Every charge controller and DC-DC charger gets a score from 0 to 100% built from four factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. MPPT solar controllers and DC-DC chargers are ranked separately, each on its own scale.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per amp of charge current | 35% |
| Features | app, lithium profile, temperature sensor and input range | 25% |
| Efficiency | peak conversion efficiency | 20% |
| Warranty | warranty length | 20% |
Where the numbers come from
Charge current, input limits, efficiency, features and warranty come from the maker’s datasheet, manual or warranty page. There’s no independent certification for these products, so efficiency is the maker’s own peak figure; independent measurements are listed on product pages where a reviewer has published them.
The factors
Value is the price divided by the maximum charge current: dollars per amp.
| Type | Scores 0 | Full marks |
|---|---|---|
| MPPT solar | $10 per amp | $2.50 per amp |
| DC-DC | $14 per amp | $3 per amp |
Features adds up the things that make a controller easier to set up and kinder to a lithium battery:
| Feature | Share of the factor |
|---|---|
| Bluetooth app built in (half credit for an add-on dongle) | 35% |
| A lithium (LiFePO4) charge profile | 25% |
| A battery temperature sensor in the box (half credit if sold separately) | 20% |
| MPPT: maximum PV voltage, from 75 V (none) to 150 V or more (full) | 20% |
| DC-DC: works with smart (variable-voltage) alternators | 20% |
A feature the maker doesn’t state either way gets half credit. A temperature sensor lets the charger stop before charging a lithium battery below freezing, which damages it, and adjust voltage for lead-acid. A higher PV voltage limit lets you wire more panels in series.
Efficiency is the maker’s peak conversion efficiency: for MPPT controllers 95% scores zero and 99% full marks; for DC-DC chargers 90% scores zero and 98% full marks. Real efficiency at partial load is lower and is rarely published.
Warranty: 1 year scores zero and 5 years full marks.
What isn’t scored
Displays, load outputs, parallel operation, standby draw, water resistance and size are listed but not scored. Independent tests are listed where they exist, but there are too few to score.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated.
Ties and discontinued models
Products are ranked by score within each type. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.