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Steve_S
Member
# Posted: 20 Nov 2021 10:35
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There are a "few" threads on Valence LOL.... lot's to absorb.

paulz
Member
# Posted: 21 Nov 2021 09:38 - Edited by: paulz
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No replies yet on the DIY forum, perhaps they've heard of me, but I have made an all important discovery! To cut to the chase, the alligator clip test leads, clipped to the VOM meter set on amperage were causing too much resistance. I had suspected this but non of the wires or clips felt even warm. Anyway I switched to 4awg cable, bolted down at both ends and whamo, 30 amp charge right off the bat. Yeah, I feel dumb but I guess it is possible to lose that much current and not have an heat in the wires or connections.

So now I have the charger going and the battery plugged into my computer with the Valence software going to work on cell balancing and other stuff going on in there. It's also measuring the current coming in so I don't need the external VOM.

I dialed the Meanwell back to 14.1 from 14.6 as you suggested.

Anyway very happy to know I should be able to shoot some decent current back in at the cabin in a short time when the solar charging is low.

Steve_S
Member
# Posted: 21 Nov 2021 10:09
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SHIT ! I AM SORRY and I Deeply Apologize for that. I normally do ask if you upgraded the charging wire size. That is like the 1st thing that has to go with all of the chargers that are supplied with wires. WanTek, TekPower and numerous other Benchtop Power supplies come with the crappiest of wires... I should NOT have assumed you updated the wires.

ALIGATOR Clips = EVIL but sometimes nescessary. When people are getting set to build their own battery packs, the cells have to be top balanced first and that means charging cells in parallel with respectable amperages. In such cases we tell folks to get Good Wires with Terminal Ring ends to connect to the battery string and to NOT use Aligator clipped wires (too damned many problems, resistance, voltage drops and even heat to point of meltdown.)

paulz
Member
# Posted: 21 Nov 2021 13:27 - Edited by: paulz
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No need to apologize, I should have realized it earlier myself. Good word of warning to others too.

Now that that is behind me, a couple other concerns. I noticed while connected to the software and charging, the cell spread varied up over 10mvs, up to 12 or so. Is that OK while charging? After I unplugged the charger but still hooked to the software the balancing icon lit up, now sitting the spread is 2.

Speaking of unplugging, as I was hooking up the new 4awg cables I got a big spark at the battery terminal. The Meanwell was unplugged from AC. I didn't keep it connected. Instead I plugged in the Meanwell, no more spark. Is it correct to power up the Meanwell before attaching to the battery, or was this a capacitor in the Meanwell that getting charged by the battery, like inverters do? I actually tried twice, big spark both times.

Steve_S
Member
# Posted: 21 Nov 2021 15:11
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10mv is nothing, even up to 30mv while charging is not unusual, but the differential will increase the higher the voltage goes. Also the quality/grade of cells has an impact on that, Valence uses A+ cells but that pack is 10 years old if I remember the screenshot. The balancing will take care of the cells as you saw.

Just for "educational fun" now that you can watch and log the data with the software connected. Charge the battery to 14.5V (3.625Vpc) and watch the cells. As the voltage goes up, the differential will spread now with variable current & fixed voltage @ 14.5 the current should drop as the battery saturates so you can cutoff at 5A or lower.

Stop charge and then watch over the next hour as the cells settle. That will show you what the cell behaviour is like and once settled (2 hours) that can be used as the "top charge" value.... as a sidebar, it is also an indicator of retention.

Assuming A+ cells, 2 hours post full saturation charge should settle to 3.525 +/- a small amount. When NEW. 10 Years later they won't be that high, but let me put it another way.
Bulk LFP (Grade B typically) will settle to 3.425 +/-.050 under the same conditions typically. (usually lower BTW)

Inverters have capacitors and when connecting batteries with discharged capacitors, there is an initial surge draw from the capacitors charging up, it is short but can be huge ! The Arc Flash. That is a BAD Thing ! A Pre-Charge circuit is something that takes care of such things (not included in your Valence Batteries).

The Meanwells precharge the capacitors from the AC if memory serves. There are different models & variants so...

Now that you have your charging issues figured out and the software setup to read the BMS' so that you can monitor what is going on and do some basic tests. You'll be able to get a good Health Picture of what you have in hand and what it can really do for you.

