Harakeke Innovation Hub — Future Scope of Works
Prepared for: Mark Henderson, Meritelle Ltd Site: 26 Homeward Bound Drive, RD4, Wellsford 0974 Prepared by: Joshua Babbage — JB Solar & Electrical — 021 161 4366 — josh@jbse.co.nz Date: 10 August 2026 Status: Scope outline for discussion. Not a quote. Costs indicative only.
Purpose
This sets out where the three power systems on the property stand, what can and cannot be done with the equipment already there, and a recommended direction for the two shed systems once the house battery rebuild is complete.
Nothing here is committed work. It is here so you can see the whole picture and decide what you want to do and in what order.
The three systems
House — Selectronic SP PRO, 48 volt. Covered by quote HIH-Battery-2026. Four new Pylontech modules replacing the three end-of-life PowerPlus modules.
The three PowerPlus modules coming out are the reason for this document — the question is whether they can be put back to work rather than scrapped.
Middle shed — Victron MultiPlus-II, 48 volt. Its own solar array and two PowerPlus lithium modules already installed. The strongest of the three systems.
Bottom shed — Victron EasySolar-II GX, 24 volt. Its own solar array and two lead-acid batteries. Monitoring is built into this inverter.
An AC cable already runs between the middle and bottom sheds.
The constraint that shapes everything
The house modules are 48 volt. The bottom shed inverter is 24 volt.
They cannot be connected. This is not a settings change — it is a hardware incompatibility. Putting the recovered house modules into the bottom shed would mean replacing that inverter first, at around $1,600 plus GST for the unit alone before any labour.
The middle shed is 48 volt, so the recovered modules will work there.
Recommended direction
Rather than replace a working inverter, use the AC cable you have already run between the sheds to link the two systems together. Each shed keeps its own battery and its own solar array.
Middle shed becomes the primary system
- The three recovered modules join the two already there
- Hardware from the house cabinet is reused where possible
- The inter-shed cable is landed into the switchboard beside the inverter on its own breaker
Bottom shed stays as it is, with a new battery
- The ageing lead-acid batteries are replaced with a 24 volt lithium battery
- Its existing solar array and inverter both stay in service and keep earning
- It is fed from the middle shed through the cable already in the ground
- The feed is configured so the bottom shed can never overload the middle shed system
Because monitoring is already built into the bottom shed inverter, a new lithium battery there communicates with it directly. Nothing extra is needed — it manages itself.
Why the new battery at the bottom shed matters
This is the part that makes the whole arrangement work. With a healthy battery of its own, the bottom shed covers its own demand and the feed from the middle shed only trickles in to top it up.
Without a battery down there, the bottom shed's entire load would land directly on the middle shed's inverter and overload it.
The new battery is not an optional extra. It is what allows the two systems to support each other rather than drag each other down.
What you end up with
- Two systems, each with its own battery and solar, backing each other up
- Both solar arrays stay in service — nothing stranded
- No inverter replacement
- The recovered house modules put to work instead of scrapped
What needs confirming first
Any one of these could change the recommendation.
1. Whether the recovered modules still have useful life in them. They came back from a deep shutdown and are running again, but how much capacity they have left is not yet known. When I am on site for the house changeover I will pull the data off the inverter and see what it can tell us about their condition. That will guide whether they are worth reusing. No extra visit, and the modules never leave the property.
If they do not stack up, they do not go into the middle shed — weak modules in an otherwise good bank drag the whole bank down.
2. The modules all need to be the same. All of these systems went in at the same time, so the two already in the middle shed are very likely the same as the three coming out of the house. It just needs confirming on site. If they do turn out to be different models they cannot be run together, and this part of the plan does not proceed.
3. Space in the middle shed cabinet. Internal dimensions to be measured to confirm five modules will fit.
4. Condition of the bottom shed lead-acid batteries. Believed to be at end of life. Worth replacing based on the evidence.
5. Earthing between the sheds. This makes the bottom shed a submain fed from another building, so the earthing arrangement needs to be brought into line with AS/NZS 3000.
Indicative costs
Labour at $95 per hour. All hardware pricing to be confirmed with suppliers — no figure below should be relied on until quoted.
| Item | Indicative |
|---|---|
| Install three recovered modules into the middle shed | 6–7 hrs — $570 to $665 |
| Mounting hardware, cabling, lugs, labelling | To be priced |
| 24 volt lithium battery, bottom shed | To be priced |
| Install and commission the bottom shed battery | 4–5 hrs — $380 to $475 |
| Inter-shed connection — breakers both ends, terminations, earthing (labour only) | 6 hrs — $570 |
| Inter-shed materials — breakers, cable, conduit, inline crimps and heat shrink | To be priced |
| System configuration and commissioning, including protection settings at the middle shed so the inverter stops before the batteries do | 3–4 hrs — $285 to $380 |
All figures exclude GST and are estimates, not fixed prices. A firm quote follows once the points above are confirmed.
What is not recommended
Replacing the bottom shed inverter with a 48 volt unit. It would let the recovered modules go there, but it means discarding a perfectly good inverter and spending around $1,600 plus GST plus labour to achieve what the AC link achieves for less.
Running the two inverters as one system. Not possible — they are different units at different voltages in different buildings. Linking them by AC cable as described above is the correct way to tie them together.
JB Solar & Electrical Joshua Babbage | 021 161 4366 | josh@jbse.co.nz