Current Sharing 101 w/ Large LiFePO4 Battery Banks

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Litime
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Epoch Batteries
My favorite high-quality 12V battery:
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Renogy
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[@WillProwse]

The server rack bus bar needs to be connected to loads/chargers at opposite or diagonal ends, as shown in the video. You can safely use other wiring configurations, but your crimps need to be perfect, and the size/length of conductor. Using a bus bar has the lowest chance of screwing something up. Highly recommended for beginners! Beginners should check out this resource on battery bank wiring configurations: diysolarforum.com/resources/wiring-unlimited.2/ *Does off-grid solar confuse you?* Check out my DIY friendly website for solar system packages and product recommendations, and so much more! www.mobile-solarpower.com *Join our DIY solar community* #1 largest solar forum on the internet for beginners and professionals alike: www.diysolarforum.com *Check out my Book* Best-selling and beginner-friendly guide to 12V off-grid solar! amzn.to/2Aj4dX4 If DIY is not for you, but you love solar and need an offgrid system, check out Tesla Energy! They will price out a system and get your house offgrid: ts.la/william57509 *My DIY Solar Equipment Recommendations (Constantly updated! Check here first):* 12V/48V Lithium Solar Batteries: www.mobile-solarpower.com/solar-batteries.html Complete Solar System Component Directory: www.mobile-solarpower.com/solarcomponents.html Complete 48V System Blueprint: www.mobile-solarpower.com/48v-complete-system-blueprint.html Plug-N-Play System Recommendations: www.mobile-solarpower.com/full-size-systems.html Complete "Add to Cart" 48V System Kits: www.mobile-solarpower.com/complete-48v-solar-kits.html DIY Friendly Air Conditioner/ Heat Pumps: www.mobile-solarpower.com/solar-friendly-air-conditioners.html *My Favorite Online Stores for DIY Solar Products:* *Signature Solar* Offgrid One-Stop-Shop. Best Value 48V LiFePO4, Victron and Offgrid Specific Heat Pumps: www.signaturesolar.com/?ref=h-cvbzfahsek *Current Connected* SOK, Victron, Mr.Cool Heatpumps and High Quality Components. Fantastic customer support: currentconnected.com/?ref=wp *Litime* My favorite 12V budget battery!: www.litime.com/?ref=XBIA62RFcalHns *Epoch Batteries* My favorite high-quality 12V battery: www.epochbatteries.com/products/12v-460ah-lifepo4-battery-ip67-heated-bluetooth-victron-comms?rfsn=7352625.50494d *Renogy* A classic 12V solar store that has been around for ages! DC to DC Chargers and more! renogy.sjv.io/n1VjXx *Rich Solar* Renogy's biggest competitor! Similar products, but at a better price: richsolar.com/?ref=h-cvbzfahsek *Battery Hookup* Cheap cell deals bit.ly/2mIxSqt 5% off code: diysolar *Contact Information:* I am NOT available for personal solar system consult! If you wish to contact me, this is my direct email: [e-mail] Join the forum at diysolarforum.com/ if you wish to hang out with myself and others and talk about solar *FTC Disclosure Statement and Disclaimers:* Every video includes some form of paid promotion or sponsorship. Some links on this youtube channel may be affiliate links. We may get paid if you buy something or take an action after clicking one of these. My videos are for educational purposes only. Information is subject to change/update at any time. Electricity is DANGEROUS and can kill. Be smart and use common sense :) DIY Solar Power with Will Prowse is a participant in the Amazon Services LLC Associates Program, An affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com

[@AIM54A]

Great video.. Bus bars also need to be sized appropriately for the current.

[@OhRonaldo]

That's sort of the same as connecting the load to the center battery in your pack, but in reverse. The outer battery packs will likely charge first and you still have issues with packs of differing specifications/condition.

[@WillProwse]

@@OhRonaldo no, opposite ends as in diagonal connection. See the pdf resource above or look at the diagrams in the video to see what I mean.

[@WillProwse]

@@AIM54A good point!

