sunshine_eggo
Happy Breffast!
It's a sickness 
SAMLEX PST-600-24 DC-AC INVERTER PURE SINE WAVE 24VDC IN 120VAC OUT 600 WATT...
- Thread starter 2Big2B
- Start date
2Big2B
Free Wheeler
It's just a phase...Admitting you have a problem is the first step……..
A few thoughts:
Make sure the Renogy battery BMS is rated for series use. Link a product spec sheet if you’re not sure. EDIT: SEE POST BELOW ASAP!
You will need to check each battery voltage occasionally to be sure they are staying balanced. You don’t need to disconnect the series setup, just properly place your DVM probes across one battery at a time.
At 29.2 V that is 3.65 V per cell. A bit high for my taste. Read some of the millions of posts on proper charge Voltage per cell and draw your own conclusions.
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Bad news, but glad we caught it in time (I hope). I found the model number on the picture you posted and then found Renogy’s documentation for the batteries you bought.
To quote from that document :
“DO NOT string batteries in series. Doing so can cause catastrophic failure.”
I understand that “Catastrophic Failure “ is a bad thing..
I assume that you are already on eBay looking for a 12V inverter to use with the Renogy batteries?
It seems you are good at making lemonade when life gives you lemons so I have no doubt you will sell something or make something else work.
To quote from that document :
“DO NOT string batteries in series. Doing so can cause catastrophic failure.”
I understand that “Catastrophic Failure “ is a bad thing.
.I assume that you are already on eBay looking for a 12V inverter to use with the Renogy batteries?
It seems you are good at making lemonade when life gives you lemons so I have no doubt you will sell something or make something else work.
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2Big2B
Free Wheeler
Naturally I am going to want to charge and balance them first.
"Make sure the Renogy battery BMS is rated for series use. Link a product spec sheet if you’re not sure".
- Well, ok. What am I supposed to be looking at ?
Here's the charger.
So, why might this charger be incompatible?
The battery:
Renogy 12V 50Ah Lithium-Iron Phosphate LFP BMS Battery
SKU: RNG-BATT-LFP-12-50-US
"Auto-Balancing Function
Thanks to the excellent auto-balancing function, you can use identical batteries to connect in parallel to extend power capacity safely. Up to 8 batteries can be connected in parallel. Please note that series connection is not allowed."
oops...
| Charging Parameters | Discharging Parameters | ||
| Charge Voltage | 14.4 ± 0.2V | Maximum Continuous Discharge Current | 50A |
| Maximum Charge Current | 50A | Discharge Cut-off Voltage | ≥10V |
| Charge Cut-off Voltage | 14.6V | Warranty | |
| Certifications |
| Electrical Specifications | Mechanical Specifications | ||
| Rated Capacity (0.2C) | 50 Ah | Dimension (L x W x H) | 7.8 x 6.5 x 6.7 in / 197 x 166 x 171 mm |
| Nominal Voltage | 12.8 V | Weight | 14.7 lbs / 6.7 kg |
| Energy | 640Wh | Terminal Bolt Size | M8 x 1.25 x 12 mm |
| Cycle Life (0.2C, 20±5℃) | 2000 Cycles at 80% DOD | Housing Material | ABS + PC |
| Minimal Rated Capacity (0.2C) | 47.5Ah | Temperature Parameters | |
| Energy Density | 114.4Wh/L | Operation |
For reference:
I bet I could cancel the order if I ask... Should I ?
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YOU CANNOT PUT THOSE BATTERIES IN SERIES. PERIOD. THEY WILL SELF DESTRUCT.
Although it was not listed in the battery spec document (come on Renogy, really?) it was listed in the second document on that page (titled User Manual). Although I reviewed both documents I only linked the one with the appropriate warning. Check that link from post #25 ASAP.
You can only use them as 12V nominal batteries.
Although it was not listed in the battery spec document (come on Renogy, really?) it was listed in the second document on that page (titled User Manual). Although I reviewed both documents I only linked the one with the appropriate warning. Check that link from post #25 ASAP.
You can only use them as 12V nominal batteries.
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2Big2B
Free Wheeler
Quelle' drag ...
I got them phenominally cheap. But this changes everything.
