Portuguese Powerwall in Poland

I connected the ABB Shunt trip to the Batrium Watchmon and it works nicely.
Here's a video of me trying it out:


I also added a Victron fuse of 100Amps just next to the Batriumshunt.


image_qjlxtf.jpg


I got my crimp and made sure all cable lugs are well crimped.


image_lopvkp.jpg


Now I guess it's time to plan for the winter temperatures and protect the batteries since they're in my unisolated garage.
I'm thinking something along the lines what Simon did with some cable heater inside aStyrofoam made enclosure.
It can get here sometimes down to -20 Celsius, and regularly -10. So I'm hoping I can get 5-10 increase.
 
I've been working on some idea to predict the amount of Wh that my panels will generate the next day, so that depending on that prediction I charge from grid during night (cheap tariff) more or less.
Putting it simple: if the next day there will be sun, no need to charge during night, but if next day will be mostly cloudy and SOC is low, than it's better to charge before 6am (when cheap tariff ends) and have at least 70% SOC for comsuption without sun.

So I'm currently using an API from yr.no (http://api.met.no/weatherapi/documentation ), which provides an hourly cloud forecast and a simple parameter cloudiness from 0-100%, and based on that, onhow much Wp my panels can produce, and also on sunrise/sunset values for next day,I calculate the predictedWh amount, basically by just multiplying my Wp value to cloudiness/100 and adding all hours between sunrise+1 and sunset -1.


image_wijnxo.jpg


I'm using Node-red as a quick proof of concept, and it can nicely parse xml response and with some JS function do what I want.


image_kycnin.jpg


Let's see if this gets at least close to what in reallity the panels produce the next day.

I will be comparingitto actual gathered Wh, and eventually tweak the code to more precisely reach a reliable prediction.
Next improvement is to take into account the sun's position on sunrise/sunsetdepending ontime of the year and panel orientation relative to this angle.

If someone finds this usefull to their case, I can provide the code.
 
Nice work...very intersting stuff... gone follow and maybe copy :D
for now i amusing darksky https://api.darksky.net... same thing...
Easy to do witha arduino, still testing but very promising.

In your videoabout the shunt trip, you installed a switch to "restart" your bms... maybe it is a idea to power the batrium with battery power before the breaker.... this way the power for the watchmonstays on in case ofa critical event. ( no needfor the switch anymore )
The breakercan bereset after the critical event is gone, and the bms keeps on logging.
Just how i have done it... :)
 
I prefer to not have anything powered by the batteries in case of a critical situation. Maybe it's ok maybe not, but in doubt I prefer to be on the safe side

Consider you left it running and travel to other side of the globe for 4 weeks vacations on Thailand....watchmon would drain the batteries with no charger connected.
 
I would imagine in that situation, you could set it up with safety configuration for when the voltages get to low. Or, you just turn it all off when you leave. I agree with wim about having the watchmon connected before the breaker. What if the breaker pops, and you want to do some configuration remotely. If it's after the breaker, you can't do anything. Or, as wim said, there was a fault and recording gets halted when the breaker pops. Those readings after the breaker popped could be critical. It could let you know why the breaker popped in the first place.

But, that's how I view it ;)
 
Frnandu Marti?ski : If you gonna drain your packs in 4 weeks with the longmons you must have some very very very small battery bank :)

and YES you ned to have the watchmon before the breaker!! It should be sitting rather close to the battery with only a small fuse! The watchmon need to be able to still monitor the battery bank afterwards otherwise you loose monitoring.
 
Daniel, now I have a complex about mine being smaller than yours ;):D

Consider this:

- Watchmon for some reasontrips the shunt in the worst moment,when for example SOC is about10-20% (in my tinymicro incredible shamefully small powerwall of 10kwh) that means that I'm left with (best case) ~2kwh, now Watchmon from my observations consumes typically between 1-3W, but let's consider worst case scenarioat 3W*24h*28days = 2016Wh. Consider also that we don't know why it tripped, might have been that one of the packs got too low voltage because some bad cells. So I can imagine a situation where leaving it for a few weeks draining (slowly but still considerable) my battery which can be in bad shape (meaning lower voltage than usual). That for me is not acceptable, sorry guys. Maybe when I get a bigger one like Daniel and stop having complexes ofinferiority ;)

- Watchmon will log until the moment when it pops, so the reason for it to go critical WILL be recorded and I will have this information, and that is the most important thing.

- Korishan, what do you mean configuration for when the voltages get to low? I don't think you can configure watchmon to turn itself OFF. Watchmon will work until Vin = 8v, so that would mean each pack would be practically dead.

I understand that you guys might not even consider leaving your battery for that long unattended, because either you prefer to turn if off when going on vacations, or you just don't go on long vacations.....;)
I'de like to have it working, am I too wishful thinking here about DIY powerwall?

Now I can imagine a solution where the powering of the watchmon before the breaker is somehow controlled by some relay that you can remotely turn off, iffor example you receive a notification that thebreaker is off, and you decide after checking up on the watchmon status that it's better to turn it's powering off until you come back from vacations.
That might be something to improve in the future, but for now I prefer to have it after the breaker.
 
