Need help choosing a solar controller

[StewB]

I have 6, 53 watt Siemens panels I am going to use to keep 4 100amp batteries charged up at my cabin.

I am looking for some help picking a 30 amp controller suitable for the job. I looked on ebay and see many different suppliers with an amazing range of price.

Any one have some advice on one to pick?

Thanks very much.

[jrnymn7]

Kalegley wrote:

jrnymn7 wrote:
Electrical Conductivity Payment Conversion Calculator

I did?

[craz_z]

Morningstar ts45 or ts60 pwm
Cheap controllers are a hazard and a disappointment
Mppt is a waste of money until u reach 1000watts or want to go to 24v or higher panels to neck down to 12v
Wiring is just as important go huge 0 gauge or bigger
Read bob is the solar guy everything he said is 100 percent correct
Make sure u get the remote temp sensor all controllers should come with one

Again wiring and the controller are the most important part of the solar system

Rarely if ever do I need to start the geneie only use it boondocking for ac and the microwave. I've disabled my converter don't need it anymore

[Kalegley]

jrnymn7 wrote:
Electrical Conductivity Payment Conversion Calculator

[StewB]

Thanks to everyone for all the input.

[BFL13]

smkettner wrote:

BFL13 wrote:

pianotuna wrote:
53 watt panel

PT, those guys are as bad at math as your are! 🙂 The USA NEC says you need a 20% margin but these guys say you should multiply by 1.25 for controller size in amps. That is a 25% margin.

Hint for the "math disadvantaged"--

- 25 expected amps. 20% is 5 amps so you need a 30 amp controller.

1.25 x 25 = 31.25 (6.25 more not the NEC required 5 more.)

NEC says 20% margin on the wire/equip for continuous duty (3+ hours).
30 amp x 20 % = 6 amp derate or 24 amps. Or as they suggest 1.25% of the 24 amps.... wait for it..... 30 amps.

So the 1.25 is same as NEC 20% because they are going in opposite directions.

I understand that going from 25 to 20 is a 20% reduction.

It seems there is the 1.25 x the PV Isc to get you that amps, called the "PV 1.25 " and then you do 1.25 on that to get the "NEC 1.25" for the fuse and wiring--after doing some de-rating on the wiring for temperature. Not too confusing! 😞

Scroll to Appendix E here, where he starts by explaining how to apply this all to various parts of the set-up. Also mentions the actual articles in the 1999 NEC.

Farther down is an example set-up using eight of those 53w panels!

http://www.senecass.com/NEC2000.pdf

[time2roll]

BFL13 wrote:

pianotuna wrote:
53 watt panel

PT, those guys are as bad at math as your are! 🙂 The USA NEC says you need a 20% margin but these guys say you should multiply by 1.25 for controller size in amps. That is a 25% margin.

Hint for the "math disadvantaged"--

- 25 expected amps. 20% is 5 amps so you need a 30 amp controller.

1.25 x 25 = 31.25 (6.25 more not the NEC required 5 more.)

NEC says 20% margin on the wire/equip for continuous duty (3+ hours).
30 amp x 20 % = 6 amp derate or 24 amps. Or as they suggest 1.25% of the 24 amps.... wait for it..... 30 amps.

So the 1.25 is same as NEC 20% because they are going in opposite directions.

[StewB]

jrnymn7 wrote:
Hey Stew,

The eco-worthy does not pair well with even two 12v panels in series. It has a 42v input limit. So that's out.

The solar30 will work, but is pwm, so some power will be lost, especially if there is shading, and will require heavier wiring. Also, it must be manually adjusted down to a suitable float voltage before leaving the cabin. So that may not be suitable.

The Tracer-3215RN is not adjustable, and requires an additional remote meter. So I would pass on that, personally.

The Tracer-3215BN is adjustable, but also requires an additional remote meter. This may be a good option

This is a forested location so there is considerable shading. Thanks for the info, I will look into the 3215BN

ebay price

[MrWizard]

okay
i was off by one volt
still i think a PWM controller is the way to go for his setup with these panels

[jrnymn7]

Voltage Drop Calculator

[jrnymn7]

Hey Stew,

The eco-worthy does not pair well with even two 12v panels in series. It has a 42v input limit. So that's out.

The solar30 will work, but is pwm, so some power will be lost, especially if there is shading, and will require heavier wiring. Also, it must be manually adjusted down to a suitable float voltage before leaving the cabin. So that may not be suitable.

The Tracer-3215RN is not adjustable, and requires an additional remote meter. So I would pass on that, personally.

The Tracer-3215BN is adjustable, but also requires an additional remote meter. This may be a good option

ebay price

[BFL13]

KD4UPL wrote:
BFL13, what is the NEC reference about a "20% margin". That's pretty vague.

.

OK I may have been wrong on that. I will try to find where I picked up that 20% margin for NEC idea.

This says that the actual NEC rule is for a 25% margin, by multiplying by 1.25.

It says NEC does not apply to autos, trains, etc. Not clear about RVs.

From:

http://www.senecass.com/NEC2000.pdf

"The ampacity of conductors in PV source circuits shall be at least 125% of the rated module or
parallel-connected modules short-circuit current [690-8]. The ampacity of the PV-output circuit
conductors shall be at least 125% of the short-circuit output current [690-8a]. The ampacity of
conductors to and from an inverter or power conditioning system shall be 125% of the rated
operating current for that device [690-8a]. In a similar manner, other conductors in the system
should have an ampacity of 125% of the rated operating current to allow for long duration
operation at full power [215-2]. These NEC requirements are to ensure that the connected
overcurrent devices or panelboards operate at no more than 80% of their ampacity. Operation
when snow or cloud enhancement increases the PV output above normal may require additional
ampacity. Daily expected values of solar irradiance will exceed the standard test condition of
1000W/m2 at many locations."

[StewB]

pianotuna wrote:
53 watt panel

They are the M55 model

Thanks for the link

[KD4UPL]

BFL13, what is the NEC reference about a "20% margin". That's pretty vague.

OP, There are a lot of charge controllers available for sure. The PWM controllers are less expensive but leave some of the array's potential output "behind". To get the most out of the array an MPPT charge controller is necessary. If the input voltage of the controller will allow wiring your panels in series will simplify the wiring and reduce voltage drop.
Morningstar and Blue Sky would be my 2 choices for a small charge controller. Both offer PWM and MPPT versions. Most with options for remote temp. sensors, meters, etc. You need to decide what features you want.
A proper charge controller won't need you to reprogram it depending on if your using the cabin or not. You would simply program it to the manufacturers recommended charging specifications for the batteries and leave it alone.

[JiminDenver]

I'm proof that you can "stack" three Eco-Worthy's.