Powermax 110 Volt to 12 Volt DC Power Supply Converter Charger for Rv Pm3-55 (55 Amp)

It has a three stage charging system.

Out of box the voltage was set right. Measured 10A from a battery 90%+ full. Waited until morning battery was on 12.2v and measured peak of 46A. After 30 minutes it stabalized at ~40A. Some reviews have you believe these only output about 55% of rated capacity. Not true but you need the proper size wiring at least 4awg with sub 2ft run), enough battery to accept it, and it has to be drained enough. Runs fine off sportsman 2000 open frame generator at 2000ft elevation.

Was very easy to install and works great, have had on my rv for a couple of months and still working great.

Easy to install and simply works great. Can have all 12v lights in my travel trailer on and they never run down when the unit is on - which was not the case with the original unit i had. This Powermax is really a great repalcement unit

This item has to have a constant power voltage coming into it of 110 to 120 to keep your care battery charged

Use it to replace a 30amp unit

Works great!!

Update Jan 29 2015, Sent back,. Told it was a mislabeled 15 amp unit. I would recommend others use a good clamp-on ammeter and see what they really got. I ended up buying an Arterra WF-9865 65 Amp DC Deck Mount Converter. Puts out 74 Amps, Fused for 80 Amps, linear reduction in charge until final trickle charge @ 2mA @ 13.25V. Just perfect. Matt Update Jan 8 2015, My 55 Amp unit still performs as if it is a unit rated for 19 amps. After talking with a very polite Service Engineer about this issue and given all the good ratings, I figured I owed an extra round of tests to verify my initial findings. This time using a different set of conditions. Instead of discharging the battery set @ 120 Amps down to 10.5V I reduced the discharge rate to 27 Amp/hrs until the battery source reached the same 10.5V. At this point the load was removed and this charger connected and recharge was started same as in the first tests. Of course, at that point the 230 Amp/Hr battery was in need for the 55 Amp charge rate. Unfortunately the charge rate was again, just 19.3 Amps. Bottom line is.... at this point I am very suspicious. The documentation shows operational mode curves without numbers which makes them curious but useless to me. The units 3 stage charge control intelligence logically transitions as expected but the units maximum output is still just 1/3 its claimed rating. Working with seller to resolve the issue. Matt Submitted Jan 2 2015 (by the guy that bench tests stuff before installing) * Unit is rated for 55 Amps but its maximum output will never exceed 19.3 Amps even while loaded down to 10.5 Vdc. No explanation can justify this as normal. Otherwise it controls excellent as the 3 stage chart indicates. I imagine this unit is mislabeled or defective. * I wish I understood why it came with a 30 Amp fuse. Documentation says its for Reverse Polarity Protection. Sounds like a good feature given this units output connectors are not labeled at all. Meter it and label it immediately if you get one. * If the unit is just defective and not just a overrated output claim I will very likely bump it up a notch and get a 75 Amp replacement but waiting to hear from the seller first. Judging by other readers I hope for a 5 star update soon. Matt

I installed this in my RV to replace my factory converter. The factory converters are loud and inefficient. I installed this unit in my front cargo compartment and ran new 6 gauge wires directly to my batteries. As other reviews have stated the fan speed is not variable, but it does only turn on when needed. For example, my factory converter runs the fan at full speed when pushing 8 amps into the batteries, this unit can do over 8 amps without the fan running at all. Also, in my initial testing this thing pushed 3x the amps into the batteries as the factory unit. Strongly recommend this unit for mounting in a cargo area. This will allow my to charge the batteries much more quickly when dry camping and using the generator.

Directions left a little to be desired but works great in my RV