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Since this forum is living advice I would bring up tractor. It is good investment. When figuring out what your going to do you might want to consider tractor. Wife and I bought 40 primitive acres. It is on a snow mobile trail above a lake and so on. Driveway is near 1500' of hardpack...

I worked on design team for this inverter when I was a very young engineer back in 1980. We built over 300/day of these little units.

My wife and I just built off-grid home on a hilltop in New Hampshire. We had a large 12'x8' pad poured for wood stove. We surround stove with pavers to moderate heat. When stove cranked the pavers absorb most of the heat so we don't have to open windows. Pavers then re-radiate heat through...

Simple is a component of reliability. The more shit you got the more shit you got to go wrong. Keep it simple. If clunky is simple then keep it clunky.

Charge relay circuit uses digikey parts A122275-ND & 570-1393-ND

I use Meanwell and buy through TRC electronics. I am power conversion engineer with 40+ years of design experience. i am impressed with their gear and buy from them when I can. They are the good Chinese from Taiwan.

When wife and I started construction on off-grid home ( Bed & Breakfast ) I would collect sliding doors I would find at dump. I stopped collecting at 30 panes. I wasn't quite sure why I was saving them, but knew they would come on handy. (Wife thought I was nuts.) I decided to plaster them...

I will post .pdf of schematic when it is complete. I am creating symbols today.

It is a 48v inverter, so 120A should get me to near 5kW considering efficiency. We have well pump that takes near 8kW for 20 cycles to get up. I was surprised it is go stubborn. It is about 6A FLA so 36A on start is not too wild of a number. I believe motor inrush current is in-phase, so VA...

Let me take a shot at it. I've been off grid for about 5 years now. Off grid except for the 1000gal LP tank that gets filled up once a year. I own tank so I pay about $1.50/gallon. I'm most likely running a deficit over what I would have paid had I had the 1500' of power lines strung up my...

My concern is BMS shutting power down to inverter and then coming back up. I am not sure if BMS is rugged enough to take a 2000A surge on mosfets to bring dc bus up. Also there is the question of what the class T fuses can take for inrush. This circuit would take care of both potential problems.

If you are in the military then current flows in a particular direction. Once you get out it changes direction.

I would buy a battery that would pass an electrical inspection. That would be my most critical must have. The last thing I would do is DIY a home brew battery pack. I know that the Tesla Power Walls are being installed in many residential systems. Others I can not say. I would most likely...

The appliances may be key to this discussion. Ranges, microwaves, toasters, coffee pots, griddles and similar can blow a hole in your budget. A 1500w inverter will only operate one of those at a time.

What kind of a BMS was it that you smoked? There has been a lot of chatter recently concerning BMS capability as far as surviving direct short circuits and powering into a large cap bank. My feeling is that a BMS should be able to handle any type of short or power up into any size cap bank...

maybe better to run them up and down a few cycles before you add balancer.

Pull some current out of the pack 1/2C? 1C? and measure the voltage drop across each cell if possible. I think I am about 200uOhms per one 280Ah Eve cell. As a first approximation scale your ESR to (200uOhmsx2.8). How does that compare to the data sheet? to what you calculated with...

Is Omicron an anagram for Moronic?

The average commute to work is about 26minutes each way. I suppose that is near 50 miles/day The average mileage put on a car is near 14000. Assume 12000 is used for back and forth commute then that is near 250 miles/week or 50mi/day. I am talking average, not what any one person might do...

I would consider a charger with PFC if running on small generator. Meanwell has some nice looking units. I cannot give recommendation, but plan on using one when my new cells arrive.

I don't think I would use this one post to make a decision on which inverter to purchase. I have 48v system also. My growatt 6kW inverter arrived today. I intend to use Growatt only for inverter. I have other solar charger and PFC charger for generator. The manual is lacking, but sounds...

Me neither. I worked with the Finns at ABB. An impressive bunch of engineers

#10 wire is 0.001ohm/ft I think that works out to 0.2ohm total. At 11A the loss would be about 24Watts.

