Midnite Kid PV Input

[ralova_24]

Is it possible and safe to use the Midnite Kid as a battery charger/regulator?  Suppose the Kid PV input will be connected to a 48Vdc dc system (source) with SCC connected and the Kid battery terminal will be connected to a 24Vdc battery bank (to be charged).
If this is possible, what appropriate operation mode shall I use Hydo, wind or solar?

Your inputs and explainations is highly appreciated

[ClassicCrazy]

I have used the Kid to charge 12v from 24v battery pack in the past. I believe I just  used Solar. I think I had the current limited down somewhat too.
There has been past discussion on doing this - maybe go to main Forums home page and do a search. I forget all the pro's and cons on doing this.
You would not want to share the same negative as the input negative and output negative have to be separate on the Kid.
Not sure if you are talking about using a power supply as a source as opposed to batteries - that might be different.  Of course you do any of that at your own risk to the Kid.
I was using small 12v battery to power my 12v loads like ham radio and other stuff. So that was a way to get 12v from my 24v battery pack. In the end I bought a Samlex DC to DC converter 24v to 12v .  It is a lot easier and less trouble that keeping another battery system going , probably more efficent,  and very reliable too.

Larry

[ralova_24]

Thank you Larry...

But during the time you were using the Kid as a charger, have you noticed any malfunctions or unexpected problems happen to the Kid?

[Vic]

Ralova,

Do not know what is the SCC.  Often that is a Solar Charge Controller.

Just remember,  that the DC input negative  MUST be separate from the  battery negative.

And if the charge source  is a battery,  you would need to be  careful of its ability to  source large  currents.  PVs are current sources,  but,   they are inherently limited in maximum  current.

FWIW,  Vic

[qrper]

Ralova,

Do not know what is the SCC.  Often that is a Solar Charge Controller.

Just remember,  that the DC input negative  MUST be separate from the  battery negative.

And if the charge source  is a battery,  you would need to be  careful of its ability to  source large  currents.  PVs are current sources,  but,   they are inherently limited in maximum  current.

FWIW,  Vic

Vic....

does the kid or even the classic control the negative lead?  I thought they were high side controllers.

mike

[Vic]

Mike,

The Shunts  need to be  in the low  side.   The KID  measures   current   in the  low  side   of   the PV input,   and guess that   it does   not measure output current (that would  be in the high side).   Guessing it calculates the  output current from the   input V and  I    ...   but  could well  be  wrong.   The Classic has a shunt in the output (high side),    and  IIRC  it  may be opto isolated  for the Classic to  be able  to read  it     ...

FWIW,  done guessing for  now,   73  Vic

[ClassicCrazy]

Thank you Larry...

But during the time you were using the Kid as a charger, have you noticed any malfunctions or unexpected problems happen to the Kid?

I had no problems using Kid to charge 12v battery from 24v battery .

Larry

[Vic]

Hi Larry,

IMO,  charging one battery from another,   can be a bit  risky.   Believe that the  KID is fast at limiting output current   ...   but,   bad things can sometimes happen very quickly,  as the source battery often  can supply very high currents.

boB,   or others will chime in,  to correct  my bad guesses.

Hi Larry,

IMO,  charging one battery from another,   can be a bit  risky.   Believe that the  KID is fast at limiting output current   ...   but,   bad things can sometimes happen very quickly,  as the source battery often  can supply very high currents.

EDIT: Using Legacy O & P,  in these situations  has been mentioned  as helping,   when using a stiff power source on the  input of the MN CCs (O & P,  in the case of the KID).
We have used an SMPS as the input source,   but,  it was running very close to its max available current,   so it was soft.   Was using O&P,  as well.

boB,   or others will chime in,  to correct  my bad guesses.

73   FWIW,   Vic