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Wheelchair (Powerchair) Battery Sizes

Powered electric Wheelchairs come with a relatively few "standardised" battery case sizes. When talking about powerchair batteries "Group 27","Group 24", Group 34" and "Group 22NF" size batteries are often specified for each different model.  These are the four sizes most manufacturers use. Deep Cycle mobility batteries are available from many companies in these four sizes.

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At the bottom of this page is a table specifying the actual dimensions of these BCI Standard battery sizes.

We don't really need to know the actual sizes unless you are trying to fit a different battery size than your manufacturer specifies. Which is often possible!

My own powerchairs for e.g. originally used a group 34 battery of 56ah. (Amp Hour capacity) As specified by the manufacturer, Sunrise medical.

But knowing the actual dimensions of a group 34 battery allowed me to know a larger capacity group 24 battery would also fit.

How? Well that's easy! A group 34 is the same length, and the same width as a group 24 battery. Bit the group 24 battery is taller. 

So I just looked at the space above the batteries and decided that the taller group 24 ones would also fit.

Group 27 batteries are around the 90 to 105Ah capacity but much longer. And heavier. Making powerchairs too big for sensible indoor usage and very heavy. "Bounder Wheelchairs" use these in some powerchairs. And many off road all terrain and 4x4 outdoor powerchairs use them too.

Group 22 batteries are considerably smaller capacity (see table) and smaller sized physically too. In general group 22 batteries are good only for slow 4mph mostly indoor powerchairs and are limited in range. If you are serious about powerchairs absolutely avoid powerchairs that use these!

Group 34 batteries are typically 50Ah to 70Ah and are (or can be) almost as good for range as the taller group 24 batteries. And in certain cases better for heavy loads. A standard automotive starter battery size case with mounting lips at the bottom. Depending on actual battery chosen***.  These are generally good in all indoor / outdoor powerchairs up to 6 mph and often used where seat electronic riser mechanisms take the space that that the similarly sized footprint but taller Group 24 batteries needed. Some like the Odyssey batteries are exceptionally good.

Group 24 batteries are taller deep cycle case versions of the group 34 ones above. They are usually 70 to 75Ah and for most indoor / outdoor 6mph powerchairs are the only sensible option if Gel batteries are used.

*** I PERSONALLY use Group 34 Hawker Odyssey 68Ah AGM batteries in my home built powerchair (even though I designed it to take group 24 batteries) since they can make much more current (power) when used in extreme conditions off road/beach/snow etc than any group 24 Gel battery.   And the capacity is almost as high too.

And they also have equally as good a range as the bigger (taller) group 24 batteries due to a lower internal resistance value than Gel batteries that is typically half or even better...  So if you are currently using and limited to group 34 batteries take a look at the Odyssey PC1500DT battery! It can be charged in 1 hour too...

And if space is tight remember that these are the MAXIMUM permissible sizes for each "class" of battery in the chart below. So actual measurements cannot exceed this chart usually... But some batteries are notably smaller in one dimension or another. EG the Group 34 Optima Deep Cycle battery is shorter than the allowable 260mm,  And the Odyssey is bigger (longer).

BCI Group
+ Typical Ah (Amp Hour) Capacity of
Commonly Used Wheelchair Battery Sizes
Maximum Overall Measurements (inc. terminals)
Millimetres Inches
       Group 22NF  (35Ah to 50Ah) 240 140 227 9 7/16 5 1/2 8 15/16
       Group 34   (50Ah to 70Ah) 260 173 200 10 1/4 6 13/16 7 7/8
       Group 24   (65Ah to 75Ah) 260 173 225 10 1/4 6 13/16 8 7/8
       Group 27   (75Ah to 105Ah) 306 173 225 12 1/16 6 13/16 8 7/8

CAUTION - Having said all that, this Odyssey battery below is a D34 (Group 34) battery. But is about 14 mm (half inch) wider at the top than the table above says it should be!

Battery sizes are at best "nominal" values it seems... So it still pays to measure them.  This is because D34 batteries are an automotive size. They are the correct size at the bottom where it would fit into the battery tray in your car. But the top is less important. They also have a lip at the bottom for an automotive battery bolt on style clamp.

So in the case of D34 batteries especially it pays to read the specs specs for the actual battery you wish to buy. Most powerchairs will have room at the top for an extra 7mm length each side (14mm extra width) but some may not! So it pays to measure exactly.

This one below is actually the battery I prefer over all of the group 24 Gel batteries that most top end powerchairs come with. It handles big currents that I need without "sagging" and fast charging is much better/faster. Although it has a slightly lower deep cycle life expectancy.

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Related Pages

Charge a Powerchair directly from a vehicle. via the same Anderson connectors

Anderson Style connectors and why you need them

Fast Charge YOUR Powerchair in Around 1 Hour

Inverters & Chargers

Batteries for Both Vans & Power Wheelchairs

Which Batteries to Buy

Very Flexible Charger!


Lithium Ion Batteries for Powerchairs and Scooters

My Power Wheelchair or Scooter Will Not Charge

BCI Battery Sizes, Group 22, 24, 34, 27 etc

Drive Your Powerchair by Radio Control

A Superior Powerchair overnight charger

Battery Planning How to organise yourself for every eventuality!


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