| O3a | O3b | ||
| Module Costs | 16 cell | 8 cell | |
| μC | 32 bit fast processor | £1.50 | £1.50 |
| isolation | Capacitor | £0.20 | £0.20 |
| MOSFET Driver | MIC 4604 | £1.45 | £1.45 |
| MOSFET | NVMFD5C446NL | £1.21 | |
| NVMFS6H801N | £2.68 | ||
| Current transducer | CHB-50A | £1.20 | £1.20 |
| Total | £7.03 | £5.56 | |
| PCB | £0.50 | £0.50 | |
| Assembly | £0.50 | £0.50 | |
| Misc | £0.10 | £0.10 | |
| Total | £8.13 | £6.66 | |
| % target | 203% | 333% |