[@OhRonaldo]

@@WillProwse Oh you mean opposite end of the other polarity not opposite ends of a single bus bar. Gotchya.

[@immrnoidall]

What would we do without free info like this critical knowledge? A lot of sellers of these products, know and tell nothing, about proper installations. Thanks Will. Lives and property will be saved.

[@brian_abroad]

This video effectively combines applied electrical theory with the fundamentals of multi-battery configuration. I am no longer a newbie to electrical and solar technology (thanks to Will), yet I thoroughly enjoyed this video refresher presented using layman’s language.

[@myhificloud]

Answers to your LiFePO4 Battery Bank/System Build Video: This is the video we've all been waiting for. Assembly of all the important questions and answers regarding battery bank scaling, fusing, conductor sizing and conductor length, the gotchas and much more. Well done and very, very much appreciated. Thank you for this @Will

[@Dennis-mq6or]

A very old (77) engineer's comment: There is an old way to solving the equalization problems with those 5 batteries you have connected in parallel, And since it's very easy to do I would like you to try it and report on the results. (If not in a video, then at least to me). Ready? Disconnect the black feeder lead from the side of the parallel batteries that is on the same side as the red feeder lead, and simply move it to the other end of your group of parallel batteries. The result is all feed and discharge for the red lead comes from one end of the parallel battery bank, and the other feed and discharge for the black lead comes from the other end of your parallel battery pack. You can forget your buss bars if you were only adding them for balancing; because the resistances of the wires connecting the cells in parallel will act as balancing resistors during both charge AND discharge. You can easily calculate the series path length of any battery in the system to the load and back, and they will all be of equal loop resistance. If you still have any questions about why this old 'tried and true' method works so well, contact me and I will try to give you a more detailed explanation.... Regards, Dennis Ostrowski Astro Electronics

[@user-hh6ex9md4w]

Thank you for sharing your old engineer's method for equalizing batteries in parallel! It's always great to hear different approaches and solutions. The Segway Portable PowerStation Cube Series seems like a reliable option for outdoor enthusiasts and RV lovers. With its massive capacity, powerful output, fast recharging, and comprehensive protections, it definitely seems worth considering. I'll be sure to check it out! Thanks again!

[@Floyd112007]

This sounds very interesting, I would really like to see that video or at least a diagram to make sure I understand this properly. I need to add more battery and I want to do it safely.

[@rookm13]

@@Floyd112007 if you watch the video, he mentions it @5:50

[@tannerh3002]

This is the type of video I have been looking for for years and couldn’t ever find it laid out in one place. Thank you!

[@kellyflanagan5264]

Will, thanks for taking the time to make your videos. I’ve watched quite a few and admire your passion for the subject and your continuous reminders to be safe around high energy density, and low internal resistant energy sources, yes batteries. It’s easy to think 12-48 V is safe, but these babies can make great accidental welders in the blink of an eye or the drop of a wrench, or your wrist watch in the wrong place. Thanks for reminding all of us!

[@5400bowen]

I have to say also that your comments about using the largest cable that fits safely really hit home with me. I went way way past the recommended conductor gages as soon as I got over 2,000 watts. It also conserves the precious energy you've worked so hard and spent so much on to produce and store. So much in this video is familiar in it's approach, the approach I've learned over the last 60 years.

[@stevezozuk9622]

I absolutely love how safety orientated you are Will It's very clear that you know your way around the box not just outside. That was a great lesson Will and I thank you for doing what you do for all of us. Take care and we'll see you on the next one. Cheers

[@jasper2110]

Hello

[@madalitsojere9107]

pĺ

[@MrPlasma01]

id say he does know his way around the box.

[@flyingbirdz7456]

@@MrPlasma01 and inside the box too😊

[@TK-123]

Will, you addressed an area that was just had to be covered. 🙏 Thank you!

[@solargarage]

Thanks will , for putting this out. We have been running a mix of Eve and Fortune banks, using a central buss bars and each pack having it's own Class T fuse. So far it's working great.

