PowMr 48 volt 3500 watt hybrid inverter review


Solar Addict
Jan 15, 2022
I initially wrote this review for Amazon but never posted it. I thought those who were considering purchasing this might find this review helpful. This review is probably a bit more basic than necessary for this audience so much of what I mention you probably already know and You may want information that I haven’t thought of. So ask and correct me as you wish.
We purchased a Powmr 3500 all in one solar inverter/charge controller. Ours has the orange and Black color scheme. I originally purchased the white color scheme unit that has the same specs and I believe the same model number. I had to return it because it was damaged. The first unit was slightly different than the unit I have now and I prefer the one I have now because the connections for AC output include a connection point for the ground wire and the previous unit did not. This all in one inverter has worked well for us. We have used it off grid continuously for over 2 months and for the last 2 months connected to a 15a outlet.
What I have this unit connected to is as follows
Power in.
A 3500w Harbor Freight predator inverter generator connected to my travel trailer shore power plug that is wired through this unit when we were off grid and a 15 amp outlet now that the camper is back at our house.
Power out.
The line out from the inverter connects to the electrical service that came with the trailer and an upgraded 12v converter/charger that can fully recharge the “house” battery in a typical day.
I have 4 12v 100ah deep cycle flooded lead acid batteries connected in series. We also have a single battery with the same specs for the “House” system
My array consists of 9 240 watt solar panels 3 panels Per bank connected in series and the resulting 3 banks connected parallel giving me just over 2100 watts. My array is oriented flat to simulate its eventual installation on our travel trailer roof. I get well over 1500 watts in peak sun on a clear day and about 650 watts on an overcast day.
Why we bought this.
We chose this unit because We have a very limited budget and limited space in the trailer. I wanted the 3500 watt inverter because it matches the 30 amp input on my rv almost perfectly. 3500w at 120 volts = 29 amps.
The limitations of this unit that I have discovered so far are
1.No grid pass through.
Shore power (in our case the generator) will not pass through or charge the batteries if the inverter is turned off.
2.The display does not always work.
No display will function if the inverter is turned off unless the solar array is producing power.
3. MPPT issue.
The MPPT solar charger tends to get stuck at 60v if the solar array is connected to it when the sun comes up. Once the sun is up disconnecting and reconnecting the solar charger resets it and then the maximum power point will be discovered, Improving my solar input by as much as %50 .
4. Not parallel capable.
This unit cannot be paralleled with more units to expand the system. So buy something else if you want to grow your system later on. This was not an issue for us as our travel trailer maxes out at 30amps
5. No power sharing.
This unit cannot limit incoming power and subsidize it with inverter power like some of the more expensive Victron inverters.
6. No intuitive remote monitoring/control.
This unit has no practical means to monitor it or program it or turn It on or off from a remote location. It works well for us because our only installation point is very accessible but if you must mount this in a difficult to reach location this unit is probably not for you.
7. Significant idle power consumption.
This unit uses 55w of power with no external loads. If you wish to leave the inverter on all the time you will need a very large battery bank and a decent amount of solar to maintain that load. This unit will completely flatten a 100ah battery in less than 4 days if left on with nothing recharging it.
8. 48 volt has added battery challenges
This unit is 48v. You will need eight 6v golf cart batteries in series or 4 standard 12v deep cycle batteries to get that voltage. If you use lead acid batteries your battery bank will be very heavy.
9. 48 volt requires extra safety precautions.
48 volts can shock you the 58 volts that the batteries can reach when they are being charged can certainly shock you. The solar array used to on this unit will always be at 60v or more when charging and mine often clears 100v when the batteries are nearly charged so the solar array can shock you. The inverter input and output is 120v and can shock you. Know what you are doing when you set this up.
10. 48 volt requires an additional conversion to operate 12 volt devices.
This unit must have a converter of some sort to connect the 48v batteries to the 12 volt systems of an rv. We opted to ignore the efficiency losses of converting 48v to 120v and then back again to 12v and left our rv 12v system untouched and with it’s own converter and battery. At night we turn off the inverter and the “house system is more than able to carry us through the night and is recharged in the morning when we turn the inverter back on.
11.Narrow voltage range for solar.
This unit has a fairly narrow range for solar panel voltage.
You must have a solar array output of over 60 volts in order for the solar charger to work.The max open circuit voltage is 145. This means with the solar panels we have 2 in series won’t produce enough power to charge the batteries until they are in direct sun and if we put 4 in series we risk over voltage in cold weather. Therefore we can can only use our panels in multiples of 3.

