Battery Temperature Sensor multiple.

[Mrnotming]

Having had a number of battery cell failures over the years, I feel that the facility offered by the Sterling Alternator Regulator (basic model) to have one battery sensor is desirable but does not account for events which may be happening in another battery location, say underbunk, in a bank of maybe three or four batteries.(manufacturer says one is limit)
Has any Forumite been able to rig multiple sensors, perhaps thence to a monitor or even a simple alarm function?

Any pointers will be helpful and acknowledged.

Thanks,

Good sailing and boating to all.

 

[Talbot]

Not a great idea either if your battery is made up from a number of 2v cells!

 

[Andrew_Fanner]

I specifically asked Mr Sterling this one recently as part of another enquiry and was advised "not needed".

I bow to his expertise here, while not understanding.

 

[Mrnotming]

Sterling Battery temp sensor

Thanks Andrew,

Maybe someone else has an answer?

A separate system perhaps?

Thanks all,

Paul.

 

[Stu Jackson]

There appears to be no reason why multiple temperature sensors can't be fitted to multiple batteries. They're simply switches, not graduated controllers, so put in parallel, they'd perform the shutoff function you appear to need.

 

[VicMallows]

There appears to be no reason why multiple temperature sensors can't be fitted to multiple batteries. They're simply switches, not graduated controllers, so put in parallel, they'd perform the shutoff function you appear to need.

Not on the Sterling regulator in question .... it's a thermistor.

Vic

 

[pvb]

There appears to be no reason why multiple temperature sensors can't be fitted to multiple batteries. They're simply switches, not graduated controllers, so put in parallel, they'd perform the shutoff function you appear to need.

Temperature sensors aren't "simply switches", they allow the charge voltage to be adjusted to compensate for battery temperature. Maybe you're getting confused with the "high temperature trip" devices which can sometimes be used, and which can indeed be fitted to every battery.

 

[Graham_Wright]

I too have an interest in this. It always seemed strange to use one battery sensor to govern the charge to three.

Thermistors in series?

 

[Mrnotming]

Sterling Battery temp sensor

Interesting, PVB and others!

A battery high temperature switch.Now would that function when current is being applied by a hefty battery charger, or would it trip only when the draw from the battery exceeds a fixed amperage?Would it be measuring current or temperature?

What the boaters want is a method of detecting the truant battery (the one with the shorted cell), before the whole bank gets madly overcharged, sometimes resulting in a fire or explosion.
If you have access to any part No.s or schematics, would be grateful, thanks all for contributing so far,

 

[pvb]

A battery high temperature switch.Now would that function when current is being applied by a hefty battery charger, or would it trip only when the draw from the battery exceeds a fixed amperage?Would it be measuring current or temperature?

A "high temperature switch" works by measuring the temperature.

 

[noelex]

Multiple temperatures sensors are unlikely to be worth the trouble. Battery temperature curves are reasonably flat. If the various batteries had a 5 degree C difference in temperature the correct charge voltage would only change by about 0.1v.

My vote would be for more finely adjustable voltage points, so they could be matched correctly to the battery manufacturers specs. At least then the charging could be set up to be correct at the average temperatures encountered. Often the regulator only allows a small number of options and no adjustment in the slope of the temperature curve so the charge voltage is significantly wrong even if the temperature sensor is reading the correct battery tempreture.

 

[Mrnotming]

Sterling Battery temp sensor

Thanks for that PVB,

now I found a possible catch-all solution, but for those with batteries in the engine space, it could cause problems!

But it might save someone's ass!

http://www.extech.com/instruments/product.asp?catid=67&prodid=392

 

[Mrnotming]

Sterling Battery temp sensor

Noelex,
I understand your argument and there is a veracity about it that is had to fault.

But will your solution account for a battery charger forcing a 10v battery (i.e.one cell shorted) up to accepting 14.8/15v (open cell) thus causing the other say three batteries in the bank to have to accept the same regime?This seems to happen in real life all to often, and the amount of heat generated is scary in high ambient temperatures encountered onboard in the Med and elsewhere.

The fact that is that my installation shares ventilation with the engine compartment, blower cooled. Setting acceptable temperature levels might be tricky with a device monitoring solely ambient temperatures.(This device seems to be available see earlier post).
But I doubt it is the solution in my case.The present thermistor is fitted to only one of the batteries as per Sterling schematic. The other batteries are opposite side of the cabin aft, I feel they pose a risk as they are fitted underbunk, do have ventilation but are difficult to access constantly.In present cruising grounds they must be topped up weekly, which gives me an opportunity at least the check the Specific Gravity, which, as has been oft pointed out, will often reveal a fault in time to dump a failing battery.
If you wish to comment on my possibly errant logic, please feel free,as most of my knowledge is experiental other than a short course involving Basic Electrotechnology, by I think, GM Patchett, and that was yonks ago and I still struggle with resistor codes!

 

[noelex]

Noelex,
I understand your argument and there is a veracity about it that is had to fault.

But will your solution account for a battery charger forcing a 10v battery (i.e.one cell shorted) up to accepting 14.8/15v (open cell) thus causing the other say three batteries in the bank to have to accept the same regime?This seems to happen in real life all to often, and the amount of heat generated is scary in high ambient temperatures encountered onboard in the Med and elsewhere.

The fact that is that my installation shares ventilation with the engine compartment, blower cooled. Setting acceptable temperature levels might be tricky with a device monitoring solely ambient temperatures.(This device seems to be available see earlier post).
But I doubt it is the solution in my case.The present thermistor is fitted to only one of the batteries as per Sterling schematic. The other batteries are opposite side of the cabin aft, I feel they pose a risk as they are fitted underbunk, do have ventilation but are difficult to access constantly.In present cruising grounds they must be topped up weekly, which gives me an opportunity at least the check the Specific Gravity, which, as has been oft pointed out, will often reveal a fault in time to dump a failing battery.
If you wish to comment on my possibly errant logic, please feel free,as most of my knowledge is experiental other than a short course involving Basic Electrotechnology, by I think, GM Patchett, and that was yonks ago and I still struggle with resistor codes!