The Valences are good deal if properly shopped around, some price gouged when all the write ups etc happened. They are good because they are made for & used within medical & scientific equipment and junk is simply NOT acceptable ever. They are cycled out of service on contract and rarely if ever abused in any way. 10 Year Old LFP that's lived in these condition should give you another 10, unless you abuse them. Trick with them is to know the Models & Revisions and Date Coding to know what's what before buying them.

paulz
Member
# Posted: 22 Nov 2021 08:37 - Edited by: paulz
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Thanks Steve. I did as you suggested, last night I raised the Meanwell to 14.6, charged both batteries until they showed 14.6 and amps dropped below 5. This morning all cells are 3370 within 10 or so. And yes, they are dated 2011 so perhaps nearing end of useful life? I don't suppose additional charging would help?

Also, I'm headed back to the cabin today for most of the week, hopefully. The other two batteries have been on the solar for a couple of days, should be at least 13.2 or higher. Will it be OK to add these batteries (in parallel) or should I charge the others close to equal first?
v17d.JPG
v17d.JPG


Steve_S
Member
# Posted: 22 Nov 2021 09:39
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Always connect batteries in Parallel at the Same Charge Level or the High Ones will backfeed to low ones and the Amp Draw will exceed the BMS's capacity.

I did that once, when there was significant voltage difference, the new pack tried to pull over 500A so the BMS cut the relays off. Mine can handle 300A so.

LFP can Burst Discharge up to 5C of rating ! Be aware of that wee detail !

IF the cells went from 14.6 / 3.650Vpc to 13.8V / 3.370Vpc that's "fair" the top of the working range is 3.400Vpc or 13.6V, they have degraded a bit (Grade B level) but still 90% Capacity likely. You'd have to fully charge the battery pack and then discharge via Inverter with a fixed load of 50-75A till LVD cutoff to know what the actual capacity left in the battery. There is likely a good 5 Years left in them, it's not like you will hard abuse them.

Try to charge the other batteries so they are at the same voltage (or very close) and connect them in Parallel. Now you will Hate me for this... BUT, the two at the shack, should also be brought back to town so you can fully test while monitoring the BMS activity. so that you know exactly what state & condition each battery is at. That is the only way to know what amount of stored energy you have access too.

It is ironic that now (November 2021) there are several 12V/100AH prebuilts available between $299-$399 USD and with several of them being quite good like AmpereTime, SOK, Rebel and others. On the UPSIDE, vendors flogging the Valence Batteries will have to lower their prices because who wants a Used Battery for $399 when they can get equal for less and NEW.

I dunno what your computer status is, but a cheap Windows Lappie can be bought for <$300 these days or a used one for much less. Something to be said for mobile computing. Saw a Blackfriday deal (BestBuy ?) for Asus i7 lappie with 8GB and 1TB HDD for $200 with windows included.

paulz
Member
# Posted: 22 Nov 2021 10:07
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OK got it on, only connect at same voltage. I have a Chromebook (mini laptop) I use at the cabin, if the Valence software will load I can use that, charge the other two off the genny. Goes pretty darn fast with 40a going in! If not, I can run off these two batteries (supposed to get sun all week), then bring all four back to town and get them all sorted.

If I get 5 more years out of these I'll be very happy. Then, depending on the state of my solar, the cabin, me, I can get new bats or maybe some recycled EV stuff.

Another thing has me curious. As I was charging the first battery yesterday, cell 1 was lagging behind quite a bit, 40mv, and never caught up to the others. The others came down off the charger and the active balancing brought them all within 10. Weak cell I figured. Then I charged the other battery, same thing, same cell 1. Maybe cell one gets the most action?
v17b.JPG
v17b.JPG


paulz
Member
# Posted: 22 Nov 2021 12:48
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One more thing.. if I start pumping in 40a at the cabin, will the SCC be OK or should I unhook it from the bank?

travellerw
Member
# Posted: 22 Nov 2021 13:04
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Quoting: Steve_S
It is ironic that now (November 2021) there are several 12V/100AH prebuilts available between $299-$399 USD and with several of them being quite good like AmpereTime, SOK, Rebel and others. On the UPSIDE, vendors flogging the Valence Batteries will have to lower their prices because who wants a Used Battery for $399 when they can get equal for less and NEW.


You must have a source that I can't find. The lowest I'm seeing those batteries is $499-$550..

Steve_S
Member
# Posted: 22 Nov 2021 15:20
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40A for those are fine, and remember when in parallel they split charge & load, so if the Batteries are at same SOC and they start taking full charge, each will only get 10A. Now the fun part is which ever is weaker will take more then shift off as others then take more... If watching BMS' it's like a choreographed dance.

