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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.

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 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 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...

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...

I read in NEC that grounded array systems use white for the negative. I can't seem to find that clause. Anybody know where it is?

Just curious.

I read tht freighters are piling up on the west coast because of problems at the ports. Will cells be stuck on freighters that cant dock?

The SPF 6000 DVM unit shut down by itself - unit went dark. In order to restart I just turn switch off and then back on. Unit powers up as usual. Has anyone seen this? thanks Bob

I am interested to know what works (as well as what doesn't work). I have a 2kw AIMS that will not start well pump. I have a 6kW Aims that starts pump but it took a lightning hit and looking to replace. What do you have?

Sorry I haven't posted any news on the osi design. Looks like we will be doing a pc board for the inverter. The inverter will be very compact. The inverter may best laid out with a beefy 4 layer board. or a pair of 2 Layer boards. The inverter has 4 serious wires going into it. Best is...

I am about to bring a good size 48v LiFePO4 array on line with new Midnite Classic 200 charge controllers. I have been using some Make Sky Blue controllers on my existing Lead Acid array. I have not had such good luck with these controllers. I get these big fat sparks when I connect them up...

Here is what I am looking at to charge 280AH pack. I am going to drive this with Champion inverter generator. Links below. The charger has Power Factor Correction (PFC) PFC pulls nice sinewaves off of the generator. This is important as I intend to run the 3500w inverter generator at max...

Does the typical BMS use resistors or strictly fets for balancing? Fets with a low thermal resistance are as good as resistors getting heat to the sink with I would expect a small cost penalty.

Just jumped from Verizon to Tmobile and got Netflix with the package.

Is anybody using paraffin as a thermal storage medium?

I have just received a Meanwell DBU-3200-48 charger. I am using to charge the EVE280 cells. The default programming curve is 57.6v boost and 55.2v float. 57.6v/16=3.60v Are these good numbers? I can purchase the programmer and program a custom curve if I need to. thanks Roswell Bob

I would like to control my Growatt with a simple relay closure for on/off. I don't see any obvious terminal connections for that Has anyone hacked that operation mode? Thank you

I am looking for an inrush limiter to mitigate the charging spike when powering up inverter. I am aware of the REC unit. I am looking for other options. I'm not interested in manually connecting resistor. This has to be automatic.

I heard it was McCain that launched the rocket.

Do the smaller passive balancers work ok? I have to wonder if a few hundred ma of balance current is enough to do the job.

Here in New Hampshire (The Granite state) we have a lot of ledge to deal with so running wires underground may be difficult/impossible. To complicate matters I have a large stone wall between point A and point B. I am thinking a combination of underground and overhead. I have two panel...

I am looking for a half-dozen or so boards fabbed. 2 layers through hole 3"x5" solder mask and silk one side. Looking for local USA source with 1-2 week spin.

I have 4 of the EVE 280Ah calls in series. No BMS yet.. I am putting 20A into pack. Power supply current meter agrees with DC clamp on and 30A fuse is as warm as I would expect. After 2 hours at 20A not one of the cells has moved up a millivolt. My guess is they should have moved close to...

I can't imagine that an inverter would produce cleaner power than a generator. Can anyone educate me?

I am thinking 4MWH sizes. I am curious as to the technology is being used for peak shaving. That would be about 4000 of the 280Ah cells.

I am thinking that a BMS which is attempting to charge balance would be more efficient if it knows what all of the cell voltages are. I assume that is the current state of the art. The most simple balancing system would be individual clamps across each cell to prevent over voltage events. I...

My 48v Sears Die Hard lead-acid pack is about dead. I am doing a 48v LiFePO4 pack to replace it. But first I am doing a 12v LiFePO4 battery pack to run lights and small TV at night. I want to get some experience with the LiFePO4 with a smaller 12v pack before I put the 48V pack together. So...

I am curious if the bargain cells (that many seem to be happy with) have any problems staying balanced? Are there some balancers which do a better job than others?

I am looking for a document that might explain how to set up BMS. Manual I have is vague or does not address some settings at all - to be fair I do like the BMS though.

I spoke to Growatt today with concerns of inrush currents clearing fuses. The application engineer (Cody) told me that David Pos has a very good you tube presentation on the subject. Can anyone provide a link? Thank you.

Here is a drawing of power section. Tear it apart. Please supply input as I expect to start putting tracks down next week. I will complete the schematic and get it out tomorrow or Tuesday. Keep in mind that this inverter board will be used for HF design, but is fine for a LF desoign as well...

I need to know the gauge of the balance wires. Documentation calls out #16-22, but connector on board end of wires calls out #22 - #30. thank you.

I have BMS from Overkill. I was putting about 40amps into pack and state of charged jumped from 33% to over 90%. I have no idea why it would do something like this. I have not email them yet. Thought I would throw it out here first.

I need to measure inrush current on my well pump. I don't have a peak reading clamp-on ammeter. I am thinking to use an (off the shelf) AC Current transformer - maybe 100:5. I have DSO to observe. I can use a small value resistor to load the CT and look at it with voltage probe. I also...

Does anyone build chargers with built in balancing? It would be 16 individual chargers for a 48v system. I have seen this topology used in the aerospace industry for 28v systems.

I am picking out wire for underground run. I think either one of these would fly. The stuff is a little pricy - glad it's only 150' run. I just want to get some more eyes on it before I pull out the credit card. I will probably go with nassaunationalcable.com as they are close. Comments are...

