Renogy 40A DC-DC MPPT Charger
#12 in 40 A and upFull review
A cheap dual input charger for a van with a 200 Ah lithium bank and a modest solar array.
Amazon $185.38$185.38
The Renogy 40A DC-DC MPPT Charger is the better DC-DC charger overall, rated 3.2 to 2.6. The Renogy 40A DC-DC MPPT Charger leads on value and features. The Sterling Power BB1240 40A wins on efficiency. The Renogy 40A DC-DC MPPT Charger costs $196.27 less ($185.38 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 October 31, 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 Renogy 40A DC-DC MPPT Charger for value ($4.63 per amp ($185.38, 40 A) vs $10.04 per amp ($381.65, 38 A)) and features (solar input, smart alternator support vs smart alternator support).
- 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 | Renogy 40A DC-DC MPPT Charger | Sterling Power BB1240 40A |
|---|---|---|
| Overall rating | 3.2/5 | 2.6/5 |
| Value 30% | 89 $4.63 per amp ($185.38, 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% | 50 solar input, smart alternator support | 25 smart alternator support |
| Warranty 20% | 25 2-year warranty | 25 2-year warranty |
Specifications
| Renogy 40A DC-DC MPPT Charger | Sterling Power BB1240 40A | |
|---|---|---|
| Charging | ||
| Charge current | 40 A | 38 A |
| Input battery | 12 V | 12 V |
| Output battery | 12 V | 12 V |
| Battery types | AGM, gel, flooded, LiFePO4 | - |
| LiFePO4 profile | Yes | Yes |
| Smart alternator support | Yes | Yes |
| Peak efficiency | 93% | 98% |
| Solar | ||
| Solar input | MPPT, up to 670 W | No |
| Build | ||
| Bluetooth | No | No |
| Ingress rating | IP31 | - |
| Weight | 2.6 lb | 1.8 lb |
| Warranty | 2 years | 2 years |
| Released | 2026-08-23 | - |