I will try to wiggle out of this ...
I got them phenominally cheap. But this changes everything.
I will try to wiggle out of this ...
I have one of those 600w Samlex inverters. No RFI, but the fan is loud and the speed is variable, it goes up and down, based on load.
I couldn't have it in the same room with me. but it is exceptionally clean and I feel good powering my computers with it. :D
I couldn't have it in the same room with me. but it is exceptionally clean and I feel good powering my computers with it. :D
Hopefully this link works :
The fifth bullet point under “Safety Considerations “ clearly states :
• DO NOT string batteries in series. Doing so can cause catastrophic failure.
You would think that would be the first point made. And it certainly should be in the spec sheet. Piss poor job Renogy.
IF a manufacturer chooses to use a BMS that is unable to handle higher Voltages you simply CANNOT put those batteries in series.
Unfortunately you really need to research what you’re buying nowadays before pulling the trigger.
The fifth bullet point under “Safety Considerations “ clearly states :
• DO NOT string batteries in series. Doing so can cause catastrophic failure.
You would think that would be the first point made. And it certainly should be in the spec sheet. Piss poor job Renogy.
IF a manufacturer chooses to use a BMS that is unable to handle higher Voltages you simply CANNOT put those batteries in series.
Unfortunately you really need to research what you’re buying nowadays before pulling the trigger.
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2Big2B
Free Wheeler
Having been a piece of sensitive military equipment, is this like forgetting to tell the guy driving the jeep to not use truck diesel fuel? Or not using NATO .308 ammo in the M16?
Having been a piece of sensitive military equipment, is this like forgetting to tell the guy driving the jeep to not use truck diesel fuel? Or not using NATO .308 ammo in the M16?
More like forgetting to tell them not to fire the M16 when the barrel is plugged with mud
. Now that’s a catastrophic failure !
2Big2B
Free Wheeler
Something that I noticed when watching a tear down video of this battery somewhere, the bms being used was rated for 100ah (on a 50ah battery..?) So, as they were identical that they were 100% compatible, and like the Power Queen 12.8v 100ah lifepo4, I should be able to combine them the same way. Who knee. Worse, I saw the note in the specs about the affirmative ability to string these in parrallel, I guess the subtle advice to not string serial in the next sentence was lost in the haze of marketing - emphasize the features and benefits, don't bring up any negatives. It is probably typical sales protocol. Had they said they couldn't be strung in serial FIRST, to catch attention to it, countered by the good news feature/benifit about the ability to string in parallel, in that order I would have picked up on that. They made it the "'fine print"...
"Thanks to the excellent auto-balancing function - (feature) - you can use identical batteries to connect in parallel to extend power capacity safely -(benefit)-
Up to 8 batteries can be connected in parallel.
Please note that series connection is not allowed."
See what I mean! Now I see why Renogy is losing its reputation.
Thanks for the catch!
See Will' s Renogy "Smart" 100Ah LiFePO4 Battery Tear Down...(4 years ago)
It is the first thing out of his mouth!
Ok, here's the bms - which is from the thread:
Renogy 50Ah Lifepo4 tear-down
Sep 10, 2022
My interpretation was that the bms was 100ah and couid handle any load....
The more I learn, the less I know
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2Big2B
Free Wheeler
Or don't look down the barrel of your .loaded .45 side arm when it jams...More like forgetting to tell them not to fire the M16 when the barrel is plugged with mud
I once caught myself doing just that with my Colt 1911, carried away in my confusion at the pistol range. Thank god for the grip safety. I was staring down the barrel, pulling hard on the trigger, trying to clear the chamber! Here's your sign!
(that will give you a dose of religion... and reality !)
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My interpretation was that the bms was 100ah and couid handle any load....
The more I learn, the less I know
Although the BMS has a number of functions there are two ratings that are important for your system design :
What is the maximum Amperage it can deliver and what is the maximum Voltage it can operate at. Either can be derated by the manufacturer, primarily for cost savings, and I get that. Not everyone needs additional capabilities for a single battery system.
However, as you state, Renogy seems to have gone out of their way to downplay or bury critical information like this that folks need to know and that’s just wrong at any price point.
