Lithium Batteries Overheating

[rajlaw]

In my Airstream Globetrotter, my lithium batteries overheat during the hot parts of the day. I have 300 watts of solar power on the roof. Does anyone know what the potential causes as to why my lithium batteries are overheating and how I can prevent them from overheating?

[SuperTrouper]

Hi Rajlaw,

Can you give us a few more details?
Where are the batteries located?
How do you know they are overheating?
What brand batteries/charger do you have?
What are the ambient and battery temperatures when they overheat?
How long have you been running lithium? Is this a new issue?

Many things may be at play including charging and discharging parameters, ambient temp and ventilation, loose connections etc. Let us know more.

[GettinAway]

Following this one. Mine haven’t shown any high temp alarms. Only low temps.

[rajlaw]

Thanks. I will try to provide the information you requested:
1.My batteries are located in a battery box located in the front of the Airstream between the propane tanks and the front outdoor compartment.
2. Lithium Batteries-EXPION 360/12.8v-120Ah
LIFEPO4
3. I do not know the ambient and battery temperatures when the batteries overheat. Both the inverter and solar panel control shows that the batteries go up to 19v when the normal is 14.3v.
I have a Magnum Energy Inverter which shows a fault with a danger warning for batteries overheating.
4. We bought the Airstream used about a year ago and the lithium batteries were already there. We noticed the problem within a few months after purchase. The problem happens only in the hot part of the day. It leads me to believe the battery box may not be vented enough, or the solar panels are overcharging the batteries. There could be some wiring problems I am not aware of but a dealer mechanic could not find a problem. We called Magnum Energy and got new settings for the inverter.

Any help would be appreciated.

[waninae39]

something is very wrong if the batteries are showing 19V
likely miss-wired or wrongly configured.

best to bring LION batteries inside as this reduces tongue weight and keeps their temp in a more steady state condition

[PaulBristol]

Originally Posted by rajlaw

Thanks. I will try to provide the information you requested:
1.My batteries are located in a battery box located in the front of the Airstream between the propane tanks and the front outdoor compartment.
2. Lithium Batteries-EXPION 360/12.8v-120Ah
LIFEPO4
3. I do not know the ambient and battery temperatures when the batteries overheat. Both the inverter and solar panel control shows that the batteries go up to 19v when the normal is 14.3v.
I have a Magnum Energy Inverter which shows a fault with a danger warning for batteries overheating.
4. We bought the Airstream used about a year ago and the lithium batteries were already there. We noticed the problem within a few months after purchase. The problem happens only in the hot part of the day. It leads me to believe the battery box may not be vented enough, or the solar panels are overcharging the batteries. There could be some wiring problems I am not aware of but a dealer mechanic could not find a problem. We called Magnum Energy and got new settings for the inverter.

Any help would be appreciated.

Battery terminal voltage should never get to 19 volts. Solar panel output may get to 19 volts. Solar controller should lower the voltage to 14.4 volts or lower for battery charging. Sometimes the voltage may be 13.6 or even 13.2, but never 19 volts on the battery terminals.

Get a cheap digital voltmeter from your local hardware store. Measure the voltage directly on the battery terminals when the Magnum display says 19 volts.

Most Magnum models with a temperature probe should have the temperature probe unplugged from the Magnum for use with lithium batteries. The temperature compensation is designed for lead acid batteries. Post Magnum model number and model number of remote control for better advice.

Switch the solar controller "OFF" when voltage is at 19 volts. If voltage drops, then the solar controller is at fault.

Switch the solar controller "ON". Switch the Magnum "OFF". If the voltage drops, then the Magnum is at fault.

[rajlaw]

Thanks so much for the information. I will try what you say.