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
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
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
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 .
Be aware the classic has a internal cooling fan that will make fan noise when charging hard.
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
Quote from: mike90045 on May 14, 2020, 05:42:55 PM
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 .
Quote from: ClassicCrazy on May 14, 2020, 11:09:24 AM
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 ?
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
Quote from: Narrowboat boy on May 15, 2020, 08:56:48 AM
Quote from: mike90045 on May 14, 2020, 05:42:55 PM
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
Quote from: ClassicCrazy on May 15, 2020, 11:15:42 AM
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
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
Quote from: Narrowboat boy on May 15, 2020, 01:20:20 PM
Quote from: ClassicCrazy on May 15, 2020, 11:15:42 AM
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
Quote from: mike90045 on May 15, 2020, 05:05:33 PM
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 ?
Quote from: Narrowboat boy on May 16, 2020, 05:34:31 AM
Quote from: mike90045 on May 15, 2020, 05:05:33 PM
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
Snubber for a SSR
http://www.omron-ap.com/service_support/FAQ/FAQ02088/index.asp
AC & DC circuits can both generate damaging spikes.
even simple DC loads, with long cables, can have enough inerrant inductive qualities to generate spikes.
Also, most SSR's really need a good heat sink, and reducing the switching helps, every on-off cycle runs the innards, for a split second, at a high heat generating condition, so the less switching, the less heat.
Quote from: mike90045 on May 17, 2020, 02:30:31 AM
Snubber for a SSR
http://www.omron-ap.com/service_support/FAQ/FAQ02088/index.asp
AC & DC circuits can both generate damaging spikes.
even simple DC loads, with long cables, can have enough inerrant inductive qualities to generate spikes.
Also, most SSR's really need a good heat sink, and reducing the switching helps, every on-off cycle runs the innards, for a split second, at a high heat generating condition, so the less switching, the less heat.
Hi Mike /Larry
Many thanks for the info most appreciated just a couple more questions if I maybe so bold
1. It says in the long linked article that snubber is for inductive loads like motors should I use it for resistive loads ie immersion heater too ?
2. Any input on resistor and cap values I should use for a crydom ssr ?
Thanks
Simon
Also worth pointing I am using a dc output ssr for dc heater not ac form what I can see you only need a snubber if switching inductive or ac loads ? Is this right ? Amazon sell a nice little rc snubber module for 5 quid if I need it though
Simon
I believe what Mike was saying is that even in DC loads the wires going to it can form inductance.
That being said I don't have any snubbers on my SSR controlling resistive heating elements - AC or DC . Not sure if something is built in my relays or not - but I keep thinking I should put something on.
Larry
Quote from: Narrowboat boy on May 17, 2020, 03:18:25 AM
Also worth pointing I am using a dc output ssr for dc heater not ac form what I can see you only need a snubber if switching inductive or ac loads ? Is this right ? Amazon sell a nice little rc snubber module for 5 quid if I need it though
Simon
I think this article is a bit easier to understand . Look up your SSR and see it already has snubber built in.
http://www.crydom.com/en/tech/newsletters/solid%20statements%20-%20protecting%20ac%20output%20ssrs%20against%20voltage%20transient%20phenomena.pdf
Larry
Simon ,
Is this the same circuit you saw on Amazon ?
https://www.ebay.com/itm/RC-Absorption-Snubber-Circuit-Relay-Contact-Protection-Resistance-Surge-Module/123406357902?hash=item1cbb97958e:g:~SQAAOSwP~lbtz3k
Larry
Quote from: ClassicCrazy on May 17, 2020, 04:29:51 PM
Simon ,
Is this the same circuit you saw on Amazon ?
https://www.ebay.com/itm/RC-Absorption-Snubber-Circuit-Relay-Contact-Protection-Resistance-Surge-Module/123406357902?hash=item1cbb97958e:g:~SQAAOSwP~lbtz3k
Larry
Yes that’s the chap
Quote from: ClassicCrazy on May 17, 2020, 04:01:12 PM
Quote from: Narrowboat boy on May 17, 2020, 03:18:25 AM
Also worth pointing I am using a dc output ssr for dc heater not ac form what I can see you only need a snubber if switching inductive or ac loads ? Is this right ? Amazon sell a nice little rc snubber module for 5 quid if I need it though
Simon
I think this article is a bit easier to understand . Look up your SSR and see it already has snubber built in.
