Top-Post, Side-Post or Threaded Stud? Choosing the Right Head
Three connection styles that are not interchangeable, and the one check that prevents most returns.
Three connection styles, and they are not interchangeable. Tapered top posts take a standard terminal. Side posts and threaded studs need a different clamping geometry entirely — which is what a modular interchangeable-head terminal is for.
Check which one you have before you order anything. This is the single most common reason a terminal arrives and cannot be fitted.
The three styles
Tapered top post
Two round posts rising from the top of the battery, cone-shaped — wider at the base than the tip — with the positive noticeably fatter than the negative. This is the standard on the large majority of cars, trucks, RVs, boats and motorcycles in North America and Europe, and it is what most terminals are made for.
Covered by the SAE, DIN and EN standards. All three are within the range our clamping faces are machined for. Identification guide.
Side post
No posts on top at all. Instead there are two threaded holes recessed into the side of the battery case, and the cable attaches with a bolt threaded into the case. Long associated with GM vehicles, and still common on them.
A top-post terminal cannot be adapted to this — there is nothing to clamp around. The connection is a bolt into a threaded insert, so what you need is a terminal that presents a bolt face rather than a clamp bore.
Threaded stud
Studs projecting from the battery, usually with nuts fitted, and the cable lands as a ring terminal over the stud. Standard on marine batteries, many deep-cycle and AGM types, and a lot of RV and off-grid installations. Some batteries offer both a top post and a stud on the same terminal, giving you the choice.
Stud sizes are not standardised across manufacturers, which is why a head system that covers a range of thread sizes matters more here than anywhere else.
What fits what
| Battery style | What you need |
|---|---|
| Tapered top post (SAE / DIN / EN) | Any of our terminals — Kaas Series |
| Side post | Modular terminal with the appropriate head |
| Threaded stud | Modular terminal with the matching thread size head |
| Dual terminal (top post + side) | Either, depending which you wire to |
| JIS pencil post | Nothing we make. Do not order expecting a fit. |
How the modular head system works
The modular heavy-duty terminal separates the two jobs a terminal does. The body handles the cables — the clamped holes, the set screws, the current path. The head handles the interface to the battery, and it is interchangeable.
The supplied heads cover M4 through M10 plus 1/4-20 and 3/8-16, which spans the thread sizes used across automotive and marine batteries. So one terminal body serves a top-post car, a side-post truck and a stud-terminal boat battery — you change the head, not the terminal.
Where this genuinely earns its price is a fleet, a workshop, or anyone who changes vehicles more often than they change batteries. If you have one car with tapered top posts and no plans to change, a standard terminal does the same job for less money, and we would rather say so.
Why you cannot bodge between styles
People do try. It is worth being direct about why it does not work.
- A top-post clamp on a stud has nothing to grip. The clamp bore is a cone sized for a tapered post; a straight stud contacts it at a line at best. Whatever contact area you get, you will not keep it.
- A stud adapter screwed into a top post adds height — often several centimetres — and puts an extra joint into the highest-current path in the vehicle. Two interfaces where there was one, both able to loosen.
- A side-post to top-post adapter bolt is a legitimate product, but it moves the connection point outward and upward. Check clearance before assuming it fits, especially if you are then landing a multi-way terminal on it.
Every one of these adds a connection where the current is highest and the space is tightest. If there is a way to avoid it, take it.
Height is the hidden cost
Modular terminals are physically larger than a plain clamp — necessarily so, because the head has to attach to something. Adapters add height too. Both matter in an engine bay where the gap between the battery top and the hood liner may be only a few centimetres.
Measure the space above your battery before you order, not after. This is the failure mode behind most returns we see: the terminal is correct in every electrical respect and physically will not fit.
Before you order
- Identify the connection style. Top post, side post or stud — look, do not assume from the vehicle make.
- If it is a stud, measure the thread size, or read it off the battery documentation. Do not assume it matches your last battery.
- Count the cables for each post. Sizing guide.
- Measure the space above and around each post, including room to get a wrench in.
Four checks, five minutes, and it removes the most common reason a terminal goes back in the box.
Free: Battery Terminal Fitment & Torque Guide
Post identification chart, clearance dimensions for every terminal, torque table, and a print-to-scale paper template you can hold in your engine bay before you order.
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