[@bboypanda7776]

Hey Will, thank you for your videos! I'm a newbee in this space, am like 4 videos deep, but I'm learning a ton from you! I admire your straight-forward, complex, yet easy to understand approach... Keep up the great work, brother!

[@john_in_phoenix]

Excellent subject choice Will, very happy to see this!

[@Five0Music]

Great video, Will, and it answered a lot of questions that have been hard to get manufacturers to answer directly. Your videos inspired my first build in 2020, which has been operative 24/7 since, with no failures at all. You’ve really got me wanting to build a larger EG4 rack system now. Just need the cash!

[@swillinil7198]

Will, I've been watching your channel for a while now and your videos keep getting better and better (they were great to start off with!) Thank for sharing your knowledge, skills, expertise and hours and hours of research!

[@jerrytusch1758]

Thanks, Will! I have done exactly as you said, paralleling several LiFePo4 batteries of different sizes(capacities) to a common buss. I could not afford to change all batts out each time I wanted to increase storage. Each battery is fused with a 100A Windy Nation fuse, and the bus output to my inverter is also fused at 100A. Solar charges everything nicely, and batteries maintain a fairly equal SOC under a longer discharge cycle at lighter loads. So happy to hear your reasoning on this, I feel less anxious now! Have had bad experience with cheap breakers developing high resistance and heat while operating at well less than ratings, causing inverter shutdown. All fuses now. No problems now.

[@johnsuggs7828]

Subscribed. Very easy decision. Very refreshing to see videos of someone who actually knows what they're talking about. First, Safety Second, Safety Backup to backups and leave as little open to chance as possible. Extremely smart way to do things.

[@marvinsauer8493]

Very good advice on Ohms Law. Very simple, AND having an intrinsic understanding of electricity is best way to fully understand what Will is saying. Thank you!

[@callummacleod8634]

Thanks Will, this is just the info I've been looking for. I've got an RV trailer with solar and one 12V 110 AH Lith Ion battery and want to add a second 12V battery. Wasn't able to get an exact match (now out of production) so am adding a 100AH battery Lith Ion by a different maker - both are US made - and now I'm much more confident it will work just fine. So many other sources say don't mix batteries of different age, size, or manufacturer, and here I am doing all three.

[@greenidentity3789]

Hello Will Prowse, I want to say a very big thank you for your special way of impacting knowledge. I've learnt a lot through your videos. Pls keep doing what you're doing. You're great!

[@GurdeepSingh-ek6tt]

Sew dw v rafters anda man gya gis óddsraaddaaa

[@om617yota8]

Interrupt rating on DC is no joke. Anyone who's arc welded can tell you how much heat 100a at 50v can generate when arcing, and how much distance you can maintain an arc over. I spent $200 on my Class T fuses and holders. Blowing one is $30 down the drain. Completely happy with that though, as it's hugely less expensive than burning up my trailer mounted solar system.

[@WillProwse]

Exactly!! This guy gets it

[@merkel2750]

Could you use a circuit break in place of a fuse?

[@merkel2750]

Never mind, just watched the video 😂 t class fuse, here I come.

[@merkel2750]

Never mind, just watched the video 😂 t class fuse, here I come.

[@om617yota8]

@@merkel2750 Sure, an appropriately spec'd circuit breaker would be fine.

[@centerrightproudamerican5727]

Great Video will!!! This has been asked about a lot on the forum lately! Thank You. One thing to add: We had a forum member that had on battery with a Fet Based BMS and another battery with a relay BMS. The difference in resistance was enough to make the difference in the current very large even though the cells were about the same size.

[@WillProwse]

Wow no way!!! I did not think of that one. That's wild!

[@D2O2]

Voltage drop measurements under load from cells to case output terminals might be a good measurement to compare quality across packs, commercial and DIY.