http://www.crydom.com/en/tech/newsletters/solid%20statements%20-%20protecting%20ac%20output%20ssrs%20against%20voltage%20transient%20phenomena.pdf
Larry
It’s a Crydom one I am looking at but DC output which they seem to suggest may not need one but I guess it is not a high cost item to add it anyway , belt and braces approach and all that
Hi Ok now after a few sad sleepless nights thinking about this I have a couple more questions . about set up and diversion load sizing
Victron put the absorption range for my AGM batteries at 14.2V to 14.6volts they also say that 14.35 v is the gassing range so I think best level is 14.4V . I dont cycle these batteries too deeply so a full absorption cycle at full voltage could result in overcharging which is not good on AGM's therefore my thoughts are to set absorption at 14.4v or 14.5 v with an absorb cycle time of 60-90 mins instead of the normal 2 hrs 18 mins . then set offset 1v down which would be 13.4v to start ssr is this a little low as isnt the diversion occuring during bulk cycle ? Also once Absorb cycle is complete the classic goes to float and it sits there , Do i set the set point the same -1v of float ? as that would be about 12.8v which seems low again . What are your thoughts ?
Regards Snubber circuit would adding this anyhow cause any problems ? should I just add the module from Amazon as a belt and braces approach or will be potentially cause issues if not needed ?
Lastly but not least is about selecting the diversion load , I have a couple options for DC immersions , one 300W 12v and one 600W 12 V
It is likely that I will have 300w available alot of the time but 600W only in high summer but I will have alot of spare power then , My array is large for a narrowboat at 1620watts but UK weather , Climate and partial shading means unlikely to see 600watts spare power for most of year , If I can only divert 300 watts in to a 600 watt heater will it perform as well as a 300 heater or will it be slower to warm up etc ? I have no experience of these things , The 600 watt is basically 2 x 300 watt heating elements together . Any thoughts on load selection appreciated
Does all this make sense or am I overthinking all this ?
Simon
Did you ever decide if you are going to get a use a Whizbang ?
If so you can use ending amps to terminate Absorb time based on what the battery needs instead of time.
Snubber circuit on a SSR won't effect anything .
What is your ultimate goal with your diversion load ? Are you doing it to get some water up to temperature for use ? Or just somewhere to dump extra power that you don't need. If it is the second it really doesn't matter if you use that power or not. If it is that you want to heat water then you can put a thermostat in series with the Aux output and that will shut off the power to the heater when the water gets up to temperature.
Larry
Thanks again Larry for your help,
I really want to use pwm to make sure I am not micro cycling the batteries more than possible
Thr conditions here are too changeable.be really nice to have but the options whiz bang and pwm
Maybe Classic 2 could fix that with AUX 3 hint hint midnite people lol .hence plan is to use victron bmv for all accurate monitor functions except end amps which I will have to live without . Think i will just need to experiment with offset settings to see what works best I have a lite cycle depth so i think if diversion starts at a low voltage say 13.4 or 13.5 i will still have enough excess for classic to take voltage to absorption level of 14.4 or 14.5 and hold there for 60 to 90 mins while diverting all excess to the load ? This should charge batteries pretty much without overcharging them . Any thoughts on this strategy?
I am looking to get hot water to use if possible. But conditions mean I have quite narrow window so am thinking bigger heater is better I guess it will just act as the smaller heater if less excess is available ? Yes thermostat is a must for sure .
OK now really thinking about this and I wonder what you think of this strategy . If I use Aux 1 waste not hi and set classic to 14.6 v absorption with a - 0.5v offset and have Aux 2 set with Whizzbang jr set up for end amps then in theory when diverting the voltage will always be in the range of the batteries Absorb voltage and if it reaches 14.6 v and enters absorb and end amps are met it will go to float so wont overcharge or Cycle the batteries much if at all ? . Does this sound like it would work ? . Best of both worlds scenario as will also mean I will be diverting max load current if its available . In this case I would probably have a 300 W load as it would not pull the battery voltage down as much if the power is available . But does this mean I would be diverting mostly in Bulk mode ? Are you able to do this ?