There is an incredible amount of peak power in just 1 280AH cell. Theoretically there is 28kW available in just one cell. A string is very dangerous. These cells are used on the NAVY 275kW laser because of the peak energy available.

Yes. They are all over the place. I have done a few simulations. The largest contributor would be the battery chemistry. A large LiFePO4 call array would have a small impedance leading to large current pulses. Likewise a large inverter with lots of capacitance will pull a nice pulse...

Here is board. If anyone is interested in a board then get with me. I am not quite sure of price until I know of anyone else wants one. I have a circuit description I will post a little bit later. I have errands to run for now. If anyone want to spend an hour or so to critique then I will...

I believe you are using 600Ah total LiFePO4@48v, with 6 packs in parallel? 4/0 wire is fairly sturdy stuff. Your impedance is very low with the potential of some large fault currents. Have you given any thought to fusing each battery pack? The reason this may be worth looking at is if one...

Throughout the years I have always asked for a SEM, scanning electron microscope when it came time for budgeting test equipment for the upcoming year. It was more of a joke than anything real. When I got to Creare and asked for one, I was told, "We don't need another one." It was an amazing...

Thank you all. I will put BMS on it

I would like to share this with the group. I worked for Creare here in Hanover, NH. They do all kinds of R&D work for DOE, DOD, military and at times NASA. They re-designed the chilling system for the Hubble telescope when the first system wore out. The particular design I would like to...

This thread may contain false or misleading information.

Pull Test?

Good comments. Yes, the magnetics are the difficulty. We've been doing planar designs for a few years now and that takes a lot of the grief out of winding. We're in the middle of a 2.8kW design now. I think transformer is 16oz copper. I've done a bunch of the ZVS full-bridge designs that...

Joao Pedro Beirante and Beatriz Vieira Borges—A New Full Bridge Zero Voltage Switched Phase Shifted dc to dc Converter with Enlarged Duty Cycle and ZVS Range Project PraxisXXI/98/P/EEI/12026/1998.

There are ring terminals on the arresting cables to catch aircraft on the aircraft carrier. They use hydraulic press to put them on. https://www.creare.com/wp-content/uploads/2019/08/Creare_CSM_Case_Study_Aug2019.pdf

I am laying out a simple board for inrush limiter. Board is automatic so that BMS never has to start into an empty capacitor bank. While charge resistor will be on board there will be connections for an external contactor for the main current. There is also hooks for an external on/off...

a rule of thumb I use. If you can hold the wire in your hand then it probably isn't too hot.

I am interested in leading an effort to design an inverter. If anyone else is interested in this then maybe it could happen. I am semi-retired after 40 years of power conversion engineering. I spent 30 of those years doing nothing but industrial inverters. The last 10 years I have been doing...

Use the grid for now and put solar on the back burner. You got enough shit to take care of.

I have cobbled up a short Mathcad file which calculates inverter losses and heatsink requirements for a 5kW inverter at 10kHz. The transistors will do 200% continuous given a good heatsink, This file could be used to develop both low and high frequency designs. I expect that this bridge...

I picked up this load for almost nothing. Looks like it was made to test cells. I have had it for a few years and haven't yet powered it up. I will get it running and report back. It is a TDI 50-120-1500

Should be fine for what you want to do. If you need a thermal analysis for a heatsink/fan I run Sauna here and would be happy to run it for you. I buy heatsinks off Ebay for pennys on the dollar. I got a bunch over here that ate about 4" tall and very high density. I can part with one no...

I expect maybe your battery may not be full charged or maybe even sulphated. Is the battery brand new? Has it been sitting for any time without a full charge?

One other point to mull over. If you have excess power then efficiency becomes less of a concern. I have a very large excess of power. I have 4kW of panels, 6 hours of sunlight, and use about 6kWh/day. On the very cloudy days I still have enough juice to keep me happy. Efficiency is not a...

Yes. this is one of the construction methods. Sheets of copper are often used. They can be cut like paper dolls and folded back on each other to get more turns. Copper could also be used as bus bars plugged into the pc board. Instead of using 16oz copper to do a power board - use bus bars...

