John Frum
Tell me your problems
- Joined
- Nov 30, 2019
- Messages
- 15,233
For the SCC's, I would think re-bulk voltage offset might help trigger the SCC to kick back into bulk mode if you're significantly undercharged, though there'd still be a delay for the battery to settle, as well as the risk of microcycling under normal usage since you have to go into bulk mode before you can drop back into absorption.
You talk about discharging to 10% but I think what you want is to rebulk when the sun starts shining in the morning.
The part we haven't really talked about is low voltage disconnect.
Lets leave that for a later message if you are really interested.
The problem with re-bulk in the context of a solar charge controller is that you want to use solar power when the sun shines.
If you use a re-bulk voltage that corresponds with 10% SOC the SCC will not charge until the voltage dips to the re-bulk point.
You also want to power your loads directly off of the SCC while the sun shines.
In order to do that your SCC voltage must be higher than that of the battery.
You could set a float voltage higher than full resting voltage to achieve that goal.
Its a bit more stress on the batteries but most everything in life is a trade-off.
Shooting for 10-90% is aspirational ideal but the sun rises when it rises and sets when it sets.
You want to make use of that power when it is available.