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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...

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

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...

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 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.

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...

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

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 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...

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'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?

I am familiar with circuits that switch resistors in and out to balance cells. I am curious to know of any balancers exist where a mosfet is used in the active region. A mosfet can dissipate as much power as a similar size resistor and the power can be varied as necessary to balance the pack...

I am thinking to use wire with ring terminals rather than bus bars. Tin plated terminals I think will work with cell studs??? I'm concerned with bloating of cell packs with rigid bus bars. I will most likely compress cells with 1/4" thread rod and springs. Comments please. thanks Roswell Bob

(EDIT) I just want to mention that these NTC inrush limiters are HOT. Keep them away from flammable shit and don't get burned. I have used NTC thermisters to limit inrush current on large industrial inverters. It is actually a very old idea as we used them in the 1970s. The idea is when...

This is a Midnite Solar number. I will put it between the battery pack and the inverter. I am looking for 100A-125A DC breaker for my 48V inverter. I prefer DIN rail mount. Has to be Bussman / Eaton / Schurter / ABB or other brand I can trust. I would like 20k AIC, but I can get around...

Does anyone know how the bus capacitance of an inverter is chosen? I have been told that a 6kW inverter should have 0.1F from one source, and 0.028F from another source.

Do It Yourself Open Source Inverter. DIYOSI Notes 4/26/21 Work has been progressing on the DIYOSI. I have decided that I will build a couple for my own experimentation. There was a question as to would this ever get beyond a paper design. I have answered that question. This initial design is...

I live on a hilltop in New Hampshire. We get a lot of snow. I put a pair of 2kW arrays on poles. In the fall I place panels nearly vertical. Best for low angles of sun. Snow doesn't bother my panels - if any collects it is gone soon after sunrise. I didn't want to bolt panels to a brand...

https://www.digikey.com/en/products/detail/te-connectivity-aerospace-defense-and-marine/5-1618388-8/2362831 The contactor runs directly off of 48v pack. Max voltage is about 54v. Spec says 60v is max input. I noticed the contactor was running very warm. I let it go and after 3 months the...

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...

I am winding a 60Hz transformer to charge my 280Ah cells in top balance fashion. I got 20 in parallel. I will keep power to about 10kW input to 10kVA tape wound transformer. What I need is a model of the battery array. A reasonable way for me to simulate the setup would be to model the cell...

Do most BMS count Coulombs to determine SOC? I am thinking to rum my packs from about 20% to 80% SOC and expect Coulomb counting may be the best way to control charging.

I would like to buy the Overkill BMS unit. My cells will be here in August and I thought now would be a good time to order BMS. I am curious to know where I can get one. I am a little reluctant to order and find unit is out of stock or backordered or ???? I will want some value added...

I have completed a board design for a pre-charge circuit. I then decided I could do autiomatic inrush limiter with 2 or 3 parts. I have attached picture of 2 component design. With a 0.1ohm NTC the inverter bus is up in a couple of ms. The charge contactor will take a few ms more to switch...

I'm trying to do some inrush current simulations on the Growatt 6kW unit. It is the SPF6000T DVM. If you can tell me what the input bus capacitance is then that would be perfect. I think it is a string of 3300uF/80V or 6800uF/100V caps. Signature Solar wasn't able to tell me what they are...

CONTACTOR will not switch any current. I will load up to 125A or so. Is Gigavac contactor any better?

I can run an inrush simulation based on your battery pack and inverter. This will tell you if you are going to clear your fuse when you power up. If you power up manually with an outboard charge resistor - you may still have a problem if your BMS removes inverter from cell array and then...

I bought 32 Die-Hard deep cycle batteries 5 years ago. Big, heavy, smelly, and full of nasty stuff(?) that need a lot of attention. I knew then that today would be here and I will replace them. So new pack/old pack cost about $1900/$3200. Weight ratio is 240/1440 pounds. volume is 1/4.2...

Is there any reason to use 3 stage charging profile?

I have 4 stancions for lead-acid battery racks. Each pair has held 16 Die Hard deep cycle batteries - about 1000 pounds worth of cells. Shelves will accomodate about 11" tall batteries. Stancions weigh about 60 pounds each. These are rugged uprights. Free to you for shipping from New...