This diversion setup lark is a real mind bender lol
Simon
First I don't understand what you mean by micro cycling batteries.
If you want to see their lifespan look at this chart ( by another manufacturer but probably similar for yours ) .
see cycle life vs longevity graph
https://www.mkbattery.com/application/files/5515/3815/3319/AGM_Brochure.pdf
They are showing the cycle life based on 2 hour capacity - so it doesn't mean your batteries are shot after number of cycles - they will still work at lower discharge points which might be all you needed anyway.
https://www.mkbattery.com/application/files/9615/3374/2592/Valve_Regulated_Lead-Acid_VRLA_Gel_and_AGM_batteries.pdf
If you get the Whizbang you can do controls based on your state of charge too. I have used it on Aux1 to turn loads on and off by SOC but didn't ever use it with waste not on Aux1 . I probably should have tried it .
Larry
Hi Larry
I have found an app on Android for classic can I use this to connect to classic If using whiz bang and see battery status soc etc ? If so how do I do it ? I take it it is not Bluetooth? If I can it will save me buying victron bmv monitor as I won’t be able to easy see screen of classic once installed so need a remote monitor of some kind .
Quote from: Narrowboat boy on May 23, 2020, 08:13:58 AM
Hi Larry
I have found an app on Android for classic can I use this to connect to classic If using whiz bang and see battery status soc etc ? If so how do I do it ? I take it it is not Bluetooth? If I can it will save me buying victron bmv monitor as I won’t be able to easy see screen of classic once installed so need a remote monitor of some kind .
Grahams Classic Monitoring app available on the playstore is excellent . That is what I use. He and Matt also just developed the program so a Raspberry Pi can connect up to Classic and send the data out MQTT for the app too ( special version of app) .
You need to have the Classic connected to a wifi router for the android apps ( or Pi) to work.
More info in opensource general area of forums or here
https://github.com/ClassicDIY
Yes it looks great , though I expect the classic needs a hard connection to the router or will it do it by WiFi ? As am on boat my router is mobile 4g with no inputs except for antenna. So if so will need new router though been. Threatening to for a while , kind of clunky having wires all over but can prob make it work
Hey just thought can i plug a WiFi USB modem into the classic USB port and will that allow it to connect to my router wirelessly? Would that work ? Or does it have to come from the Ethernet jack ? If so I suppose could attach a usb WiFi modem to that just a not as neat . Wires are a narrow boats worse enemy when your living space is 6feet 10 wide by 50 feet long lol
The classic has no internal wifi, so you may have to get a ethernet - wifi gizmo to plug into the ethernet jack.
I hard wired my classic ethernet jack to a conventional wifi router and it works fine that way with the Local App & windows.
I don't believe the ethernet jack on the classic provides any power, so you may have to steal power from somewhere to power the wifi
Quote from: mike90045 on May 30, 2020, 03:38:24 PM
The classic has no internal wifi, so you may have to get a ethernet - wifi gizmo to plug into the ethernet jack.
I hard wired my classic ethernet jack to a conventional wifi router and it works fine that way with the Local App & windows.
I don't believe the ethernet jack on the classic provides any power, so you may have to steal power from somewhere to power the wifi
Hi Mike
Thought as much , I have a plan to buy a new mobile router which has an Ethernet input . It has a 240volt power adapter but actually that puts out 12volt 2amp so I can wire a 12volt supply through a dc dc converter to regulate the supply and mount it on the outside of my electrical cupboard and run cables for enet and power through the wooden divide.
Still can’t decide which approach is best though pwm via aux 2 and ssr or aux 1 for dump load and whiz bang on aux 2 ? Any thoughts on best approach are appreciated really want to have a bigger load as will have loads of spare power in summer but worried the load will be too big in autumn and spring if just controlled by aux1 simple on off rather than aux 2 gradual control. But using whizzbang and end amps etc is also very attractive.