library(dplyr)
library(DBI)
library(RPostgres)
library(tibble)

conn <- dbConnect(RPostgres::Postgres(),
  host = url$host,
  port = url$port,
  dbname = url$dbname,
  user = url$user,
  password = url$password
)

test <- tibble(
  words = c("hallo","ja", "nein"),
  value = c(3,4,5),
  time= as.POSIXct(c("2016-05-04 04:32","2016-06-02 09:37","2016-07-12 10:43")))
test2 <- tibble(
  words = c("hallo","ja", "nein"),
  value = c(3,4,5),
  time= c("2016-05-04 04:32","2016-06-02 09:37","2016-07-12 10:43"))

dbWriteTable(conn = conn, name = "words", value = test)
> Error in eval(substitute(expr), envir, enclos) :
> ERROR:  invalid input syntax for type real: "2016-05-04 04:32:00"
> CONTEXT:  COPY words, line 1, column time: "2016-05-04 04:32:00"

dbWriteTable(conn = conn, name = "words2", value = test2)
> [1] TRUE

library(dplyr)
library(DBI)
library(RPostgreSQL)
library(tibble)

#connect to db
url <- list(user="postgres",password="postgres",dbname="test")

conn <- dbConnect(drv="PostgreSQL", user=url$user, password=url$password, dbname = url$dbname)


test <- tibble(
  words = c("hallo","ja", "nein"),
  value = c(3,4,5),
  time= as.POSIXct(c("2016-05-04 04:32","2016-06-02 09:37","2016-07-12 10:43")))
test2 <- tibble(
  words = c("hallo","ja", "nein"),
  value = c(3,4,5),
  time= c("2016-05-04 04:32","2016-06-02 09:37","2016-07-12 010:43"))


dbWriteTable(conn = conn, name = "words", value = test)

dbWriteTable(conn = conn, name = "words2", value = test2)

dbDisconnect(conn)