Battery temperature sensors

[DenisHeinrichs]

Last year I purchased 4 Rolls Surrette L16 batteries (856AH total). I wish to attach battery temperature sensors from my Xantrex charger and my Balmar regulator to them.

The standard way is to attach the sensors to the battery stud, except the manual for these particular batteries say not to do that, and to attach them to the battery case, about 1/2 way down.

My question is: How do I glue these to the side of the battery case?

I tried thermal tape that I got from an electronics store, but the sensors fall off as they are too heavy....surprising considering the sensors are pretty light.

My problem with using any normal glue or epoxy is that I am concerned about getting a correct temperature reading (ie: I don't want the glue to act as insulation)

Any thoughts?

[john61ct]

Thermal conductive adhesive paste that sticks to both the materials concerned.

Meticulous surface prep will help.

[Lake-Effect]

What is the make & model of the temperature sensor? What is the temperature range you're interested in? More to the point, what's the good temperature, and what's a bad temperature?

I'm guessing there will be a serious difference between "good" and "bad" readings- eg 5 degrees C or more - so absolute positioning may not be that critical.

if that's the case, then I'd try thick tape (eg duct tape or wide electrical tape), or some insulation wedged in to hold the sensor against the battery. I suspect epoxy might not grip onto a plastic battery body, but silicone or Shoo Goo or 3M 5200 should work.

[DenisHeinrichs]

The sensors are the standard ones the come with Balmar mc-614 and a Xantrex Truecharge2.

I just check the Xantrex manual, it shows the 3 ranges as:
Cold = < 5C
Warm = > 5C and < 30C
Hot = > 30C

The Balmar manual says that it cuts the field current out at 52C

I guess that I don't really need any thing too sensitive....

I have some sikaflex already opened....do you think that would work?

[Ded reckoner]

You could try a thin coating of thermal grease (google "electronics thermal grease") as an interface. These products are meant to provide thermal conductivity between uneven surfaces. Only a very small amount of grease is needed.

[john61ct]

Temp sensors are mostly for automatically adjusting the voltage setpoints as temps change, necessary for proper coddling of an expensive bank.

The safety aspect is only an issue for the rare case that a charge source puts out amps over say .3C, or 30A per 100AH bank capacity

Or in the event the regulator breaks lets V climb too high, but then the safety aspect may well be broken too 8-)

[Lake-Effect]

Originally Posted by DenisHeinrichs

I have some sikaflex already opened....do you think that would work?

Which Sikaflex? If it's just a caulk/sealant, and not also a glue, it may not have the strength.

[DenisHeinrichs]

Originally Posted by Lake-Effect

Which Sikaflex? If it's just a caulk/sealant, and not also a glue, it may not have the strength.

I believe it is 291.

The sensors are very light. I guess the real problem is whether or not it will adhere to the battery case. Next time I am at the boat maybe I will try a test blob.

[smac999]

the balmar one comes with a battery post ring... bolt it to the battery.

some temp sensors come with tape and no hole. those ones stick one..

[RaymondR]

A couple of large, linked cable ties all the way around the battery???

[john61ct]

It seems Rolls wants the temp measured from the side of the case rather than at the post.

One would think they have their reasons, results in much slower more conservative adjustments, keepin voltages higher longer.