Peak cash deficit: the working capital a ramp actually consumes

Ask what a Supercharger site costs and the answer comes back as capex: so much per stall for hardware, so much for install, a contingency, a loan. That number is real and it is not the cheque. The cheque is the capex plus everything the site needs before it can pay its own way, and for a site that ramps, that second part is large.

The engine carries it as a single headline line, peak cash deficit: the most negative point the cumulative cash position reaches in year one, month by month. This post shows where it comes from, what moves it, and why it belongs on the same page as the down payment.

Where $447,390 comes from#

The default eight-stall site has $1.21M of capex, financed 20% down on a ten-year loan at 8%. The down payment is $242,000. The engine's total upfront capital is $447,390. The difference:

The sales tax is simple: 9.375% on $500,000 of hardware, due when the hardware is. The deficit is the ramp.

Twelve months of digging#

Here is the Standard ramp, month by month. Net operating cash is revenue less electricity, the network fee, rent, insurance, entity fees and the loan payment:

Month one is the worst by far: the sales tax lands, the site runs fifteen operating days, and the first full loan payment is due regardless. After that the monthly loss settles around $11,000, interrupted every third month when the quarterly LCFS cash arrives and nearly closes the gap. Volume rises fivefold across the year. The site is almost breaking even by December, and it has spent $158,515 getting there.

That is the working capital the ramp consumes. A budget that provides the down payment and stops is $205,390 short on the day the stalls energise.

What moves it#

Four inputs set the size of the hole, and they are not the ones people expect.

The ramp curve. The engine's three presets consume $130,313 (Premium), $158,515 (Standard) and $191,398 (Slow-ramp). A slower curve is not just a longer wait; it is $61,000 more cash at risk before the site turns.

Stall count. The deficit scales almost linearly, because most of the monthly loss is per-stall: rent, the share of the loan, the demand subscription.

The down payment. Counter-intuitively, more equity means a smaller deficit, because a smaller loan means a smaller payment through the months the site cannot cover it: $158,515 at 20% down, $108,918 at 50%, $53,010 for cash. Loan vs cash sets out the full trade.

The loan term. The same loan over five years instead of ten carries a $235,531 annual payment instead of $140,934, and the year-one hole grows from $158,515 to $253,112. Over fifteen years it shrinks to $129,932. A short term is a working-capital decision as much as an interest one.

The year-one number is not the whole hole#

One thing the headline line does not say, and the fifteen-year table does. Peak cash deficit is a year-one, month-level measure, and it is the right one for sizing the opening cheque. But on the Standard ramp with 20% down, the cumulative position keeps falling after year one: −$255,363 at the end of year two, −$469,764 at year five, −$556,572 at year ten, the last year of the loan. Only when debt service stops does the curve turn, and cumulative cash crosses zero in year fourteen.

So there are two working-capital questions, and they have different answers. How much cash does the site need to get through its first year? $158,515. How much does the owner fund, in total, before the site has returned it? On this site, with this loan, $556,572 over ten years. The first is the number to hold at closing; the second is the number to know before signing.

The ramp post explains why the three curves produce the different first years above, and the build-cost post covers the capex that sits beside this line. The scenario wizard reports total upfront capital for any address and financing structure, with the deficit broken out, and the methodology page documents how the monthly ramp year is built.

Engine outputs are model projections under the stated assumptions, not advice or guarantees. All figures are the engine's documented default site unless a table states otherwise.