Upgrading to Lithium with Solar...
Fellow RVers, My first post here, so please excuse any ignorance on my part. I have a 2012 R-Vision Crossover, 19' travel trailer. I have been using a 160w roof-top solar panel to charge two 12...
Forum Discussion
It seems when the "thinking of switching to lithium" threads come up there are always 2 things that get stated.
1, too rich for my blood and will wait for the price to drop.
2, cold temp use/ charging. This is where having individual cell temps/ voltages come into play. If your looking at dropin batteries does the brand you're looking at have that capability. I know lifeblue does (which are also prismatic pouches) compared to Battleborn many little cells made into a battery case and last time I checked weren't able to see cell info.
From the link I previously posted about temps.
What is the operating temperature of the LFP cells?
The operating temperature of the LFP cells is based on the specification and the application. There are several points to be clarified in this matter. The first to clarify is the three different temperatures in relation to the batteries.
The ambient temperature
The ambient temperature is usually given as the air temperature of any environment where the batteries and related equipment are kept. The ambient temperature is given at the specification of the cells. It is also called the operation temperature.
The cells can be stored and operated within these temperature limits. However the performance of the cells is dependent on the temperature so the performance of the battery differs in various temperatures. In simple words, when the cell is cold (bellow zero) the performance is limited, when the cell is hot (above 40 °C) the drain of the cell must be limited as well in order to protect against overheating.
The cell temperature (surface)
The cell temperature is the temperature measured on the surface of the cell. As the heat has the tendency to go up, the temperature of the cell is usually measured at the top part of the cell.
When not in operation the cell temperature will be similar to the ambient temperature. Since the cell is mostly composed of metals, the cell temperature is usually slightly lower than the ambient temperature.
When in operation the cell emits (dissipates) heat and starts warming up. So during the operation the cell temperature is usually higher than the ambient temperature. When the cell is cold (bellow zero) the cell temperature will increase quickly to above zero and keep growing depending on the drain rating (the current in Amp). When the cell is in hot environment, the temperature of the cell will increase quickly as well. That is why it may be necessary to arrange for ventilation, cooling or air-conditioning to maintain the temperature within the limits.
The cell internal temperature (inside)
It is the estimated temperature inside the cell at the hottest point. During the operation the cell warms from inside. When continued operation under high currents, the temperature of the cell may increase quickly. Inside the cell is the warmest place. However it is not possible to measure this temperature, as it is inside the cell and there is no access. This temperature is only estimated.
Typically, the internal temperature maybe about +15°C higher than the cell temperature on the surface. The internal cell temperature is mainly important in hot operating environments. It is necessary to avoid the over heating of the cell. That is why the cell may needed to be cooled to keep the internal temperature within the construction limits.
Example for Winston cells
The specification for the ambient temperature is given at -45°C to 85°C. The typical operational temperature of the cells (at the surface) is at 0°C to 40°C (max 60°C). The internal temperature under load should not exceed the maximal limit (<85°C) that is why the surface temperature of the cell should be kept within a limit of 40°C (to 60°C).
Even with "dropin" batteries you might have to think about placement. Also, just because it 0c/ 32f doesn't men you can't charge the batteries unless maybe they've been sitting unused for an extended time, if that's the case in your planning stage thought should have been given to warming them some before charging, whether with a warming pad or another source of heat.
I posted this in another thread a couple days ago.
I've seen outside temps as low as 25f with my front unheated compartment (other than my inverter/ charger & solar controller throwing a little heat) at 40f +/- and cell temps 45-50f. Using the batteries will warm the cells. Now if temps were dropping into the single digits for an extended time a warming pad or just covering the batteries helps hold them warmer. Just my observations from living off of solar/ lfp 24/7/365 for the past 3 years. Besides longterm psoc won't hurt them. ;)
These temperatures are read from my batteries having individual cell temp/ voltage reading, a remote thermometer in the compartment and a remote thermometer outside the 5th wheel.
1, too rich for my blood and will wait for the price to drop.
2, cold temp use/ charging. This is where having individual cell temps/ voltages come into play. If your looking at dropin batteries does the brand you're looking at have that capability. I know lifeblue does (which are also prismatic pouches) compared to Battleborn many little cells made into a battery case and last time I checked weren't able to see cell info.
From the link I previously posted about temps.
What is the operating temperature of the LFP cells?
The operating temperature of the LFP cells is based on the specification and the application. There are several points to be clarified in this matter. The first to clarify is the three different temperatures in relation to the batteries.
The ambient temperature
The ambient temperature is usually given as the air temperature of any environment where the batteries and related equipment are kept. The ambient temperature is given at the specification of the cells. It is also called the operation temperature.
The cells can be stored and operated within these temperature limits. However the performance of the cells is dependent on the temperature so the performance of the battery differs in various temperatures. In simple words, when the cell is cold (bellow zero) the performance is limited, when the cell is hot (above 40 °C) the drain of the cell must be limited as well in order to protect against overheating.
The cell temperature (surface)
The cell temperature is the temperature measured on the surface of the cell. As the heat has the tendency to go up, the temperature of the cell is usually measured at the top part of the cell.
When not in operation the cell temperature will be similar to the ambient temperature. Since the cell is mostly composed of metals, the cell temperature is usually slightly lower than the ambient temperature.
When in operation the cell emits (dissipates) heat and starts warming up. So during the operation the cell temperature is usually higher than the ambient temperature. When the cell is cold (bellow zero) the cell temperature will increase quickly to above zero and keep growing depending on the drain rating (the current in Amp). When the cell is in hot environment, the temperature of the cell will increase quickly as well. That is why it may be necessary to arrange for ventilation, cooling or air-conditioning to maintain the temperature within the limits.
The cell internal temperature (inside)
It is the estimated temperature inside the cell at the hottest point. During the operation the cell warms from inside. When continued operation under high currents, the temperature of the cell may increase quickly. Inside the cell is the warmest place. However it is not possible to measure this temperature, as it is inside the cell and there is no access. This temperature is only estimated.
Typically, the internal temperature maybe about +15°C higher than the cell temperature on the surface. The internal cell temperature is mainly important in hot operating environments. It is necessary to avoid the over heating of the cell. That is why the cell may needed to be cooled to keep the internal temperature within the construction limits.
Example for Winston cells
The specification for the ambient temperature is given at -45°C to 85°C. The typical operational temperature of the cells (at the surface) is at 0°C to 40°C (max 60°C). The internal temperature under load should not exceed the maximal limit (<85°C) that is why the surface temperature of the cell should be kept within a limit of 40°C (to 60°C).
Even with "dropin" batteries you might have to think about placement. Also, just because it 0c/ 32f doesn't men you can't charge the batteries unless maybe they've been sitting unused for an extended time, if that's the case in your planning stage thought should have been given to warming them some before charging, whether with a warming pad or another source of heat.
I posted this in another thread a couple days ago.
I've seen outside temps as low as 25f with my front unheated compartment (other than my inverter/ charger & solar controller throwing a little heat) at 40f +/- and cell temps 45-50f. Using the batteries will warm the cells. Now if temps were dropping into the single digits for an extended time a warming pad or just covering the batteries helps hold them warmer. Just my observations from living off of solar/ lfp 24/7/365 for the past 3 years. Besides longterm psoc won't hurt them. ;)
These temperatures are read from my batteries having individual cell temp/ voltage reading, a remote thermometer in the compartment and a remote thermometer outside the 5th wheel.
