Why I Removed The RV Battery Disconnect.

Подписаться 255 тыс.

Просмотров 181 тыс.

50% 1

Today I wanted to explain why I removed the stock Battery disconnect and install one that I prefer. The original style doesn't cut power to everything and was easy to bump and turn off. This newer style is easy to use and I don't have to worry about bumping it and turning the DC power off. The battery disconnect is great to use when you need to work on the system to change something or when storing the RV. It should remove all loads from the battery so it won't have a small draw draining the battery. Nobody wants a dead battery.
New Battery Switch. amzn.to/3IILeZd
Here is our Amazon page for our favorite gear. We will be adding more products as we find more products we use and love. As an Amazon Associate, we earn from qualifying purchases.
www.amazon.com/shop/jaredgillis
Learn the fundamentals about Your RV bit.ly/3z6jSbc
To save 10% on solar setup at Renogy you can use the linkbit.ly/31FTO73
And enter code “AllAboutRVs “
jaredallaboutrvs@gmail.com
Passport America WE USE THIS ALL THE TIME. passportamerica.com?rfsn=2638351
Harvest Host Link www.harvest-hosts.com/J6SQHS/...
Lithium Batteries bit.ly/2WZpYr9 Save 15% with code “allaboutrvs”
Need more info? Here is our Website: allaboutrvsinfo.com
Membership link
/ @allaboutrvs

Хобби

Опубликовано:

10 дек 2021

Ссылка:

Скачать:

Готовим ссылку...

Добавить в:

Мой плейлист

Посмотреть позже

Комментарии : 162

@RoamingwiththeRamsays 2 года назад

Very informative as always Jared. The way you explain things makes it easy to follow and informative at the same time. Your channel is always a go to channel for me when I need to repair or work on my rig.

@iair-conditiontheoutsideai3076 2 года назад

Glad people like you expose these RV flaws. Otherwise the RV industry would never fix it

@eddaeges9309 2 года назад

Thank you Jared for another informative video. I really mean it when I say you have the best and most informative website for RVs. You're straight to the point and not allot of clowning around. Keep up the great work.

@AllAboutRVs 2 года назад

Thank you!

@paulwinkelman 2 года назад

That’s the exact one we have that I installed on our rv months ago. I love it, as it doesn’t switch on without you deliberately switching it and no lines are exposed. Great video!

@AllAboutRVs 2 года назад

Thanks!

@russ3580 2 года назад

Good information and thanks! Yours is one of the few RV sites worth watching - most are just blather from people that have no idea.

@shepgre 2 года назад

I subscribe to all the most popular RV channels and love them all. Your channel is by far the most informative for RV mods, updates, fixes, repairs, you name it. I have a long list of improvements, upgrades, fixes etc based on your experiences. And the quality production of your channel and your presentation style is superb. Thank you for all the effort you put into it, Jared. Have a blessed Christmas.

@AllAboutRVs 2 года назад

Thank you that is very kind, Merry Christmas!

@williamfry6087 2 года назад

This video convinced me to install a similar switch last year. I installed it between the 2 6 volt batteries on the jumper cable, so it shuts off all power. Great peace of mind that all power is now off for storage and safety.

@HomewardBoundRV 2 года назад

We appreciate all you do, Jared! Happy holidays to you and yours!

@AllAboutRVs 2 года назад

Thank you!

@madweazl 2 года назад

That's a clean install!

@theodoredekoninck5613 2 года назад

Installed one on my class A (kept killing the coach battery) works great easy to use and install.

@deansorgan 2 года назад

Absolutely a great video on something I wondered myself…why GD’s battery disconnect didn’t shut everything off in my 2021 340RDS. I wired in to my + side of battery a new disconnect like you but have yet to disconnect the OEM battery disconnect. Going to do that today!

@markaustin4370 2 года назад

I love your wiring!!! Nice and clean

@homesteadingusa 2 года назад

Great Info and very informative like always. Love all you do and share. Stay safe and Happy Holidays. Peace

@john0119 2 года назад

We used the 1st one you showed, and it failed. So I installed a A/C Disconnect (60 Amp Dummy Breaker) and it works great. Put a little lock on it. My parasite draw was the CO/Propane Detector.

@housesOTR 2 года назад

Had the same problem in my Imagine. When I put in my lithium batteries I installed a new one which cut ALL the power off. Good video and merry Christmas.

