120 to 240V step-up transformer?

[johnr]

I wonder if hauling around a small step-up transformer would make it possible to charge at level 2 rate from 30-amp service (120V). The upgraded rev2 EVSE draws 16 amps at 240V, so using a transformer would double it to 32 amps at 120V. Unfortunately, that's a bit more than 30 amps so it might risk popping the breaker. But it would be enticing to be able to use the 30 amp TT-30 receptacles so common at RV parks.

http://welectronics.com/TRANSFORMERS/THG-4000watts.shtml

 

[TangoKilo]

45 pounds....

 

[TomT]

All other considerations aside, finding a 30 amp 120 volt outlet is not going to be an easy task...

I wonder if hauling around a small step-up transformer would make it possible to charge at level 2 rate from 30-amp service (120V). The upgraded rev2 EVSE draws 16 amps at 240V, so using a transformer would double it to 32 amps at 120V. Unfortunately, that's a bit more than 30 amps so it might risk popping the breaker. But it would be enticing to be able to use the 30 amp TT-30 receptacles so common at RV parks.

 

[LEAFer]

All other considerations aside, finding a 30 amp 120 volt outlet is not going to be an easy task...

Just about all campgrounds ! with a 30-amp service TT-30 receptacle

 

[TomT]

Sorry, I've never been to a camp ground... I was referring to commercial or residential situations...

All other considerations aside, finding a 30 amp 120 volt outlet is not going to be an easy task...

Just about all campgrounds ! with a 30-amp service TT-30 receptacle

 

[smkettner]

If you have an evse that limits you to 12a 240v you would be good to go.
I would not carry it just in case. Only if a definate need was anticipated.

 

[tps]

Rather than a step-up transformer, why not consider a 120 - 120 isolation transformer at half the wattage and hook the secondary winding in series with the incoming 120V to provide 240V... This way you could get away with a 2KVA isolation transformer as opposed to a 4KVA step-up.

 

[TomT]

What is known as a buck-boost arrangement. It's very common in mechanical voltage regulators...

Rather than a step-up transformer, why not consider a 120 - 120 isolation transformer at half the wattage and hook the secondary winding in series with the incoming 120V to provide 240V... This way you could get away with a 2KVA isolation transformer as opposed to a 4KVA step-up.

 

[muus]

Rather than a step-up transformer, why not consider a 120 - 120 isolation transformer at half the wattage and hook the secondary winding in series with the incoming 120V to provide 240V... This way you could get away with a 2KVA isolation transformer as opposed to a 4KVA step-up.

Interesting. Do you know where one could purchase such a thing? Would it really be cheaper that what the OP suggested at about $100.

This would be very useful in combination with an upgraded Panasonic EVSE (version 1)

 

[garygid]

Using the transformer would give you 240v, but the Mod-L1 (12 amp) EVSE would need to draw 2 x 12 = 24 amps (plus a bit to heat the transformer) from the 120v circuit, which is generally not available in homes.
However, TT-socket 30-amp 120v could be available at RV parks.

So, this transformer would seem to have limited usefulness.

 

[planet4ever]

Using the transformer would give you 240v, but the Mod-L1 (12 amp) EVSE would need to draw 2 x 12 = 24 amps (plus a bit to heat the transformer) from the 120v circuit, which is generally not available in homes.
However, TT-socket 30-amp 120v could be available at RV parks.

So, this transformer would seem to have limited usefulness.

i.e. limited to the 13,000 RV parks in the US. How many 240v charging stations are there in the country?

Ray

 

[TEG]

Using the transformer would give you 240v, but the Mod-L1 (12 amp) EVSE would need to draw 2 x 12 = 24 amps (plus a bit to heat the transformer) from the 120v circuit, which is generally not available in homes.
However, TT-socket 30-amp 120v could be available at RV parks.

So, this transformer would seem to have limited usefulness.

i.e. limited to the 13,000 RV parks in the US. How many 240v charging stations are there in the country?

Ray

Many (most?) of the campgrounds & RV parks which have 30A TT30 120V also have 50A NEMA14-50 240V.
So, lugging around a big step up transformer would be a waste of time for many locations.

(It is my understanding that 50A/NEMA14-50 is common on west coast campgrounds, but no so much on the east for some reason... So maybe there are some places where it would be useful.)

 

[garygid]

240v "stations" ... well, how many houses are there?
Apparently about 70 million single-family detached homes.

Assume at least half have 240v dryer sockets.
Most of the rest have 2 phases of 120v, to "make" 240v fairly easily.

So, 60,000,000 is a lot more than perhaps 5,000 120v-only RV Parks.

If one wanted to facilitate EV progress, standards to make it EASY to use the existing electrical network would be in place.

If one wanted to smother/slow the EV revolution, the "standards" would require adding $2000 charging docks and "prohibit" using existing 240v circuits, with overwhelming paperwork and permits ...
Oh, My! That's what we seem to have, right?

 

[planet4ever]

Plugshare notwthstanding, it is unfair to include private homes when considering charging opportunities while traveling. I haven't been using RV parks for several years, and things may have changed, but my experience was that virtually all private RV parks had TT-30 outlets at every space. In stark contrast, a large majority of the parks had 50A outlets only at pull-through spaces, if they had pull-through spaces, which many didn't have. Pull-through spaces require twice as many roads, which reduces the number of spaces per acre.

Incidentally, I excluded RV campgrounds on public land (parks, forests, monuments) in my 13,000 number because my experience at those was that they usually had only 15 or 20A power. I was never sure which, because there were no breakers at the individual campsites.

Ray

 

[garygid]

I agree, and 30A 120v to 15A 240v transformer/trick to allow 12A 240V ("10-hour") charging is quite useful.