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Will, thank you for sharing this safety tip! I've seen others that have a DIY build for a 24 volt system and they never talked about this!

Lots of "light bulb" comments. Remember that any simple electrical heating device (incandescent light bulb, hair dryer, soldering iron, heat gun, glue gun, etal) is essentially a resistor and will do the same thing as long as you don't exceed it's power-handling capability. Great job as always Will, I'm SO glad I found your YT channel!

Never saw your idea implemented before. It was good that you proved what damage can happen. Usually, you hear a laugh when the batteries spark and never hear how it can hurt your system! 👍

This worked for me. Thank you. I damaged an inverter years ago not knowing this. You do a great service with your fine programs.

Im glad you mentioned this as its something not a lot of people are aware of. For me, I use a lightbulb in a holder to charge as its a resistor and the bulb will dim once the capacitors are charged.

I've watched countless videos related to this type of equipment but this is the first time I heard of this. Thanks!

Great public service / safety announcement! I frequently see people doing this wrong, and it's so simple not to. Now with a short video that I can point to, if I forward it on people will actually watch it! Thanks Will! Keep doing what you love.

This video has been incredibly helpful. I blew the fuses in the exact same inverter you have used in your video by not pre-charging the capacitors and hope this fixes the issues

Thanks Will. Pretty much found everything I need to know to build my van solar system and feel confident its safe and will perform from your videos alone. Saved me endless trawling through questionable advice on forums.

I sparked the contact between a 3000w psw inverter and 12v/100ah LifeP04 battery bank. The result was an unrecoverable BMS in the first battery in the bank! Good thing BattleBorn has a 10-year warranty. I wish I had seen this video first! Another FANTASTIC video, Will. Thanks for all you do.

Awesome video as always saw your interview with Jamie, that was so stoked.

No kidding, you probably just saved my eyes and my life. Great video. Short to the point and extremely valuable information!

All I could look at was the wrenches on the magnets above the batteries. Seriously though, love the content, it's refreshingly simply delivered and any unintentional humor only adds to the charm. Keep it up!

I used to use a incandescent test light to charge the capacitors in high power car audio systems. The benefit is the light glows dimmer and dimmer as the caps charge. The light across the inverter input will discharge too. Nice videos. Thanks.

Thank you for this useful info. I have always wondered how to connect high voltage inverters without a spark, now I know

I listen to Wills videos just so i can hear him say “TITAN”! My favorite part every time!

Thank God I saw this video before connecting my first inverter and battery together today. Thank you!

Thanks again Will for keeping things simple and easy to understand. Really appreciate your useful examples…..I’d be burning alot of money if not for folks like you….learning important stuff here.

That is good to know, I would have assumed big inverters would have some circuitry to prevent this but guess it's bad to assume! For a permanent setup you could probably have a resistor as part of the circuit by default and a separate switch to bypass it. I guess ideally two switches so you can still isolate the entire thing.

good advice well done I have been in this trade over 50 years now .

I discovered a method of precharging capacitors using no extra parts. Just the battery and the inverter. However, this method can only be used if you built your own battery from 3.2v cells. Simply attach the positive inverter cable to the positive side of the battery, then touch the negative cable to the negative post of the first cell in the series. Then touch it to the second negative post, then the third, etc. This allows you to use the battery itself to slowly ramp up the voltage, 3.2v at a time.

Great video! Higher value resistors at lower wattage will work too. Just takes longer. Large value capacitors do definitely pack a punch.

dude your videos are ALWAYS on point, to the point and incredibly clear and helpful - thanks a metric TON bro!! My new litto batts are ALMOST here and I just so HAPPENED to see someone popping a small switch and searched out what it was, i have a 10000w 24v split phase inverter!! You just saved me ruining alot of expensive stuff thanks thanks thanks!

super informative and helpful!! Thanks for saving everyone's eyes and bank accounts !!

I'm in the process of researching setting up a solar system on a small narrow boat over here in England. All the videos I've looked at and read up online I've not come across this information. Thank you very much.

Thanks for the great advice and safety tips. I hope all your viewers heed your advice. Like your channel for the great information about solar products and your honest reviews of the products.

The first time in all my years of doing solar that this has been mentioned. Thank you sir!

For my backup power system i built for my computer room. After i burnt up the contacts in a pair of high current relays i added a pre charger. Just using a resistor and a car horn relay. From memory the resistor im using is one of those ones designed for if you use LED replacement lights on your car to load the circuit more. The arduino i use to control it all just turns the precharger on for 5seconds before closing the main relay to the inverter.

Thanks for addressing safety issues!

Solark 8k comes with 2 resistors just for this reason to topup the capacitors initially.

I had seen this video, but forgot about the caps after blowing out a 30A fuse during some load testing. Putting in the new fuse was a little scary! The lesson is now welded in, so to speak. I didn't have a 10W low resistance resistor handy, so I put some clips on a 120vac 40w light blub. Works fine.

