DES MOINES — The cost of owning an all-electric car may get higher, but it will have nothing to do with the cost of the electricity used to charge the battery.

The Iowa Department of Transportation will ask the Iowa Legislature to change the registration for all electric vehicles from a flat fee to the same formula for determining the registration cost for other vehicles, said Elizabeth Baird, the DOT’s legislative lobbyist.

Since 1927, owners of all-electric vehicles have paid an annual registration fee of $25.

“It’s amazing that it’s been there that long,” Baird said. “I think back then there might have been some people who were creating home-designed and manufactured electric vehicles.”

The issue hasn’t received much attention “because there were not very many of these vehicles out there,” she said.

According to the DOT, 41 all-electric vehicles are registered in Iowa, including 10 in Polk County, eight in Linn County, four each in Johnson and Story counties, two in Scott County and one in Cedar County.

The DOT is proposing to base the registration fee on weight and value — the same formula used for other passenger vehicles.

In the case of a $36,000 Nissan Leaf, the registration would go to about $366, according to the DOT.

The increase would be about the same as a Leaf driver would save on gasoline over three months, according to J.D. Powers, which says the difference between the cost of electricity to recharge a Leaf’s battery and gasoline to drive a month is $129.

The change was approved by the legislature in 2012, but the bill was vetoed by Gov. Terry Branstad for unrelated reasons, Baird said.

There was some opposition to the registration fee increase from auto dealers.

However, Baird said it makes sense to treat the all-electric vehicles like other passenger vehicles.

“It’s small, but growing number, so makes sense to make that change before it becomes a big impact,” she said.