Solar v2 – choosing the components

Since my first attempt at solar, I have learnt a few things and several new bits of tech have been introduced into the market. Some of the new tech include; all-in-one inverters, bigger “better” batteries, shingled solar panels and micro-inverters…

Time to take the learnings from my first solar project and scale-out

New Parts

An all-in-one solar inverters can include the following functions in a single device;

  • Solar Controller – MPPT (2x string inputs)
  • Inverter – Converts DC (48v) to AC (pure sine wave @230v, 50 hertz)
  • Battery Charger –
    • from Grid (AC -> DC)
    • from Solar Panels (DC -> DC)
  • ATS / Line mode – Flicks over to Grid if solar or batteries are low
  • BMS, Timers and Controls – Can program battery types, priorities and timers depending on how you want to power your loads and utilize your batteries.
  • Stats / Alerts – WIFI enabled

I have committed to an 8kW PV all-in-one inverter. My house doesn’t have a north-facing roof, but it has a NE and NW facing roof which isn’t too bad, the bonus of having 2 string feeds on the inverter means that each side of the roof will act independently without dragging down the total power output.

I’m currently running a few lead-acid batteries on my solar. I’ve been in two minds about whether I continue with batteries or go with a hybrid system that effectively uses the grid as a battery. I ended up deciding to go with batteries one last time, here in NZ the solar rebate is not really worth the effort of exporting – we typically get wholesale prices which can be 1/3 of the cost of power. I’ve also been pretty excited about how quickly the new LiFePO batteries can charge and discharge, so I’ve committed to a couple of 48v PylonTech batteries in a stack, totaling 7kWh.

Us3000 48v/74ah 3.5kwh Lithium Battery Solar Battery Pylontech 48v  Residential Battery - Buy Pylontech Us3000,3.5kwh Lithium Battery,10kwh  Lithium Battery Product on Alibaba.com

They can peak at 100A (15s) but the recommended rate is 37A each. At 48v this will give me a charge / discharge power rate of 3.55kW (37A x 48V x2) in total. In some cases it may be beneficial to charge with cheaper off-peak power from the grid.

Singled solar panels are pretty nice, with more surface area and better resiliency. I found a 480W mono Hyundai panel which I’ll use to build 2 strings of 4 panels. In total, this gives me 3.84kW (480W x 4 x 2)

In terms of power, for my next venture I decided to stay with the more traditional DC solar panels. There is however another choice thanks to the introduction of micro-inverters. These little devices convert power on each panel direct to AC, which includes several advantages (higher voltage, operate in parallel (independent of other panels). Each also has its own sensors if you want to see stats!

The next sections – powering things, ROI, the build, safety

M365 Electric Scooter – must have mods

I’ve been riding my m365 xiaomi scooter for quite some time now… over its time i have made a few mods to make it a better and more reliable ride…

First – The tyres.


Sticking with pneumatic are best, they are lighter and generally have better grip when they are in good shape (i.e. not plastic). The only downside is the tube puncturing every now and again. The slime you can inject into your trye also is pretty average, it increases weight slowing you down.

To avoid punctures I’ve found best to ensure your PSI is approx 40 – 50 PSI. I weigh about 70Kg, and find 40PSI pretty good.

Also, dont get the cheap tubes from AliExpress, get the slightly more expensive ones, they have a thicker rubber and so far have really lasted. See Amalibay here – https://bit.ly/2KKorBp

Second – the firmware and battery bms

If your lucky enough to have 2nd generation scooter you will not have to worry about the small and easily blown “z-fuse” on the bms. If you have one of the 1st gen scooters you can just replace the bms with a 2nd generation one. Easy enough to find on AliExpress.

Installation will require a bit of soldering and careful workmanship – as the battery can give yo a bit of a jolt if you short it out! (I’ve accidentally done it twice and it can give you quite the fright)

Also your going to want to load a custom firmware. The android app M365_DOWNG is going to be your friend, it can connect to your scooter via Bluetooth. Making the custom firmware has been made easy at this site –
https://m365.botox.bz/

Disclaimer : firmware mods can break stuff, be careful. Ensure you have 2nd gen BMS first!

I’ve started using another app on my android for my 365, it has a much better battery information display – “M365 Tools”. Pretty handy for watching your cell balance across the battery pack. You can see my battery is a bit out of balance at moment, with a difference of 0.042 volts between my lowest and highest cell.

I’m dabbling at installing an active battery balancer so i can auto balance the cells (they seem to fall out of balance some times).

Third – The handle catch

Get some of those rubber “reducers” to go in the hinge gap. Works a treat when its been worn down after extended use. Makes the connection more firm, and stops the horrible squeaking sound. Check them out here – https://bit.ly/2ZVr07e