D
Deleted member 2439
Guest
Hi all,
I thought that you might be interested in seeing this quite informative reply from InstaVolt, who I contacted yesterday regarding slow charging at two of their rapid chargers. The rates were 21 & 29kW, which were undertaken yesterday with a battery which was approx 25% full - however at an ambient temp of roughly 3 degrees C. Quite a useful reply I thought & I hope you find it useful. For context, the car had done a run of roughly 25 miles before the first charge, followed by a similar distance directly onto the second charge which was a bit faster. I’d add that both charges were fairly short, perhaps 15 mins or so.
thanks - Rob
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I have been passed your details by my colleague in relation to charging speeds you have received at our stations.
The majority of our stations are rated to a max output of 50Kw which we regularly see, including on the MG. However the charging speed is, in the main, determined by the car and there can be lots of factors involved in this. During cold weather the charging rate will be reduced as a cold battery doesn’t charge as fast as a warm one, however excessive heat can also cause the charging speed to be reduced. So if the weather was cold when you arrived at the charger and the battery hadn’t been sufficiently warmed during a long journey the car will reduce the charging speed.
In essence the car controls the charge, not the charger unless there is an issue, and it does this to protect the battery. The recommendation for DC rapid charging is to arrive with approx. 20% and charge to approx. 80% and complete the additional 20% using a home charger. This is due to the car considerably slowing the DC charge after 80% and the last 20% will take an excessive amount of time.
A good way of thinking about rapid charging is filling a water bottle, the main part of the bottle can take a lot water very fast but when it narrows to the neck of the bottle, unless you turn the pressure down, the water will squirt out of the top. This is the same analogy as rapid charging, hence why the speed is reduced to protect the battery and not input too much energy towards the end of the charge.
The car does everything to protect the battery and this is why we see a fluctuation in charging speeds. We don’t often see full output if the battery and environmental conditions aren’t exactly right and unfortunately a lot of manufacturers don’t tell you this when purchasing an EV. I have a Nissan Leaf and the charging speed varies significantly depending on weather, temperature etc and also slows down if it has been rapid charged more than twice in the same day, so every vehicle has different quirks to how it charges
I thought that you might be interested in seeing this quite informative reply from InstaVolt, who I contacted yesterday regarding slow charging at two of their rapid chargers. The rates were 21 & 29kW, which were undertaken yesterday with a battery which was approx 25% full - however at an ambient temp of roughly 3 degrees C. Quite a useful reply I thought & I hope you find it useful. For context, the car had done a run of roughly 25 miles before the first charge, followed by a similar distance directly onto the second charge which was a bit faster. I’d add that both charges were fairly short, perhaps 15 mins or so.
thanks - Rob
==========================================================
I have been passed your details by my colleague in relation to charging speeds you have received at our stations.
The majority of our stations are rated to a max output of 50Kw which we regularly see, including on the MG. However the charging speed is, in the main, determined by the car and there can be lots of factors involved in this. During cold weather the charging rate will be reduced as a cold battery doesn’t charge as fast as a warm one, however excessive heat can also cause the charging speed to be reduced. So if the weather was cold when you arrived at the charger and the battery hadn’t been sufficiently warmed during a long journey the car will reduce the charging speed.
In essence the car controls the charge, not the charger unless there is an issue, and it does this to protect the battery. The recommendation for DC rapid charging is to arrive with approx. 20% and charge to approx. 80% and complete the additional 20% using a home charger. This is due to the car considerably slowing the DC charge after 80% and the last 20% will take an excessive amount of time.
A good way of thinking about rapid charging is filling a water bottle, the main part of the bottle can take a lot water very fast but when it narrows to the neck of the bottle, unless you turn the pressure down, the water will squirt out of the top. This is the same analogy as rapid charging, hence why the speed is reduced to protect the battery and not input too much energy towards the end of the charge.
The car does everything to protect the battery and this is why we see a fluctuation in charging speeds. We don’t often see full output if the battery and environmental conditions aren’t exactly right and unfortunately a lot of manufacturers don’t tell you this when purchasing an EV. I have a Nissan Leaf and the charging speed varies significantly depending on weather, temperature etc and also slows down if it has been rapid charged more than twice in the same day, so every vehicle has different quirks to how it charges
