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How to replace the 12V battery in a Hyundai Ioniq Electric (& also 12V battery issues)

How to replace the 12V battery in a Hyundai Ioniq Electric (& also 12V battery issues)

Video by Go Green Autos via YouTube

A dead or partially drained 12V battery is a fairly common issue on the Hyundai Ioniq Electric, on both the 28kWh and 38kWh versions. However, after owning these vehicles over the last 4 years, I have never personally experienced any 12V battery issues myself, until last week. For the first time, our Ioniq 12V battery went flat and the car wouldn’t start.
As we already had a BM2 bluetooth 12V battery monitor fitted, we did get prior warning that the battery was draining, so for the previous two days we were monitoring it. So on the morning that it was flat and the car wouldn’t start, it didn’t come as a surprise and we were prepared and had the car running within a couple of minutes with a jump pack.
In this video I go through how to fit a new 12V battery in a Hyundai Ioniq Electric and explain the battery drain issues we were experiencing.

The Ioniq Electric uses a 12V 350A CCA 40Ah battery. The size is 054H. Suitable replacements are:
Exide EA406 (as shown in this video)
Yuasa YBX5056
Varta A13
Exide W054TE
Bosch S4 030
The Yuasa YBX3056 also fits, but at only 36Ah capacity, it would be better to get the YBX5056.
It is possible to fit a larger battery if you modify the battery tray, see

BM2 bluetooth battery monitor

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00:00 Intro
00:39 What does the 12V battery do?
01:16 No previous issues
01:32 BM2 battery monitor showing the battery drain
06:40 Jump pack to start it
07:04 New 12V battery
08:26 Tools required
08:58 Battery replacement instructions
14:25 Testing original & new batteries
17:43 Installing new battery
19:47 Why was it discharging?
21:10 Outro

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