Features I use and what I like about this unit
1. Size
This unit is very small for what it does and we needed that as our travel trailer has no out of the way space that we could mount solar This was one of the reasons we went with an all in one system.
2.All the solar input capability I can use.
The MPPT solar charger is very powerful and exceeds the amount of solar that is possible to put on my rv roof.
3. Small wire size.
The wire size needed for a 48 volt setup is much smaller than a 12v system. Freeing up much needed space and cash.
4. Fewer connections for setup.
Most of the bus bars and connections of a typical solar system are eliminated due to the all in one design again freeing up cash and space.
5.powerful inverter.
The inverter works really well. It does everything we can do with shore power. Battery capacity is our only limitation.
6. Quiet
This unit is reasonably quiet. It generally does not make noticeable noise unless we are using a larger appliance. most of the larger items are louder than the inverter such as the air conditioning, coffee percolator or microwave.
7. Solar always works
The MPPT charge controller charges the batteries even if the inverter is turned off.
8. Safe connections
All of the connection points are internal and covered virtually eliminating shock or short hazards at it’s connectors once assembled.
9. Good price
For what it does the price is super cheap. Less than half what the individual components and connections would cost even if buying the cheapest thing out there.
10. Ups like performance
This unit has an internal transfer switch so it acts like an uninterruptible power supply. I can unplug shore power and power continues as if nothing happened.
Although the internal workings of this unit are quite complex it’s setup and use is surprisingly easy.
My 11 year old son already knows how to turn it on and off and how to determine battery levels and when it is time to turn on the generator on heavy overcast days.
13.gradual start up
When you connect shore power this unit gradually transfers the load from the inverter to “grid” power. We usually supply power from a generator so this feature is very nice as it prevents sudden surging or arcing when the generator is plugged in.
14.Secure mounting
Some hybrid inverters mount only on the top. This unit has a center mounting point at the bottom as well making it solid when mounted.
15.light weight.
The whole thing including the packaging was less than 25 pounds. This is helpful in an rv application.
16.Adequate display information Although the display is not fancy the information it provides is enough for proper operation. I found the display to be more intuitive than my father in law’s growatt unit.

HARG Hunter

Thirsty for Off-Grid Knowledge
Jul 10, 2020
Iola, Wisconsin
Nicely done. This type of review is priceless for someone like me that is considering purchasing this exact unit. Thanks!


It's not happy hour, I'm just like this.
Nov 23, 2021
Thunder Basin Wyoming
We purchased a Powmr 3500 all in one solar inverter/charge controller. Ours has the orange and Black color scheme. I originally purchased the white color scheme unit that has the same specs and I believe the same model number.
Cool, tons of great info. Thank you.

Can you provide your Model number please?

I have the POW-LVM3K-24V


Solar Addict
Jan 15, 2022
Cool, tons of great info. Thank you.

Can you provide your Model number please?

I have the POW-LVM3K-24V
POW-LVM3.5K-48v is my model number. I wouldn’t put to much stock in model numbers this unit was noticeably different than the one I returned. Some Amazon listings mentioned “upgrade model” that’s what I got. The manual was still for the older one though.


New Member
Oct 19, 2021
I've been looking at this myself, but I don't like that it gets stuck at 60v and having to reconnect the solar charger every day. (n)


Solar Addict
Jan 15, 2022
I've been looking at this myself, but I don't like that it gets stuck at 60v and having to reconnect the solar charger every day. (n)
I asked a few questions regarding this problem and here is the response I got