Renogy 20A DC-DC Charger
#5 in Up to 30 AFull review
For a van or camper with one 100 Ah lithium battery and a short cable run. It does the basic job well at the lowest price of the big brands.
Amazon $140.99$140.99
The Renogy 20A DC-DC Charger is the better DC-DC charger overall, rated 3.1 to 2.9. The Renogy 20A DC-DC Charger leads on value. The Redarc BCDC Alpha 25 wins on features and charge current. The Renogy 20A DC-DC Charger costs $548.01 less ($140.99 vs $689).
Redarc BCDC Alpha 25
#7 in Up to 30 AFull review
For 4x4 and truck builds that need the toughest sealed charger with Bluetooth. Buyers on a budget get more amps per dollar elsewhere.
Redarc $689$689
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 20A DC-DC Charger for value ($7.05 per amp ($140.99, 20 A) vs $27.56 per amp ($689, 25 A)).
- Choose the Redarc BCDC Alpha 25 for features (solar input, smart alternator support, Bluetooth vs smart alternator support) and charge current (25 A vs 20 A).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every up to 30 A DC-DC charger; a clear win is highlighted. How we rank explains each one.
| Factor weight | Renogy 20A DC-DC Charger | Redarc BCDC Alpha 25 |
|---|---|---|
| Overall rating | 3.1/5 | 2.9/5 |
| Value 30% | 59 $7.05 per amp ($140.99, 20 A) | 0 $27.56 per amp ($689, 25 A) |
| Charge current 20% | 50 20 A | 75 25 A |
| Efficiency 10% | 67 94% peak efficiency | 50 efficiency not published (neutral score used) |
| Features 20% | 25 smart alternator support | 75 solar input, smart alternator support, Bluetooth |
| Warranty 20% | 25 2-year warranty | 25 2-year warranty |
Specifications
| Renogy 20A DC-DC Charger | Redarc BCDC Alpha 25 | |
|---|---|---|
| Charging | ||
| Charge current | 20 A | 25 A |
| Input battery | 12 V | 12/24 V |
| Output battery | 12 V | 12 V |
| Battery types | AGM, gel, flooded, LiFePO4 | AGM, gel, calcium, standard lead acid, LiFePO4, heated LiFePO4 |
| LiFePO4 profile | Yes | Yes |
| Smart alternator support | Yes | Yes |
| Peak efficiency | 94% | - |
| Solar | ||
| Solar input | No | MPPT, up to 500 W |
| Max solar voltage | - | 48 V |
| Build | ||
| Bluetooth | No | Yes |
| Ingress rating | IP32 | IP67/IP69K |
| Weight | 2.7 lb | 2 lb |
| Warranty | 2 years | 2 years |