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Steve_S
Member
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# Posted: 31 Jul 2024 11:39am
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@Paul, "Pro" I dunno, "Serious Hobbyist" ? 
Ahh the worklight (with LED Bulb) and there is a clamp spot light you can't see with a Super Bright LED bulb (scares the critters at night).
The Old Style Work Lights with LED's Bulbs (ala cheapo from Walmart) are so much better no heat, no burn, no shattering, no "ruckus, stuckus, frickus, fruckus"!
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paulz
Member
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# Posted: 31 Jul 2024 02:44pm
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Quoting: Steve_S , "Pro" I dunno, "Serious Hobbyist" ?
Closest thing to a Pro we got around here. I have depended on your input I don’t know how many times. Don’t read DIY solar forum, I’d have to read DIY foundations, woodworking, water wells.. Cabin forum is my only go to.
I mentioned I did some wiring yesterday. When I was done, I noticed my wall mounted volt meter showed 13.2v while the gauge on my charge controller (Epever MT50) showed 13.6. Long story short, one of the battery terminals on the bank was still only hand tight. Tightening solved the difference. It’s funny, no corrosion anywhere but just only hand tight wasn’t enough.
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gcrank1
Member
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# Posted: 31 Jul 2024 03:09pm
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Steve, pls do a thread here if you don't mind; your stuff adds so much to us without us needing to wade thru the other forum
Glad to know you are still feeling good enough to get into project(s).
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Steve_S
Member
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# Posted: 31 Jul 2024 03:18pm
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Lock Washers are OK, Serrated Washers are Better, along with Serrated Nuts is even better. A single "loose" connection CAN make for a very bad day ! Takes little to get to Glowing Hot and that causes nasty nasty things to happen.
An Example to PONDER:
When I'm done with 7 Packs, they will be able to "naturally" discharge at 200A (Limited by my BMS') so that put 1400A potential at the Common DC Bus. Now these packs CAN do a 5C Burst Discharge for a few seconds, 5x280A which is 1400A per Pack X 7 Packs that's 9800A. While a Burst Discharge would be cutoff within 5 seconds, 9800A could cause a KRAP-LOAD of OUCH !
Simply put, No Half Measure & no screwing around with cheap safety things like fuses/breakers,busbars or cables.
I have 200A MRBF Fuses on every battery (at busbar).
Each Battery Pack has a 200A DC Non-Polarized Breaker on it.
The E-Panel has a Monster Carling 250A Master Breaker. All other DC Breakers are Polarized Carling Tech breakers (supplied by Midnite Solar).
I'm not into Welding my Keister to anything !
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Steve_S
Member
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# Posted: 31 Jul 2024 03:28pm
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SORRY but I am giving more info for anyone considering the possibility of Building their own packs.
The Steel Cases, the JK-BMS Inverter Edition (the latest with firmware upgradability & interconnection) and the cells all came from Luyuan Tech in Shenzhen China and shipped by boat (30-40 day delivery)
I used the 8S Cases for 24V but they also have 16S Cases for 48V. Also some 12V (Steel or ABS Plastic) cases for cheap as well (can't take Inverter BMS because they are too big).
IF you want to persuse & Ponder here is a Link. This is a Well Known Good Reliable Vendor Supplier and you get "exactly" what you pay for.
LINK: https://szluyuan.en.alibaba.com/
NOTE: Proper Pricing (current as it changes a lot) & S&H details can only be had if you open a Chat/Messenger session with Amy Wan (owner of Luyuan) Use plain English (no slang) and keep it simple. Her English is fairly good but still uses translator to verify things and that hates shortcuts, slang etc.
You can feel free to say "Steve_S from DIYSolar" sent you - may give you a discount if your nice.
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paulz
Member
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# Posted: 1 Aug 2024 02:37pm
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Quoting: Steve_S https://szluyuan.en.alibaba.com/
Links not working for me, could be just my safari browser. When my Valence pack, cheapo inverter with no racking finally give up the ghost I’ll be shopping.. thanks for posting.
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gcrank1
Member
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# Posted: 1 Aug 2024 02:54pm
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So, maybe in a another 10yrs?
lol,
The longer we go with this lfp thing the closer we get to a whole new, or at least more energy dense, battery tech/chemistry. I thinking my bat-bank will outlive me.
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paulz
Member
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# Posted: 1 Aug 2024 04:11pm
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Ha, maybe me too. My LFPs are dated 2012! This winter I had to run the genny about a half hour an evening to charge the bank. My big solar problem, besides the tree shade and branch breaks, is when the sun travel is low in the sky the hill to my south blocks the sun almost all day, assuming it’s even out.
