The Kia Soul EV has a real Achilles heel: the battery pack lacks active cooling and heating, which means degradation and longer charging times are the main concern with used examples. This thermal management is also missing in competing models from the same period. As a result, the battery is sensitive to extreme temperatures and intensive use. Want to know how to check this issue and which solutions are available?
How the Kia Soul EV battery pack works
The battery pack in the early Kia Soul EV, built up to 2018, has a gross capacity of 31 kWh with a usable capacity of 27 kWh. This delivers a realistic driving range of around 160 kilometres. Newer versions from 2018 onwards offer 33 kWh gross and 30 kWh usable, good for an NEDC range of up to 250 kilometres. The lack of thermal management means one thing: the battery has no system to regulate its temperature during fast charging or in extreme weather conditions. This can lead to faster wear when fast chargers are used frequently. Long periods of charging to 100% also speed up wear.
The Kia Soul EV, however, performs better than expected. Tests show that a 2020 model with 140,820 kilometres still retained 97% State of Health, i.e. the percentage of remaining battery capacity. At that point the pack still delivered 61.94 kWh net from the original 64 kWh. Kia batteries often stay close to 100% capacity over four years. This does depend on use and charging habits. Degradation does occur, but more slowly than with many other electric cars from the same period.
Checking battery degradation on the Kia Soul EV
The factory State of Health reading is inaccurate and is mainly used for warranty claims. For a reliable assessment you need an independent measurement. Have a State of Health (SoH) measurement and cell balance check carried out. This check shows the total percentage of capacity that remains. It also reveals any differences between individual cells in the battery pack. Large cell voltage differences point to early problems and can lead to faster degradation.
Thinking of buying a used Kia Soul EV? The mileage alone is not enough. It does not tell you the true condition of the battery. A car with low mileage can be more worn if it has been fast charged often or regularly charged to 100%. Always check the fault code history and have a diagnostic check done that shows how the battery has been used. Pay attention to the following:
- Intensive fast charging shortens the service life of the battery pack
- Charging to 100% regularly accelerates degradation
- Exposure to extreme temperatures without cooling speeds up wear
- Differences in voltage between battery cells (cell voltage differences) greater than 0.1 volt point to problems
Causes of range loss in the Kia Soul EV
There are several causes of range loss. The lack of active cooling has one consequence: under intensive use or at high outside temperatures, the battery gets warmer than is optimal. This speeds up the chemical processes in the cells, which leads to capacity loss. At low temperatures there is no heating system for the battery. As a result, range drops sharply in winter. Driving style also has a strong impact on range. Driving fast uses more energy. Speeds above 100 kilometres per hour increase consumption significantly.
Owners report that in winter they manage about 420 kilometres from a 64 kWh model, while in summer this can rise to 460 kilometres with calm driving. The early models with 27 kWh usable capacity therefore deliver considerably less. Make sure you do not drive faster than 100 kilometres per hour for optimum range. Also avoid frequent fast charging and do not always charge to 100% in order to minimise degradation.
Common charging issues and charging times
Charging times from an empty battery pack to 80% depend on the charging method. Using a domestic socket takes 14 to 15 hours. With a 6.6 kW AC wallbox this is reduced to 4 to 5 hours. Fast charging at 100 kW DC brings the battery to 80% in around 30 minutes. These are normal charging times that do not indicate problems. Degradation can affect these times, though. Reduced capacity means the battery can absorb less energy.
One common problem concerns the 12V battery, especially in models from 2019. This battery frequently gives low voltage warnings. These are alerts that the voltage is too low, often around 9.6 to 9.7 volts. This blocks functions such as Smart Cruise Control and the battery no longer charges while driving. Recharging helps temporarily. However, the battery often fails after 4.5 years or 61,000 kilometres. Owners report unpredictable discharging (inconsistent discharge). This happens even after long journeys when the battery should normally be charged.
Measure the 12V voltage regularly and replace the battery if the voltage drops below 10 volts. Choose a type that is compatible with the Kia Soul EV. Not every 12V battery is suitable for electric cars. The high-voltage battery pack itself requires little maintenance. Replace the coolant every 210,000 kilometres or 120 months and check the reduction gear oil every 120,000 kilometres in heavy use. Preventive replacement saves costs and prevents faults.
