Battery temperature logging - where to put a thermometer?

GHA

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Can't see that it will make an enormous difference but always worth an ask, usually something to learn amongst the noise and bickering :) .
One of these getting wired in today which will end up getting saved to a database in a raspberry pi.
DS18B20-Sensor_0.jpg

Think it will be bluetack somewhere up near the top of the battery for now to see how it goes.

Thoughts?
 

northwind

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Can't see that it will make an enormous difference but always worth an ask, usually something to learn amongst the noise and bickering :) .
One of these getting wired in today which will end up getting saved to a database in a raspberry pi.
DS18B20-Sensor_0.jpg

Think it will be bluetack somewhere up near the top of the battery for now to see how it goes.

Thoughts?
Do you have a single battery or are there a couple of them side by side if the later then stuffed in the gap between them.
 

Poey50

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Up to now I've just tucked mine under the battery retaining straps. I'm not sure I trust the accuracy of the absolute figures but the relative changes are reliable in which case location is not crucial other than avoiding being near any flow from fans.
 

Boater Sam

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Could you explain to me why you would do this? Is there a new reason for such monitoring? Its something I have never done, the alternator controller has a thermistor to ensure that it does not cook the cabin batteries, I can see the reason for this one.
 

GHA

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Could you explain to me why you would do this? Is there a new reason for such monitoring? Its something I have never done, the alternator controller has a thermistor to ensure that it does not cook the cabin batteries, I can see the reason for this one.
Many reasons, if you don't look you won't know..... a 10degC increase in battery temperature will roughly half it's lifespan so seems a good idea to look.....costs , well nothing as the thermometers are cheap as chips and I bought a bagful ages ago, everything else is running already so just a little wiring.

....and if you need to ask, you'll never know the joy of data & graphs just cos! :) :cool:

Voltage of each 6v T106 next .

Up and running with messy wires for now, bluetacked to top of terminal >

Or7zV9E.png


JicGVyC.png
 

Poey50

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Many reasons, if you don't look you won't know..... a 10degC increase in battery temperature will roughly half it's lifespan so seems a good idea to look.....costs , well nothing as the thermometers are cheap as chips and I bought a bagful ages ago, everything else is running already so just a little wiring.

....and if you need to ask, you'll never know the joy of data & graphs just cos! :) :cool:

Voltage of each 6v T106 next .

Up and running with messy wires for now, bluetacked to top of terminal >

Or7zV9E.png


JicGVyC.png

Knowledge is power. GHA, therefore, is a boating Superman.
 

prv

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All the made-for-purpose battery temperature sensors I've seen have been designed to bolt onto one of the terminals. I don't think there's any electrical significance to it, but firm contact with a solid chunk of metal reaching deep inside the battery is obviously a good place to sense internal temperature from, compared to a position vaguely near an insulating plastic case.

Pete
 

GHA

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Well that wasn't a great success... :rolleyes:

A fan blowing into the bottom of the battery box fitted yesterday lunchtime seems to have made no difference to the battery temperature, though just a tiny little CPU fan and I can't even feel the air coming out of the box.

Think we're gonna need a bigger fan... ;)

xtZNWto.png
 

Skylark

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...........but always worth an ask, usually something to learn amongst the noise and bickering :) .
I’m more of an analogue person and don’t subscribe to the digital age so I guess that I’m as guilty as any ?

I find the thread interesting and informative; as you say, battery temp is often reported to have a big influence upon its performance so useful to know but rarely measured. Watching with interest.

Re your post number 6, I’m “really impressed” by the 29.6353 deg C ?

If you can consistently and significantly reduce the temperature, what do you expect to be the affect on battery performance and how will you make the assessment?
 

Forty_Two

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Can't see that it will make an enormous difference but always worth an ask, usually something to learn amongst the noise and bickering :) .
One of these getting wired in today which will end up getting saved to a database in a raspberry pi.
DS18B20-Sensor_0.jpg

Think it will be bluetack somewhere up near the top of the battery for now to see how it goes.

Thoughts?
I did read somewhere that midway up the battery case is good as that will show an increase quicker than the top due to the air space at the top.

And another on the Stern Gland
 

geem

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Well that wasn't a great success... :rolleyes:

A fan blowing into the bottom of the battery box fitted yesterday lunchtime seems to have made no difference to the battery temperature, though just a tiny little CPU fan and I can't even feel the air coming out of the box.

Think we're gonna need a bigger fan... ;)

xtZNWto.png
I run a Jabsco centrifugal fan connected to a temperature sensor and switch. Set the temperature and the fan comes on a blows a lot of air through the box. Even with a big fan it takes time to drop all that lead down a notch or two
 

GHA

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If you can consistently and significantly reduce the temperature, what do you expect to be the affect on battery performance and how will you make the assessment?
I think without lots and lots of money and a lab with keen students and about 10 years any kind of accurate assessment is near impossible. But what fun that would be :)

Plus many other factors involved - I charge the trojans higher and stay longer at absorption than most as well when on the hook with solar. And doing an accurate constant current/constant temperature load test is just not going to ever happen on a cruising boat so any results will be very hard to tell anything from.

But.. going on the battery datasheets it seems fairly consistent among manufacturers that for each 10degC increase in operating temperature you could likely be looking at halving the battery life so well worth a look and a play, since it costs basically nothing. :cool:
Interesting that the mirror the boat temperature during the day but never cool down as much at night. On float at the moment on the hard which might be a factor. Maybe I'll turn off the charger tonight & see what happens.
 
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