But this time of year, the bank gets up to 13.6 or so by end of day, down to 13.2 by morning after running TV, LEDs and fridge all night.
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gcrank1
Member
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# Posted: 1 Aug 2024 04:25pm
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With your system's limitations you have done remarkably well, it sure has seemed to be pretty well balanced to your usage needs.
Im sure there are a number of folks that wish their system worked as well as yours.
If I would break down and buy a proper lfp friendly 30a charger Id have it on bat so whenever I ran the gen it would be charging the lfp. I used to do that with my lead acid bats when I had the solar up, it was easy because I have a number of car bat chargers to choose from.
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paulz
Member
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# Posted: 1 Aug 2024 05:07pm
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I’m still using the Meanwells (I have two, ~80 amps), but only while the genny is going. If you turn it down to low 13s can you just leave the Lfp on full time? No equalization or float to deal with..
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Steve_S
Member
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# Posted: 1 Aug 2024 06:02pm
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I have an external 24V/50A Charging setup using 2 meanwells paralleled. I use it only for testing and an emergency backup charger. My Inverter is also a charger capable of delivering 100A but I set it to do only 80A so I have lots of room for Passthrough Power (many Inverter/Chargers are limited with that). The Inverter is 97% efficient so when delivering the 80A Charge it's only pulling 120V/22A +- a bit from the L5:30A plug on the Inverter Generator.
Paul, you have it all pretty well tweaked out for your usage and I agree with GCrank that likely some would be envious.
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paulz
Member
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# Posted: 1 Aug 2024 08:52pm
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Thanks for the compliments. Yeah summertime’s been great, hardly glance at the juice meter. But I'll tell ya, on those long winter nights, in the morning first thing I’ll do is crack one eye and make out what the voltmeter says. Anything in the 13s and I can roll over and back to sleep. 12s and it’s wake up and ponder.
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DaveBell
Moderator
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# Posted: 3 Aug 2024 12:12am
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battery pics.
Left_Batt_Charge.JPG
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Right_Batt_Charge.JP.jpg
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Right_Batt_on_Charge.jpg
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paulz
Member
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# Posted: 4 Aug 2024 11:33am
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Well that doesn’t look good. Did Super Droid get back to you about replacing it? If you end up with that duff battery one way or another, my inquisitive (and bored) nature would want me to try and find out what happened. Is there an open in there somewhere? Every cell gone out?
Grass must be getting long
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gcrank1
Member
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# Posted: 4 Aug 2024 12:44pm
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Break out the Dremel for a pop top job?
This reminds me of when one of my multi-bat flashlights wont work it is often just one bad bat.
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paulz
Member
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# Posted: 4 Aug 2024 02:46pm
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I opened up my dead chainsaw bat, just screws. Found a dead cell but there was so much solder and wiring in there I gave up. At least I could do that. That 10 volt car fla I was fooling with showed one dead cell with the hydrometer. I tried to flush and refill it, no luck. It’s in the core pile now, for good.
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DaveBell
Moderator
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# Posted: 8 Aug 2024 01:10am
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Quoting: paulz Well that doesn’t look good. Did Super Droid get back to you about replacing it? If you end up with that duff battery one way or another, my inquisitive (and bored) nature would want me to try and find out what happened. Is there an open in there somewhere? Every cell gone out? Grass must be getting long
Yes the grass is long.
When I Google LiFePo4 battery warranty, I find examples of 5-10 years.
I emailed the mower manufacturer, Super Droid Robots with this info. They replied they only warranty the batteries for one year. So I emailed the battery manufacturer and they replied they warrant their LiFePo4 batteries for three years.
I forwarded the email reply from SHENZHEN CBT POWER showing them the three year warranty and demanded they honor the manufacturer's warranty and replace this defective battery.
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DaveBell
Moderator
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# Posted: 9 Aug 2024 07:01pm
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Super Droids Robots replied to my email. They won't honor the manufacturers warranty. Can any of you guys look at the pictures and tell me what format this battery is? I know car/truck batts are type 31, etc.
I'm going out to the mountain for a week. The Cat backhoe repair guy is coming out.
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ICC
Member
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# Posted: 9 Aug 2024 07:58pm - Edited by: ICC
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I am not aware of group numbering applicable to this battery type. I have used either or both the Ah capacity needed and the actual dimensions of the old battery to help in finding a replacement.