2Big2B
Free Wheeler
"Just live between the knees!" ??? (cute!)
This is the kind of stuff that makes me want to cross my legs!
I only wish I had watched Will's podcast about that similar Renology battery that was parallel only... I might have caught on sooner.
What is the maximum Amperage it can deliver and what is the maximum Voltage it can operate at
Where do you see the incompatability ?
Same bms - rated for twice the maximum draw. I don't see a problem there.
The Specs? The voltages and triggerd look exactly what I would expect.
So, apart from missing the muted mention about it in "that fine manual", what did I miss?
I think I will just avoid the Renogy brand altogether from now on...
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I’ve never learned how to intersperse comments on my iPad so I’ll address the three above quotes in order.
Just live between the knees is actually a reference to the discharge curve you posted in your post #26. That discharge curve is not specific to Renogy but is accurate for all LiFePO4 Batteries based on the individual cell voltages.
On that curve you can see that the voltage “bends” upwards above 99% charge. That is the upper knee. You can also see that it bends downward below 10% SOC. That is the lower knee. In between those knees is a beautiful, fairly flat discharge curve. If you live between the knee’s you wouldn’t charge above 99% SOC or discharge below 10% SOC. You could double those voltages for an upper and lower limit on 24V nominal batteries and see why I think your current charger takes the voltage too high, above the 99% upper knee. Not a major problem as it may shorten the battery lifespan an insignificant amount for most folks, just something I choose not to do. My batteries live between those knees.
The incompatibility I refer to is simply that the Renogy BMS won’t handle a series connection to get to the 24V normal you wish. No problems with current draw on the Samlex inverter, just the Voltage you wish to operate at.
Although I own equipment from more than a dozen different manufacturers I don’t own Renogy stuff and after this education I likely never will.
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2Big2B
Free Wheeler
Thank you!
Actually I picked up on your rather cute footnote, and hence my pun in reply about "crossing my legs" which was to imply a dead short across two legs of a ciruit...
. I had included the basic SOC curve chart along the way earlier in conversation, learned from a deep dive into all of that when building and balancing my own DIY project battery packs a couple of years ago. Basic training for any real dialogue here...But actually I am still a little mystified about why the BMS is inappropriate for serial connections. Maybe it was common back then? Just like Icom vs Kenwood, Nikon vs. Canon, Apple vs Microsoft... I guess they all have their reasons buried in history.
But limiting the bms like that seems pretty stupid. Who's idea was it to dismiss that half of the potential commercial applications that way for the sake of a few cents of production costs? Did someone in corporate fall asleep in Marketing 101 ? Maybe the design of that bms was to fullfill some government bidding contract requirement that bled into the adoption of that spec into their basic market limitation? Or maybe I am just naieve that it was a rational decision to allow the competition like Power Queen to have such a marketing advantage.
And here I was operating on the assumption that Renogy was king of the hill based upon Will's enthusiasm on his videos about them 4 years ago - an eternity in this market space. Are they publically traded, or are they free to make unfettered blunders like that? There was probably some earlier corporate politics involved. I have an insight about such things because in the late 80's I was spearheading the establishment of the fledgling Canon Printer Division, as lead product / sales marketing and development engineer giving technical sales seminars to potential major distributors throughout the country, flying 5 days a week, two cities a day as we embraced the US market' to make our own foothold. I was a real road warrior back then - when I wasn't running Comdex trade shows or back in HQ working with third party developers gaining software compatibility and establishing our marketing presence. Long story, a lifetime ago...
Here's an aside though... When you look at your driver's license you will see a DMV color photo of you. I was involved with putting it there. An early part of my career was working "Third Party Developer Relations", and was once part of my title. Some where the big league fish like Microsoft, Word Perfect, Adobe, and then the lesser mainstream. Without printer software drivers right out of the box, nobody would buy our printers no matter what magic was under the hood. Every hardware and software manufacturer was intensely scrambling to establish themselves. I had some real amusing independent guys calling me with pitches for our development support for helping them invent and sell their better mousetrap. I had all kinds of weird stuff to have to deal with.
