Completely discharged/dead battery, Classic 150. Fun!

[Onlooker]

Its been running 'great' for a few winters, but lack of sun and age.. A remote Canadian installation running camera/inet/PIR-lights ran completely dead.. Last reported voltage was ~6.x on a "12V industrial flooded lead-acid scrap battery"..

The next days, nothing 'came back up again'; So presumably the charge controller isn't trying to charge battery with ~0-6.5V to the existing 12V settings... Even in overcast during the 'day' it should provide the sufficient 'running power'...


I'm writing instructions to a friend to try and get it charging/up again... The 'worst case' I figure is to disconnect incoming solar and the 'main battery'; put a temporary/jump battery in the system, connect charge controller, connect (part) solar(See that it's awake/taking current); then connect the 'dead/main battery' up momentarily before removing the 'temporary/jump battery'...  Early on a hopefully 'sunny day'..

Does anyone have experience with this on the Classic 150? Is this necessary instruction to leave; or do you know from personal experience that it might be possible to just "jump" the dead battery while the sun is out and the Classic is 'powered from solar' seeing a 0-6.7V battery;  Will the Classic 'start' charging in this state once it sees a 12V battery there? This would be a lot easier(short jumper cables to dead battery)..

Is there any jumper/setting in the classic that would force it to charge 12V from dead in the future?. Goal now, have the 12V system/devices powered when the sun is up, battery 'care' not a priority; if it recovers with capacity BONUS!

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Not to complicate things, but there is an Xantrex c35 on the same battery normally charging from a smaller array; It is also not attempting to charge the dead battery; but otherwise flashes 'on /function' when sun comes up... I add this information only if someone has any tricks for getting this one starting a dead battery.

It's tempting bypass the C35 and connect 1(or 4) "12V" 85W panel's directly to the battery without regulation(old school<grin>) that might 'trick the classic into thinking it is starting from battery'.

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I know I "should have" put a solenoid on the AUX port to disconnect/kill all load before the battery approached dead, but there were reasons...

[Vic]

I do not meet your initial qualification, of having personal experience.

Connecting PVs directly,  through a DC breaker, to the dead battery should help getting this battery up to the voltage where the Classic can begin to operate (about 10 V battery, minimum).

BUT,  then there needs to be a person to do the charge control function.

It is possible, that the Classic will begin operating from a different 12-ish V battery,  and, then continue to run from PV input, while the transition is made to the dead battery  ...   no personal experience with any of this,  thank goodness.

All for now,  Good Luck,    Vic

[ClassicCrazy]

Like Vic said - the Classic will shut down if the battery voltage is too low.
So getting the battery up high enough to turn on the Classic so it will start charging is the only option.
And then hopefully the battery isn't so bad now that it will still hold a charge.
Otherwise a new battery is going to be the only way to fix it.
Regarding just jumping the pv to the battery - that should work though how high is the PV voltage ?  You would want to make sure it doesn't jump the voltage up way too high and start cooking the battery.
You mentioned that it was a scrap battery - meaning old ? It may have gone so low in voltage and the plate are so sulphated up it isn't going to work well or at all any longer.
Larry

[Onlooker]

Maybe I am mistaken, but I thought the Midnite Classics will still 'power on' from solar input only; just some 'safety' thing keeps it from attempting to put a voltage onto a to-low/dead volt battery? 
Won't be getting any new batteries until spring; looking for way to keep some of the equipment running when the sun is out.

Some "Lithium Supported" charge controllers has a mode to supply 12V to a "dead battery" to 'wake up a lithium BMS'.  Hmmm..

[ClassicCrazy]

My lithium batteries bms shut them off last winter cause I got them too low. That shuts off the Classic and the inverter. So I couldn't even use the generator into inverter to charge them. I had an ebike charger that was high enough voltage and ran the generator into that . It only took a minute to wake up the bms , which turned the Classic and inverter back on. So I know that the Classic won't provide any power with no battery. I also learned that the Classic SOC provided by Whizbang is more accurate  than the bms provided SOC .
Larry

[boB]

Sorry to say that the Classic (and most) MPPT controllers will not power from the PV input side from a dead start.

Your idea of jumping PV to battery is the way to go.

If the Classic is simply in RESTING, you can just take a short piece of wire and connect from PV+ to BATT+ and the Classic should come alive where you can view the battery voltage.  Doing it this way, with the PV+ still connected to the Classic's input should NOT cause the Classic to come out of Resting because the input and output voltages will be the same.

If you do that, just watch the battery voltage come up to to 13 or 14 volts and then remove the jumper.

If there is enough energy in the batteries at that time, the Classic should come out of resting and start charging.

Do not connect the PV+ to battery+ if the Classic is NOT resting though.

OR you could unscrew the PV+ wire from the input and touch it to the BATT+ wire or screw instead.

It MAY be that you have a dead-enough battery where things won't work but worth giving it a try.

boB

[Onlooker]

Plan now is to unplug/switch off any direct powered 12V PIR/flood lights ( https://www.amazon.com/GLW-Waterproof-Daylight-Security-Equivalent/dp/B00W4ZMIP4/ ); then everything else is on a DC-DC step up/down buck converters; so I'm thinking disconnect the 4 85W (17.8VMP) from the C35 and connect it directly to the battery.. Solar voltage from that should wake the Midnite Classic; If the battery is toast it could voltage spike-maintain to 17.8v or maybe 21.8(voc) but if sufficient power that alone should power 'the other stuff' converters . If the battery takes a charge it should be in the 10-15V range and the Classic will try doing its usual charge.. Unfortunately when/if it succeeds the 4 85W might then burn the @*#& out of the battery if too much sun, but thems the breaks .. Flooded, maybe I could keep it well topped off..

I've verified from years of use that those flood lights don't get destroyed from 15VDC; but sadly I don't think the PIR sensor or LEDs are likely to tolerate  17.8-21.8V...

Seeing how the Canadian fascists(Corporate and government collusion)   have arranged it so that I cannot continue to purchase scrap batteries(or lead acid/flooded legally technically)... Will likely switch to LifePo4 after this... Then gotta buy heated and hope they actually work properly...

https://archive.is/X7YvX
https://archive.is/mJQcs

[boB]

Sounds like you will get it to work.

At least you aren't converting down from, like, 100 volts to 12V and having to connect THAT to your 12V battery !

boB

[Onlooker]

IT'S ALIVE!


We will see... But taking some amps, and 'mid day'... as soon as ~12V  is seen on the battery side the classic did start up(I was worried it might not, if PV power came in first, as it did)..
Classic was switched on from the raw panels normally going to C35, connected directly to battery.. now 'over charge' is the worry.. but soon as voltage goes over 14.6V~ the Classic should 'stop producing' and it'll be up to the 4 85W panels(perhaps I/we should limit it to just 1 connected directly but we will see).

Not much sun... Questionable odds if it powers through the night; not likely me thinks...