@ TravellerW, come find us at https://diysolarforum.com/index.php and check out Wills Teardowns plus a few others. Now a recent new addition (US Company) started something quite interesting. First Blush prices are high BUT this is not 100AH small stuff, 200+AH.
https://www.sunfunkits.com/

Kicker is, many companies that get Good Reviews with Teardowns etc, the sales demand spike and some immediate gouge with "market bears pricing".

I have sources and connections + some relationships that I have built up over the years, haven't bought much retail in years. I can tell you that you will find better deals on Amazon versus EBay but again you are dealing with ??? Vendors as Valence does not retail anything.

Another reasonable Public Source is here: https://batteryhookup.com/ and something more in-line with the 12V stuff, check this out: https://batteryhookup.com/products/new-12v-100ah-lifepo4-kit-w-bms-low-temp

AND they can now ship to Canada THAT'S NEW !

Personally, I deal direct with specific vendors & manufacturers in China & Taiwan after wasting time playing the other route. I am fortunate with this particularly because I established connections and contacts many years ago courtesy of the Computer Industry and that opened certain doorways shall we say.

I started with a Lead Bank and when I wanted to go Lithium, all I got from a few was gobbledegook alphabet soup (1980's PC Shop protectionist horse pucks trying to keep it all a zekret) I went off and studied, learned and grew out from there to educate & inform others without the Gobbledegook Alphabet soup. I have little tolerance for those who think information should not be shared unless it is for profit. I have always been an opensource/shareware type of guy and that won't change. Physically my body is done and I "may" have a year left on this rock but in the meantime help others I shall when I can.

gcrank1
Member
# Posted: 22 Nov 2021 15:32
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Well, it just dawned on me that maybe Im a lot like a battery....
The Bulk info phase gives me lots of info to consider but the real Absorption phase takes longer than I anticipate.....

Steve_S
Member
# Posted: 22 Nov 2021 15:39
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hahaha Yes indeed ! So much Bulk Info and lots to absorb... Even worse is learning (rather unlearning) LEADisms and rejigging the thinking to Lithium... similar but not the same, can get quite confusing.

paulz
Member
# Posted: 22 Nov 2021 15:47
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I'm at the cabin. The Valence software won't run on the Chromebook, need Windows. There is something called Remote Desktop where possibly I can make the Chromebook mimic my home computer, I'll be looking into that. Otherwise yeah I will need to look into a dedicated Windows laptop.

Meanwhile, even with a few days of sun, albeit shaded by my trees, the two batteries still hooked up were at only 13.2, and quickly dropped to 13.1 when I powered up the cabin. Solar was charging about 1 amp. Sure seems like it did better a year ago, I need to check my old posts.

So, without a way to monitor them, I swapped them out for the freshly charged two batteries. Showing 13.5 on the meter, cabin powered up. Heading back to town on Thanksgiving, should make it to then, and I can charge them off the genny since I know pretty much where they stand. I'll bring all 4 bats back then and get them all charged and balanced.

paulz
Member
# Posted: 22 Nov 2021 17:43
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On another note, I'm now wondering if I can charge my shop solar (also suffering the winter blues) with the Meanwell. 4 bats in parallel, but 80ah FLA deep cycle RV/Marine. They should be able to take 40 amps at 14.6v, right?

Steve_S
Member
# Posted: 22 Nov 2021 18:11
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The lead should handle it fine, make sure they are topped off with Pure Distilled water.

travellerw
Member
# Posted: 22 Nov 2021 19:03
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Quoting: paulz
I'm at the cabin. The Valence software won't run on the Chromebook, need Windows. There is something called Remote Desktop where possibly I can make the Chromebook mimic my home computer, I'll be looking into that. Otherwise yeah I will need to look into a dedicated Windows laptop.


Unfortunately its HIGHLY unlikely RDP (remote desktop) will work. Its doesn't mimic a home computer, you just remote control another computer with it. You still need a Windows computer to remote control.. and then its doesn't really expose the ports (USB, serial, ect) to the controlling computer well.

No way around it, you will need a Windows computer.

gcrank1
Member
# Posted: 22 Nov 2021 20:10
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Check your old posts? Yeah, check all those old connections

paulz
Member
# Posted: 23 Nov 2021 08:08
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Quoting: Steve_S
The lead should handle it fine, make sure they are topped off with Pure Distilled water.


