PD or Iota for my upgrade?
I'm thinking about a converter and battery upgrade. The batteries will be wet cell lead acid 6 volt Possible T-105s or the 230AH, EGC2 from Sam's club. I'll probably go for four. (Does nayone have...
Forum Discussion
BTW, I'm not trying to tell users here how battery charging works. I'm new to this forum, and I'm trying to learn, not teach. I'm trying to explain how I think battery charging works with the one charger I've studied in detail - the PD9200 series, and I hope to get feedback from those who have studied this for longer or more carefully than I have where I go wrong.
For those who read my comments above, you may see an inconsistency. On the one hand I said the charger stops raising voltage at the voltage limit, and it then starts to taper the charge current, while I also said the Trojan recommendation is to stay at bulk constant current charge rate until 90% State of Charge - SOC. There's no good way I know of for the charger to know SOC. It can't measure the SG. I don't know if having the charger reach it's voltage limit - which it uses for the absorption stage - automatically means the battery is at 90% SOC. I suspect not.
The optimum charge profile might actually have the charger voltage climb above the absorption voltage limit as long as the battery is below 90% SOC.
From what I can tell, the PD9200 series will drop out of bulk charge mode in 8 hours if it entered it automatically regardless of voltage. It will drop out in 4 hours if it was manually forced into the bulk mode by the pendant.
I'd like to know more about this, but the automatic profile is in the firmware program in the PD - it's not something that can easily be changed.
What I may be able to change however are these two aspects:
It may be possible to change the voltage monitor to remotely monitor the battery voltage, not the charger output voltage. That shouldn't be too hard based on my initial review of the circuit.
It may also be possible to make it adjust the voltage limit by sensing battery temperature so it increases charge voltage in the cold. That's a bit trickier, but looks do-able.
For those who read my comments above, you may see an inconsistency. On the one hand I said the charger stops raising voltage at the voltage limit, and it then starts to taper the charge current, while I also said the Trojan recommendation is to stay at bulk constant current charge rate until 90% State of Charge - SOC. There's no good way I know of for the charger to know SOC. It can't measure the SG. I don't know if having the charger reach it's voltage limit - which it uses for the absorption stage - automatically means the battery is at 90% SOC. I suspect not.
The optimum charge profile might actually have the charger voltage climb above the absorption voltage limit as long as the battery is below 90% SOC.
From what I can tell, the PD9200 series will drop out of bulk charge mode in 8 hours if it entered it automatically regardless of voltage. It will drop out in 4 hours if it was manually forced into the bulk mode by the pendant.
I'd like to know more about this, but the automatic profile is in the firmware program in the PD - it's not something that can easily be changed.
What I may be able to change however are these two aspects:
It may be possible to change the voltage monitor to remotely monitor the battery voltage, not the charger output voltage. That shouldn't be too hard based on my initial review of the circuit.
It may also be possible to make it adjust the voltage limit by sensing battery temperature so it increases charge voltage in the cold. That's a bit trickier, but looks do-able.
