Spike current at Sunset

drraptor

I noticed a very strange phenomena today. I have installed a Moving iron ammeters between my controller and the battery, at sunset, when battery was at 50% SOC, VOC on the panels was around 36V and dropping (max is 58-62V depending on temperature these days). Ammeter pointer moved suddenly to it's full reading and deflected back to zero. This happened quiet a few times.

After this I removed the negative of the Solar array from charge controller and replaced it. Nothing happened after this.

Cariboocoot

Re: Spike current at Sunset

Things wrong here:

drraptor wrote: »

...at sunset, when battery was at 50% SOC,

If your battery is at 50% SOC at sunset it hasn't been charging properly. Ought to be closer to 90% SOC at that time of day, otherwise you have no overnight power.

VOC on the panels was around 36V and dropping

You don't mean Voc as that can not be measured on a connected panel.

Ammeter pointer moved suddenly to it's full reading and deflected back to zero. This happened quiet a few times.

No idea what a "moving iron Ammeter" is. Analog? No idea how you installed it either, nor what type of charge controller. It is possible with some controllers that before 'going to sleep' they will click in and out of Bulk mode to see if there is any usable power coming from the array. The sudden input of power when they turn on may cause a mechanical meter to momentarily spike. It means nothing, though.

After this I removed the negative of the Solar array from charge controller and replaced it. Nothing happened after this.

Not sure what you mean by removing the negative of the array and replacing it, but it sounds like the problem was faulty wiring; intermittent connection that would show current flow when it hooked up and none when the connection failed.

waynefromnscanada

Re: Spike current at Sunset

Cariboocoot's thoughts are also my thoughts. What hit me the hardest was the 50% SOC at sunset. Ouch. If this is a regular happening, new batteries aren't far away.

drraptor

Re: Spike current at Sunset

Devil is always in the details.

It is a hybrid system, batteries are charged by both Solar and UPS. Don't know why UPS wasn't charging ? Temperature as shown by the charge controller was 36C

This type of ammeter. Installed in series between the + battery terminal and + terminal of the Charge controller.
Attachment not found.

It's a MPPT charge controller.

I removed the negative of solar array and waited a few seconds and re-installed it.

BB.

Re: Spike current at Sunset

Digital "stuff" can have very high/short current spikes... It is possible that a a (relatively) small/short current spike (that sweep of the array) started the meter movement turning, and momentum carried the needle the rest of the way to the right.

-Bill

westbranch

Re: Spike current at Sunset

I'm with BB on this, at wake up and shut down the CC is very busy trying to get that last bit of energy and sweeps almost constantly... just background noise...