Lucky to have a Fry's that is still stocked - many are suffering due to business changes. Good idea on using a resistor.

By far one of your most important, accurate and useful video that I have seen since subbing. Way better than you loosing time on overpriced underperforming fraudulantly called solar generators.

I had no idea! My problem is now solved. I was about to return this brand new inverter 4000 watt. Thanks Will!!!!

Wow I had no idea we had to do that great information thank you.

Making something as boring as a resistor, interesting! You've done it again. Thanks for the great info!

Love your videos. I've learned so much and I understand it. You have a way of explaining these ideas in easy to understand language. Thank you! Also...will you be evaluating the new Ecoflow Delta 1300 solar generator? That one looks promising but I would love to see what you find out about it.

Thank you for telling and EXPLAINING about the resistor to charge and to discharge. That was something nobody mention to me lol. Gordon.

Dude, you are perfecting the perfect off grid system that can power a house out of a shed, including transportation! Wow! Using solar panels that can be downgraded to charge anything less powerful than and including a house! Shit, if you pakcage that like you have done with generators and sell it undercutting the market to get it out there would change everything! You do this and that's revolutionary. ✊🏽

Great info and safety PSA also! Save your eyes!

Hi Will, Thanks for all the videos and detailed explanations. You have helped to make our RV electrical upgrade easier and safer. Thank you! Tod

Just found your channel today. Already subscribed. You just gave me an answer to an issue I have in my RV power system. I have two Battle Born batteries wired in parallel going to a Blue Sea battery switch. I also have a Victron Energy MultiPlus Compact 12/2000 Inverter Charger. Every so often when I switch the batteries on the system would not start. I would have to cycle the switch off and back on to get it running. After watching your video, I now know that I was triggering a disconnect on the Battle Born Charge Controllers. To fix this I will get a momentary toggle SPST switch and that wire-wound resistor and put them across the switch terminals. I will toggle the switch on for a couple of seconds before switching the batteries into the system. Thank you very much.

Looking dorky is being safe, thanks for the video, 👍👌❤🇨🇦

Great video, thanks. What about if the inverter (connected) is turned off for extended period of time. Do the capacitors remain charged?

I always wondered why I would only get one spark and wondered why the spark was so big! Thanks! I've done 3500 watt magnum inverter chargers with 600ah busses and never could get around the massive spark! Unless I used the battery disconnect lol

Thanks! Glad I saw this video before putting together a new solar system.

Excellent video as always Will 👍

The thought of the spark when I am about to connect these terminals always gives me concern. Thanks Will.

All good info. I was just looking for how to safely discharge my inverter.

Thanks for this excellent information.

Great info! Ordered some resistors today after having to recently take a die to the threads on my old inverter. After sparking heavily on hookup, I couldn’t thread the nut on the stud without chasing the threads. I believe my new inverter is the same one featured here (PS-3000KAR). Was going to design/build a low voltage disconnect for it, but discovered it has the newer style ‘tactile’ on-off switch. It requires that you hold the button down to turn it on after disconnecting, negating the ability to turn it back on unattended. Any workaround you can see?

Thanks bro! This video was very helpful...

Thanks man, this really helps.

Powerful information thank you

Will, thank you, I did not know this. I have a 2000 watts inverter and 6 lead acid batteries in parallel.

Thx for this info. I built a 3 battery bank about 4 years ago with a 2000 watt inverter and nobody ever mention this to me. Yes, i got some nice sparks when connecting the terminals to the inverter, but i figured it must just be a mild normal thing (not dangerous). Your $1 resister is about $10 with shipping.

Thanks Will, another informative episode. I am surprised to learn that large wattage inverters don't have a high value leakage resistor soldered across the input terminals to allow them to discharge over a few seconds once power is removed.

Hey Will your awesome thanks for all of your info.

Thanks for this educational video!

Nice video Will...safety first...

I never knew this,thanks!

On old submarines the action of switching on those massive battery banks would sometimes release ball lightning .

Very useful info for DIY enthusiasts, I personally use car/mo-bike tail lamps [filament type not LED] for charge discharge those capacitors. ;)

Thanks Will. Very good to know

The Epever Ipower plus (5000W) has current limit to prevent sparkles/Arc when connecting the 48V batteries bank, this is nice, I did not have to use a resistor (LifePO4)

Ty4Sharing Great vid as always Will !!! Wolf🐺 👍

Thanks, Will...great tip!

Thanks, you are the only one on you-tube that has said to do this, I guess all those experts need to learn a little more. You would think that at least Battle Born would tell their customers that in a video??

Excellent video. I fried my inverter during hurricane Fiona (I'm in Prince Edward Island, Canada) and this would have saved me some grief. Thank you

I enjoyed the video. Thanks.

Thank you Mr Will,you save me thousands euro's with this video. (καλημέρα )from Greece.