[@onyxsolo1]

Not my major but stuff like this reminds me of how much fun I use to have in school learning about thermal conductivity using a program called labview. This video unexpectedly clarified some things I wanted to know about using bus bars. I was curious why I rarely see them used in videos. Your explanation helped a lot with the benefits I was looking to confirm; Good to know how much more efficient they can make things instead of being the danger I was concerned about due to lack of representation in practically every solar battery bank video I've seen.

[@CountryBoyMoto]

You have no idea how much I appreciate you sharing your knowledge. I wouldn’t be doing the build on my RV if not for you, Thanks!

[@viktorchu2641]

I have learnt a lot from you bro you have shared knowledge that I cannot afford to pay for .I am good with solar energy now courtesy of your teachings .I come from a country where people know little or nothing about solar energy and we have up to 7 hrs of sunshine every day so I feel good about myself ever since I grabbed a lot from your teachings God bless you always

[@SignatureSolar]

Holy cow those batteries are BIG! I love seeing these huge babies when we bring them in for testing.

[@davidlawlor1583]

So happy I stumbled along your channel, I've been bingeing your videos. You're a true subject matter expert and are a wealth of knowledge. This video partially addresses a question I've been pondering. Some background - My RV's House batteries 2x deep cycle 100AH Lead-acid batteries are nearly dead. Since we are so late in the season and I only have a month or so before I winterize it, I decided to make the leap to Lithium in phases.... starting with the batteries now (which means I also have to change out the onboard charger and engine battery isolation manager for the lithium profile), I will add solar and whole house inverter in the spring. I just purchased a Weize 12v/100AH LiFeP04 self Heating. (Actually bought 2, but only received 1, the other was "lost" in the mail and now they are out of stock with no ETA). Our RV House batteries are under the steps outside (thus why I need the heater versions). When I add the Solar and Inverter, I will have to install it INSIDE the RV under the dinette table bench. Space should be good. When I do that, I might like to add MORE capacity to support whole RV inverter, and was poking around at the newer CHIN 300AH battery that would also fit under the bench. (again GREAT CHIN breakdown review video!) My question I hope you can spare the time to answer has to do with the battery locations and differing AH capacity. With the "Smart" BMSs in both Weize and CHIN batteries I can see a scenario with the self-heating function engaging on one outside battery but not on the other? lets assume the external 100AH battery detects low temp, engages heating element and waits to charge, while the internal 300AH battery starts charging? How would the batteries and BMSs react? would any damage occur during that state, how about when the 100AH heats up and starts to charge? can you speculate if either batteries life would be diminished by this? I'd love to have a conversation over a beer on this one ;-)

[@Wrenchen-with-Darren]

Thanks for spending a few min. Explaining why, T fuses, are so important. 👍

[@upnorthandpersonal]

So many people skip them because they're expensive. Don't. If I can manage to find time, I'll record a dead short on a 48V LiFePO4 some time in the future. That should make people understand ;)

[@markgriffith8463]

Great information, I've been wondering about these things. I have 3 EG4's and 2 Jakery's running in parallel as you do here, except I have the negative and positive wires on opposite sides. There are differences in charged state, but usually within 2-3 % of each other. Glad I bumped everything up to 2 gauge wire also.

[@aldencole1099]

Will, very good explanation of correct wiring of parallel banks, I have been installing off grid systems for over thirty years, primarily in the marine industry but also custom RV systems and residential systems. Correct sizing of the interconnects is key. Size matters. Less voltage drop. Voltage drop=resistance=heat.Heat is not ony inefficient but dangerous. Plenty of info out there to size cableing appropriate to the current demands of a system. The math is straight forward. The equal length of conductors and same batteries in a multi battery setup arranged in a hub and spoke system vs a daisy chain system is codified in Kirschoff's laws which are built off of Ohm's laws. Also, the purpose of current limiting by fuses/circuit breakers is to protect the wiring to a device not to protect the device per se. If there is a fault in the device, the device has failed. Devices like inverters generally have their own circuit protection internally. There fore, circuit protection for a system is to be calculated to the demands of the device and the ampacity of the cabling, if mismatched, the cable can overheat sometimes with dire results. Keep up the good work. Safety is paramount.

