Why does my classic want to stay in float mode from daybreak on?

[littleharbor2]

 Actually my friends Classic 150. Even though it says it's in float MPPT mode it is making full wattage as if in bulk mode. I will reboot it when I am over at her place and it won't make any more power than when it says it was in float mode.

The charging setpoints are very standard for her AGM batteries bulk/absorb, 58.8, float, 54.4

[ClassicCrazy]

You didn't say if there was  a load on the system.  The Classic will make as much power as needed to run the loads . Float Mppt is I think when the classic was in float but then there are more loads than the Pv coming in so the voltage drops below the Float setpoint and it goes to Float Mppt .
Did you check the clock on that classic to make sure it is set correctly ?
Other things to check are to see what Absorb time is set for, and if ending amps are set.
Either of those things could lead to a battery going too quickly in morning from absorb to float. Also if batteries are cold and the temp compensation is not set correctly.
Larry

[boB]

Also, if the ending amps is set too high, it can exit Absorb too quickly and go to Float.

[littleharbor2]

 Minimal load on system. This is around mid morning when I would expect to be into bulk mode.  Making 9xx watts at the time, when rebooted and in Bulk MPPT the power production stays about the same

I'll take a look at those settings, Thanks

[littleharbor2]

You didn't say if there was  a load on the system.  The Classic will make as much power as needed to run the loads . Float Mppt is I think when the classic was in float but then there are more loads than the Pv coming in so the voltage drops below the Float setpoint and it goes to Float Mppt .
Did you check the clock on that classic to make sure it is set correctly ?
Other things to check are to see what Absorb time is set for, and if ending amps are set.
Either of those things could lead to a battery going too quickly in morning from absorb to float. Also if batteries are cold and the temp compensation is not set correctly.
Larry

Again, minimal load on system. This morning in Float MPPT it was making 1200 plus watts. Rebooted and in Bulk MPPT was making the same 1200plus watts.
Checking settings I found ending amps set to , actually, never set to zero, amps. Set to 2 hours.
Absorb was set to zero, set to 8 amps. (405 amp hour @48 volts battery).
Clock was 10+ hours fast. Set to correct time. What would the clock being wrong do to the charging modes?
Also does setting ending amps negate absorb time, and vice versa?

[boB]

Ending amps set to zero is "disabled"   Can't charge below zero amps so that is why that is set there by default...

Otherwise, yes, Ending amps, of charging amps were go go below the setting (higher than zero of course) would stop the Absorb.

If Absorb was set to zero time, that would also end the Bulk/Absorb as soon as the battery voltage rose to the set-point absorb voltage.

Remember that the "target" voltage is the set Absorb voltage  plus or minus some depending on how hot or cold the battery is IF the battery temp sensor (BTS) is plugged in.

boB

[littleharbor2]

Thanks boB. Hopefully, starting tomorrow the Float MPPT will be a thing of the past.

[littleharbor2]

 Larry, still curious about the clock question.  Could you elaborate on that?

[ClassicCrazy]

Larry, still curious about the clock question.  Could you elaborate on that?

I think the Classic starts a new day after midnight. So if the clock was way off it will not start the new absorb cycle for the new day at the right time.
Ryan just talked about this in some recent post but I don't remember which post or topic it was.

Larry

[littleharbor2]

Thanks for the clarification.

[littleharbor2]

Everything looks right now on her classic. Thank you all who contributed.

[FNG]

Yes the clock can cause lots of issues, Everything the classic does for a day is based on the clock and trips at midnight so if the clock is off the classic will start a new day at the clocks midnight not the actual midnight

[littleharbor2]

Never knew that as I never got that far into settings before. I better check the clock on my Classic now, although I have never had an issue with mine going on 10 years now.

[boB]

Just checked the code...

IF the Classic itself has not had its time/date set from the connected MNGP or over its network, then after two (2) hours of NO sun, the Classic will force itself to be midnight and should then start a new day next time the sun illuminates the PV array and the Voc goes somewhat above battery voltage.   No sun usually means that the PV voltage is below battery voltage and it starts counting time with no sun from there.

Anytime there is power, the Classic resets that time with no sun timer.

How the Classic determines that the clock has NOT been set is that it looks at the date and if the year is lower than, say, 2014, it will force the time to be midnight  inside the Classic.

Classics come programmed as year 2000 or 2003 (One of those years is the MNGP)  and starts from there if the clock has not been set.

boB

[littleharbor2]

Wow, that's a lot of thought and programming for something as basic as what time it is. One of the hundreds of reasons why Midnite makes vastly superior products and is second to none in the Offgrid PV world.