PowerMax PM4-55
#6 in StandaloneFull review
A low cost standalone converter for owners who are comfortable setting a charge voltage by hand. A common budget replacement for a WFCO 9855 class unit.
Amazon $143$143
The PowerMax PM4-55 is the better RV converter charger overall, rated 3.6 to 3.2. The PowerMax PM4-55 leads on value. The PowerMax PM4-55 costs $105.99 less ($143 vs $248.99).
WFCO WF-9855-AD
#11 in StandaloneFull review
An easy drop in for an RV that already has a WFCO 9800 deck mount, with lithium detection built in. A safe default for a typical trailer.
Amazon $248.99$248.99
Prices were last checked November 3, 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 PowerMax PM4-55 for value ($2.60 per amp ($143, 55 A) vs $4.53 per amp ($248.99, 55 A)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every standalone RV converter charger; a clear win is highlighted. How we rank explains each one.
| Factor weight | PowerMax PM4-55 | WFCO WF-9855-AD |
|---|---|---|
| Overall rating | 3.6/5 | 3.2/5 |
| Value 35% | 67 $2.60 per amp ($143, 55 A) | 34 $4.53 per amp ($248.99, 55 A) |
| Output 10% | 50 55 A | 50 55 A |
| Features 30% | 80 lithium mode, multi-stage charging, fan runs only as needed | 80 lithium mode, multi-stage charging, fan runs only as needed |
| Warranty 25% | 25 2-year warranty | 25 2-year warranty |
Specifications
| PowerMax PM4-55 | WFCO WF-9855-AD | |
|---|---|---|
| Charging | ||
| Output | 55 A | 55 A |
| Lithium mode | Yes | Yes |
| Multi-stage charging | Yes | Yes |
| Build | ||
| Build | Standalone | Standalone |
| Fan runs only as needed | Yes | Yes |
| Remote or display | No | No |
| Weight | 7 lb | 5.5 lb |
| Warranty | 2 years | 2 years |