Charging the Lifelines questions
As you all know, anything more than clipping the auto charger onto a battery is well above my pay grade, so I have some questions. For the regular charge before the conditioning charge, the Lifelin...
Forum Discussion
Mexico Wanderer
Standard LFP will discharge at fairly low temperatures. The minimum values given in literature for discharge at low temperature are between –20°C and -30°C. The problem is in charging at high C charge rates and there the minimum temperature is 0°C. It is quite likely that the low C charging rates of solar in the morning may mitigate this. We left our rig at son's place in mountains of northern NM for the last two years when we flew to Central America one winter and South America for another winter and it got down to –30°C. Inverter was off (it has a parasitic draw of about 100 W) and so the battery suite was never discharged more than -300 W (-3% of total charge) so that charge rates would have been extremely low.
It is possible to heat the battery storage area with heating pads and/or incandescent light bulbs (30 W or so). We have done this to keep the main luggage are (basement) warm on cold nights to prevent the pipes from freezing. This kept the baggage area to upper 30's on nights that got down to –23°C. We have sufficient battery storage to do this.
The other worry is high temperatures and the limits are 45°C for charge and 60°C for discharge. Cris Dunphy of Technomadia blog has written candidly with problems of possible overheating when they were parked on tarmac in Phoenix during the summer for several weeks. The LFP battery bank was in a non vented compartment with the inverter and the temperatures could have been fairly high. We leave the battery/inverter compartment (8' x 2' x 3' or so) open when using inverter to run air conditioner. We plan to eventually install a couple of 12 V receptacles for 12 V fans (12 W) for increased circulation.The same receptacles will work for incandescent lamps.
Have installed a remote thermometer in the battery (otherwise known as a $15 Walmart inside/outdoor thermometer) to monitor the temperatures in the bay. The highest we have measured was 32°C when it was 34°C ambient.
Reed and Elaine
Standard LFP will discharge at fairly low temperatures. The minimum values given in literature for discharge at low temperature are between –20°C and -30°C. The problem is in charging at high C charge rates and there the minimum temperature is 0°C. It is quite likely that the low C charging rates of solar in the morning may mitigate this. We left our rig at son's place in mountains of northern NM for the last two years when we flew to Central America one winter and South America for another winter and it got down to –30°C. Inverter was off (it has a parasitic draw of about 100 W) and so the battery suite was never discharged more than -300 W (-3% of total charge) so that charge rates would have been extremely low.
It is possible to heat the battery storage area with heating pads and/or incandescent light bulbs (30 W or so). We have done this to keep the main luggage are (basement) warm on cold nights to prevent the pipes from freezing. This kept the baggage area to upper 30's on nights that got down to –23°C. We have sufficient battery storage to do this.
The other worry is high temperatures and the limits are 45°C for charge and 60°C for discharge. Cris Dunphy of Technomadia blog has written candidly with problems of possible overheating when they were parked on tarmac in Phoenix during the summer for several weeks. The LFP battery bank was in a non vented compartment with the inverter and the temperatures could have been fairly high. We leave the battery/inverter compartment (8' x 2' x 3' or so) open when using inverter to run air conditioner. We plan to eventually install a couple of 12 V receptacles for 12 V fans (12 W) for increased circulation.The same receptacles will work for incandescent lamps.
Have installed a remote thermometer in the battery (otherwise known as a $15 Walmart inside/outdoor thermometer) to monitor the temperatures in the bay. The highest we have measured was 32°C when it was 34°C ambient.
Reed and Elaine
