Search results

Don't confuse the bypass diodes of the panels with the reverse blocking diodes in the combiner box. Ideal diodes for more than 60 to 100V are difficult to find. The high voltage Mosfet's internal resistance would make them as inefficient as silicon diodes.

For larger LiFePo4 batteries, Aliexpress is just not the right place. The small 5Ah round cells might be ok if you are lucky. Good for @augiedoggy that you got decent cells, but many others have been scammed. For 600$ the risk is just too high, and in the end you still end up buying from Docan...

They have high internal resistance and are garbage. My ones even started to leak. Search for Liitokala here in the forum, there are a few posts from myself and other victims of their G-grade cells. Now write them off and buy quality from the recommended sellers.

This seems the most likely. A failed mosfet or IGBT in the bridge could cause this. But the local electrician will have issues to figure this out. There was no report of what voltage has been measured in the dark on the SPD.

Very good ideas, I'm thinking of adding a 2-3 s wait time after turning the inverter on, and then connecting the compressor motor so that the inverter does not need to start with a near short circuit on the output.

Just one more little thing: So you took out the thermostat out of the 230V circuit completely, and you use it only to pull INT0 of the attiny to GND to wake up from deep sleep . Then from the schematic, you must have put L of the power directly to the compressor?

Thank you anyway, this was interesting. I've never seen a fridge thermostat too closely, but your procedure looks good. My pure sine wave inverter 12V 1000W beeps for overload at every fridge start, but then runs fine. This inverter might be at the lower limit for running a fridge. I've measured...

Thank you so much for sharing your experience with the SPD that burned. Here is another video which shows a similar device. I wonder if there are any good ones out there, or only this crap which does not disconnect. With this behavior, one can skip these SPD completely.

Fully agree. Whoever has seen CO2 on a hot fire, will discard this option completely, it would just be a joke on a burning battery. I have never seen a burning LiFePo4 myself, but there are some scary pix here in the forum, and they are certainly not fakes.

As Mattb4 spotted, you are at 10.9V, completely and utterly discharged. This battery needs to be disconnected immediately from anything, and be recharged. If you have nothing else, you can hook up a 12V panel directly during day time for at least 1h in sunshine. This will restore the voltage and...

I tried this by sanding the spot first and putting the red paint as you can see, but it was hopeless, as the corrosion came from inside the cell to outside. There must have been a micro crack where the electrolyte came out.

I like the tidiness of your balance wires. Unlike other battery builds here where the wires fly all over the place.

But your reasoning is ok. That's why we now see 48V aircon and fridges appearing. 12V is only good for lights, because you do not want to handle currents above 50A.

The issue is that most household appliances are AC, but there are no AC batteries. DC has disadvantages such as arcing at high voltages and you cannot transform it easily. This is why 120 years ago, most of the world adopted AC.

Could you explain how you go through the load that quickly? In your picture, you seem to take 30ms?

Oh poor you, so much snow already in october. I find your construction in the other thread beautiful. As you said, it seems to be made for an airplane. Could you show more photos of your welding of these smaller arrays?

All these Silicon diodes have a forward voltage around 1V or above. At 10A, you are looking for a whopping 10W heat from one single diode. A couple of these in your combiner box, and you will need a special aircon to cool your box. Ideal diodes are the way to go.

The Wh for your battery is easily calculated. 12V x 250Ah = 3000Wh for each battery. Being Lithium you might get 80% out of it, but if you get Lead Acid, then max 50%. This means, with 4 batteries, you can run a single fan for a couple of hours in the best case, because each fan takes 1000Wh...

So you probably use these swimming paddles which can be seen in the shrimp ponds? Depending where you are in Thailand, air pollution like this smoke from Malaysia will reduce your panel output, maybe to 70% of the panel rating. Then on days of dark rainclouds, the output will be considerably...

Are you sure you will run 7x 1.1kw single phase 230v air blowers 24/7? This is quite big fans. Is this for a chicken farm or something? Could you post an approximate price they quoted you for all this material plus installation?

This is correct. One can measure a voltage between + or - and the cell case. You can see in my pictures that this was the case. All cells have a foam insulation inbetween. Underneath you cannot see, but it never touched any metal. Anyway, my defective cell already came corroded from the...

It started slowly from the corner. The red paint is from me. I thought it would protect further corrosion LOL. But the corrosion comes from inside. If you have 15 cells, you could still do 48V, depending on your BMS and inverter supporting it. Some commercial batteries have only 15 cells. Adjust...

Thats how my cells from Liitokala looked when I got them, one out of 4. I though it was corrosion from the outside, but probably it was a crack. 8 months later the cell started to leak. Thats the risks of buying garbage grade cells on Aliexpress. Would never do this again.

Can you elaborate a bit on "- of course, shutdown the inverter when the thermostat trips" This seems a clever feature, especially as most energy for a fridge would be lost by running the inverter in idle most of the time. How do you interface the fridge thermostat with the microcontroller and...

@Alkaline has a very good point here with the Wh Less average voltage means that the internal resistance of this cell is higher. Then this cell will make problems in a pack, where it charges faster (reaches max voltage earlier) and discharges faster than the other cells. Individually the cell...

I have a theory on this since I had one of these bloated cells loose electrolyte. It might create very small cracks on the edges, and then electrolyte comes out. First you will see white spots on the Aluminium. That doesnt mean that your cells will crack, but I had one of the Liitokala G- grade...

Sorry for the off topic, but I got attracted to your Docan experience. I recently bought 100Ah cells from Docan, but new ones, and they were 109Ah and new. So I'm quite happy with their service. The swollen cells is a bad sign, very bad. I had such ones before from Aliexpress, and they are...

I made a small tester like this, but it's only for small cells. I measure the cell via an INA226 current sensor and an arduino. The arduino then switches 10kOhm, 3Ohm and 0.5Ohm Loads via a mosfet. Maybe that is the way to go with your 150A Load, because you cannot connect a 150A Load in any...

They are most likely old cells. Crossy who is under this name here and in the Aseannow Forum bought some. But he bought them as second hand cells. AFAIR they were not great even as second hand cells. Edit: it probably also says there in thai that they are second hand LOL

If your cells are at 3.3V and your power supply is at 3.65V and current is only 2.6A, then you have a big issue with the cables and connectors. With a correct electrical connection, your cells should be a few 10mV below the power supply voltage. Or one of your instruments is wrong.

Be very careful when charging with a voltage of more than 3.6V. I had a similar event a couple of days back. As you can see, the runaway cell was still ok at 8am, just when the charging starts. 30min later it was already out of spec and 1 hour later hopelessly at 3.8V. Once the voltage runs...

Yes, and this was the mistake. Welcome to the club of Liitokala victims. Enjoy them before they leak electrolyte. These are second hand cells which have been abused in electric motor bikes or similar. Write them off as a loss and check the reputable suppliers via the forum. And dont forget to...

Thank you for this insight. Now you got me started on a new little project. I need to get currenttransformer and ESP8266 out to measure my fridge consumption over the day. I'll try this out manually first, switching the fridge off for 1 hour from time to time. I

yeah this is too much old style, and would make life too easy now we have everything in software, even the switches LOL

That's an interesting aspect. I didn't know of this behavior. How would you measure the defrost cycle? I have the possibility to measure fridge temp inside the fridge and send it to a database, but I suppose the defrost is done in the back at the cooling radiator. My one is behind plastic and a...