I have unlimited Tesla modules...could use help designing a RV system

[Dzl]

You mentioned, "I would like 3 outlet plugs (50amp RV plug, 30amp RV plug, 20 amp standard house plug).". In order to supply all outputs simultaneous at their rated loads you would need an inverter(s) capable of supplying 100A + 25% wiggle-room at 110V or 13,750W. That is a very, very big power demand, but let's roll with it...

Cables above 250A start getting very big, and very expensive, very quickly. 250A at 48V (nominal) only gets you to 12,000W so, unless you want to go up to 96V (niche) then you're looking at at least two inverters sharing the load. 24V (nominal) is, imho, simply not an option for this application.

@tictag I can't speak for OP but I can give you some context as to things in North America. "50A" 30A" and "20A" in the context of RV's in America refer to the three standard 'services' at RV parks / campgrounds, and each has its own distinct plug

20 Amp​	30 Amp​	50A​
120V	120V	240V (split phase)
2,400W	3,600W	12,000W

In my limited experienced, RV'ers often use these terms to refer to plug type + ballpark power level, as opposed to specific current or power requirements.

I suspect OP wants all three plug types for versatility but will not be using more than one at a time, but this is just speculation.

But still 12kw / 240v, is still a tall order (~275A from the batteries @ 48v)

OP: You can use adapters for the various plug types, might simplify things a bit.

 

[tictag]

Don't do it unless you are prepared to extinguish a serious fire with lots of water.

You can't extinguish a lithium fire with water, in fact, that's the last thing you should do as lithium reacts exothermic-ally with water. There is no putting out a lithium-ion fire until the energy within the cells has been destroyed/converted (i.e. to heat!).

 

[Dzl]

You can't extinguish a lithium fire with water, in fact, that's the last thing you should do as lithium reacts exothermic-ally with water. There is no putting out a lithium-ion fire until the energy within the cells has been destroyed/converted (i.e. to heat!).

So best recourse would be what? Fire proof blanket or something?

 

[tictag]

I can give you some context as to things in North America. "50A" 30A" and "20A" in the context of RV's in America

Interesting, I had seen the one on the left before, but the middle and right sockets are new to me. Thanks for the heads up! I suppose we do have something at least similar but for RVs (motorhomes, in the UK) we just have one type:



They are usually rated for 16A so 3,680W at 230V. The connector itself, no matter where it is fitted, is IP44 'weather resistant', but not waterproof (as many caravanners will undoubtedly know! They tend to trip RCDs if left out in the rain too long).

 

[tictag]

So best recourse would be what? Fire proof blanket or something?

Typically all you can do is let it burn, I mean if the battery is small and portable you could attempt to move it onto some metal to avoid the 'china syndrome' (BigClive calls this his 'fire prevention pie dish' ) but doing so would be at extreme personal risk. You can use powder or CO₂ extinguishers to dowse the surrounding area, maybe limit the damage, but there's nothing you can do about the lithium fire itself. One of the many benefits of the LiFePO4 chemistry - very difficult to create a thermal runaway.

 

[tictag]

Hey, I'm not trying to scare here, all I'm saying is that you have to take care when using the 'explody' types of lithium-ion. Making sure you charge with good quality components and, of course, have a solid BMS, configured correctly, the risks are minimal. But, like everything in life, all you can do is minimise risk, nothing in life is 'risk-free'.

 

[Hedges]

So best recourse would be what? Fire proof blanket or something?

Sodium Chloride.
For a metal fire, pour table salt on it. Add more where hotspots appear.
Then flip it over with a spatula and do the same for other side.

I'm not kidding you. Salt melts, encapsulating the metal and excluding oxygen. It would take considerable effort to free the sodium and chlorine from each other.

But if these batteries contain their own oxidizer (which they must, right?) then this metal-fire extinguishing approach isn't likely to work.

Only solution probably is water. Lots of water. Shove it off a dock into the ocean.

 

[tictag]

Battery University has an interesting post about lithium fires.

 

[John Frum]

A power house at a safe distance from the living quarters is worth considering.

 

[tictag]

But if these batteries contain their own oxidizer (which they must, right?) then this metal-fire extinguishing approach isn't likely to work.

A 'lithium fire' isn't a 'fire' in the intuitive sense i.e. requires access to atmospheric oxygen in order to continue combustion. It's more of a chemical reaction between the battery's internal chemicals, an extremely exothermic chemical reaction. Like if you pour concentrated sulphuric acid into water, that reaction is extremely exothermic and doesn't require atmospheric oxygen in order to be so. And oxygen is only one chemical in the table of 'oxidisers' i.e. gives up its electron, or takes electrons, I can't remember which. Florine, for example, is a far more potent 'oxidiser'.