@glamphiker 2 года назад

I bought the three-way switch for two batteries, so I could only use one at a time. Not for my RV but rather on my inflatable boat with a trolling motor. Works great.

@kilcranp 2 года назад

Great switch, I use the same one on my TT out at the batteries.

@jeremyolson2593 2 года назад

Most large equipment and semi trucks put the disconnect on the negative side. The service techs have told us that the disconnects last longer. Especially if you are running them off at the end of the day, every day.

@markaustin4370 2 года назад

Always great info!!!

@robertowens8108 2 года назад

Jared, thank you so much for the information. Just ordered the batteries, what a smoken hot deal. Be safe and keep up the great videos.

@AllAboutRVs 2 года назад

Glad you were able to catch the deal! Enjoy!

@charlesyoungblood7561 2 года назад

Great idea, love your explanations, and ordered one today. My wife and I met you and your wife at Creekfire in Savannah and think about that brief encounter often.

@AllAboutRVs 2 года назад

Thanks yes I remember meeting you when we were on our walk! Hope you both are doing well!

@jarodsnyder1698 2 года назад

for smaller rigs, I recommend a resettable DC breaker as a battery disconnect. it just adds an extra layer of short circuit protection. I typically install them right on the side of the battery box as they are waterproof and provide the most protection the closer the yare to the battery. these keys suck I just recently diagnosed an intermittent power loss to a failing one of those.

@MrJello4 2 года назад

Jared - Great video, I did the same thing on my RV

@willymueller4587 2 года назад

So true, we have a Reflection Fifth, & I have accidentally turned that switch off inadvertently, not realizing, and in ours lights on other side of pass through still work with switch off, good video thanks

@captainskippy6622 2 года назад

Same here for our Reflection 320MKS 5er.

@Wb8wfk 2 года назад

I had the same problem. Replacing it fixed it.

@DavidHBurkart 2 года назад

Thanks Jared, appreciate the heads-up!

@AllAboutRVs 2 года назад

Thanks David!

@XLSLife Год назад

I learned the "exciting" way that my battery disconnect didn't actually cut DC power to everything. I got some nice sparks when replacing my battery with a 200AH Renogy when I connected the second battery lead. Thankfully didn't hurt anything but certainly gave me a surprise. I've been thinking about replacing and rewiring mine as well so it actually disconnects the battery if I'm working on the electrical system or something.

@RickandDarcirvadventures 2 года назад

We really appreciate your videos

@AllAboutRVs 2 года назад

Thank you.

@Joker45678 2 года назад

I have a switch like your first one. It is in a good location though. I had trouble with my battery not charging back up through the converter. I turned that switch on and off a couple of times and got the voltage back to 13.4v going to the battery. I didn't replace it, and just remember to do that if I have problems in the future. I'll probably replace it with that other style later on.

@s.mendez7160 3 месяца назад

Great production. If your running LFP batteries, ANL fuses will not handle the instantaneous short circuit current a stack of LFP batteries could deliver if there was a short. You risk having the fuse melt into itself, thus, a welded piece of metal, and fully conducting current. Think major fire as the insulation melts off the cable. For LFP designs, use a Class-T fuse like you have in series with your inverter. A simple tip from an Electrical Engineer.

@joefriday950 2 года назад

Great video. Thanks

@fyter889 2 года назад

Thanks for this video, wife and I just bought a 5th wheel last fall and have not picked it up out of winter storage yet, I was curious about battery charging and brakes if battery switch was off. Thank you for clarifying this question.

@MitchOfCanada 2 года назад

Trailer running brakes do not use trailer battery, they use trailer controller 12v from the vehicle. Battery is required for Emergency Disconnect when detached from Vehicle to activate the brakes.

@brucemontgomery8136 2 года назад

always well produced videos

@AllAboutRVs 2 года назад

Thank you

@mikebrooks6126 2 года назад

Another great video Jared good job As others have commented below just be aware that by changing the configuration of the 12VDC switching you are also now turning off things like electric brake disconnect function, and your carbon monoxide detector. Not a big deal when the unit is in storage but for everyday use some of these safety systems need to be left powered up. For the experienced user having the ability to cut power to the entire coach without cutting power from the battery bank is handy, but for the casual or inexperienced user this could lead to problems. Anyway, keep up the good work on the videos and take care.

@AllAboutRVs 2 года назад

Thanks Mike!

