Temperature effect on batteries

[Leon 12]

How does temp effect batteries?  Ie if it's 10 degrees will the voltage be lower at full charge. 

[nicknorman]

No, surprisingly it doesn’t significantly affect the no-load voltage at full charge. It does affect the rate at which a battery can give up charge - aka the terminal voltage under significant discharge. And the necessary charging voltage.

Well actually, when I said “surprisingly” in the first sentence, it’s not that surprising. The reaction that turns acid and lead into current, runs faster in the warmth, slower in the cold. But when no current is being taken the reaction is stationary. So the fact that it would be slower in the cold is irellevant when it’s stationary.

[WotEver]

That’s always assuming we’re not referring to lithiums

[MtB]

1 hour ago, Leon 12 said:

How does temp effect batteries?  Ie if it's 10 degrees will the voltage be lower at full charge. 

 

Low temp means you have to charge at a higher voltage, or you'll not get to 'full charge' in ;ess than half a lifetime.

What do you mean by full charge anyway?

[WotEver]

.

Edited December 1, 2017 by WotEver

[MtB]

1 minute ago, WotEver said:

Norty 

Not sure why its norty. The OP might be asking because as the weather gets colder, he is seeing an ever lower voltage after fully charging them for an hour each week. 

(And incorrectly associates it with the weather, I mean.)

[WotEver]

Just now, Mike the Boilerman said:

Not sure why its norty. The OP might be asking because as the weather gets colder, he is seeing an ever lower voltage after fully charging them for an hour each week. 

Yes, that’s why you’ll see that I changed my mind and deleted my post

[MtB]

Bloody hell, I made a point you agree with!!!!!!!!!!!!!!!!!

[WotEver]

26 minutes ago, Mike the Boilerman said:

Bloody hell, I made a point you agree with!!!!!!!!!!!!!!!!!

I often agree with you

Usually only when you’re right though

[MtB]

1 minute ago, WotEver said:

Usually only when you’re right though

 

I'm always right. 

I though I was wrong once, but it turned out I was wrong about that and I was right after all. 

Errr...

[Leon 12]

OK.  Let's say voltage is 12.70 and smartgauge is reading 100% on a beautiful hot summers day. Then pretty much  it's all lovely. Now say it's down to 33 degrees f on a winters day. How will said voltage be affected, is it drastic or negligible. Quite a lot of difference of opinion. Through various Internet based views.

[nicknorman]

Negligible.

[Tony Brooks]

20 minutes ago, Leon 12 said:

OK.  Let's say voltage is 12.70 and smartgauge is reading 100% on a beautiful hot summers day. Then pretty much  it's all lovely. Now say it's down to 33 degrees f on a winters day. How will said voltage be affected, is it drastic or negligible. Quite a lot of difference of opinion. Through various Internet based views.

I think Nick has already explained this to you but I suspect that you are confusing voltage with the batteries ability to produce current. As Nick said with no load, that is with everything turned off the temperature will make little, if any difference to the voltage but as you turn things on and ask the batteries to produce current then the voltage will start to drop. The fact that it drops when current is being produced has nothing to do with temperature but the degree of drop does.

For any given load the lower the temperature the greater the loss of voltage.

For at given temperature the greater the load (current) the lower the voltage.

Until you start defining the current flow it is impossible to answer your question other than Nick and myself have done.

One thing is for sure and that is even ignoring friction in the engine you get far less current out a start battery at a useful voltage when starting on cold days.