A Few Classic questions prior to purchase

[Narrowboat boy]

Hello from Sunny ( today at least ) UK .

First a little background . We live on a Narrowboat on the Southern Grand Union Canal in England . We have a lovely mooring alongside a small woodland in a small canal village . We are off Grid . Over the last few months I have been designing a new larger solar system to replace our current system which is too small for our needs . After much research I have tentatively settled on the Midnite Classic 150 for our new solar controller . Main reasons amongst others for settling on this over Outback and Victron are
1. Current output at 96A ( it is a 12 volt system )
2. PWM Aux 2 output to drive a diversion load ( DC water heater )
3. Compact dimensions ( no room on a narrow boat so need to fit my electrical cupboard
4. Recommendations and good reviews

Some systems specs
Battery bank is 550Ah Victron deep cycle AGM's
12 Volts
Victron Phoenix 3000w combi invertor with 120A battery charger
Current Solar system ( inherited with boat )330Watts with EP Ever 20A controller

Proposed new solar system
Midnite Classic 150
6 x 270w perlight PGM54 delta black compact panels
300 watt dc immersion
40A Crydom DC SSR ( with heatsink )

Some background on mooring , We are partially shaded for roughly 1/2 the day with full sun available ( on a sunny day ) for max 4 hours , plus 52 degrees latitude and being UK many non sunny days

The reason for so many panels ( they just fit ) is the fact that for most of the time only a portion will be in the sun . Also in UK we never see full panel power , most I have seen on current system is 16 Amps on a blazing day . Winters are long and sun low so more panels the better to stretch the window


Questions I have before finally placing the order
1. As said above I dont anticipate ever producing the full 1620 watts I have never heard of a boater who has . But does the Classic have a current limit that will prevent damage in the eventuality it did go over 96A ?
2. I have been reading about using AUX2 in waste not hi mode to drive an SSR diversion load and I cannot for the life of me understand how I should set it up . Simply do I set it to come in at 0.2v under artificially high absorb set point ( 14.4 is absorb on my batteries so if I set absorb to 14.5v and Waste not point at 14.3 it will come on at 14.3V and then will it go off again if it falls below 14.3 or if I have set up float spec at 13.6 will it keep on when the controller goes from absorb to float until volts drop to 0.2V under float then turn off ? Sorry it is very confusing just want to understand what to set simply if thats possible .

Thats all for now

Sorry if question is not clear I will try to clarify

Regards
Simon

[Narrowboat boy]

Hello again I have just found the excellent knowledge base and I think this has answered my diversion questions , So if std Absorb is 14.4 I should set Classic to 14.6 absorb with a -0.2v diversion point and then it will turn on at 14.4 V and thus give a proper absorb while diverting excess . and this also gives full pwm range ? I am I reading this right ? and same would be true for float etc etc

[ClassicCrazy]

I just set up Aux2 for waste not - I will have to look at the knowledge base too !
I have mine set .9 or 1 volt above  -just because I think I saw this somewhere.
But one thing you should consider is that if you use AUX 2 for the PWM you will give up your ability to use Whizbang for SOC and accurate monitoring of loads.
I have two Classics in Follow me - one has the Whizbang on Aux2 and I just set up the other with waste not on Aux2.
Before I used the second Classic Aux2  I used for a long time Aux1 on the first classic to control water heating. There are a few different strategies to use some of the logic in there to heat water. The one I often used was SOC High which I could set for example to turn on Aux1 at 94% SOC and shut off at 93% .  I would do that or some variation if I was around and knew that we would have full sun. But if I was away and wanted to make sure I came back to almost full batteries I would set it to on 99% off 98% so that if sun came out and I had all the extra power it would be diverted to hot water. But if it clouded up battery was going to stay at 98% . If sun came out again later then the Aux1 would turn back on load.  Worked pretty good.
With the choice of having Aux2 - I would not give up the Whizbang option because of it's accuracy and control capability ( such as using ending amps to terminate Absorb) .
And I think the answer to  your question is that yes the Classic will limit the current in case you were to get some perfect sun conditions there 

Larry

[Narrowboat boy]

