Question on max input to CL 150

[Vic]

I purchased 4 AWG welding cable to go from mini dc disconnect battery breaker to Classic and from the shunt for the negative battery cable to Classic but had a whale of a time to get it into the Classic blue terminal box.  I was ready to pull my hair out!  I don't have specialized tools but is there some kind of process to make this easier?

Hi elesaver,

Electrical terminals with screws that compress the bare end of cables (compression terminals,  in my book),  and almost never designed for use with Fine-Strand cable.

Fine strand cable is designed to be used with crimped connections  --  lugs,  ferrules,  butt-splices,  etc.  Fine stranded cable is larger in average diameter,  than traditional 19 & 31 strand cable,   due to the way that the fine cable bundles are laid-up.

Fine strand cable has much more "flow"  away from the compression connection.   So,  even when one manages to jam a #4 AWG fine strand cable into the Classic terminal block,  it can create a DANGEROUS situation,  as the connection will become more,  and more loose  (a progressively poorer connection).  This worsening connection can damage the terminal to which it is connected,  as well as damaging the cable.   As this connection point becomes a higher and higher resistance, the heating keeps increasing.   This increase in connection resistance will produce more and more heat,  which often creates an avalanche condition,  destroying the cable end and the device to which it was connected.

Some suggest crimping ferrules onto the fine strand cable ends,  where the connection to compression terminals must be made.   This adds an additional junction,  with some resistance.

IMO,  one does not need to use fine strand cable when #4 AWG cable is desired.   When connecting to Classic terminal blocks and compression terminals on breakers,  and many bussbare,  19 strand THHN type cable is what these connection points are designed for.   Trying to connect fine strand cable directly to these terminals is dangerous,  and will usually necessitate replacement later,  as well as the need to often replace the device to which the connection was made (Classic PCB,  breaker,  bussbar,  etc),  due to heat damage of cable insulation and whatever the cable was connected to.   Why not start with the proper cable (usually 19 strands for cables up to about #1 THHN,  IIRC).

#6 and #4 AWG 19 strand THHN type cable can be easily formed to neatly fit  into the box,  tray,  gutter,  etc,  by using Electrician's Pliars,  without scarring the cable jacket,  by taping serrations of the jaws with electrical tape.

More opinions,   FWIW,   and so on.   Vic

[Westbranch]

On the newer editions there is a blue cover for the TBlk that you put in place AFTER you get those bigger wires into the hole in the metal part of the block.... a great improvement...

[elesaver]

Vic, once again, thanks for the info.  I will get some ferrules for AWG 4 and 6 and use a crimping tool.  I wonder how long until my hair grows back?! 

[Vic]

Hi elesaver,

Sorry to pick,  pick ...   pick at you.    But poor connections are a large problem when they occur.   The heating from them can be very damaging.

Thanks!    Vic

[elesaver]

Vic, I don't consider this "picking" at all.  I so appreciate being able to learn.  Feel free to offer suggestions, criticisms, remarks of any kind!  When I am able to do a better job, I attribute it to you...and all the others... who take the time to help. 

[Jacotenente]

Why not just solder or "tin" the #4 wire cable ends onto the ferrules? Or have Midnite design and offer a terminal lug/crimp for their Classics terminal block?

What about something like this: https://www.amazon.com/Morris-90971-Products-Connector-Compression/dp/B00UKGB4PO/ref=sr_1_2?ie=UTF8&qid=1472172866&sr=8-2&keywords=solid+pin+terminal+crimp+4+awg

or

4 AWG butt connectors: https://www.amazon.com/Insulated-Seamless-Butt-Connectors-Pack/dp/B01I5M4LT0/ref=sr_1_25?ie=UTF8&qid=1472173729&sr=8-25&keywords=Non-Insulated%2C+Butt+Splice%2C+4+AWG

[australsolarier]

if anybody is worried running his midnite classic at max currents over longish periods because of over powering, just reduce the max amps in the settings. for example reduce them to 80 amps and the midnite classic will never run at max power, extended or spikes.
current limitation, the midnite classic seems to handle that pretty good. occasionally it goes like 0.6 amps over the set limits for short times. like 2 seconds.

as for if anybody is worried about heat, install an air conditioner. this prolongs the life of the battery and electronics and is more pleasant to work when doing things in the shed. also dries out any humidity. usually when it gets hot the sun is shining and there should be plenty of unused solar generation.  just keep in mind, if it prolongs the life of the battery for just 10%  the investment of the air con has paid for itself.
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[Powerplay]

australsolarier said:

for example reduce them to 80 amps and the midnite classic will never run at max power,

This is a good tip for running more than one classic to power the same DC distribution panel as well.  There is one place in my setup on the DC output side that has a 2 AWG wire under a 100 AMP breaker.  Both classics working together could easily overwhelm the breaker in bright sun under heavy loads but I set limits to divide up the 100 Amps between the two classics and they get along with the system fine.  One classic has 45% of the PV and the other has 55%.  So the output amp limit on one is 44 and the other is 54.  It is rare that my loads need all the amps available but if they ever did the battery would supply the difference and the classics would both limit themselves.  It also helps distribute the heat in the system.

[Jacotenente]

australsolarier said:

for example reduce them to 80 amps and the midnite classic will never run at max power,

This is a good tip for running more than one classic to power the same DC distribution panel as well.  There is one place in my setup on the DC output side that has a 2 AWG wire under a 100 AMP breaker.  Both classics working together could easily overwhelm the breaker in bright sun under heavy loads but I set limits to divide up the 100 Amps between the two classics and they get along with the system fine.  One classic has 45% of the PV and the other has 55%.  So the output amp limit on one is 44 and the other is 54.  It is rare that my loads need all the amps available but if they ever did the battery would supply the difference and the classics would both limit themselves.  It also helps distribute the heat in the system.

That sounds good. Running any solar charger at full tilt is not my idea of a good idea. On my main array (2,400w into a 24v battery bank)...it usually runs at about 60-65 amps (with peaks up to 75-80 amps).