[@benmoody2975]

Ah Will, this is one of the best videos you've done for a long time! this is exactly the knowledge that you should be sharing, thank you

[@cutchinstreeservice]

Great job Will. I have been watching you from your start and must say you are inspiring. Keep the freedom train moving for us all.

[@k.kapper2657]

Hi Will, after starting with lead acid 24V 250Ah batteries (12 cells of 2V), I have later added a parallel LiFePO4 24V 280Ah battery (8cells of 3,2V). I agree to be somewhat limited with max. voltage. Issues with different cell voltages with LiFePO4 cells have settled after half a year. Least voltage ever was 24,01V. Thank You for Your videos!

[@Patrick_Cashman]

Great video, Will. It clears up a question that many people have, and about which there are many misconceptions.

[@bzu4113]

Very interesting and timely topic! I’m planning to add parallel 48v batteries so that total internal resistance drop and voltage drop will be reduced. Though I was concerned of amps imbalance between strings of 48v batteries. Your video explained this very well.

[@coffeecoconutstermites8597]

Good Morning Will, Thank you for publishing a highly informative, beginner through expert level, and safety oriented channel.

[@5400bowen]

First off, my brother was an electronics technician in the Navy, and that was 1964-68. He then worked for the Naval Electronics Systems Analysis Laboratory in San Diego, We did a lot of working together, I learned a bunch from him and elsewhere later without formal training. So on to my story. I came to the conclusion recently that series connections for solar batteries was no good for running systems near full capacity, with the current running through each battery and cables/connections from the charger and to the inverter. One thing that got me thinking this is a battery I was running (Lossigy 12 volt 200 AH in series with the same) going weak and the need for balancing series connected batteries. I just bought 24 volt batteries for my 24 volt system. So I watched your video on series and parallel configurations, and you said more than 3 batteries in parallel was no good. After scratching my head and doing some thinking and research, I started thinking, why not run equal length cables from a bus bar to the batteries in both directions, in other words, from the charge controller one cable goes to a bus bar and then equal length cables from the bus bar to each battery post, 2 busbars of course, one + and one -. Ditto for the inverter connections. I also found another video on tube where the guy shows a sort of compromise between that and what you say here and what I decided to do. I don't have rack mount units, so I was already shopping for busbars on Amazon before I found this video, and all the pieces came together listening to you explain exactly what I had thought of. After hearing you say in the Series/Parallel video it wasn't good to do more than 3 batteries in parallel, I thought maybe you didn't have a deep enough understanding of it all, or maybe there was something else I was missing. Full circle, you cleared all that up in this video. Only thing I can complain about is that when you said that it isn't good to have more than 3 in parallel as a blank statement in the other video, it threw me off quite a bit, as I have found most all your presentations so accurate and useful. And another useful comment you made was about the difference between running low level usage and charging as opposed to running at or near the capacity of the components. Very helpful to here it set out so clearly by someone I know is knowledgable.

[@slowoldandugly8299]

about to replace the old 12v system on the sailboat i live on, your videos have been a huge amount of help.

[@SiriusSolar]

I like the end of your video where you asked to hear questions, get ready the questions will come by the thousands on this mystic topic.

[@ivanmarden7179]

Thank you for your expertise and clear and straightforward advice on the subject. I’m going to try to design a system soon for my RV travel trailer using solar. Keep the great information coming

[@herbertvonsauerkrautunterh2513]

I've been running 72 AGM 7.2ah batteries in parallel. In parallel banks of four in my 12v off grid system. Special parallel wiring.. Nearly 12 years now 👍👍

[@dragasan]

Your timing is impeccable. I am very familar with Ohm's Law, etc, but I was just wondering about this. Thanks so much for sharing.

[@Eldon_Dice]

As an electrical engineer who specializes in battery integration (UPS systems)-- I'm very impressed with your knowledge and hands on skills. Are you self taught? If so, bravo. Batteries can be very tricky to work with and can be very dangerous. One only learns by doing and being hands on.