Hey Thanks will, perfect timing. I just got my 3k Renogy inverter yesterday. I am starting the 800watt solar for my 5th wheel Montana I live in full-time. I am wondering how I am going to wire it to my 50 amp system though.

Great info as always! This channel is amazing.

Do you have a video on connecting power from an inverter to a breaker box?

Just what I was wondering about , thanks.

Great information to know!

thanks! more of these videos plz. safety first ;)

Switching on three MultiPlus-II 48/5000/70-50 in parallel with just the bms (jk bms b2a20s20p) works fine for me so far 👍

Chunky soft shop pencils work well too! Mine measured about 20ohms.

Thank you. Great info. I recently bought 4x Lifepo4 cells for a 12 volt battery bank, a Daly Bms 200 amp and Victron gear including a Victron 12/1600/70 Inverter / charger. Do I also have to do a pre-charge with this inverter / charger? And do I have to do this once when connecting the inverter / charger or do I have to do this every time I want to use the inverter function?

The bigger issue is actually the capacitors especially on the larger inverters as I don't think I have seen any that have a soft charge up feature (like some computer power supplys have, the ones that don't spark when you plug them in do have it, they limit the power to the psu for 1-2 seconds then allow full power pass) , I have seen the solder or traces blown off around the the capacitors legs due to the very high amp inrush current At basic level I guess using thermistors to limit inrush

Do You Recommend Using A Super Capacitor like 2 Farad Before The Inverter To Smooth Dips From Heavy Amp Draw?

Great video. I have done exactly what you are doing using a value of 200 ohm or larger and leave it connected for a minute or so. Another thing I have done is use a tail light bulb from a car in series with the inverter and the battery. (12 volt system) I just leave it connected unitl the bulb goes out and give it a few seconds more for good luck. The bulb will be bright and slowly dim. If the bulb suddenly goes out it may have burnt out so be careful if using the bulb method.

Outstanding information . Please , could you help with the mystery "WIFI on the road" subject ? There seems to be similar misinformation in this area . THANKS

You are best video I watch 100 %

Thank you!

Many people install a switch or circuit breaker between the battery and inverter. Whenever the switch is flipped on, it will also generate a spark. I suppose we could manually pre-charge manually or install a push-button switch with resistor before flipping the switch but is there some kind of contactor, delay, relay, and/or device available off the shelf that can be installed across the breaker/switch to AUTOMATE the pre-charging? I doubt such an accessory cost much to make.

I’m having troubles with my outback system. Are you supposed to transfer the load from the resistor to the battery fast ? Or can it sit for a moment

Would it be worthwhile to add a capacitor bank to help with large pulls from the battery bank? Like the Maxwells

Great Tip Will !! , Do you Have a recommended Sequence of Wiring a New System , Solar Panels to MPPT to Battery to Inverter? Which Components should Get Wired First Safely and sequence of NEG to NEG & POS to POS

Good job 👍

Hi, I dont see alot of people pre-charging inverters with 12v batterie battery banks AND 2000/3000 inverters. I found your video interesting and Im wondering if this applies to 12v or is more a concern with 24v batterie system and up? Cheers!

Good clear information.

Used to drive a 48V EV in the 90' and the solution was to keep a 60W incandescent bulb in the battery compartment, so whenever I had disconnected the battery pack, but didn't want the bang and sparks when re-connecting, it was simply a matter of placing the center prong of the bulb on the battery terminal and the cable on the threaded part of the bulb, and when the bulb extinguished, the caps were charged so I could simply slide the cable onto the battery terminal with no fireworks. But yes, the authorised way of doing that is with a precharge resistor and a push button, and a small bulb to have an indication of when current is no longer flowing and the pre charge is complete.

Would be interested in your thoughts about the new "Silent 80" all electric/solar luxury catamarans...

Good video. I have a question that I hope you can answer. I found a 100W 50 Ohm Resistor for the same price. Can I use that one instead?

Thank you for a nice presentation, can Infind somewhere this résistivité,

Just another tip when it comes to capacitors, it is really easy to calculate the resistor needed. But this only work IF you a aware of the capacitance of the bank. What you calculate is the time constant or RC R=resistor C=capacitors. t=R*C so if you got a 30ohm resistor and a bank of 100'000uF (0,1F), just put those values in the formula and BAM! 30Ohm * 0,1F = 3s to about 60% charge if they're completelly drained. The second advice is, why bother with dischargin when you easily can just permanatly mount a resistor beetween the power "poles/skrews" and as soon as you disconnect the battery bank it starts to drain the capacitors. Same formula just the opposit result. But I'd use a larger on, let's say 1K (1000Ohm) which will drain the capacitors within 2min. A 1000 ohm resistor will draw about 0,012A or 0,144W so you'll ned atleast a 1/4W or 1/2W resistor. No disessambly required at all for any of this tips.

Do you have to do this with an Inverter/Charger as well? Just bought a Victron 3000W Multi Inverter/Charger.