I have bought numerous batteries, LFP and Li-ion from batteryhookup.com. A few weeks ago I got a 34 Ah LFP for a power gate, with 30 amp BMS for $55 + shipping. I had several items in the order. Might be worth a look.
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paulz
Member
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# Posted: 10 Aug 2024 12:01am - Edited by: paulz
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I too have not seen those size batts by ‘type’. I sure wouldn’t pay $600 something for what super droid wants. Same dimensions as this one?
IMG_3201.jpeg
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IMG_3202.jpeg
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gcrank1
Member
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# Posted: 10 Aug 2024 12:47am
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Dave, with lfp you don't have to age match or ah match the batteries. Your real limit is the bat box.
See if you can get a matching volt bat (24?) and 'somewhere close' to your 42ah? that will fit in the hole.
Amazon has had some good prices of late.
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Steve_S
Member
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# Posted: 10 Aug 2024 01:02pm
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I would suggest looking at LiTime Batteries which are readily available in the US. They have a big selection with various options. Their Trolling Batteries actually rate pretty well and have been reviewed & torn apart with all good results. 121V/24V/36V & 48V and various AH ratings and sizes. Prices are "Respectable" as they are exactly what they say they are.
https://www.litime.com/
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paulz
Member
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# Posted: 4 Oct 2024 01:16am
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Why are these new lifepo4s labeled 12.8? The charts I see say that’s only about 20% SOC. That’s been panic mode for me.
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ICC
Member
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# Posted: 4 Oct 2024 03:02am - Edited by: ICC
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Quoting: paulz Why are these new lifepo4s labeled 12.8?
I'm not sure what you are comparing to. LFP batteries that are labeled as being a "12 volt" battery have always had a nominal voltage rating of 12.8 volts. That comes from having 4 cells of 3.2 volts rating.
Don't confuse the nominal voltage rating with the actual voltage at various states of charge.
Below are images of two charts, one for LFP and the other for lead-acid. You can see that a 12 volt lead-acid battery also has a range of actual voltages at different SOC. (different charts may have slight differences in voltage at various SOC)
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Steve_S
Member
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# Posted: 4 Oct 2024 09:49am
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Ahh marketers.
A few companies like this one use the NOMINAL Voltage which is 3.200Vpc X4 = 12.8V
Some companies use 3.650 (Top of Allowable Range) and will advertise their batteries as 14.6V
I've never heard of that brand.
100AH cells are retailing for around $32ea USD
A dumb BMS (no balancing, Bluetooth etc) about $20
ABS Box to put it in about $15
* USD Retail with basic discount.
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paulz
Member
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# Posted: 4 Oct 2024 02:24pm
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Got it, thanks guys.
My days of summer Off Grid Bank Fat City are slowly coming to a close, seeing 12.9 mornings occasionally got me wondering if my old LFPs will go another winter. So I was looking at maybe grabbing a couple new ones to have around here, can’t just run down to the Auto Parts like the cars (although you can run down to Walmart now I guess). Anyway going online and seeing 12.8 labels threw me.
Noticed these, Lfp starter batteries with posts? What’s with these?
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Steve_S
Member
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# Posted: 4 Oct 2024 03:10pm
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Paul, honestly those scare the hell out of me ! Car alternators are not designed for anything other than Lead/AGM and have the wrong voltage/amperage setup. So many have gotten screwed one way or another, either blowing battery pack and/or frying the alternator... this applies to cars/trucks & "boats" who learned long ago. Doesn't matter what Lithium chemistry either.
Cold Cranking is quite possible for Li based batteries as long as the cells & BMS handle it and many do, usually targetted for trolling motors though.
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ICC
Member
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# Posted: 4 Oct 2024 06:28pm
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Many have burned out their alternator after installing a lithium starter battery. The lithium can accept so many more amps than lead-acid and can cause the alternator to overheat.
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gcrank1
Member
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# Posted: 4 Oct 2024 08:53pm
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A friend with a fishing boat kept his LA starting bat when he switched to LFP for the 2 trolling motors. He runs an inverter off the starting bat which charges off the engine alt) to his LFP charger to keep the trolling bat charged up. He has been running this system all this year with great satisfaction.
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paulz
Member
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# Posted: 5 Oct 2024 02:53pm
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This auto Lfp is a new thing to me (yes I was hiding under a rock). Seems like the holy grail, perhaps they have jumped the gun? And assuming they get the auto alternator issues worked out, there’s still the low temp problem. They have them with heaters now too, and BMS should handle any charging issues?
No I don’t want one, still got a pile of usable FLAs..
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