[@martijnheeroma5492]

Thanks Will, good story, helping me to think more 'safely', WILL use a cementboard behind my next setup

[@ronaldjean-baptiste6070]

Dropping knowledge like rain!!! Thank you for sharing!!

[@kswis]

Excellent, ive had a rough day and youve now improved it. Always get stoked when i see a new video from you. Keep em coming Will youve got much to teach! I've been experimenting with lith-ion in parallel with grade B lifepo4. Each with its own bms and undersized dc breakers. Only issue I'm having in my experiment is the inverters high voltage cutoff. Pretty fun little side experiment though I must say.

[@WillProwse]

Thanks buddy 😁

[@consco3667]

New off grid subscriber! Just wow! This guy knows his stuff!

[@justinharrell9256]

Great video, thanks for addressing mixing capacities in parallel. Annoying that both SOK and Battleborn say that you cannot mix capacities in parallel, SOK says its due to internal resistance, Battleborn due to voltage imbalance, leads to much confusion about how IR and balance works in parallel. Andy with off-grid garage has great series of videos showing an extreme difference in battery capacity in parallel with no issues and goes over how IR allows that to happen.

[@danielardelian2]

I'm also a DIY'er but I did some research on parallel battery strings and I found it very interesting that a lot of commercial and industrial devices that use parallel Lithium-based strings use a bidirectional DC-DC converter *for each string*.

[@rjlinnovations1516]

Excellent tutorial. I always watch your videos and I learned a lot. You are an excellent speaker and you knew very well the topics which you’re talking about. You’re like an instructor and Eletrical Engineer and may be you do 👍

[@ronkappa]

Brilliant tutorial. Well done. Explained in simple and straightforward English.

[@Shmade0304]

Wow your system is so sophisticated 🙌🏽🙌🏽🙌🏽🙌🏽🔋🔋🔋

[@Renegade040]

You are one smart cookie when it comes to battery systems like these. I planning to install lithium battery pack to my roof top solar system. when i get closer. I will be asking heaps of questions.

[@10Flat]

Class T fuses are definitely best practice. Equipment Peak through voltages and withstand ratings should also be taken into account when designing system over current protection.

[@billyjacksimmons9947]

Thanks for your time.

[@jeffreyhill3960]

Wow. Never thought a few feet of cable would make that big difference. You know I’m a pro electrician and I never thought this out. I deal with 4160 volts regularly and 480 but this is a very different thing. Humbled again by you and I will be watching for ever as I am new to solar and battery ect. Just goes to show you that you can think you are a pretty good electrician and there is always more to learn. I’m humbled next to your expertise. Bought your book. And thanks.

[@alanpetersen4497]

I have worked with 12,460V chillers, but they don't compare to working with DC voltages, and battery systems. I have seen the results of a 480V battery system going to ground, and it was horrifying. The difference with AC, at 60 hz, is that the current will let you go on a reverse cycle, but DC current locks on, and will never let go. I am sure that it is the same with 12V-24V-and 48V battery systems. They are all dangerous.

[@traumagas123]

Your a Great Speaker and Clearly Gifted Teacher

[@timburk6097]

This is awesome! I’ve been pondering this issue for the past few months. Thanks!

[@ZonaEA]

Nice Explanation. I can even understand how to connect those batteries and protect the system itself! GREAT VIDEO!

[@ProspectorTripp]

Good information Will.. having a 67 kw lfp battery bank that has five 48v 280ah batteries in parallel with slightly different 1/0 cable lengths all with individual bms’s and circuit breakers. I never pull over 40amps on any single battery! So far so good 😊 Having a working current of 14.2% of C max 280a = 1c is a small enough where all batteries charge and discharge at a very similar rate. I’m reconfiguring my battery bank and buying other 80 280ah cells! 134kw of lfp battery storage should do it! I hope 🤞 Thanks Will, keep up your good and very necessary work! ✌️PT

[@carlosaquino8917]

I have learned alot from your videos. Learning so I could build my own system so I could go off grid. Thanks for your knowledge 😊 thanks for what you do

[@yougotthatright1635]

Will, this is your first video causing me to blow split bubbles but I’m gonna watch it 10 more times and study Ohm’s Law. When I can conjure up a question deeper than, why is the second positive cable longer than the rest, I will raise my hand. Thanks for this, I think, but the battery bank needs to be installed this Summer so I better figure it out… Cheers, Dan

[@abramsonrl]

This is the greatest video. Thank you. It addresses all my safety questions in one video.