Thanks, will do. The Meanwell has no amp gauge, I am going to add a 60 amp automotive gauge to it, should work.

Quoting: travellerw
Unfortunately its HIGHLY unlikely RDP (remote desktop) will work.


OK thanks, yeah upon further reading the bats would have to be plugged into the Windows machine. There are some small tablets that run W10 and have USB ports, might look into that.

Quoting: gcrank1
check all those old connections


I've been jockeying panels around a lot lately, trying to get optimum sunlight, and have pulled apart one or two MC4 connectors that did have wetness and corrosion inside. How it gets in I don't know.

The usual method I have been using to measure panels is to measure open voltage but recently I tried measuring amperage of each parallel string by disconnecting one connector and putting the VOM between the connections. Seems to work and makes sure they are putting out power.

I'm running several strings of 3 panels, at around 100v each, with maybe one string at a time getting sun. My understanding is the shaded strings, which still put out .5 to 1 amp, do not compromise the one in the sun as they are in parallel. My SCC will take 150v input, so I could rewire to 4 panels in series in the hope of improving MPPT, but I'm not sure it would do much. Maybe I'll test that today.

gcrank1
Member
# Posted: 23 Nov 2021 09:33 - Edited by: gcrank1
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Per a thread I just read on Diysolarforum.com this week the MC4 connectors are the cheapest 'approved' con they can get away with and make wiring simple, quick and easy for pro's and hobbyists alike. One poster said that in his experience bad cons, thus elec production, is a main reason arrays are pulled down (and end up on the used market?).
And, surprise, they are not all made to 'a standard' but can vary enough between manufacturers (then there are the clones) to not always fit and seal well. Time and exposure likely take a toll, too. Are you mixing panel brands?
Afaik once you have corrosion inside you cant kill it, ya gotta cut it out, get to clean, dry bare wire and replace the ends or butt-splice.
That said, after I pretty much finalized my wiring I 'cleaned' my old MC3 cons as best I could (and lead tested the output) filled with the dielectric grease used in auto bulb sockets, tight wrapped with stretchy plastic elec tape and tucked each con out of the elements as best I could.
Fwiw, Ive had occasion to get into a couple cons this year and they have been good.

ICC
Member
# Posted: 23 Nov 2021 11:13
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I believe they are not really designed/made to be pulled apart and reconnected multiple times as a regular thing.

paulz
Member
# Posted: 23 Nov 2021 11:53 - Edited by: paulz
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Yes I have multiple brands of MC4 connectors, my panels were used, the cable it came with was used, and I've bought new connectors, not knowing what to match to, and figuring the 'should' be the same spec. And yes they vary, some I have to dress the male end down a bit to fit inside the female. The rubber gaskets and nuts vary too. I don't think the MC4 is a bad design, but the metal on the ones I have crimped is a little skimpy.

I wish there was a clip on meter you could put over the wire and slide past the connector to check the connection. I bought an expensive meter that does that but on AC only.

I still have my old Harbor Freight cheapo 100 watt solar kit, use it to keep my tractor FLAs charged on the work bench. It has simple non shielded push pin connectors, and they corroded green over the years. I put some vinegar in a jar and socked them in it till they were clean, then reassembled with di grease. So far so good.

gcrank1
Member
# Posted: 23 Nov 2021 12:08 - Edited by: gcrank1
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Clean em up and dry if needed as you go into them
dielec grease inside
plug together
smear some silicone seal around the cable boot and the MC4 joint
let dry
wrap with stretch elec tape
Not a perfect solution but lets ya dance with who ya got.

travellerw
Member
# Posted: 23 Nov 2021 12:49
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Quoting: gcrank1
One poster said that in his experience bad cons, thus elec production, is a main reason arrays are pulled down (and end up on the used market?).
And, surprise, they are not all made to 'a standard' but can vary enough between manufacturers (then there are the clones) to not always fit and seal well. Time and exposure likely take a toll, too. Are you mixing panel brands?
Afaik once you have corrosion inside you cant kill it, ya gotta cut it out, get to


^ This.. I cut out SO many MC4 connectors on boats I have lost count. I found some that were getting so hot you couldn't even touch them. Others looked good, weren't hot, but the panel performance was poor.

Its tough to beat a good soldered joint (as long as things will be permanent). I would use quality lead solder, then cover the joint in sealant (high quality non acid silicone), then shrink wrap that. You end up with a very low resistance connection that is completely weather proof and will last forever, even in the harshest places. Unfortunately you need to know how to solder properly (most people go WAY to hot).