@northernredneck9997 2 года назад

Thank you for clarifying that the negative should be disconnected 1st and why. As a firefighter I've argued this many times After working accident scenes and even so called mechanics don't understand why.

@AllAboutRVs 2 года назад

Thanks

@ericpeysar2593 Год назад

Yes thank you for the explanation. It happens. Years ago i did this exact mistake on my 24 volt Toyota Landcruiser. I went to disconnect the positive side first and my wrench slipped. The wrench contacted the body frame and welded itself to the frame. I was very lucky that there was no permanent damage to me or my truck. It easily could have gone the other way.

@Demoguy87 3 месяца назад

You guys are wrong. You always disconnect positive first. Please stop spreading fake news

@TimsWorkshopTJY 2 года назад

We are on hookup at our storage unit so the batteries are trickle charged. We have the nob old style switch which is very strong. My boat has one too but it's one to switch between batteries, run both or just shut off. Marine quality too to prevent corrosion.

@AllAboutRVs 2 года назад

Marine is a great way to go.

@jgazaway4944 2 года назад

Jared, thank you so much for the information you put out. During the video I saw a quick look of your solar system. I want to start adding solar to my fifth wheel. Can you please tell me where I can access of the schematics of your solar system and how it ties into the rv electrical system.

@herb7877 2 года назад

Agree 110% with replacement of that type of switch. I think I may have gone even one step simpler or more (?). I wired a 30 amp in an inline blade fuse right off the battery. I remove it when storing and replace it as I am hooking up. It stays in while we are using the tt. I keep extras in the truck & trailer. Adds about 10 seconds to hookup. Before doing this I found that my batteries were slowly discharging when just the switch was turned off. I found out that the CO detector is wired around the switch and always working as a fail safe.

@AllAboutRVs 2 года назад

Thanks

@washingtonarias4476 Год назад

Great information I have a 600 amp hours power power bank which which do you recommend

@JonathanBritt1 2 года назад

Yep. I have turned off my power in my 27bsb jayco feather a few times taking while taking out supplies.

@AllAboutRVs 2 года назад

Happens to the best of us.

@ShortyzProductionz Год назад

Sounds like you had the same issue I did with my RV. The disconnect was way away from the battery. It only turned off about 1/3 of things... not sure the point if it didn’t turn everything off. So I relocated the switch to the battery. Was able to shorten the longest wire that fed the back by 3’ (hopefully help with power drop) and now it’s a true disconnect

@PierreMichael2020 Год назад

Hi Jared, as always, great video. Does the switch need to be rated much higher amp than the total battery amp, for example the box rating show 275 A continuous at DC 12V, 455 A. Does that mean it's good for a battery bank of 400amp? thanks much.

@brisonpalmer6730 2 года назад

Jared have a question do you have to have your battery disconnect on when you are using shore power to the camper and jack systems?

@cpwatching5647 2 года назад

Good video and content. Sounds like experience talking when using a wrench on a positive terminal and hitting the frame. I've never done that either..:-) Take care.

@AllAboutRVs 2 года назад

;-)

@bretvanzanten 2 года назад

I figured to have the disconnect switch on the negative, which is what I did with this same disconnect this spring. I figured this because as you mentioned you always take the negative cable off first. How come you put it in the positive instead of the negative?

@cloudsintheozarksoutdoors9538 2 года назад

This just happened to me. Switch in the storage bay got bumped to the off position while moving boxes around and I didn't know it. Went to turn on the front cap light and it wouldn't come on. I checked the battery voltage and it was dead at 2.5 volts. I checked fuses, check the converter, traced wires, and BOOM it hit me. CHECK the battery disconnect switch. That's it problem solved. I will invest in a switch like the one you show in this video.

@niteshranjanjha4540 11 месяцев назад

ur switch was detected. it's works awesome on my suv

@Humble-Engine Год назад

Question 2023 grand design 247bh. When I use the battery disconnect in the off position does the onboard solar panel and controller , continue to charge the rv battery? Do recommend two weeks storage for example, putting the battery disconnect in the off position even though there is an onboard solar system (mppt ,165w panel going to a sealed battery) always active. Thanks for the help.

@douglassnyder9612 11 месяцев назад

I have two battery disconnects in the storage bay... I bumped one when loading up on travel day and it came out (kinda spring loaded). Found it, replaced to on position and now no dc inside the rv unless connect to shore power of using the generator. Wondering if the disconnect got damaged or maybe a mystery breaker nearby... Still loving my toolbox BTW.