I had a discussion with friend this week concerning scrapping my 32 Die-Hard batteries. He told me I would only get a few dollars for each. I am wondering if I should just try and reclaim lead myself and stick it next to my pile of brass. Is anyone reclaiming lead acid batteries? I'm not...

I am curious as to the variability in same design batteries over time. If you smoked a battery and had to replace one in a string then what have you observed? Has new cell performed ok? Did the cell balancing mechanism do it's job? I expect as processes matures and recipes are tweaked the...

I received a Meanwell NPB-1700-12 charger on Monday. The unit was supposed to have been cancelled as I ordered a larger 3200W charger. I spoke to the salesperson at TRC and she was very apologetic. She said her fault and no problem they will send me a shipping sticker to send back. I told...

https://www.amazon.com/ARES-4-inch-Visibility-Markings-Readings/dp/B07BFGN53Y

With all of the chatter about bus bars and proper compression of cells - I am leaning hard towards using hardwire with ring terminals. I prefer a connection made with the proper tooling. I have a pair of crimpers that will get them on, but this is not a place to go backyard. I understand...

My son just picked up a wrecked Prius Hybrid. He said it is totaled. Are the battery packs worth anything?

I will be receiving a Meanwell NPB-1700-12 charger on Monday. The unit was supposed to have been cancelled as I ordered a larger 3200W charger. I spoke to the salesperson at TRC and she was very apologetic. She said her fault and no problem they will send me a shipping sticker to send back...

I am putting a LiFePO4 pack together. 48v/280ah. I have a section of the basement with 8" walls and a concrete ceiling. Basically a bunker which maintains about 50-60F temperature. (this is where I keep my present lead acid batteries for safety reasons) The inverters are on one of the...

Warner New Hampshire is here for me.

I am thinking to build my own inverter and would like to know if there is any interest. I know this sounds crazy but I have been designing Inverters for almost 40 years. Parametrics, ASEA, ABB, TB Woods and AC technology are companies I have worked for-with great success. I have done...

I ordered 16 of the Lishen LIFePO4 272/280 Ah cells to replace my Sears Die Hard units that I have 5 years on. Seems there is some kind of cluster-F**K going on behind the scene delaying shipments. If I don't get good news on LiFePO4 units I will go another round with the lead acid units. I...

If I put a dead short on the output of your BMS will it survive? I have the overkill 16S BMS with a EVE 280Ah string. If I were designing a BMS I would want to pass the dead short test. Has anyone any intel on this protection mode? thanks

There doesn't seem to be any recent / relevant news to the 787 Dreamliner story. It's been over 5 years since the smoking battery fix has been implemented. I haven't heard a whisper tho I don't travel oin those circils anymore. Anything out there?

I am buying a small inverter to run TV and Refer off of 12v. I am thinking that I should get UL1741 listed inverter. I am off grid and aware that I have not paid enough attention to NEC and so forth. Is UL1741 listed inverter what I want? I would entertain suggestions for 12v/1kW pure...

When connecting up a solar charger is there an order to follow? It seems to me that the panel side should be connected first and then the battery side. I am concerned that the diode in the upper transistor might fail from surge current. I think there is probably a good sized capacitor on the...

I am mulling over the top-balance issue. I have a 60amp bench supply that I was going to use to balance. I recall having to repair a few of these over the years and am dealing with some reluctance hooking this thing up to my brand new cells and walking away. I also have a good size variac and...

Looks like my cells have left west coast for New England. I'm putting system down on paper. I am going to do a precharge system for powering up the inverter. I would like to use a golf cart solenoid for the main contactor. Is this a fairly common way to go? thanks Bob

I did a thermal simulation this morning. The simulation was run with the IXYS IXFH94N30P3 mosfet - 2 on each corner. The inverter was run at 10kHz, 5kW, 120v output. The heatsink was a 8" piece of Aavid 71145 with natural convection. Simulation contours are in attachment...

Title says it all. Target cost is $1000. 6kW/6kVA. I have outboard chargers for solar and generator so not necessary. I would prefer a bare-bones inverter only,but will take what I can get. I will not deal with Ali and prefer a brick and morter type of place that will stand behind a...

I heard (today) that the president owns a 10% share of a battery company in china. Has anyone any intel on this?

Has anyone given any thought to using a large Class T fuse and a breaker? I am considering using a breaker to protect #2 wire to inverter and a fast Class T or Semiconductor fuse to protect against short circuit events. The fuse would open and clear large fault current before breaker would...

Is anyone stocking the EVE 280 cells or comparable here in USA?

Most switched mode power supplies (smps) exhibit what is called negative resistance. Many motors pull less current when loaded than when unloaded. Any more?

I would like to be able to monitor my battery array remotely. I have a flip phone and have no plans to upgrade to smart phone. Is there some kind of bluetooth device that will pair with my BMS that is reasonable price? I am using the Overkill Solar BMS. My battery pack is in a corner of the...

I am looking at different approaches to dealing with DC Arc Fault protection. I have seen some fancy charge controllers with arc fault protection, but they are very pricey. I understand the engineering required to detect arc, so not whining about price. NEC tells me that I do not need arc...

I have had some problems with lightning strikes. I'm thinking I may have a grounding problem - that may be difficult to resolve. My array is a home brew pole mount with the (8" schedule 40) pole sunk about 6' down with a 3'x3'x3' block of concrete to anchor the array. Array is about 100'...

Do I need a fast acting or slow blow fuse for Growatt 6kW inverter? I'm looking at about 125A I have used Class T fast acting fuses in industrial inverters. These inverters have resistor/relay charge limiting circuits though. Those damn fuseholders are expensive :(