Yes, it seems the usual rule of thumb is 3x your daily usage in kWh for cell storage. I suppose a 16S2P array of the 280Ah cells would be good. Maybe split into 2 systems would be good. If one go down you have another. I think 2000Ah is about 100kWh at 50v so maybe too big for your needs...

These big modules want the gate drives right on top of them. You may be able to get away with some twisted pair if you have a negative gate drive. keep them short tho. The modules want to be mounted very close together as well. I think you are running the dual modules. You will want a low...

What does a DC-DC converter do?

https://www.stanleyengineeredfastening.com/brands/optia/heli-coil

Me and wife use about 6kWh/day. We use 900 gallons of LP each year.

I expect similar numbers to the paper presented using silicon switches at 100-200 kHz with resonant secondary. 5% would be 250W out. The difference there in lost power between 90% and 96% is only 15w anyway so not too too concerned there. I am heating 2" concrete slab on second floor with...

You cannot let an SCR meander on. That is a sure way to get it to fail. You have to hit it with a good size pulse with a fast rise time so the current spreads across the device quickly.

I'm planning on using springs :)

Thank you for the comments HaldorEE. The low frequency inverter does have a few advantages. It is a fairly straightforward implementation, and actually quite simple. Your point is taken. No one should get electrocuted. The high voltage must be discharged to under 50v in 90s I believe...

I just order this unit. It is dirt cheep through Amazon and even dirt cheeper from Powermrsolarsolutions I am putting redundant system together - getting ready for another lightning strike https://www.amazon.com/gp/product/B0CP8P5VKW/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1...

It is 280Ah EVE pack. It was near 0% when I started. It is new setup and I was just filling it up. I'll keep charging and see if it finds it's soc.

I have a LT Spice file if you are interested I will get it to you. Push-pull transformer with voltage doubler secondary - that gets you about 100v out. Two of these supplies on one board with outputs in parallel is then near 200v.

The bottom line is the watts. The charge controller can manipulate the volts and amps to make battery happy. Some (boost) chargers can deal with panel voltages that are quite a bit less than the battery voltage. There are other secondary issues to keep in mind. In general a buck type...

I was just thinking there really isn't a rule of thumb or a clear cut formula . When running 3 phase motor drives off of grid there is quite a bit of 360Hz ripple. If there is line imbalance we see 120Hz as well. Both the fundamental output frequencies and the carrier rates each produce...

no

I know what they do. I design converters and chargers for military. It was a response to your converter makes DC from AC. One of the early lessons in college I recall. I'm a little reluctant to use my does everything Growatt inverter for anything beyond inverting. Just DC in and AC out...

You would most likely be better with a generator. Panels and heaters can gobble up a lot of power. Let's see what others say. P.S. can you post link to the Rich/Bluetti/Delta solution?

You need to produce as many watts as you are using. I use about 6kWh of power each day. I have 4kW worth of panels. as long as I get 1.5 hours of sun I am good. The best plan is to have enough panels to provide your minimum requirements on a cloudy day and a strategy for putting extra power...

yep

Where are you located? I have big diodes and heatsinks and capacitors that I am willing to make a deal on. If you have system particulars I can see what I have.

These 3 units will not keep a small heater running for more than a couple of hours. Can you deal with propane?

Lot's of compliance testing to make sure the widget meets the spec - It's the only way to do it. I did industrial 3 phase inverters for a long time. We developed a stress test rig that beat the crap out of the inverters as a compliance test before they even got out of engineering. We normally...

I'm using the resonant push-pull to get from 48v up to near 200v to invert. I've got it simulated in LT Spice and looks reasonable. It's open source so simulations are up for grabs if anyone wants.

I'm about to pull the trigger on the 280Ah cells and am thinking that I might want to assemble with plastic wrench. Google wasn't very helpful Anybody got anything?

It was an attempt at humor. I have a quirky sense of humor, but it keeps me amused. You said a converter makes DC from AC and I just pointed out that there are DC-DC converters.

