Solar Charge Controller Advice Needed
I have a truck camper with a 7 year old solar system: 2x135 watt Kyocera panels in parallel, 2x150AH Lifeline AGM batteries and a cheapie replacement Nature Power controller. I have a compressor r...
Forum Discussion
I read the details on the Bogart. First I would see no gain over an MPPT and I would lose the efficiency boost MPPT provides. Next I am not sure how well the Bogart measures battery drain and replenishment. It does not seem to have any way of tracking the actual recharge of the battery or compensating for the efficiency of the recharge, power lost to heat, or the need to charge older batteries longer. Regardless of theory the Bogart would not work for me. I have a compressor refrigerator that I rewired. I bypassed the rest of the electrical system and used heavy gauge wire directly to the battery posts. The Bogart would not be able to monitor my major use of electricity.
After reading pianotuna's recommendations on optimizing the controller, I did some additional reading. It seems that there is an issue with ending absorption charging and switching to float charging. There are two main ways this is done. The ideal way is to measure the current flowing into the battery at the absorption voltage. When the current drops to a very low level, the charger switches to float. For some reason this current sensing system is not built into the Blue Sky or most other charge controllers. The Blue Sky does have this option if the remote unit is added. Instead many controllers switch to float after a specified time at the absorption voltage. I wondered if this would overcharge the battery and reduce battery longevity. From what I have read this is not an issue. As the battery voltage comes up to the absorption voltage the current drops to a low level and overcharging is not an issue. It appears that the float is more for longer term storage. I plan on doing some additional reading. There is a solution, if needed, I can cut back the absorption voltage from about 14.3 to about 13.7. That has been my battery float level for the past 7 years and the batteries still seem to be going strong.
The more I read, the more I realize there are a lot of factors involved.
Thanks to all of you for additional comments and ideas.
After reading pianotuna's recommendations on optimizing the controller, I did some additional reading. It seems that there is an issue with ending absorption charging and switching to float charging. There are two main ways this is done. The ideal way is to measure the current flowing into the battery at the absorption voltage. When the current drops to a very low level, the charger switches to float. For some reason this current sensing system is not built into the Blue Sky or most other charge controllers. The Blue Sky does have this option if the remote unit is added. Instead many controllers switch to float after a specified time at the absorption voltage. I wondered if this would overcharge the battery and reduce battery longevity. From what I have read this is not an issue. As the battery voltage comes up to the absorption voltage the current drops to a low level and overcharging is not an issue. It appears that the float is more for longer term storage. I plan on doing some additional reading. There is a solution, if needed, I can cut back the absorption voltage from about 14.3 to about 13.7. That has been my battery float level for the past 7 years and the batteries still seem to be going strong.
The more I read, the more I realize there are a lot of factors involved.
Thanks to all of you for additional comments and ideas.