[@anthonyrichardson7543]

Good discussion about relevant safety issues.

[@jeffreyrapkin6177]

Dude you are awesome FINALLY everything is starting to make sense thank you so much for making these videos!!!

[@huiponoholoholonapaws-pono1032]

Appreciate this, a bit over my head but able to absorb the safety concerns. Mahalo.

[@emilhwilkins3275]

Nice video Will. You could wire each negative and positive with its own wire to a buss bar, keep wires the same length if possible.

[@Sanwizard1]

Perfect timing as I am about to connect my DIY EVE 280ah banks in parallel with my new Seplos Mason Rack batteries at 135Ah. I will use a Selpos JASSN busbar to connect everything together with the pair of LV6548's.

[@issabangura4350]

I really admire and enjoy the lectures

[@yanfishtwig2356]

Thanks will i have been looking for a deeper dive video like this from you since i found your channel over a year ago. Would love to hear more🤯

[@mjrootz]

THANKS WILL, THIS WAS YOUR BEST VIDEO AND HAD A LOT OF INFO THAT I NEEDED. But i can imagine: if you have a fire.. man.. it'd really go up so yes.. continue to be careful.. thanks again.. great info and video.

[@jimmyg6215]

Thanks Will for spending a good amount of time on T class fuses. I have placed comments over the last few years on people’s sites that are using ANL fuses, recommending they replace with a T class fuse. For the $50 or so for a 150A T fuse and holder it is well worth the money to save a setup from a catastrophic failure. I think those ANL fine for automotive applications, but not with high current LiFePo banks. I run my signature solar 6 bay rack with 4 gauge to the buss bar and 2 gauge from bus bar to inverter. I do have a 150A T fuse on the + side outside the rack and I also diagonal the connections inside the rack. Seems to keep things balanced between the 5 packs in the bank, and 2 of the battery packs are 1 year older than the other 3 packs. I will post in 10 years if they stay balanced 😂. Excellent video as always.

[@WillProwse]

Very nice!!! You get it. And it is very important. Agreed!

[@careygagnon5853]

@Jimmy G I have the signature solar rack as well, with 3 batteries for now. How did you connect diagonally on the buss bars? There are only the larger lugs/bolts on the top on the buss bar. Edited for typo: Originally stated 2 batteries. Should have been 3.

[@jimmyg6215]

@@careygagnon5853 I drilled and tapped one of the bottom hole connection on the negative buss bar to accommodate a 5/16” lug. I put a lock nut, the ones with nylon inside, on the other side where the screw came out the other side of the buss bar just as added security to lock the screw in place. I actually put a lock nut behind every battery screw connection just to ensure nothing loosens up due to any heating and cooling cycle that may occur since it is an off grid cabin. I also put a very fine film of carbon conductive paste between the battery terminal and the buss bar. I was a little concerned since this is off grid that if any moisture found it’s way between the buss bar and terminal it could oxidize. The cabin has spray foamed walls with a 120V mini split heat pump, so it is climate controlled, so maybe it was a moot point to do. Sometimes I way overthink my installations :)

[@careygagnon5853]

@@jimmyg6215 Nothing wrong with over thinking and over protecting. That's why I can't get my system running. Learn more...over think more...over protect more. If I can get up and running just to test things out (mine is a back up system for the house) then I will start swapping things out, like larger cables etc. Although I have 4/0 from batteries to inverter so no need to change those.

