Under a user-pays model, run properly, the answer is a measured zero: the units drawn, the metering hardware, the wiring work and the monthly reading time are all billed back to the people who use the point, and nothing lands in a non-EV member's maintenance dues. "It should be zero" is an argument, though, and arguments lose annual general meetings; this page produces the figure instead. You list every cost line a charging point can create, assign each one to the user or to the society, show how each is measured, and finish with a single rupee figure per flat per month.
The seven cost lines a charging point can create
This page supplies no tariff, no equipment price and no claim about what other societies do. Every input below is one your treasurer fetches from the society's own electricity bill, meter register, written quotes and general-body resolutions; our guide to reading an electricity bill line by line shows which entry does what. Where a figure is missing, the honest entry is "not yet measured", never a number borrowed from elsewhere.
| Cost line | Who bears it | How it is measured | Evidence for members | If not isolated |
|---|---|---|---|---|
| Units the vehicle draws | The resident charging | Closing reading minus opening, same dates monthly | Dated photos of both readings, and the bill raised | Units spread across every flat's dues |
| Common-meter units nobody attributed | The charging users, apportioned | Meter movement, less baseline, less all sub-meters | The reconciliation line in the register | An unexplained rise non-EV members fund |
| Sub-meter, cable and labour at the point | The resident, on their own quote | Quote and paid invoice in the resident's name | Invoice filed with the written approval | A capital item from the shared repair fund |
| Reading, billing and record time | A per-point service line | Minutes per round, priced as the general body votes | The service line and the resolution behind it | Volunteer evenings, or a paid hand on overheads |
| Making good civil work on the route | The resident | Reinstatement scope named on the quote, then inspected | Photographs and the deposit release note | Patching folded into the repair budget |
| Capacity added only for the points | The residents who connect | The electrician's written statement of what it serves | That scope and the apportionment resolution | Every flat funds headroom only a few use |
| An upgrade raising capacity for all | The society, from the voted fund | Beneficiary test: needed if no point existed? | The test answers minuted before the vote | Nothing improper, but not a charging cost |
Rows one to six are the treasurer's work. Row seven gets misfiled, and that is expensive: an upgrade the building needed anyway is a society cost, so booking it against charging hands objectors a figure that was never theirs. Our guide to billing EV charging fairly covers the models that make rows one and two measurable; the objection debate belongs to a separate discussion held before this worksheet.
Step one: the energy line, closed to the rupee
Suppose your society's own bill shows a marginal energy figure of ₹9 per unit; substitute the figure printed on yours. Suppose the register shows one point moving from 1,412 to 1,586 units over the month.
- Units attributed to that flat = 1,586 − 1,412 = 174
- Billed to that flat = 174 × ₹9 = ₹1,566
- What those units added to the common bill = 174 × ₹9 = ₹1,566
- Net movement in the society's account = 1,566 − 1,566 = ₹0
That is the whole mechanism, deliberately dull: a metered point is a pass-through, so the common account ends the month where it started. A sub-meter or the charger's own logging changes the paperwork, not the arithmetic; our comparison of sub-meter versus smart-charger billing sets out that trade-off.
Step two: the two honest leaks
A worksheet that lands on zero and stops is not trustworthy: two lines genuinely can leak onto the common account, and each has a measurement and an apportionment method.
Units the common meter recorded and nobody claimed
This appears whenever the points draw from the common supply, and needs a baseline: the same calendar month before the first point was energised. Suppose the common meter moved 4,920 units this month, the same month last year moved 4,540, and the three sub-meters recorded 174 + 96 + 61 = 331 units.
- Unattributed units = 4,920 − 4,540 − 331 = 49
- Reconciliation factor = (331 + 49) ÷ 331 = 1.148
- Rate the society bills = ₹9 × 1.148 = ₹10.33 per unit
- Collected from the three users = 331 × ₹10.33 = ₹3,419
Lifts, pumps and lighting vary month to month, so treat the residual as a range watched over several cycles, not one exact figure. Before attributing any gap to charging, ask your licensed electrician in writing what else sits on that circuit. Which supply the point runs from decides how large this line gets, so the own meter, sub-meter or common meter choice belongs before installation.
