Believe I am done with lead acid batts, going 120 full time with a Tesla Powerwall

[ElvistheKing]

Originally Posted by tfryman

I don't know if you were mistyping or miscalculating, but your math makes no sense.

Ignoring power factor, a 1 watt is 1 amp at 1 volt regardless of AC or DC.

So:
"5Kw @ 120v is 42amps.
7Kw @ 12v is 58amps."

is really 120 x 42 = 5040 Watts (5 KW)
but 12 x 58 = 696 (.7 KW)
This is the Power being used.

There are other issues where I think you substituted the wrong unit in your equations or your units make no sense.

For example:
"312minutes @ 2.5Kw is 13kW"
When you include time in the equation you end up with Energy, so Power x time = Energy or KW-Hour (not kW).

Mistypes

Yer I assumed a power factor 1 (this is all back of the envelope stuff)
should read
7Kw @ 120v = 58 amps

and

312minues @ 2.5Kw is 13kWh


Won't let me edit it now!

[Boomertx]

Still want to hear how you intend to charge the Powerwall? Per the Powerwall specs it requires AC power to charge; so if using solar another separate inverter will still be required. Lots of dollars involved but still, if the spirit is willing

[ElvistheKing]

Originally Posted by trx430ex

The main goal on this is not to be an energy pig, but to have all the 120 volt AC appliances work "full time", just like all the 12 volt devices work right now,, "full time". Want to make a pot of coffee without turning on the generator or plugging in, just do it.

Originally Posted by Boomertx

Still want to hear how you intend to charge the Powerwall? Per the Powerwall specs it requires AC power to charge; so if using solar another separate inverter will still be required. Lots of dollars involved but still, if the spirit is willing

I'm guessing from the above quote he is planning to use either shore power or the generator to charge it............

[Boomertx]

I agree, but if hooked up to shore power there would be no need for a lithium/inverter which really is all a Powerwall is. Besides packaging I'm trying to understand what if anything "unique" a Powerwall brings into the equation, especially at its price point when compared to individual lithium batteries and inverter.

[ElvistheKing]

Well it is 1/2 the cost of the equivalent individual lithium batteries so there is that.

It must also include a pretty decent inverter too , how much do 5kW inverters cost?

And a 10 year warranty (if it covers RV use) too.

[radar]

Originally Posted by ElvistheKing

Well it is 1/2 the cost of the equivalent individual lithium batteries so there is that.

It must also include a pretty decent inverter too , how much do 5kW inverters cost?

And a 10 year warranty (if it covers RV use) too.

Yah, for the right coach integrator this is a no brainer.

I don't think the OP was trying to replace shore power, he is suggesting to replace the generator with a lithium inverter combination...the power wall. Just as he does no, he would charge the battery back (power wall) with shore power and then use it when dry camping like he would a generator. This makes total sense to me and I can see high end coach manufacturers integrating this soon. On a large coach a 2000 watt soar system is easy to install so a full day of sun will provide significant charge capacity.

NIssan has a system called "leaf to home" which allows leaf owners to connect their leaf to their home through an interface panel (which is really just a big inverter and sub panel). The cable goes from the DC fast charge port to the house. Both of our vehicles are electric vehicles. This kind of aftermarket product interests us from the point of view of having a large reserve capacity to power the house in the form of a car. In our house we know we can survive on 4 KW per day with some life style changes, this would provide about a week of emergency power for the house from a 30 KWH battery. I would imagine an RV could do the same although all bets off once the Air Conditioning is on.

[MRUSA14]

I doubt very much that the Powerwall warranty would cover RV use, as this is not what it was designed for. In addition, I read online that the Powerwall must be installed by a Tesla certified installer. I'm not sure you would find one of these for an RV installation. Of course it is possible that all this could be negotiated with Tesla if a large buyer (such as a major RV manufacturer) were involved, by I seriously doubt that Tesla will invest their time on individual RV tinkerers here and there.

The real potential would be if an RV manufacturer adopted this. If they promised Tesla volume sales, they could probably get a 12VDC/110VAC version manufactured. That would be an awesome improvement to what we have today.

The other way to go is just install 12V lithium battery banks in place of the existing lead-acid batteries. This seems a lot more straightforward since it would hook right up to all the existing coach wiring. For the many if not most of us who already have inverters, this would be a seamless installation: no coach mods or rewiring needed at all.

