Redodo 12V 40A DC-DC with MPPT
#13 in 40 A and upFull review
For budget van and trailer builds that want alternator and solar charging in one cheap box. Specs are thin, so pick it on price rather than features.
Amazon $175.99$175.99
The Redodo 12V 40A DC-DC with MPPT is the better DC-DC charger overall, rated 3.0 to 2.6. The Redodo 12V 40A DC-DC with MPPT leads on value. The Sterling Power BB1240 40A wins on efficiency. The Redodo 12V 40A DC-DC with MPPT costs $205.66 less ($175.99 vs $381.65).
Sterling Power BB1240 40A
#21 in 40 A and upFull review
For boats and vans where keeping the start battery charged matters as much as the house bank.
Amazon $381.65$381.65
Prices were last checked November 2, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Redodo 12V 40A DC-DC with MPPT for value ($4.40 per amp ($175.99, 40 A) vs $10.04 per amp ($381.65, 38 A)).
- Choose the Sterling Power BB1240 40A for efficiency (98% peak efficiency vs 93% peak efficiency).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 40 A and up DC-DC charger; a clear win is highlighted. How we rank explains each one.
| Factor weight | Redodo 12V 40A DC-DC with MPPT | Sterling Power BB1240 40A |
|---|---|---|
| Overall rating | 3.0/5 | 2.6/5 |
| Value 30% | 93 $4.40 per amp ($175.99, 40 A) | 34 $10.04 per amp ($381.65, 38 A) |
| Charge current 20% | 0 40 A | 0 38 A |
| Efficiency 10% | 56 93% peak efficiency | 100 98% peak efficiency |
| Features 20% | 25 solar input | 25 smart alternator support |
| Warranty 20% | 25 2-year warranty | 25 2-year warranty |
Specifications
| Redodo 12V 40A DC-DC with MPPT | Sterling Power BB1240 40A | |
|---|---|---|
| Charging | ||
| Charge current | 40 A | 38 A |
| Input battery | - | 12 V |
| Output battery | 12 V | 12 V |
| LiFePO4 profile | Yes | Yes |
| Smart alternator support | - | Yes |
| Peak efficiency | 93% | 98% |
| Solar | ||
| Solar input | MPPT | No |
| Build | ||
| Bluetooth | No | No |
| Weight | 2.4 lb | 1.8 lb |
| Warranty | 2 years | 2 years |
| Released | 2023-07 | - |