Originally Posted by gordon2
Good.. now its your turn... and going totally off topic (might move this to the other thread but it went off topic and is now about inverters
- My Chins 100Ah LifePo4 arrives in four days.
- I want to use it in the 20 - 80 % charge range.. For the most part I am not worried about 80 Ah vs 90-95 Ah available but the option to charge it all the way would be nice.
- I have a PD9100 converter with Charge Wizard. I can remove the Charge Wizard.
- I also have a CTEK 7002 charger.
- I'm having a heck of a hard time figuring out if either or both of these chargers will be OK, or if I should buy a LifePo4 charger. So what do you think? Buy a new charger?
Normal mode: 14.4 VDC
Snowflake mode: 14.7 VDC (.1 over max for Chins LifePo4)
Supply: 13.6 VDC
Recondition Mode: Not even worth mentioning.. 15.7 VDC and way over max limit.
13.6 VDC, 30 amps
PD9100 with charge wizard:
Norm mode: 13.6 VDC
Boost mode: 14.4 VDC (prob has to be manually activated)
Storage Mode: 13.2 VDC (if no load in 30 hours)
Desulf Mode: 14.4 VDC for 15 minutes every 21 hours.
My concern with using the Boost mode with the charge wizard is that it might end too soon to charge the LifePo4 since it "thinks" it is charging a LA or SLA. Then would the Desulf mode for 15 mins every 21 hours be enough to do the additional charging for the LifePo4 over a lead acid?
I guess what I want is a BMS that reports the true state of charge... maybe this $360 100Ah LifePo4 is not the best choice, but that price!
Charging Limit Voltage: 14.6V
Over Voltage Disconnect Voltage: 15V
Over Voltage Reconnect Voltage: 14.2V
Float Charging Voltage: 13.8V
Low Voltage Disconnect Voltage: 10.8V
Low Voltage Reconnect Voltage: 11.6V
Under Voltage Warning Voltage: 12.4V
I believe that the charger doesn't work on time but rather on amps being accepted by the battery
. If you think about it, the charger doesn't know how big the battery
is, and therefore can't "know" how long it is going to take
to charge, it can only know how much current is being accepted
at any given time.
So I believe that the charger watches the current profile. Which of course is entirely different in a LiFePO4 than a PbA battery
. The charger will see a huge current being accepted clear up to the knee of the LiFePO4 and will continue to provide that current. In effect it will "think" that you have a huge PbA battery.
Now... when that current starts to drop, which is determined by the battery not the charger
... then it will switch modes, thinking that the PbA battery (which it believes it is charging) is now about 80% charged and thinks it therefore needs to slow down the charge current.
But... by then your LiFePO4 battery is already starting up the knee and almost fully charged, probably about 95-98% charged.
The only "gotcha" here is that you will have to tell the charger to start charging, by pressing the button on the dongle thingie.
BTW even this is not entirely true. The LiFePO4 will eventually drop into the discharge knee and the charger will eventually see a voltage that it believes "needs charging" (around 12.2 maybe?) and will turn on the charge current. The only downside is that the battery will discharge clear down to that discharge knee before the charger turns on.
Other than that, I believe that the charger works as well or better than with a PbA because the battery itself accepts high current all the way to almost charged.
That is what I believe.