Hi Larry
Many thanks for your help, I will take a look at Whizz bang and using Aux 1 I was attracted to Aux2 by the pwm option of 3 state charging AND diverting what was left without pulling from batteries . seemed pretty elegant to me . I was going to use Victron BMX-712 as a battery  monitor instead of Whizz bang but now I think about it , We dont take a lot out of the batteries so most of our power in the summer will go to diversion so I guess we could use Aux 1 like you outline without many worries . The new system is completely over solared for our needs for most of summer it is really designed for Autumn and winter to take as deep as possible without having to run Generators and boat engines until we have to . Good news re limit though to be honest unlikely to hit it in UK .

[mike90045]

Be aware the classic has a internal cooling fan that will make fan noise when charging hard.

[ClassicCrazy]

One other thing I forgot to point out is with Classic you have good monitoring options with Midnite Local Status app , Grahams Classic Monitoring app for Android ( and now with mqtt capabilities) , and if you have internet Grahams monitoring app is great for remote and you can also use the My Midnite remote monitoring. So lots of options .

Larry

[Narrowboat boy]

Be aware the classic has a internal cooling fan that will make fan noise when charging hard.

Hi Mike
Dont think this will be a big problem not anticipating seeing the fan on often due to high current output ,  Here you can usually only see 50-60% total panel output even on a sunny day that is about 70 amps tops .

[Narrowboat boy]

I just set up Aux2 for waste not - I will have to look at the knowledge base too !
I have mine set .9 or 1 volt above  -just because I think I saw this somewhere.
But one thing you should consider is that if you use AUX 2 for the PWM you will give up your ability to use Whizbang for SOC and accurate monitoring of loads.
I have two Classics in Follow me - one has the Whizbang on Aux2 and I just set up the other with waste not on Aux2.
Before I used the second Classic Aux2  I used for a long time Aux1 on the first classic to control water heating. There are a few different strategies to use some of the logic in there to heat water. The one I often used was SOC High which I could set for example to turn on Aux1 at 94% SOC and shut off at 93% .  I would do that or some variation if I was around and knew that we would have full sun. But if I was away and wanted to make sure I came back to almost full batteries I would set it to on 99% off 98% so that if sun came out and I had all the extra power it would be diverted to hot water. But if it clouded up battery was going to stay at 98% . If sun came out again later then the Aux1 would turn back on load.  Worked pretty good.
With the choice of having Aux2 - I would not give up the Whizbang option because of it's accuracy and control capability ( such as using ending amps to terminate Absorb) .
And I think the answer to  your question is that yes the Classic will limit the current in case you were to get some perfect sun conditions there 

Larry

Ok just has closer look at spec of batteries I have and the absorption voltage has a range of 14.1 to 14.6 volts which is a pretty big range so my thinking ( which maybe flawed so please pick it apart ) is to set the classic voltage at 14.6 and then the pwm voltage at -0.5v which would give me a proper absorption cycle within range and divert more than 50% of power only if voltage is pushed above 14.6 volts . Have i got this right ? or so I need to set it differently . I am looking to divert as much as I Can of spare power so do I need a 1 volt differential between classic setting and waste not set point ?

[ClassicCrazy]

I think the voltage range given by the manufacturers has more to do with the age of the batteries ( and some environmental conditions). For new batteries start at the lower setpoints and then as batteries age move up to the higher setpoints. Also if the batteries are very cold( below freezing )  it might be good to go up higher in the ranges to ensure they get fully charged. That is how I see it anyway.
The PWM from Aux really doesn't factor in to charging the batteries - you always want to make sure they charge properly somehow independent of Aux so you need to have the Absorb, Absorb time, Ending amps ( if you have a whizbang and use that ) set properly.

Larry

[ClassicCrazy]

Be aware the classic has a internal cooling fan that will make fan noise when charging hard.

Hi Mike
Dont think this will be a big problem not anticipating seeing the fan on often due to high current output ,  Here you can usually only see 50-60% total panel output even on a sunny day that is about 70 amps tops .

