The , branded "DENCHA" (Dual Energy Charge Train), is a two-car bi-modal electric multiple unit (BEMU) train operated by Kyushu Railway Company (JR Kyushu) on inter-running services over the Fukuhoku Yutaka Line and Chikuhà  Main Line in Fukuoka Prefecture in northern Kyushu, Japan, since October 2016, and also on the Kashii Line.
The JNR KiHa 40 series, based on Diesel Multiple Unit (DMU), were run by JR Kyushu's non-electrified railway system areas of which, a section within city yet comparably short-distance's railtracks. JR Kyushu aimed to replace the KiHa 40 series which lead to the creation of the BEC 819 series. Chikuhà  Main Line (the Wakamatsu Line) were the first of the railines to implement this series. This was due to Chikuhà  Main Line being considered suitable in terms of "route length for battery capacity that could be installed for battery-powered operation," and also because the Kitakyushu City aims to become a "World Environmental Capital," leading to the introduction on the Wakamatsu Line, which runs within the city. The modified prototype cars, converted from the 817 seriesâÂÂthe world's first battery electric train operating under an AC electrification systemâ the train was produced as a practical, mass-production vehicle. Although the car body and passenger facilities are based on the 817-200 series, feedback from the 305 series cars have been incorporated.
In November, 2014 (Heisei Year 26), JR Kyushu publically announced placing BEC 819 series into service.
On 29 January 2016 (Heisei Year 28), they announced details. The task of cars's paint and interior designs were going to be handled by Eiji Mitooka (æ°´æ¸岡éÂÂæ²»), who which were responsible for many JR Kyushu trains. (see #Design)
On 24 May 2017 (Heisei Year 29), they received the 60th Blue Ribbon Award from the Japanese Railfan club (éÂÂéÂÂÃ¥ÂÂã®ä¼Â).
As a derivative variant, East Japan Railway Company (JR East) introduced the EV-E801 series, based on thus series with adaptation for cold and snow resistance.
From 2012 (Heisei Year 24) to 2013 (Heisei Year 25), there were testing conducted on a modified 817-1000 series train and the following were identified:
Whilst resolving the issues, the designing of this series begain, and running tests were carried out with pre-production mass-produced vehicles.
Based on the earlier 817 series electric multiple unit (EMU) trains, styling of the trains was overseen by industrial designer Eiji Mitooka.
The lithium-ion battery system used has a capacity of 360 kWh and operates at 1,598 V.
The BEC819 series trains are used on through services over the Fukuhoku Yutaka Line electrified at 20 kV 60 Hz AC and the non-electrified Chikuhà  Main Line (known as the "Wakamatsu Line") between and .
Since late 2018/early 2019, they are also used on the non-electrified Kashii Line.
These newer vehicles used on the Kashii Line belong to the "300" series (11 trainsets in total), while the slightly older ones used on the Wakamatsu Line are the "0" series (7 trainsets in total).
, the fleet consists of eighteen two-car sets formed as follows, with one motorised ("Mc") car and one non-powered trailer ("TC") car.
Internally, LED lighting is used throughout.
Initial details of the new train were formally announced by JR Kyushu on 29 January 2016. A pre-series two-car train was delivered from Hitachi's factory in Yamaguchi Prefecture in April 2016. This underwent testing before entering revenue-earning service on 19 October 2016. In May 2017, the BEC819 series was awarded the 2017 Blue Ribbon Award, presented annually by the Japan Railfan Club.
The individual build histories of the fleet are as follows.