Forcing Classic to stay in float

[Rybren]

I have an off-grid camp powered by the system listed in my sig.  The camp generally only gets used on weekends; on leaving, the inverter and inverter breaker on the epanel get shut off.  So in theory, the only load on the batteries is the Classic itself; there are no DC loads.

When I arrive at the camp on Saturday mornings, the Classic is usually in MPPT Bulk.  It then transitions to absorb and, eventually to Float.  (I have EA set to 3A)  By the time that Float is reached, the Classic reports production of about 0.3 to 0.4 kWH.

I'm new to this game, but I find it strange that the Classic would go through a full cycle on a daily basis when there is no load on the system. I also wonder what effect, if any, this has on the batteries.  My assumption was that when the Classic wakes up in the morning, it would automatically go straight to Float, seeing as how the battery voltage shouldn't drop much overnight.  Guess I was wrong.

Are there any settings that could be used to prevent a full cycle under these circumstances?  Am I being a concerned newbie over a non-issue? 

Classic Firmware is what it came with from the garage sale - 1181 (I've been too chicken to attempt to do an update - I don't want to be stuck in the woods with no internet and a bricked Classic)  I think that the Serial Number is 16xx

Thanks

-Jerry

[Vic]

Hi Jerry,

Believe that the vast majority of the CCs on the market attempt to fully recharge the battery,  starting anew each day.  Believe that there are a couple of exceptions with CCs  from EU.

MidNite folks have mentioned that perhaps there will be a way for the Classic to delay Absorbing based on AH removed from the battery,  or at least the minimum recorded battery voltage.  This is  not in the current firmware,  and may well want to use the new WhizBang when it is more fully featured.

Here,  set the Classic's Vasorb to 0.1 volts above Vfloat,  and this essentially does what you want it to do.  There may well be an additional way to do it.  This setting causes the Classic to Bulk until the float voltage +0.1 volts is reached,  and then switches to Float.  So,  the batteries do see a bit of recharge every day -- we have nominal loads from the inverters and refer plus parasitic loads on the systems here.

My opinions,    Vic

[Halfcrazy]

Vic is correct most common Charge controllers do a daily Bulk charge. There is a firmware update coming soon that will have a "Days Between Bulk charge" boB will be working on this in the near "very near" future. he is working on the Current Sense module now and is basically done with the AH and End amps etc.

Ryan

[zoneblue]

We figured if we razzed you enough about those other european devices, youd probably want to get even. Way to go.

OP. the classic draws 4w tare, so thats about 100Wh per day. Assuming when you leave at the end of the weekend the bank is reasonably up there, then you could turn the classic off aswell when you depart. However with your smallish pv to bank ratio, im guessing your bank is a bit tired by the time you leave. So may not work.

[Rybren]

Thanks for all of the thoughts and insights.  Like everyone else, I am eagerly awaiting the WizBang.

I may give Vic's suggestion a go the next time I'm up at the camp.

Zone: My loads are currently light and the PVs have no trouble doing a full charge before leaving. SG is consistently 1.270+ by noon.

I could turn the Classic off during the spring to fall period, but the camp is unattended once the snow flies, so I'd need to keep it hooked up over the winter.

Thanks again,

-Jerry