The fan is still going to be running when the batteries are charging - I think the fan ramps up and down a bit as it's load changes . I don't know exactly because I have mine out in the shed so I don't have to hear all the controller and inverter fans and buzzing noises.

Larry

[Narrowboat boy]

I think the voltage range given by the manufacturers has more to do with the age of the batteries ( and some environmental conditions). For new batteries start at the lower setpoints and then as batteries age move up to the higher setpoints. Also if the batteries are very cold( below freezing )  it might be good to go up higher in the ranges to ensure they get fully charged. That is how I see it anyway.
The PWM from Aux really doesn't factor in to charging the batteries - you always want to make sure they charge properly somehow independent of Aux so you need to have the Absorb, Absorb time, Ending amps ( if you have a whizbang and use that ) set properly.

Larry

Just so I understand it right . I will have way more solar than I need to charge the batteries but uk weather patterns are such that you can regularly have max amps one minute then a cloud so a big drop for a few mins then sun again etc etc so I want to make sure that having a biggish diversion load (
600 watts being considered )  won’t drag the batteries into the dirt when the sun disappears for a bit hence my thinking for pwm . Am I on the right track or barking up the wrong tree . I understood that by going pwm route would mean the batteries for properly charging cycle and not get affected by diversion as classic adjust the modulation to compensate for falls in power etc by dropping power to the load in line with what was actually available .

so how does a 14.2 set point wit -.5 sound so I get the full 1 v pwm spread

Sorry for all the questions still learning

[mike90045]

  There is (I think) a setting called Waste Not  ??  I've heard the term somewhere

And using a SSR, be sure you use every suggestion for adding snubber circuitry to it, to prevent current spikes from generating damaging voltage surges that fry SSR's

[ClassicCrazy]

I think the voltage range given by the manufacturers has more to do with the age of the batteries ( and some environmental conditions). For new batteries start at the lower setpoints and then as batteries age move up to the higher setpoints. Also if the batteries are very cold( below freezing )  it might be good to go up higher in the ranges to ensure they get fully charged. That is how I see it anyway.
The PWM from Aux really doesn't factor in to charging the batteries - you always want to make sure they charge properly somehow independent of Aux so you need to have the Absorb, Absorb time, Ending amps ( if you have a whizbang and use that ) set properly.

Larry

Just so I understand it right . I will have way more solar than I need to charge the batteries but uk weather patterns are such that you can regularly have max amps one minute then a cloud so a big drop for a few mins then sun again etc etc so I want to make sure that having a biggish diversion load (
600 watts being considered )  won’t drag the batteries into the dirt when the sun disappears for a bit hence my thinking for pwm . Am I on the right track or barking up the wrong tree . I understood that by going pwm route would mean the batteries for properly charging cycle and not get affected by diversion as classic adjust the modulation to compensate for falls in power etc by dropping power to the load in line with what was actually available .

so how does a 14.2 set point wit -.5 sound so I get the full 1 v pwm spread

Sorry for all the questions still learning

I am using Waste Not Hi  with 1 volt and 1 volt width and it is working okay . Yes it diverts any extra power to the SSR load - it pulses load to vary current so voltage is at either the Absorb or Float setpoint. ( this load has to be pure resistive load for pwm. )

Larry

[Narrowboat boy]

  There is (I think) a setting called Waste Not  ??  I've heard the term somewhere

And using a SSR, be sure you use every suggestion for adding snubber circuitry to it, to prevent current spikes from generating damaging voltage surges that fry SSR's

Why do you need s snubber unless you are connecting directly to the panels ? I will be connecting to batteries so should not need one surely ?

[ClassicCrazy]

  There is (I think) a setting called Waste Not  ??  I've heard the term somewhere

And using a SSR, be sure you use every suggestion for adding snubber circuitry to it, to prevent current spikes from generating damaging voltage surges that fry SSR's

Why do you need s snubber unless you are connecting directly to the panels ? I will be connecting to batteries so should not need one surely ?

You connect the Aux output to SSR to control stuff and that is where Mike says to have a snubber so you don't destroy the SSR when using inductive loads because of the flyback current or voltage  .

Larry