The advantages of lithium batteries are clear and well known and I think it is just a matter of time before they replace our lead-acid house batteries, but is much less clear that the powerwall is the answer for an RV. The lithium battery marketplace is rapidly evolving and changing so it hard to predict where it will go. Personally, I am hoping to see a turnkey battery replacement product that will allow you to simply remove your lead-acid batteries and substitute lithium batteries in their place.

[ElvistheKing]

Originally Posted by MRUSA14

I am hoping to see a turnkey battery replacement product that will allow you to simply remove your lead-acid batteries and substitute lithium batteries in their place.

They already exist, but they ain't cheap:

https://www.lithiumion-batteries.com...ries/sb260.php

About twice the cost as the Tesla kWh for kWh.

[Tony Lee]

I think we should invite trx430x to return at say 60 day intervals to let us know how he is progressing. Once he has thought it through a bit more he will be in a much better position to tell us what we have all been doing wrong for the last 100 years.

[radar]

Originally Posted by Tony Lee

I think we should invite trx430x to return at say 60 day intervals to let us know how he is progressing. Once he has thought it through a bit more he will be in a much better position to tell us what we have all been doing wrong for the last 100 years.

I don't think the OP's intention is to tell us what we have been doing wrong but rather to see if there is a better way by using current but evolving technology. If I was buying a new large A class I would be all over this idea. Both our vehicles are full electric with lithium batteries and for our lifestyle and driving needs the advantages of electric vehicles made possible by the battery tech he is referring to has been hugely advantageous. I can see how many of these advantages would transfer to the RV world in a number of ways.

JMHO

[09 harley]

For the price and complexity I don't think his change is coming very soon. Most people buy RV's based on price and this would be a killer to the bottom line. It's fine to get all hopped up about Tesla but before the manufacturers make a change like this they will want to see if the suppliers are really viable long term.
With China rapidly expanding battery capacity and set to exceed Tesla's production their new factory may be obsolete before it is completed. The sales of their high priced models has slowed and their ability to mass produce their new model is in question plus there have been cancelations also. Not to mention that there is soon to be a proliferation of competing models with more features and longer mileage before charging is needed. This is an interesting time but we need to look before we jump off the cliff.

[nothermark]

I think Tesla already has a version that charges with solar and replaces/augments what comes off the grid. That would be a better choice to start with. They also make battery banks for the cars so the know about vehicle requirements. That would leave me thinking that they could be something in the pipeline as one starts picking higher up the tree. Then all we have to do is wait for the first fire...

[radar]

Originally Posted by 09 harley

For the price and complexity I don't think his change is coming very soon. Most people buy RV's based on price and this would be a killer to the bottom line. It's fine to get all hopped up about Tesla but before the manufacturers make a change like this they will want to see if the suppliers are really viable long term.
With China rapidly expanding battery capacity and set to exceed Tesla's production their new factory may be obsolete before it is completed. The sales of their high priced models has slowed and their ability to mass produce their new model is in question plus there have been cancelations also. Not to mention that there is soon to be a proliferation of competing models with more features and longer mileage before charging is needed. This is an interesting time but we need to look before we jump off the cliff.

I would agree with most of this. I think it is doubtful that Tesla would fail in the short term though as they are the only big American technology company in the game. If they are allowed to fail they will find a home in a number of European countries pretty quick as Germany France and even Spain are enticing them with lots of offers. Many feel it would take the US out of the energy technology race. That's may be ok for smaller country economies but tougher for a major world economy. Right now the Saudies are buying up a huge amount of United States refinery technology and over the next three years expect to have full control of it. I think it would be a bad thing to lose control of or not be a player in the technology that will play a major role in transportation in the next 20 to 30 years.

[CountryFit]

funny thread... futuristic idea... op, a photo about your coach as an avatar like most of us having done would be great.

this refreshed my memory 20 years ago... on a forum for mercedes 126 chassis, the big long wheelbase sedans like 300sdl, 420sel... people were sharing information on maintenance and upgrade stuffs... one day a guy joined the talk. he was very active, with a bossy attitude, an elephant in a room figure normally appeared in western movies... but the more he talked, the more out of wack feeling accumulated. we started questioning him... at the end, he admitted that he was just out of high school; he saw his neighbor the old lady had a big mb 126 and felt very cool, so he jumped on the board. then we started to praise him, "you are special", "you are a character"... .

back to the topic - i have 120v 24/7, resulted from a big array of solar panels and a big lifepo4 pack. it's nothing wrong with onan genset and necessary for rainy days... we certainly welcome new members with fresh thinking! happy trails!