question

stokie77 avatar image

Where is the Temperature sensor mounted - in the Easy Solar 48v box, or in my BYD lithium battery box?

Where is the temperature sensor mounted for my Easy Solar 48v system? Or is it mounted inside my BYD Lithium battery box? My problem is in the winter, when the shed temperature is lower than 15 deg C and I'm running the generator, then the sun comes over the hill, and my solar panels' charging capacity is throttled back, due to the low temps. I'd like to install a small heat source, say a 100w light bulb, running off the generator output, to warm the system up enough to make the most of the brief winter sunlight.

Another question: Do lithium batteries need this low temperature protection? Is it possible to adjust the temp threshold down a few degrees?

Many thanks.

EasySolar All-in-OneTemperature SensorBYD
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2 Answers
Mike Dorsett avatar image
Mike Dorsett answered ·

The Temperature sensor should be close to the batteries, this could also be linked from the BMS reading of temperature. Lithium batteries can't charge fast at low temperatures, due to electron mobility in the electrolytes. It would be good practice to regulate the temperature of the battery to above 15C by insulating the battery box and installing a regulated heater. It sounds like you are unlikely to suffer from batteries overheating - the ambient should not go above 23C for long life. If you need, also put in a fan that operates at high temperatures....

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Rick avatar image
Rick answered ·

Yesterday I tried a 60W bulb inside the battery box, then a heat gun, then today I've been running a hungry 1kW fan heater inside the battery box for over an hour, to warm up the batteries, allowing my panels to glean as much winter sunshine as possible - I now realise that this must have been an issue for the past 3 winters. My current setup inside a shipping container hardly ever gets even close to 15 degrees C in winter. I need some way of reducing the minimum threshold to about 9 degrees, or to raise the maximum charging amps permitted at colder temps, to allow the system to function. I realise that Lithium batteries don't like to be charged at 5 degrees or lower temperatures, but it is quite frustrating to watch the solar panel kW climb dramatically every time an electrical load is applied, showing me they could be charging so much more than they are actually doing.

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I don't think there is much you can do. What type of B-Box do you have?

You have to thermal insulate the battery and/or install some heating elements inside the B-Box (maybe heating foil between the battery modules).