on everything else, but lost their argument.they replaced it.

 

[jrudge]

Gold star !

 

[BartW]

The problem when using different qualty or different types of batts in one bank ( different internal resistance) is that voltages and currents will not ballance equally, so on the long run, some battery will suffer more and age faster…

 

[Daydream believer]

Has anyone in the history of the world had a battery replaced under warranty ?

Yes my 2 agms were replaced 3 months BEYOND the warranty period.No quibble. Took them for test over 7 days & said that they were "passable", but would change as a guesture of goodwill.

 

[jrudge]

Have you considered buying a lottery ticket ? If so please pm me the numbers !

 

[Daydream believer]

Have you considered buying a lottery ticket ? If so please pm me the numbers !

A lot of it is down to using a telephone, rather than emails. Speaking to people curteously & explaining the problem in clear terms, without suggesting blame on any particular party. More one of asking for advice on the way forward.
Oh, & chatting about where he was taking his kids for their summer hols & how expensive things are for a family of five these days etc etc

 

[ElJames]

Brought batteries off an EBay shop with 4 yrs guarantee 3 1/2 years latter failed had a report from Halfords emailed to them along with invoice next day 2 replacements arrived no problem