@Jbird3d 7 месяцев назад

I use two of those switches you don’t like because they only allow you to remove the key in the off position and this makes sure we keep our two battery banks completely separate. I can only turn one on at a time unless I break out key number two.

@StormyLong Год назад

thank you

@ptwob267 2 года назад

Jared, what did you do with the connections to the old battery switch? Ours is the same with only partial power removed with the battery cutoff. How do you determine where that wiring is going and how it’s getting to the battery and the power distribution panel?

@cuisinartOH1 2 года назад

Since you use Victron equipment, I would have suggested you buy a 65 amp Smart Battery Protect. Then you can use a small switch to trigger the relay in the disconnect and connect that switch with small gauge wires. It also allows you to disconnect via Victron Connect AND trigger a voltage threshold upon which it will disconnect itself automatically.

@AllAboutRVs 2 года назад

Yes victron does have a great solution for that but with being full time we rarely disconnect the battery and the price is hard to beat on this switch.

@Type1Detour 2 года назад

I have accidentally knocked out the battery disconnect in the basement area so many times. It is exactly where we put our totes with the kids; toys and the lids have knocked the key out multiple times.

@TimsWorkshopTJY 2 месяца назад

We just got a newer RV and trying to figure out why my batteries keep draining while hooked up to shore power. I have the battery disconnect turned on because if I don't my iN-command system doesn't work which runs the lights and the slides. I like having the night led lights on but there again if I disconnect the battery switch, I can't turn them on. I checked the Converter today because I keep draining the batteries at night. The Converter is working and getting 13.5v out but I think there is another hidden switch somewhere before the batteries? Will dive into it tomorrow and hopefully figure it out. It's a 2021 Keystone Cougar Half Ton with solar and a inverter as well.

@bradxoxo8269 17 дней назад

Do the two 3/8 terminals on the inside heat up while charging? Mine do so I'm switching to something else.

@digitalmediasvcs1 2 года назад

Perhaps a better title for the video would be "Why I REPLACED the Battery Disconnect Switch" It was a little confusing as to why you would remove a safety device, until you clarified at 2:36. Less liability in case someone does not watch the whole video.

@ScarmackProductions Год назад

It's called clickbait

@01AceAlpha 2 года назад

Could just use a butterfly nut on the initial battery connection.

@Woodyone1962 2 года назад

Good information! I knew my battery was still discharging after turning off the disconnect. Frustrating. While looking through the comments, I see you were at Creekfire! I thought that was you, but was not sure. Now I wish I said hello!

@AllAboutRVs 2 года назад

We love creekfire we went there 2 times this year. Once in the spring and once at the end of summer

@eunantog 2 года назад

there is a note in my RV that states that the power should be off while traveling to prevent shorts from actuating slides and such. I would almost suggest just adding a second disconnect switch to accomplish what you are trying to do.

@josephhartman2343 2 года назад

If I have a master power switch in my class c do I need a disconnect switch? Getting lithium batteries installed by dealer and have inverter and solar. Store indoors and not for long periods so assume I can just shut off master power while in storage.

@kenrosa9253 4 месяца назад

I saw this video on replacing the battery disconnect switch and want to know if I can remove my disconnect switch on my Travel Trailer and replace it with the type you show in the video and if I do will it completely shut down power, unlike the stock one that came with the unit. I only have two six volt batteries and the stock converter that came with the unit. If I can't replace the current one with the type you show (because it will have the same effect as the stock one) do I just leave the stock one in its place and leave it on or off if I have to replace it with the type shown in the video.

@mickey-fm9rx 8 месяцев назад

What disconnect do you use between the batteries and the inverter?

@user-mu7vk8yx1y Год назад

Affordable and easy is replace terminal nuts with wingnuts and just disconnect positive cable at the battery.

@steveisenhower2864 2 года назад

Does your new setup also disconnect your battery monitor? Is that a problem?

@bishopgeorge1333 2 года назад

Okay, when you took off the factory disconnect how did you add that one you have now, I want to redo mines?

@mattkaminski6618 2 года назад

Great video! Is the shelf that your Lion Energy batteries are sitting on a custom shelf or is it available for purchase somewhere?

@AllAboutRVs 2 года назад

I just built it out of 3/8 plywood and 4 shelf supports and covered the wood in felt.

