Diy car battery top post or terminal adapter on an Optima Yellow Top


A diy, step by step video demonstration on how to make car battery top post or terminal adapters on Optima yellow top 12v battery installed in a 2008 Toyota Prius.


In this video we will try to create adapters for different size top posts on a  12 volt automotive battery.

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It is recommended to replace any automotive battery with one that is the correct

case size, the correct cold cranking amps and has  the correct post size for the battery terminals.

As seen in this footage the two batteries were the same physical size and cold cranking amps.

The top posts for the battery terminals were different sizes.

While measuring with the caliper it was also observed that on both of the batteries the positive top post was larger than the negative top post.

Also on each post of both batteries the width of the base on the post was wider than the width on the top of the post.

The new replacement battery had top posts that were approximately five millimeters narrower than the older battery previously installed on the vehicle.

While measuring replacement battery terminal hardware, it was observed that the material was approximately two millimeters wide.

Because the battery terminal would need to be cut eye protection was required.

Since the battery terminal hardware wrapped around the new battery posts would add four millimeters of width they were chosen to be used as the adapter hardware.

Further consideration was given to the battery terminal hardware because the material was intended to be compressed to wrap  around the posts and is able to handle the high amperage at the post.

Loose fasteners were removed  from the battery terminal hardware to minimize material being cut and avoid potential projectiles.

Each battery terminal was then cut with a handheld  grinder and pre-compressed with the bench vise.

Once the hardware was cut the negative battery terminal was used to compress the hardware into adapters.

Since all posts are different sizes, what should have been done was both posts on the new battery should have been used to compress the hardware into adapters.

As seen since the positive terminal is larger than the negative terminal, the adapter had to  be pushed on the positive using a heavy shaft.

Four millimeters was not wide enough for the  negative post so two pieces of hardware had to be used as the adapter.

Pliers were used to hold down the adapter and terminal to the negative posts while tightening the fastener.

I had a great time making this video and hope you did watching it.

Top post adapter is no substitute for the batter of proper case size, cold cranking amps (CCA) and correct terminal post size/orientation.

Optima YellowTop Batteries:

DS46B24R Smaller diameter JIS terminals, "R" designation
indicating reverse termination Optima Batteries DS46B24R

D51 Larger SAE-style terminals
Optima Batteries D51

D51R larger SAE-style terminals, "R" designation indicating reverse termination
Optima Batteries D51R

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This video is for demonstration and entertainment purposes only. All viewers must take responsibility for their own choices and actions. The creators of this video and anyone recorded in the video are not responsible and do not assume any responsibility for all purchases, damage, injury, death or dismemberment resulting from the performance of any operation in this video. Use the proper parts, specifications and safety procedures for your own application.

10/01/2020 | Diy car battery top post or terminal adapter on an Optima Yellow Top