A Few Classic questions prior to purchase

[mike90045]

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.

[Narrowboat boy]

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

[Narrowboat boy]

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

[ClassicCrazy]

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

[ClassicCrazy]

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

[ClassicCrazy]

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

[Narrowboat boy]

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

[Narrowboat boy]

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

[Narrowboat boy]

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

[ClassicCrazy]

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

[Narrowboat boy]

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 .

[Narrowboat boy]

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

[ClassicCrazy]

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

[Narrowboat boy]

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 .

[ClassicCrazy]

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