@rosemobley4978 2 года назад

Is there one of these in TT's. Ie never heard about this?

@oscar_stefanie_1998 2 года назад

What type of disconnect switch is used for the inverter?

@dougc78 2 года назад

Great informative video thanks for sharing. My wife and I are RV newbies looking to get our first RV and GD is on the top of our list (as are your videos). Is having an battery disconnect that only disconnects some loads but not all a common thing? It just doesn’t make sense to me. Kinda like turning off a light switch that only turns off one bulb and not all of them. And why did you put a separate disconnect on the inverter? Thanks

@s.mendez7160 3 месяца назад

We put a disconnect on the inverter in the event it needs to be troubleshot, there is no risk of AC voltage on the output, and shocking the person the person.

@umbrellarv 2 года назад

Which model is your Reflection?

@joecool5477 Год назад

We have a GD RV Also & we are interested in the solar system like yours, We currently have the GD basic solar prep, inverter is needed and we only have 2- lead acid batteries, any help much appreciated

@stevenpeppers835 2 года назад

i have hade my rv for two yrs now i have no problems with my roof yet but i think its time to recoat my roof with sealer whats the best way to do that ?

@rachelthegooserv1645 2 года назад

Will you post a video on how you did this. I would like to do this for mine. Your tutorial would be a great help. I like your how-to vids

@TheMinnow101 Год назад

His videos are almost always product reviews and rarely show how any these products are installed. Basically it’s an infomercial YT channel.

@brianbelliveau5551 2 года назад

I have a 2021 keystone and it’s doing the same thing it has a wiring box and the off an on battery switch is in that box and I’m have a problem with the brakes the dealer has the trailer in ft myers and are trying to fix it

@sandimcclary8174 Год назад

Where is the battery disconnect for the Geo Pro? I can't find a video that shows this anywhere!

@funnnyfarm1 2 года назад

It looks like you stuck your finger where you shouldn’t. Have a great Christmas. Al

@peterlongton7507 2 года назад

Hi Jared, What do you do with the original wiring that the old switch was attached to? I’m in process of getting ready to install my Multi2 and realized in needed to do something there. Do you remove the original bus bars to the new ones? Thanks 🙏 for a quick response Pete

@AllAboutRVs 2 года назад

I left the original bus bars and just had a connection from our new bus bar system over to the original.

@rodneyalberta2020 Год назад

why melt if hook up to negative

@dalegigstead8337 2 года назад

I noticed the pic of your storage bay there wasn't any insulation on the ceiling. Any thoughts of doing it?

@AllAboutRVs 2 года назад

No it’s a heated bay so the other side of the ceiling of the storage is the main bedroom. So it’s all the same conditioned space.

@RandyK1ng 2 года назад

That's crazy. Could it be that someone added additional circuitry after-market, going to the hot side of the disconnect? Of course, if you're the original owner, that seems wonky. It would be like popping the 100A main in your home and getting a full shock as you wired a new bathroom light. Eeek.

@thetechnician4941 Год назад

if it melts it means the disconnect is installed in the positive terminal, the disconnect should be on the negative terminal of the battery.

@dougm1985 2 года назад

i didn't read all the comments , so someone may have said this already. if you touch the frame when undoing the red (pos) with a metal wrench you will still spark , because you are shorting the battery to ground. just need to be careful.

@Baileywandering Год назад

Where can I find a guy to do all this for me? 😊 I'd even keep him.

@glenkyle2883 2 года назад

Yep all the new ones don’t turn off the power to everything ran into the same problem so we retired it

@caseypries7559 2 года назад

Not sure I see any reason to have two disconnects. I've got one, 600amp blue sea switch that kills everything.

@greggfischer1378 2 года назад

I had a boat and the switch for the batteries used a switch with 1 batt.or Batt 2 or both batt. ( it was a two batt sys ) or off. Seems to me a lot of options to have it ant way you want.

@AllAboutRVs 2 года назад

Good point

@loveu2222 2 года назад

That switch was good in a 50s.....now day's we can have a remotely operating relay

@DavidLaFerney 2 года назад

That’s true of course, but less complexity = greater reliability in most cases. For luxury items it might not matter much, but for core functionality it does. My Airstream came with a disconnect relay, but had it been my choice I would have gone with a manual (keyed) disconnect. That’s just me though.