The battery temperature sensor only acts to set the correct charging voltage. It not designed to help with a defective battery and I don’t think it would be of much benefit in this situation.. If the battery temperature sensor was measuring a temperature of 60C on a defective battery it would reduce the boost voltage from 14.7 to about 13.5V. A battery with a shorted cell is still going to accept a lot of current at this voltage and continue to get very hot.

A battery (and alternator) temperature alarm would be a nice feature on a regulator, but this is different mechanism and purpose to the applying the battery temperature compensation curves.

There are a number of cheap and DIY engine exhaust temperature alarms that could be simply adapted.
A 50C thermostat switch and piezo alarm are all you need.

 

[Chris_Robb]

The battery temperature sensor only acts to set the correct charging voltage. It not designed to help with a defective battery and I don’t think it would be of much benefit in this situation.. If the battery temperature sensor was measuring a temperature of 60C on a defective battery it would reduce the boost voltage from 14.7 to about 13.5V. A battery with a shorted cell is still going to accept a lot of current at this voltage and continue to get very hot.

A battery (and alternator) temperature alarm would be a nice feature on a regulator, but this is different mechanism and purpose to the applying the battery temperature compensation curves.

There are a number of cheap and DIY engine exhaust temperature alarms that could be simply adapted.
A 50C thermostat switch and piezo alarm are all you need.

Having just had my 1st battery failure, when 1 of 5 domestics went very hot, and filled the boat with acid fumes - thats how I noticed it. I have a Sterling system but the errant battery was not the one monitored so pretty useless.

I had been thinking of just having 5 small digital thermometers connected and displayed in a very visible place. However, the idea of having an alarm sound is brilliant. I will ask the chap who made my exhaust temp alarm to look at adding one to his list - he posts on this board, but cannot remember his name.

 

[VicMallows]

I think you have to accept that all the charge control devices available to us mortals are pretty basic...essentially due to convenience and cost.

If I were to design an 'ideal' installation I would start by using a bank (banks) of individual cells (first choose cell technology!). I would then monitor the voltage and temperature of each individual cell, along with the current flowing in each bank. I would feed all this information to a computer so I could monitor and optimise the charge regime. This would vary of course depending on the load characteristics and the ageing of the cells, amongst other things.

ALL POSSIBLE...BUT NOT REALLY REALISTIC.

Down to earth....the Stirling regulator (at least my one) SIMPLY gives a timed boost charge of approx 1hr at 14.8v before dropping to a 13.8v float voltage. It does this EVERY time it is switched on (eg engine started). This usually works out fine; but could exceptionally result in underperformance or overcharging.

Vic

 

[Mrnotming]

sterling battery temperature sensor

t
Thanks Chris Vic and Noelex,

Glad to hear I'm not the only one wants the problem to go away by itself!

The suggestions are good and further work may produce a workable alarm system!

Others may come along and contribute something too, once the thread is understood.

Good sailing and boating to all,

 

[Mrnotming]

Sterling Alternator battery sensor

Hi again Chris Robb,

Those acrid fumes you mention would also have led to the production of quantities of Hydrogen gas, and other threads on this forum have related the effect of explosions on board of damaging extent, in one case mentioned a person witnessed the floor going up through the cabin roof, as I recall, but that person escaped unharmed thankfully.
I omitted to mention this risk or peril earlier as an outcome of the type of fault condition all too common on multiple battery banks, or even single.
Noelex has thrown some light on the function of the thermistor in only controlling charge rate.
When you noticed the smell, did you even think of hydrogen accumulation?

I'm sure you did, but it's easy to forget the danger.Thankfully in your case nothing bad happened.Any switch thrown even to energise the sealed bilge motor blower can put the cat amongst the pidgeons.

 

[mcframe]

I think you have to accept that all the charge control devices available to us mortals are pretty basic...essentially due to convenience and cost.

If I were to design an 'ideal' installation I would start by using a bank (banks) of individual cells (first choose cell technology!). I would then monitor the voltage and temperature of each individual cell, along with the current flowing in each bank. I would feed all this information to a computer so I could monitor and optimise the charge regime. This would vary of course depending on the load characteristics and the ageing of the cells, amongst other things.

Hmm...

Do Rolls have an iPhone app for their 2V cells yet?

Do their 2V cells have NMEA/wi-fi/bluetooth yet?

 

[Chris_Robb]

Hi again Chris Robb,

Those acrid fumes you mention would also have led to the production of quantities of Hydrogen gas, and other threads on this forum have related the effect of explosions on board of damaging extent, in one case mentioned a person witnessed the floor going up through the cabin roof, as I recall, but that person escaped unharmed thankfully.
I omitted to mention this risk or peril earlier as an outcome of the type of fault condition all too common on multiple battery banks, or even single.
Noelex has thrown some light on the function of the thermistor in only controlling charge rate.
When you noticed the smell, did you even think of hydrogen accumulation?

I'm sure you did, but it's easy to forget the danger.Thankfully in your case nothing bad happened.Any switch thrown even to energise the sealed bilge motor blower can put the cat amongst the pidgeons.

Paul, I was absolutely aware of the risk of Hydrogen, and opened all the hatches and doors at once to vent. Ok so I can smell Acid fumes, but as you say p the hydrogen is the danger, so I want early warning devices. In my view even more important than a gas alarm for the cooker!