I'm sure there are quality MC4 connectors that provide a good connection, but I look at everyone as suspect nowadays.

paulz
Member
# Posted: 23 Nov 2021 15:28 - Edited by: paulz
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I mentioned before that a half dozen of these connectors came with my used solar stuff, and I'm using them on heavy gauge cable. Super sturdy with screw down terminals and rubber plugs. Not cheap though.

I don't have a car ammeter here and my shop FLAs were way down without much solar hope today, so I went ahead and hooked up the genny and the Meanwell. That poor little 900w genny sure spooled up so I know I was getting some good charge, and in a half hour they were up to 13v.

I've done enough testing and mucking around now on both my solar systems (cabin and shop) to realize I just can't expect much during this time of year when the trees block most of the sun. I'm getting 2 amps right now at the cabin, mid sunny day, all panels shaded. At least now knowing I can pump some amps back in quickly will help in times of need.
Screenshot_2021112.png
Screenshot_2021112.png


paulz
Member
# Posted: 24 Nov 2021 19:25 - Edited by: paulz
Reply 


I'm back at the grid house, brought all 4 Valence bats back, after running on just the two I charged a couple days ago. Charging the 3rd battery now, and just like the other two, cell 1 is lagging behind the other 3 by 25mv of so.

I need to understand the way a lithium specific charger works. It sounds a lot like what is happening now. I have the Meanwell power supply set at 14.4v. It took about an hour at 40 amps to go from 13.1 to 14v, at which time the amperage started to slowly drop. At present it's 14.2 and 4 amps. Do I take it off the charger now, or is there a 'topping' charge?

Steve_S
Member
# Posted: 24 Nov 2021 20:04
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100AH endamps (fully saturated @ set voltage) = 5A
@ 14.2V you are at 3.550V per cell. 3.500 is "full" in reality. rember the sharp voltage curve.

you can go lower amps taken but makes no capacity difference, they will just lose that as the cells settle over the next hour after charging.

By the time you read this message, you'll be very low amps taken and full... After 3.500V the charge speed picks up pretty quick as the amps drop. Normal Behaviour.

IF all of a sudden you see Voltage Spikes & drops STOP Charging ! That is the BMS cycling (cutting off in pulses) before frully cutting off.

paulz
Member
# Posted: 25 Nov 2021 10:40
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Quoting: Steve_S
100AH endamps (fully saturated @ set voltage) = 5A


Steve, would you explain that again please? These are an advertised 140AH btw.

So anyway, what you are saying is at 14.2 and below 5A just stop charging...

Bat #3, sitting all night after the 14.2A charge, is at 13.53. Bat #4 charging now, then I have to charge 1 and 2 again after powering the cabin last couple days. Once all 4 are in the 13.5 range I need to make some new busbars and be ready for cabin duty again. I had added 3 and 4 to the bank just recently with cables.

I have some 1/2" copper plumbing pipe, can I flatten that and make busbars?

gcrank1
Member
# Posted: 25 Nov 2021 10:52 - Edited by: gcrank1
Reply 


Flatten it! No need, just strip some insul back and hose clamp those wires to the pipe as is
LOL, Just Kidding! (but now you get an idea of how cobbled together my system was when we bought the place).
To add to your question, for LFP is it still as important to have the cables be equal length and use the same 'best practices' bat wiring schematic as fla?

Steve_S
Member
# Posted: 25 Nov 2021 14:17
Reply 


Copper Pipe - NO.

EndAmps is calculated as ###AH X 0.05 = Result
140AH = 7A

Wire Guage & Length MUST MATCH it's a balance thing.
Wire Resistance & Connections also count Millivolt/milliohm sensitive right. Every connection, wire length etc = some resistance.

Tinned Copper Busbars are the best option. a 5 port pair of busbars to create the Clean DC Bus which all batteries are Paralleled into which then is connected SCC & Inverter, A Smart Shunt with Gauges/Meters is also best placed between the DC Bus Bar & SCC/Inverter so it can report both directions of enegery flow.

This is the Golden Guide on Battery Configs, starting Pg 16 ? for Lithium Based / LFP. Thank You Victron !
https://www.victronenergy.com/upload/documents/Wiring-Unlimited-EN.pdf

Attached is my last schema diagram, I have to update to reflect the final config with the 5 Packs and some new gear.
My previous schema
My previous schema


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