@mrzif0013 2 года назад

will this switch disconnect battery #1 and battery #2 and run both?

@AllAboutRVs 2 года назад

There are other switches that can do multiple battery banks but we just have one bank in our RV.

@josecamacho755 3 месяца назад

My rv lights on outside parking lights won't go off

@RoadDogMedia 2 года назад

With respect, I do believe your solution contravenes laws in some jurisdictions (such as here in Canada) in that it is able to shut off the breakaway braking if not left in the on position. Regardless of your diligence in only towing with it in the on position, I believe you are open to ticketing in my jurisdiction at least. And yes, I've had a Roadside inspection by police and they tested my breakaway switch.

@shiftfocus1 2 года назад

Interesting. May I ask which province you’re in? I added a disconnect switch to my TT and have it wired to cut power to everything.

@AllAboutRVs 2 года назад

I hear what you are saying but here is why this is how I prefer to wire it. I prefer to have the disconnect to include the brakes because I have seen 3 different times in the last couple years where the breakaway cable was accidentally pulled and started melting the wires. One case I had wire cutters close and cut the wires, the second I had to rip the wires out of my friends RV. If it had a disconnect I could have shut it off faster with less to repair. The third I wasn’t on site for and melted the wires and melted all the wires in the wire loom. When wires are smoking on the RV you want the fastest solution you can so there is less damage. Many RVers pull the battery cable off in storage, forgetting to re connect the battery would be the same as not flippling the switch, either way as long as it is connected the breakaway switch will work and roadside inspection will pass just the same. Along the same lines if the battery is dead the breakaway switch won't work, all in all it's up to the user to make sure the equipment is working.

@JS-ve1wt 2 года назад

😊

@krappinkamper7222 2 года назад

Does the battery disconnect need to be turned on for my trailer breaks to operate?

@luminousveiws 2 года назад

Here is my one disagreement with Jared. I say the batteries should ALWAYS be connected to the brakes. The consequences of not having brakes are too severe. For completeness: Normally the truck powers the brakes. Should a trailer come loose the 'break away cable's will set the brakes to be full on. And so the trailer stops, only if the trailer batteries are connected.

@AllAboutRVs 2 года назад

Yes they need to be connected for the breakaway switch to work. We always have our switch on for towing so it has battery. I prefer to have the disconnect to include the brakes because I have seen 3 different times in the last couple years where the breakaway cable was accidentally pulled and started melting the wires. One case I had wire cutters close and cut the wires the second I had to rip the wires out of my friends RV. If it had a disconnect I could have shut it off faster with less to repair. The third I wasn’t on site for and melted the wires and melted all the wires in the wire loom. When wires are smoking on the RV you want the fastest solution you can so there is less damage.

@joanmcerlean7158 2 года назад

One wonders why the manufacturer chose to design the system the way they did: installing it in an inconvenient/unprotected area and more importantly, installing something called a battery disconnect that doesn’t disconnect fully. Their choices were certainly not value-added to the customer.

@jajaj9205 2 года назад

So why didn't the flag style disconnect switch kill all the power to the system?

@flynryan3053 3 месяца назад

the original one probably did not disconnect the co2/propane sensor stuff, could always have two disconnects, one for all and one for all but important i guess?

@krisnordstrom924 2 года назад

if I use this disconnect will my solar panel still charge my battery?

@MitchOfCanada 2 года назад

depends where controller is connected, Before or after the BUS, direct to battery. The Disconnect usually does not take off the emergency brake controller or the slides/jacks. depends on how they wired it.

@jlebron6997 Год назад

So am I understanding correctly if my battery button is switched off, I have no trailer brakes?

@AllAboutRVs Год назад

Most RVs are wired so it will still function the break away switch for the brakes along with a few other items. That is why som many RVers disconnect the wires from the battery when in storage.

@jlebron6997 Год назад

@@AllAboutRVs thank you

@MitchOfCanada 2 года назад

the brakes are activated off a 12v line from the trucks brake controller. Batterys on trailer is key for if you become disconnected from the trailer the emergency pin can be pulled for brakes to be activated. Also if your 12v aux vehicle line is not connected to the trailers 12v system (needs to be disconnected for lithium setups usually) You wont have boosted power to say do leveling jacks or slide outs.f A true disconnect to battery should be on the Negative side. Like you said disconnect negative before you work on the unit, not the positive.