panel configuration reccomendations

[Highflyer]

 I have a kid and I was finally able to play with it today.  I was using some smaller panels to see what it would do with them.  Is there a "best practices" way to set up panels for the best output from the Kid?  The system is 12 volts with lead acid batteries.

I was playing with six 10 watt panels for this trial.  The voltage is 21V each.   My middle sized panels are 85 watt panels, again around 21V.  Ultimately I plan on ~250 Watt panels. 

The six 10 watt panels never made more than 17W but it is very hazy today and they were not optimally aimed at the sun.

Thanks for any help, again I have the Newby shield in place for now!!

[Westbranch]

the closer the input (nominal PV) panel voltage is to the battery V, the less down conversion that will occur and the less heat generated. 
The  place/time to use higher PV V is when you have a longer distance PV to CC and thus would suffer higher line V loss at the lower Voltage.  T
The higher the PV V the lower the line loss per foot at a given line Ga. you want < 3% total if possible in all lines PV to battery.

[TomW]

I seem to recall 1.5X battery voltage is a good open circuit PV input voltage to drive the controller. That was the Classic so may not apply to The Kid.

Tom

[Westbranch]

you're right on that Tom, a typical 12 V nominal PV will have a Vmp of ~ 17 - 18 V, so ~ 1.5X

[chris]

you're right on that Tom, a typical 12 V nominal PV will have a Vmp of ~ 17 - 18 V, so ~ 1.5X

  So, I was thinking of wiring 2 100watt panels in series so cloudy days would still produce a high enough voltage to charge........or would putting them in parallel be the better option? (12 volt system)

[TomW]

you're right on that Tom, a typical 12 V nominal PV will have a Vmp of ~ 17 - 18 V, so ~ 1.5X

  So, I was thinking of wiring 2 100watt panels in series so cloudy days would still produce a high enough voltage to charge........or would putting them in parallel be the better option? (12 volt system)

Chris;

Assuming the panels are identical.

Personally, I would go in series. I "think" it will take better advantage of the MPPT in the Classic.

If they are not the same rating I would go parallel because the lower current rated panel will limit the whole array all the time in series.

Just what I would do.

Tom

[chris]

Chris;

Assuming the panels are identical.

Personally, I would go in series. I "think" it will take better advantage of the MPPT in the Classic.

If they are not the same rating I would go parallel because the lower current rated panel will limit the whole array all the time in series.

Just what I would do.

Tom

  Thanx Tom,

   They are identical
the plan is to add 2 more this summer......so at that point my thought was to do two strings of series parallel....I think that's a little under the max for the Kid on a 12 volt system.

[TomW]

Chris;

The Kid manual says it is rated 60 amps with 2X 200 watt strings you should be quite safe at about 34 amps. Probably could go to 700 watts of input into a 12 volt battery.  Not positive but maybe 800 in if The Kid protects itself from over current.

I would ask Ryan or boB but 60 amps into 12 volts is 720 watts and 60 amps into 14.4 volts is about 830 watts so the range of power at "12 volts" and 60 amps is from 720 to 830 watts.

Anyway, maybe one of the Midnite guys will jump in.

Tom

[chris]

  So.....the kid is rated for 60 amps input on 12 volt?

  I thought it was 30 amp...so I was basing my max off of....30amp X 15 volt= 450 / .77 to get a max in put of 584 or 600 watts.

   

[vtmaps]

  So.....the kid is rated for 60 amps input on 12 volt?

I thought it is 30 amps max output to the battery.  The current into the kid will always be lower than the output, just as the voltage on the input is always higher than the voltage on the output.

--vtMaps

[Vic]

Well,  the KID has been referred to as a 30 Amp Output CC.
Robin did mention that there was a consideration of adding a fan on the front of the heat-sink fins allowing up to 40 Amps output.   In this mention,  recall that there was a reference to the maximum 10 AWG capacity of the Terminal Block,  but that some Industrial cable being capable of 40 A  at 10 AWG,  and so on.

EDIT: This was snipped from Robin's comments from the lower portion of Reply #131  Pg #8(?)  of the FID Report Card Thread,

>> " ...  Here is a good one to comment on......We have a potential customer that wants to run these in a hot climate. The regular KID is only a 20 amp controller in 40C ambient. That just sounded wimpy, so I asked Mike to rig up a small fan into the back and make the exit holes over the inductor. This turned out to work very well. I can't remember exactly now, but the KID did 30 or 35 amps at 40C with that little fan like what is inside the Classic.
How much would it do at normal ambients? Probably 40 amps. By the way, 20AWG wire is rated at 40C in industrial applications, so we may have a fan option in the future that will give you an additional 10 amps or so.
Cool huh?"   << Robin

This may not be fully on Topic,  but,    FWIW,   Vic

[Mario]

The kid is rated for 30 amps out to the battery.
IF you use Bully mode and you parallel them you can get up to 60 amps from a single array and the same batteries, Maybe that's what Tom is referring to.
And yes we are planning for a fan option that will give the kid more output current and not over heat.

Mario

[TomW]

The kid is rated for 30 amps out to the battery.
IF you use Bully mode and you parallel them you can get up to 60 amps from a single array and the same batteries, Maybe that's what Tom is referring to.
And yes we are planning for a fan option that will give the kid more output current and not over heat.

Mario

Mario;

Thanks for the clarification.

My bad.
The 30 amp fuses should have been the big clue. The Bully mode bit was what I locked on to.

I guess I will be sitting on my hands awhile and just let you guys who actually know answer these questions.

My apologies for the misinformation.

Tom

[Vic]

The kid is rated for 30 amps out to the battery.
IF you use Bully mode and you parallel them you can get up to 60 amps from a single array and the same batteries,  ...   Mario 

Sorry Tom,   I forgot about Bully mode.      Vic

[Highflyer]

Well I got to talk to Mario  today about the differences in the two Kids I have and it turns out that the calibration was off on the Rev B Kid, after fixing that, Both Kids are doing great.  Both are putting out more power than before.  So as a NEWB, I can say that even .3 volts on the batt voltage and one volt on the input makes a big difference.