‘ Prioritise battery condition over visual inspection, because this determines the car’s reliability and future performance. ‘
Costs of replacing the battery in the Kia Soul EV
Replacing the entire battery pack is an expensive job. The price varies widely. The availability of parts determines the cost, as does the choice between a new or refurbished pack. Kia offers a battery warranty, usually 7 years or 150,000 kilometres. Capacity must not drop below 70% during this period. If the battery falls below this percentage within the warranty period, replacement is covered by the warranty. Outside the warranty, costs quickly run to several thousand euros.
Fortunately, a complete replacement is rarely necessary. Most Kia Soul EV models retain their capacity well, as shown by tests in which high-mileage examples still remain above 90% State of Health. When buying, check whether the warranty is still valid. Also request a battery diagnosis. This prevents surprises and gives insight into how long the battery will last. Prioritise battery condition over visual inspection, because this determines the car’s reliability and future performance.
Tips to limit battery degradation
There are several ways to extend the life of the battery. Avoid fast charging unless necessary. Fast charging puts extra strain on the cells due to high temperatures. Preferably charge to 80% instead of 100%. This is especially true if you will be using the car shortly afterwards. The last 20% takes more time. This final part also stresses the battery more. In extreme temperatures, try to park the car in the shade or in a garage to limit exposure to heat or cold.
Keep the state of charge between 20% and 80% for daily use. This helps the battery last longer and significantly extends its service life. Drive smoothly and anticipate traffic to reduce consumption. Aggressive acceleration and hard braking increase energy use and place unnecessary stress on the battery. Regularly measure the 12V voltage and replace this battery at the first signs of weakness to avoid problems with systems and functions.
When is a Kia Soul EV still a good choice?
The Kia Soul EV remains a reliable electric car. However, have the battery condition thoroughly checked before purchase. Tests show that many examples display little degradation, even with high mileage. The absence of active cooling is a disadvantage. But with normal use and careful charging habits, the battery remains in good condition for a long time. The car offers sufficient range for daily use and short trips, especially the newer versions with higher capacity.
For drivers who mainly cover short distances and have access to a home charger, the Kia Soul EV is a practical option. Running costs remain low. Do, however, check the coolant and reduction gear oil as a preventive measure. When buying, pay attention to the warranty and request a cell balance check. That way you can be sure you are not buying a car with hidden battery problems that will lead to high costs later on.
On the Carnews website you can find much more information about electric cars, battery issues and maintenance tips for different makes and models. Discover which electric car best suits your situation and which points deserve attention when buying and using one.
Frequently asked questions
Charge the battery as much as possible using slow (AC) charging and avoid excessive fast charging and prolonged driving or parking in extreme heat or cold, because the Soul EV has no active battery cooling. Keep the charging cycle mostly between about 20–80% and only charge to 100% just before a longer trip in order to limit degradation. Drive smoothly and avoid consistently driving (much) faster than 100 km/h to optimise both the range and the thermal load. Check and replace the 12V battery in good time, because a weak 12V battery can cause charging and starting problems and thus limit the usability of the high-voltage battery.
Common causes of battery degradation in the Kia Soul EV are the lack of active cooling/heating of the high-voltage battery pack, frequent fast charging, repeatedly charging to 100% and use in extreme temperatures. Charging problems mainly arise from a weak or defective 12V battery, which can discharge spontaneously and cause starting and charging warnings. An ageing 12V battery that is no longer properly recharged while driving can also cause charging problems. Intensive use (high mileage) in combination with the above factors further accelerates degradation.
Signals of battery degradation include a noticeably lower range than originally, battery percentages that drop faster and larger differences in cell voltages during an SoH measurement. Charging problems manifest themselves in slow or incomplete charging (AC or DC), more frequent recurring error messages while charging and interruptions in charging processes at certain charging stations. Another very common sign is a weak or discharging 12V battery (voltages around or below 10V), which can cause starting problems, warning lights and systems such as Smart Cruise Control to drop out. If in doubt, a professional SoH and cell balance measurement is the best way to objectively identify early degradation or charging problems.
Battery degradation gradually reduces the usable capacity of the traction battery, which means range decreases noticeably, especially in cold weather and at higher speeds. In the long term this means charging more often, smaller practical daily distances and less margin on longer trips. The car generally retains its driving performance (acceleration and top speed), but the energy management may become more conservative, for example by issuing warnings earlier or switching to an economy mode sooner. In the Kia Soul EV, degradation often remains limited in practice, but this strongly depends on charging behaviour, temperature and driving style.