Renogy 12V 40A DC-DC Charger
#11 in 40 A and upFull review
A cheap, quiet way to add alternator charging to a van or camper with a lithium house battery. Pay more for Victron if you want built-in Bluetooth.
Amazon $179.99$179.99
The Renogy 12V 40A DC-DC Charger is the better DC-DC charger overall, rated 3.0 to 2.9. The Renogy 12V 40A DC-DC Charger leads on warranty. The Schumacher SDC371 40A DC-DC wins on value. The Schumacher SDC371 40A DC-DC costs $120.04 less ($59.95 vs $179.99).
Schumacher SDC371 40A DC-DC
#17 in 40 A and upFull review
A very cheap way to try alternator charging on an older vehicle, if the third party listing holds up.
Amazon $59.95$59.95
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 Renogy 12V 40A DC-DC Charger for warranty (2-year warranty vs 1-year warranty).
- Choose the Schumacher SDC371 40A DC-DC for value ($1.50 per amp ($59.95, 40 A) vs $4.50 per amp ($179.99, 40 A)).
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 12V 40A DC-DC Charger | Schumacher SDC371 40A DC-DC |
|---|---|---|
| Overall rating | 3.0/5 | 2.9/5 |
| Value 30% | 92 $4.50 per amp ($179.99, 40 A) | 100 $1.50 per amp ($59.95, 40 A) |
| Charge current 20% | 0 40 A | 0 40 A |
| Efficiency 10% | 67 94% peak efficiency | 50 efficiency not published (neutral score used) |
| Features 20% | 25 smart alternator support | 25 solar input |
| Warranty 20% | 25 2-year warranty | 0 1-year warranty |
Specifications
| Renogy 12V 40A DC-DC Charger | Schumacher SDC371 40A DC-DC | |
|---|---|---|
| Charging | ||
| Charge current | 40 A | 40 A |
| Input battery | 12 V | 12 V |
| Output battery | 12 V | 12 V |
| Battery types | - | standard, gel, AGM, calcium, lithium |
| LiFePO4 profile | Yes | Yes |
| Smart alternator support | Yes | No |
| Peak efficiency | 94% | - |
| Isolated | No | - |
| Solar | ||
| Solar input | No | MPPT |
| Build | ||
| Bluetooth | No | No |
| Ingress rating | - | IP66 |
| Weight | 4.1 lb | - |
| Warranty | 2 years | 1 year |
| Released | 2025-09 | 2022-10-01 |