SOC sets to 100% on reset?

[disco4wd]

I'm running 'The Kid' with the Whiz Bang Jr' on a 200Ah LIFEP04 bank (2x12V/100aH in parallel) off 3x350W solar panels on my caravan roof.(not producing anywhere near the wattage stated)
The Jr seems to indicate the correct SOC, however, if the batteries are at a lower SOC .. eg 60%, if I reset the breaker the SOC jumps to 100% .. even though I know the bank is at 60%.
It stays this way until the bank is fully charged and then starts reducing accordingly again.
Is this 'normal' .. or have I wired something incorrectly?

[boB]

At 350W times 3 panels, you have 1,125  watts label rating available.  If you take that power and calculate the amps possible current into the batteries, assuming 100% of the rating gets through, that would be  85 to 90 amps which is too much for a Kid...   That would be into a 12V bank.  The Kid will more than likely current limit.

Then , the panels will heat up in the sun and put out somewhat less power.  Usually it's about 80% for various reasons because of losses.  I still use the label rating though because it does happen that you can get that 100% some times.  The 1.25 kW  power rating is based on STC or at 25 degrees C.  That will be rare in the summer where the panels heat up and put out less power.  The PV cells could be twice that temperature which makes a difference.

Check to see if the Kid is limiting from partial shading too.  That will make a huge difference just having a shadow line across the panel(s)

At say, 40 amps output limit, that is 40/200 aH or 0.2C as they say (20% of the Amp-Hour rating)  but should be enough to get them charged as long as they aren't drained by too much power draw.

So, from what I am hearing, and I may be reading it wrong, a single Kid isn't large enough, current wise, to use all of that PV power.  If you went to 24V (series batteries)  you may still be slightly limited because that would be around 40+ amps.

Do you ever see the Kid go into the Absorb stage or go to Float on its own ?  If so, then the batteries should be getting a charge up to that set point voltage.

Let me know if I have something wrong.  I may very well have a senior moment here 

boB

[Wizbandit]

The KID does not remember your last SOC% after you power-cycle it.  It has to re-calibrate to 100% by completing a full charge cycle. Any SOC% after a power-cycle will be random and incorrect, most of the time it juts goes to displays 100% (wrong).  After that it uses math to keep track of the SOC, if you don't do a complete charge cycle at least every few days math error creeps in and your SOC will be off by a few points until it gets re-calibrated.

[disco4wd]

Thanks for your reply.
I figured it would likely be the case that the Kid would have no way of 'knowing' what the charge would be after a reset.
As I said, once the batteries have fully charged again, it reverts back to normal and show the correct SOC.

[disco4wd]

At 350W times 3 panels, you have 1,125  watts label rating available.  If you take that power and calculate the amps possible current into the batteries, assuming 100% of the rating gets through, that would be  85 to 90 amps which is too much for a Kid...   That would be into a 12V bank.  The Kid will more than likely current limit.

Then , the panels will heat up in the sun and put out somewhat less power.  Usually it's about 80% for various reasons because of losses.  I still use the label rating though because it does happen that you can get that 100% some times.  The 1.25 kW  power rating is based on STC or at 25 degrees C.  That will be rare in the summer where the panels heat up and put out less power.  The PV cells could be twice that temperature which makes a difference.

Check to see if the Kid is limiting from partial shading too.  That will make a huge difference just having a shadow line across the panel(s)

At say, 40 amps output limit, that is 40/200 aH or 0.2C as they say (20% of the Amp-Hour rating)  but should be enough to get them charged as long as they aren't drained by too much power draw.

So, from what I am hearing, and I may be reading it wrong, a single Kid isn't large enough, current wise, to use all of that PV power.  If you went to 24V (series batteries)  you may still be slightly limited because that would be around 40+ amps.

Do you ever see the Kid go into the Absorb stage or go to Float on its own ?  If so, then the batteries should be getting a charge up to that set point voltage.

Let me know if I have something wrong.  I may very well have a senior moment here 

boB

Appreciate the reply.
The panels, even though they are labeled as 350W are nowhere near this figure and my estimate is around 80 - 100W max. (dodgy eBay seller)
The max I can get out of each panel at @18V is 4.5A and this lines up with what my Fluke clamp meter, the Kid and Whiz Bang Jr are telling me. That's in near perfect conditions.
All strings measure the same, the diodes have been checked along with all connections re-crimped and soldered.
The 3 panels in series gives me around 55V @ 4.5A .. so about 250W .. which is what The Kid also tells me.
I was hoping to be able to push out close to 30A from The Kid but I still can't get anywhere near this.
Might try to get two fully functional 200W panels from a reputable supplier to swap over.

[boB]

Disco, what can help diagnose this is noting the Voc (voltage) of the PV input when it is resting and then noting the PV input voltage when it is running and saying "Bulk MPPT".

This will give an indication of how well it is tracking.

The PV input voltage when Bulk MPPT should normally be around 80% of that Voc open circuit input voltage.

Will wait for that information

boB