The watchmon can be programmed for certain events and trigger relays to do the job, it's done in the Events section. You just need that expansion board to do the job. Daromer did a few videos on this.
Or, you could even have an arduino or something that disconnects power after the voltages drop too low.

In any case, you really should keep monitoring the packs after a fault. That could be where your most pertinent information comes from.
 
Or you can power the watchmon with a simple separate power supply.... ( a mains 12v psu or so)
Thenthere is still logging after critical event, and your battery wil not be drained.
Battery voltage is messured by the shunt, so no problem.

Do not forget the longmons are always connected and use a litle bit power, so if you are taking a 6 monts vacation the battery still may getdischarged.

Compromise ... :D
 
the longmons will shut down (deepsleep) if there is no activity on the bus so their draw will be minimal but still there :)
 
I've been building a styrofoam enclosure for the batteries, since below 0 temperatures are arriving soon.

I got a 220v Heating cable 100W ready to be installed inside the enclosure and am wondering how best to connect it to the Watchmon Expansion board Heating relay, so that it is controlledby Batrium logic.

According to Batrium documentation:


image_zjyurl.jpg


I have no experience in playing with relays and such, so I'de like to ask youguys what do yourecommend?

Is something like this:

https://www.ebay.com/itm/24V-220v-5...hash=item1ecc366fb9:m:mWu32GA81sYwTI0ssdGvLdg

any good for this purpose?

Thanks in advance
 
A relay like in your link, will do, but i would go for a 10A type... less problems with thecontacts fusing together.

To set the batrium up for heating is easy, the ambient temp. is the temperature of the sensor in the watchmon, and the cell celcius is the longmon temp. sensor... depends on your setup which to use.


image_bxeald.jpg

image_fepliq.jpg
 
As said. Just hook internal relay up to drive a larger one for the heat. The internal relays are max 30VDC rated.
 
Thanks guys, again, for your support.

I order this:


image_tckfww.jpg


24V DC 1x NO 10A

Hope it'll do it.

Meanwhile I'm just temporary using a sonoff + node-redcontrolled by Watchmon reported lower longmon Temp, and turning on the 100w heating cable.

Here how it looks thestyrofoam enclosure:


image_vrkqpj.jpg


I call it thesarcophagus :)

Let the winter come.
 
I'm wondering how to drive this 24VDC - 220AC relay through Watchmon expansion relay for heating, meaning where to get the 24VDC.....
In the shunt trip case, when it closes it will only be for a breaf moment, so using half of the 14s pack seems ok, but for heating it will need to power ~24VDC for a long while, so using half of the pack is not an option.
What options do I have?
- BUCK converter from full pack to 24VDC, but this means the BUCK has to be always on, since the batrium relay is only up to 30VDC, and that also doesn't seem optimal.
- External 24VDC PSU which would be turned on by relay....
-???
What you guys recommend?
 
Get a 48V relay instead.

Or do as I do with the trip shunt with voltage divider. You will burn half the power in the air but it works fine. No need to overdo it.

Just measure the resistance of the relay kind of.
 
I agree with the 48V relay.

Does the relay power the heating element directly? If so, what voltage is the element running at; is it the 24VDC, or the 220VAC?

If the relay is powering the element directly with 24V, here's a thought, and I'm sure daromer will correct it if it's wrong ;)
Couldn't you have a set of heavy duty diodes connecting half the string (7s) with the other half and have 24V output only at that point? The diodes would keep the two portions of the series from shorting each other out. At least, that's how I think it would work. I'm sure I might be missing a key point here in my theory.
 
Korishan said:
I agree with the 48V relay.

Does the relay power the heating element directly? If so, what voltage is the element running at; is it the 24VDC, or the 220VAC?

If the relay is powering the element directly with 24V, here's a thought, and I'm sure daromer will correct it if it's wrong ;)
Couldn't you have a set of heavy duty diodes connecting half the string (7s) with the other half and have 24V output only at that point? The diodes would keep the two portions of the series from shorting each other out. At least, that's how I think it would work. I'm sure I might be missing a key point here in my theory.
Click to expand...


How would using a 48V relay help with connecting with the expansion board relay (30vdc max)?
Can you guys explain me in more detail, since I don't have much knowledge or experience in this kind of stuff.

The relay I got is for controling 220VAC (the 100W heating cable)using a 24VDC coil. This should work in my understanding if the 24VDC is run trought the expansion board relay which is logic controlled by Batrium soft.
I just need to get the 24V from somewhere, ideally with not much losses in the long run..

I'm starting to wonder if so much trouble with relay, cables and poweringis needed to control this heating thingy, or instead just keep using the sonoff which iscontrolled by raspberry + node-red using watchmon reported cellmon min temperature...

Of course one disadvantage is that sonoff/raspberry requiresthat both theinverter and the router don't fail working, otherwise there's no control over the heating. With watchmon/expansion this is much more self reliant and problem proof....

Actually...now that I tough about it, if inverter fails, then there's no heating anyway so...:)
 
Easy, first use a 48VDC driven relay. Then, you use a mosfet that can handle 48V at 1A or so (what ever the relay is rated at). Then the Batrium port controls the mosfet turning on/off. Basically you are using a small relay to power a larger relay which powers the heater
 
You must log in or register to reply here.
Back
Top