What I am saying is that removing atmospheric oxygen from a lithium 'fire' is not going to stop it 'burning'.

 

[Dzl]

A power house at a safe distance from the living quarters is worth considering.

Vastly safer than the usual van/skoolie arrangement of a powerhouse under the mattress :D

Joking aside, I have been considering ways to mitigate that risk. A semi-isolated compartment built of non-flammable materials, and some sort of heat tolerant insulation, like mineral wool, might be a step in that direction. An easy to reach master disconnect as well.

I believe @HaldorEE's approach is keep some welding gloves nearby and quick disconnects on the battery to try to chuck it out the back of the van if shit goes south ?

 

[HRTKD]

I didn't think Tesla made that many vehicles in total for there to be many available in any one wrecking yard.

Yes, but there's plenty of people with more money than brains.

 

[schmism]

I didn't think Tesla made that many vehicles in total for there to be many available in any one wrecking yard.

as of Q2 2020 they have made 1.1 million cars. So yes even if a small fraction have been totaled, its a LOT of battery packs in salvage yards.

 

[Dzl]

as of Q2 2020 they have made 1.1 million cars. So yes even if a small fraction have been totaled, its a LOT of battery packs in salvage yards.

Wow didn't realize that many Tesla's were on the road. Do they sell internationally or US only?

 

[schmism]

Wow didn't realize that many Tesla's were on the road. Do they sell internationally or US only?

International with the china GIgafactory producing as of about a year ago, the german factory is being built. Of the above ~250K were international

 

[electric]

You can't extinguish a lithium fire with water, in fact, that's the last thing you should do as lithium reacts exothermic-ally with water. There is no putting out a lithium-ion fire until the energy within the cells has been destroyed/converted (i.e. to heat!).

This is false information commonly quoted around Internet. You are referring to metallic lithium, which does not exist in rechargeable lithium batteries, only lithium compounds exist there and they do not interact with water. Water absorbs the heat, thus reducing the temperature and stopping all reactions. The best way to extinguish battery fire is plenty of water, even Elon Musk stated this many times, if you believe the guy making these batteries.

 

[electric]

Typically all you can do is let it burn, I mean if the battery is small and portable you could attempt to move it onto some metal to avoid the 'china syndrome' (BigClive calls this his 'fire prevention pie dish' ) but doing so would be at extreme personal risk. You can use powder or CO₂ extinguishers to dowse the surrounding area, maybe limit the damage, but there's nothing you can do about the lithium fire itself. One of the many benefits of the LiFePO4 chemistry - very difficult to create a thermal runaway.

Very misleading, wrong and dangerous statement. Please do not contribute to spreading false information about such critically important topic. Please do a better research before making such statements.
Water is the best way to put out battery fire, but you need a lot of it. The best is to drop the battery into a bucket of water. The more water the better.

 

[electric]

Sodium Chloride.
For a metal fire, pour table salt on it. Add more where hotspots appear.
Then flip it over with a spatula and do the same for other side.

I'm not kidding you. Salt melts, encapsulating the metal and excluding oxygen. It would take considerable effort to free the sodium and chlorine from each other.

But if these batteries contain their own oxidizer (which they must, right?) then this metal-fire extinguishing approach isn't likely to work.

Only solution probably is water. Lots of water. Shove it off a dock into the ocean.

There is no lithium metal in these batteries. This is not a metal fire. Very common and dangerous misconception. Could cost someone their life. DO NOT USE SALT or any other dry powder extinguisher, they DO NOT WORK. Only lots and lots of water to reduce the temperature and stop the reaction.

 

[cory151]

Large water filled dunk is what's used at the factory.

 

[willo]

I used a tesla module in my build. Essentially you need a proper BMS for EACH module. That BMS must keep the cells balanced and you need a method of cutting off charge and discharge to the system. All charger sources must be programmable for the limits you want, and after that you should verify that they operate as expected.

You can check out my thread for details:

Finishing up my design for my 1200w RV build

Howdy, I bought a new 5th wheel camper to live in while I build my house. I've decided to add a 1200 watt solar system for the RV, using 12x 100w rich solar poly panels. ($80 each on amazon) I'm going to upgrade the battery pack to something with a lot more capacity later, but for now it'll be...

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