Thor Forums

[dkoldman]

I wish to add info for reference https://www.thorforums.com/forums/sh...8&postcount=32

Originally Posted by Beau388

I agree modification are a personal choice. I was trying to show that cheap fixed voltage chargers can harm batteries in rare cases. The points you make a valid. For all antimony alloyed flooded batteries here are Trojan's recommendations. As a side note, I went out to exercise the generator this afternoon the ambient 98 F and the sun was shinning on the right side of the coach, The temperature of the two batteries in the compartment was 118 F.

4. How much should I compensate the charge voltage for temperature?

• Temperature will affect voltage readings. As temperature increases, voltage decreases. Conversely, as temperature decreases, voltage increases. Here are the relationships:
• Trojan recommends using the following: For every 1º F below 77º F add 0.0028 volts per cell or for every 1 C below 25º C add 0.005 volts per cell to the charger voltage setting.
• 1: A 12 volt battery @ 70º F. The recommended charging voltage at 77º F is 14.8 volts. The adjusted charging voltage is 14.8 + (6 cells * 7 degrees below * 0.0028) = 14.92 volts.
• 2: A 12 volt battery @ 21º C. The recommended charging voltage at 25º C is 14.8 volts. The adjusted charging voltage is 14.8 + (6 cells * 4 degrees below * 0.005) = 14.92 volts.
• For every 1º F above 77º F subtract 0.0028 volts per cell or for every 1º C above 25º C subtract 0.005 volts per cell to the charger voltage setting
• 1: A 12 volt battery @ 85º F. The recommended charger voltage at 77º F is 14.8 volts. The adjusted charging voltage is 14.8 – (6 cells * 8 degrees above * 0.0028) = 14.67 volts.
• 2: A 12 volt battery @ 29.5º C. The recommended charger voltage at 25º C is 14.8 volts. The adjusted charging voltage is 14.8 – (6 cells * 4.5 degrees above * 0.005) = 14.67 volts.
  • 5. Is there a maximum temperature for charging my batteries?

When charging lead acid batteries, the temperature should not exceed 120ºF. At this point the battery should be disconnected from all charging sources and loads in order to cool before resuming the charge process.

__________________
Jim & Roy Davis
2016 Hurricane 31S
1961 Rampside in tow