So I got a call from a Doug someone, another self proclaimed President and CEO of a sole proprietorship. What he was asking for was some free donation current and prototype color ink printers for his use in developing software to; aquire an image, process its printing on paper tape, in a world dominated by dot matrix printers. He was in the stage of being able to print on cash register paper receipt tape. He was trying to take it to the next step using our new fangled Bubble Jet printers. State of the art in 1987. Brilliant idea. He also needed our proprietary language programming manual for writing code for our new, not yet on the market product. Big ask. Now I tag "ISV loaner program engineer" to my latest ever changing business card. So, I let Corporate Legal prepare a standard Non-Disclosure Agreement for Doug to sign and I tracked down the proprietary jinglish programming manuals and other cryptic documentation, and together we were able to make enough sense of it he that he went on his way.
About a year later I was working Fall COMDEX ('88 I guess). The Consumer Electronics Dealers Exposition was one of the major marketing seasonal events held in major cities including; New York, Boston, Chicago, Atlanta, Los Angeles, and in this case Las Vegas. It was a corporate duty that I worked booth in all of them; standing in leather soled Florsheim wingtips on a thinly carpeted cold polished concrete floor, keeping and protecting our supply of handout Sales Literature, paper and printer supplies, in 12 hour shifts, weary and thanking god for having had the wisdom to not have gotten hammered at any of the many opening private invite only parties the in the casinos the night before. I learned after doing that once. There is nothing more miserable than trying to pretend being the Corporate image in front of a few thousand people milling through the hundreds of booths with a thousand opportunities to make business contacts.
So I am standing there at about 9:30 or so I guess, first day of the show, Monday. I was still feeling refreshed the brisk walk from my hotel from the to the main Convention Hall. It was a brisk 3 block walk a couple of hours ago, the start of my shift. It also was on about my 3rd cup of coffee, having stopped into the conveniece shop for my walking cup to go. I was in a hurry to get past a gal buying a case of codoms. I guess that is just the 7:30 early Monday morning crush in that neighborhood. Buying buisiness supplies at a quick stop a 7:30 in the morning dressed in some dingy yet colorful wrinkled short dress, slippers, hair looking slept in, her blush past bloom, looking like what the cat dragged in. Or maybe she was the cat. A tunnel rat, more likely.
So I am standing there, in my sharp suit, Canon insignia pin, smiling at the herd that passes through, passes by, or engages. I am on the lookout for booth bandits. These were a rival company with a booth whose team would raid the competition. I would be confronted by some attendee asking me some convoluted question about out new laser printer, of which I would demonstrate. It was to distract me while his partner would innocently grab all the stacks of our booth handouts, to as sabotage, which was rampant. As was our critical paper supplies. On Wednesday morning opening discovered that our entire supply we'd had shipped in had dissapeared. Catastrophe. I was told about it when I started my shift, upon which I hopped in a cab and hit found a big stationary chain store where I proceed to charge an immediate paper resupply, saving the day while everyone else was too busy playing 'cover your own ass'.
So, I think it was on Tuesday that it was brought to my attention that a Doug someone was looking for me. A couple minutes later this very enthusiastic badged business attendee reached out his hand saying "Mr. Hindley, I want to Thank YOU... You made me a Million Dollars! Skeptical, I smile him and said, in my be at New York attitude So, where's my cut ?!!""
As it turns out, he had pioneered a turnkey hardware/software application that he sold to Costco who used it to make first ever instant photo membership cards at Customer Service. Initially, the first ones where cut and pasted on cardstock with packing tape slapoed on, but soon followed by plastic laminated. I really did make Doug somebody a SOMEBODY millionaire, living the goodlife in San Diego.
I like to think that my collaberation contributed to how DMV started their own laminated cards not long after. I wonder if Doug was in on that action too.
So, as I would explain on dates:
When you look at your driver's license, think of me.
- Not a bad line, huh?
When I got back to base about a wek later, my secretary left a package on my desk, addressed to me. I opened it up to find a Thank You card and a big solid 1lb chunk of Ghirardelli Chocolate in appreciation. I shared it with the office. Everyone loves chocolate.
The following year, another package with a lb of Ghirardelli Chocolate showed up on my desk. I ate that one.
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Quattrohead
Solar Wizard
Friends don't let friends buy Renogy.
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