Is global warming more real or less real than the covid virus?

I worked for Parametrics/ABB, TB Woods, and AC Technology/Lenze. These were all 3 phase inverters for motors. Very much like what use to run the house, except no output filters. Raw PWM goes to the motor windings and the motor inductance is what filters the current into reasonably...

very unlikely as panels are glass and glass is an insulator

I was referring to the particular balance that can be found between distance and voltage. That could spur endless debates. It is more efficient to move higher voltage, but may be less efficient to convert that back to a workable battery voltage. Another question could be, what is the best...

Yea, expensive. If the spring constant is known a fairly good measure of pressure should be had by just measuring spring height. I would probably go the load cell direction if I wasn't retired and poor.

The DIYOSI power board is coming along. I changed gate drivers to a better TI part with good undervoltage protection, and added negative gate drive for the Sic Fets. Looks like Sic is the best player right now. I have not decided how to sense bus current. I am using a HP Isolator and a wide...

Is anyone using a 120v-240v step up transformer? I was fortunate to get a 30kW 3phase 240v-480v transformer from my boss when we built our home. I now have 3 transformers that are good for 120v-240v. I use one to run the other side of my panel when I run inverter or smaller inverter...

i have seen Growatt shut down on high voltage without any indication what happened. I queried sig solar but they had no clue. They asked for a bunch of useless information. I told him I thought it was the power supply shutting down because of high voltage. Changed over to LiFePO4 and prob...

I am curious what your shunt resistor value is. I would guess a 0.0005 ohm might be a reasonable value at 100A. This would translate to 125W AT 500a You might want to consider using extra large cables to attach to shunt. The cables are basically the only thing keeping the shunt cool...

Larger inverters tend to be more efficient, but not always the case. Larger transistors and more heatsink reduces losses. And yes, larger inverters will have better connections. I can't think of any issues with sizing inverter on the larger side. Inverters in this range tend to be good...

The DIY experience. Beyond that I have no idea. I think a reasonably complete paper design could be done in a short amount of time. That would include all design equations including semiconductor junction temperatures, thermal designs, costed BOMs and so forth. The initial paper design...

Ok, thank you. I misspoke. I meant to say three phase and figured 3 wire is automaticlly 3 phase. They can accelerate the pump slowly. Very good to control the speed and doesn't shock the pump when starting. Less wear and tear. I designed 3 phase VFD for many years. Parametrics/ABB, TB...

I have moved my critical loads to one side of box so when I run off of a small inverter generator I have everything I need. I understand the idle current problem with the Aims. You could possibly move your loads to one side as well. What do you have for 240v loads?

Are you trying to run this off of the 48V AC adapter? That could be a problem. (edit) You should also have a load on the 12v supply. I would put 1 amp or so on it.

Many single phase motors use a centrifugal type of switch that removes the capacitor from the circuit. Does the thermistor increase in resistance and reduce capacitor current rather than use a switch? In the early days of three phase motor inverters I compared motor temperatures running off...

Contractor used corregated steel with 8" of concrete poured right on top. The corregated can take a lot of weight. I would use caution when putting weight on an existing slab. My bunker used good size footings Yes, steel door is about 300 pounds :)

In the grand scheme of fuses it is fast. It is fast enough to protect diodes or SCRs looking into a dead short. Not quite as fast as a semiconductor fuse, but will keep up with the KTK series. The speed is generally considered to be in the sub cycle range (<16ms or so) rather than in the...

You are not crazy - so far. I heat a 1200 sq-ft slab directly on the ground with zero insulation under slab and about 4" around the outside perimeter. I am in Southern New Hampshire. I run 80,000 BTU 80gallon Rheem LP water heater about 2-3 hours a day at about 1 gallon of LP per hour...

Thank you. We hope to be dealing with DC currents so that there is no skin effect. There are some higher frequency components with dc link side of inverter so that wiring will see some AC. I'm not sure if you would be able to measure a temperature difference even if you used Litz wire...