The reading round and the treasurer's evening
Say the round takes forty minutes and the general body votes a service line of ₹50 per point per month; substitute whatever your members agree. Three points collect 3 × 50 = ₹150, which pays whoever reads, and the net effect on dues is again nil. If your society prefers to absorb the time, minute that decision; a cost openly absorbed is governance, one never mentioned is what members later call a hidden subsidy.
Step three: the per-flat figure, both ways
Now total the worksheet, carrying the figures above, with 80 flats:
- Collected from charging users = ₹3,419, plus ₹150 of service line
- What the 380 units added to the common bill = 380 × ₹9 = ₹3,420
- Paid out for the reading round = ₹150
- Residual on the common account = 3,569 − 3,570 = −₹1
- Effect per flat = 1 ÷ 80 = about one paisa a month
One rupee across eighty flats persuades better than a claim of exactly zero, because it shows the rounding instead of hiding it. Now run the same month with nothing isolated — vehicles on a common socket, no sub-meters:
- All 380 units land in the common bill = 380 × ₹9 = ₹3,420
- Spread across every flat = 3,420 ÷ 80 = ₹42.75 per flat per month
- Over a year = 42.75 × 12 = about ₹513 per flat
That second figure is one a non-EV member is right to object to. The difference between it and one paisa a month is a sub-meter, a register and a resolution. Where residents share one point, the same discipline extends to splitting the metered units between them.
When an upgrade genuinely serves every flat
Sometimes the assessment turns up work the building needed regardless; charging exposed it rather than caused it. Ask your licensed electrician, in writing, whether the work would be specified if no charging point existed, and to split the quote into the part serving all flats and the part serving only the points, then apportion on that split, not on sentiment. Suppose your own written quote reads ₹1,20,000 for the shared-benefit part and ₹40,000 for the charging-only part.
- Shared-benefit part across 80 flats = 1,20,000 ÷ 80 = ₹1,500 per flat, one time
- Charging-only part across three connected users = 40,000 ÷ 3 = ₹13,333 each
- A fourth resident joining later = 40,000 ÷ 4 = ₹10,000, with 13,333 − 10,000 = ₹3,333 refunded to each earlier payer
Write that joining rule into the policy before the first payment, because it cannot be agreed fairly once somebody is owed money. What your building can carry is a question of sanctioned load, answered by a site assessment, not a worksheet.
The one-page annual disclosure
The argument returns every year unless the answer is published every year: one page, the same eight lines in order, tabled with the accounts:
- Common-meter opening and closing readings, with dates.
- Sub-meter readings per point, with dates, from the register.
- The pre-charger baseline used, and which month it came from.
- Unattributed units and the reconciliation factor applied.
- The per-unit figure billed, as the bill figure times that factor.
- Amount billed to charging users, and amount received.
- Amount paid out of the common account for those units.
- Net effect on dues per flat, stated per month even when it rounds to nil.
Table it whether the number flatters the committee or not; our guide to putting EV charging on the AGM agenda covers how to present it.
Common questions
How can a treasurer demonstrate that the chargers do not touch maintenance dues?
By showing the pass-through, not asserting it. Four documents do it: dated sub-meter readings, the bill raised against those units, the society's electricity bill for the period, and the receipt. If money collected matches what the units added to the common bill, the residual is the effect on dues, per flat per month even when it rounds to paise.
What happens to the arithmetic when the point runs off the common meter?
Nothing breaks; you add one line. Without a sub-meter there is nothing to subtract, so the whole rise is unattributed and has no defensible answer. With a sub-meter behind the common supply, compare its movement against a pre-charger baseline for the same month, subtract the sub-metered units, and recover the remainder through a reconciliation factor.
How should the committee's own time and the monthly reading be accounted for?
Decide it openly. Either the general body votes a per-point service line that pays whoever reads and bills, so it nets to nil; or the society minutes a decision to absorb the effort as honorary work. Leaving it unspoken is what fails: unrecorded volunteer time is the cost members discover late.
What if an upgrade genuinely benefits every flat, not just the EV owners?
Then it is not a charging cost and should not be recorded as one. Ask your licensed electrician to state in writing whether the work would be specified with no charging point, then apportion the shared-benefit part across every flat and the charging-only part across the connecting residents.
What should be reported to members each year so this is never re-argued?
The eight-line disclosure above, tabled with the annual accounts in the same order every year so members compare like with like: readings and baseline, unattributed units and the factor, the per-unit figure billed, amounts billed, received and paid out, and the net per-flat effect on dues.