[@david0alinda]

@@jimmyg6215 Sorry I’m late to this, but I woud highly advice to exchange those nylock nuts for washers with spring washers. The nylon is temperature sensitive and when the nuts heat up from use, which is possible, they loose their grip and can come undone, causing a higher resistance and more heat. Sending the pack into an arc-fest. Regulations in my area prohibit the use of nylock for electrical connections, specifically for that reason.

[@davidnoack9727]

Great job. I’ve watched many of your videos and they are always excellent. Thanks, DN

[@SvetzBowman]

Great job Will!

[@widewinger1454]

1000 Thank You's for this video.

[@lisarettig2740]

I appreciate your passion and knowledge. You have helped me greatly!

[@fonix127]

Thank you for the information you put out.

[@Miata822]

I have wondered about this. Thanks for posting.

[@oshavlfarms7239]

Thanks Will, this video calmed the OCD fires if my EE brain. 😁

[@zodiacfml]

This has become more interesting than I thought. While LFP has a flat voltage curve, a 48V pack/set has 16 cells so it will show a huge voltage drop once the LFP cells experience tiny voltage drop. In other words a bus bar could be overkill. Can you measure for us the resistance between the first and last battery terminals?

[@patmitskey839]

OH MY GOD!!!! Will... You Nailed It To The Wall!!!!

[@firefightermommy1]

Would like a video over different types of fuses and circuit breakers and where/when it is appropriate to use them.

[@roland9367]

Great video! I will now build a lithium NMC system consisting out of 2 blocks in parallel. One will be wired closer to the boat motor (and charger) then the other. I will put a fuse on each block just above 1C rating. If funny things occur and the balancing current is unexpectedly high, the fuse should go. The motor is max around 0.75C of the battery bank, but if one of them disconnects through the fuse, and the master BMS is still letting the motor continue, then it will become a relatively high C rating on the remaining block, at max power.

[@ivanescobar707]

Thanks Will. I appreciate

[@michaelseah9617]

Great video and lot of good information! You just give me the answer I was looking for. Mixing same voltage and different capacity batteries. My setup is identical to yours accept smaller and batteries lock away in a server rack. I don't use busbar. I use 2cm large core hard wire as the main battery cable, solid T-joint used by grid contractor (screw down clamps type) and 1.6cm conductors soft wire to the batteries. The main battery cables is one size bigger that mains incoming line of my house 60amp 240vac cause I am worry DC would cause a bigger damage on wrong connection.

[@Harisullah397]

Excellent job Engineer ......

[@chindodawg]

Amazingly thorough!

[@mariueg]

"I can talk forever". Please do! Love the content

[@victornelson1577]

Superb video. I have now mended my bad ways! Hey! Hello from Scotland UK!! 🙂

[@valleyboy3000]

Excellent video for us newbies. Thanks!

[@parkerottoackley5587]

Your channel is the BEST.. 👍 THANK YOU SO MUCH

[@fenghuawu7521]

Thanks Will. Am Learning a lot solar system from you. From an old Asian dude living in Ohio.

[@Dutch_off_grid_homesteading]

heya and the way you tell your story we can see the passion for this stuff

[@coopshopdesigns4890]

Thank you for the lesson

[@offgridsolaruk843]

Good will! At last a video about bus bars!! Been using bus bars from my first system, so important 🙌 Great video as always 👌 👏

[@offgridsolaruk843]

Ps don't forget to size your busbar correctly!

[@dreamcat4]

thanks great video, really learned a lot from this video. i just wonder how different it would be on the solar side to use newer enphase inverters instead of the traditional string arrays

[@Electronzap]

Very good points!

[@lachlanbird9688]

Thank you for the video report .

[@kenbrown102]

Thanks for a thoughtful well designed lesson, and the consequences of not setting it up right. PS I was just looking at the T class fuses, as I’m about to upgrade, the link on your site for the 48 volt, shows one that is 12volt. While it would be easy to find the correct one. I do want to get you the credit for your affiliate program. I’ll wait a few days prior to order to see if that gets fixed. :)

[@franciscambron]

Thanks Will.