Plasmatronics External <span class="highlight">battery</span> <span class="highlight">temperature</span> sensor
Submitted: Tuesday, Aug 12, 2008 at 19:06
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richor
A month ago I installed an external
battery temperature sensor to my Plasmatronics PL20 solar regulator.
I have the PL20 set as follows :- BMAX = 14.5 v ABSV = 13.8 FLTV = 13.5
A few days after I connected the
temperature sensor I checked the previous days data and noticed that the VMAX varied between 14.5 v and 15.1 v. The
temperature reading was about 10 deg C. Normally voltages and S.G. readings are adjusted to 25 deg C and at 10 deg the electrolyte would be thicker and probably require more voltage to charge it.
My concern is that my batteries are AGM's and 15.1 volts is a bit high for them. It may have been only a momentary high voltage and probably wasn't on long enough to gas the batteries.
Will this harm the batteries and should I drop my BMAX setting or is this exactly how it all should work and I am worrying about nothing? I would appreciate any
feedback.
Regards,
Bob
Reply By: Mike Harding - Tuesday, Aug 12, 2008 at 19:36
Tuesday, Aug 12, 2008 at 19:36
You need to obtain the data sheet for your particular batteries.
I am currently testing some AGM batteries, the manufacturer of which, specifies a maximum cyclic charging voltage of 15V0 at 25C.
Personally; I wouldn't get too stressed about it (this
forum is silly on things like this) - providing their float voltage is not above 13V8 all will be
well.
Mike Harding
AnswerID:
320445
Follow Up By: richor - Tuesday, Aug 12, 2008 at 20:13
Tuesday, Aug 12, 2008 at 20:13
Thanks Mike. I am pretty sure the float voltage hasn't gone above 13V8. I will stop worrying. As an aside, I have tried to get data sheets for my batteries but haven't been able to. I know the maximum voltage is not supposed to go above 15V0 so I have turned off the equalisation. I just had a guess at the other figures. My batteries are over two years old and I haven't had any trouble with them. The state of charge hasn't been below 87% so that helps. Thanks again.
Regards,
Bob
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587253
Reply By: Nomadic Navara - Tuesday, Aug 12, 2008 at 19:55
Tuesday, Aug 12, 2008 at 19:55
The voltage required to charge a
battery varies widely with
temperature. A cold
battery requires a higher voltage to charge it than a hot
battery. That is why the voltage starts high, then as the
battery takes some charge and heats up a little the voltage output from the controller drops. As Mike said, don't worry about it - unless of course the voltage does not drop.
PeterD
AnswerID:
320448
Follow Up By: richor - Tuesday, Aug 12, 2008 at 20:14
Tuesday, Aug 12, 2008 at 20:14
Thanks Nomadic Navara. I appreciate your reply.
Regards,
Bob
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587254