Running 12v DC equipment on 120v AC (indoors)

CrownVic97

Member
May 21, 2010
3,350
Hazen, ND
I've been using the PowerMax to power my big lights for several years. I still make sure I have an inline fuse or circuit breaker between the light and the power, but have had no issues with these power supplies. There is a small switch on the side of the supply that you have to move so it supplies constant 13.8. It still works if you don't, but then it will be in battery recharge mode and the voltage it supplies will drop in stages after several minutes of operation. I have 6 or 7 of these supplies.
Good to know! I have cables with an inline 40A fuse and on/off switch. I'm looking forward to trying this supply out :D!
 

Scoot163

Member
Nov 15, 2013
848
Tacoma, WA
Good to know! I have cables with an inline 40A fuse and on/off switch. I'm looking forward to trying this supply out :D!
I use 8 gauge wire coming out of the power supply terminals. One caveat, the 100 amp rating may be a bit inflated. It will run a couple or even several bars at once depending on type and draw, but you can push it (I have) and cause the supply to burn out. I can turn on a wall of flashers on various bars and it doesn't strain it a bit.
 

CrownVic97

Member
May 21, 2010
3,350
Hazen, ND
I use 8 gauge wire coming out of the power supply terminals. One caveat, the 100 amp rating may be a bit inflated. It will run a couple or even several bars at once depending on type and draw, but you can push it (I have) and cause the supply to burn out. I can turn on a wall of flashers on various bars and it doesn't strain it a bit.

Mine will only be for testing lightbars, beacons, etc, etc. Won't be tied into a bunch of stuff ;).

I got it for the internal protection measures that my old 50 amp Pyramid (betraying bastard, now stuck in 24V :mad:) didn't have.
 

DatedGore

Member
Mar 21, 2022
69
Indiana
Just thought I'd get a pool of what everyone is using for powering lights indoors, and the setups you guys have. Especially for the larger more amp hungry bars
 
May 21, 2010
1,254
Minnesota
Just thought I'd get a pool of what everyone is using for powering lights indoors, and the setups you guys have. Especially for the larger more amp hungry bars

Depending on how big/type of bar, The Powermax series seem to be a good choice.
I made this with the supplies I am using. Has some info on a few various supplies too.

 
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emcom

Member
Apr 12, 2011
71
Huntsville, AL
Depending on how big/type of bar, The Powermax series seem to be a good choice.
I made this with the supplies I am using. Has some info on a few various supplies too.

Jennifer,

I have tried using two battery chargers for a MX7000 project I am working on and both underpowered the bar horribly. One had 85A start assist and the other 50A start assist. I am thinking that since they are newer somehow without a battery inline, they don't detect the need for higher amps. I hooked the bar up to my diesel pickup with jumper cables and it came to life at full brightness and rotor speed. I am concerned that the "smart charge" features of the Powermax might do the same. I've been watching your video and seems you have good luck with that supply. I am going to be using a Unitrol 8000 series controller to manage the different lights on the bar, as that is the same brand of controller I had on my police car with the MX7000 in the 90s. I am thinking of wiring myself instead of carting it down to the radio shop.

In summary, questions are:
1) Do you think the Powermax is the way to go to fully pull the load of a MX7000 with all lights?
2) Since I am using a switch box that uses pigtails for the 1-2-3 slide switch instead of terminals, are crimp connections ok or should I use some other type connection to connect each wire together (example: Outside rotors only for switch position 2 using the corresponding pigtail from the controller.)

Thanks!20231221_123732 (1).jpg
 
Last edited:

Scoot163

Member
Nov 15, 2013
848
Tacoma, WA
Depending on how big/type of bar, The Powermax series seem to be a good choice.
I made this with the supplies I am using. Has some info on a few various supplies too.

I use the Powermax extensively and have six or seven of them for my collection. I enjoyed your video, and noticed that you mentioned that the Powermax supply you have fluctuates in power output after awhile. It is a three stage charger and is made to do that for battery maintenance. The newer supplies have a small switch on the side to either used the supply for three stage battery maintenance, or to have steady 12v output. The older Powermax chargers do not. You probably already knew this.
 
May 21, 2010
1,254
Minnesota
I use the Powermax extensively and have six or seven of them for my collection. I enjoyed your video, and noticed that you mentioned that the Powermax supply you have fluctuates in power output after awhile. It is a three stage charger and is made to do that for battery maintenance. The newer supplies have a small switch on the side to either used the supply for three stage battery maintenance, or to have steady 12v output. The older Powermax chargers do not. You probably already knew this.
Yes, I only run it in constant output for powering lights. Mine does have the switch to put it into charge mode too. Mine has the 3 stage in charge mode but some have 4 stage too. It starts to fluctuate when nearing capacity but part of the load varies (like with using flashers). Otherwise just using rotators/steady load runs great.

Glad ya liked the video. Lots of different power setups out there so I just wanted to share mine.
 
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Reactions: Scoot163
May 21, 2010
1,254
Minnesota
Jennifer,

I have tried using two battery chargers for a MX7000 project I am working on and both underpowered the bar horribly. One had 85A start assist and the other 50A start assist. I am thinking that since they are newer somehow without a battery inline, they don't detect the need for higher amps. I hooked the bar up to my diesel pickup with jumper cables and it came to life at full brightness and rotor speed. I am concerned that the "smart charge" features of the Powermax might do the same. I've been watching your video and seems you have good luck with that supply. I am going to be using a Unitrol 8000 series controller to manage the different lights on the bar, as that is the same brand of controller I had on my police car with the MX7000 in the 90s. I am thinking of wiring myself instead of carting it down to the radio shop.

In summary, questions are:
1) Do you think the Powermax is the way to go to fully pull the load of a MX7000 with all lights?
2) Since I am using a switch box that uses pigtails for the 1-2-3 slide switch instead of terminals, are crimp connections ok or should I use some other type connection to connect each wire together (example: Outside rotors only for switch position 2 using the corresponding pigtail from the controller.)

Thanks!View attachment 248100
As you can see, chargers do not make good power supplies.

The powermax are typically a power supply/charger combo in one. They have a recessed switch to pick from one of the 2 modes. They come in a range of outputs so bigger is better for power hungry bars. A fully loaded MX can draw over 50 amps. I have been very happy with mine for running lights and using as a charger.

As for the connections, you should be fine with a good crimp and quality connectors. If the connection doesn't get warm/hot then you should be good. The cheap amazon connectors are likely to give you issues. Menards/Home Depot carry decent ones.
 
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emcom

Member
Apr 12, 2011
71
Huntsville, AL
As you can see, chargers do not make good power supplies.

The powermax are typically a power supply/charger combo in one. They have a recessed switch to pick from one of the 2 modes. They come in a range of outputs so bigger is better for power hungry bars. A fully loaded MX can draw over 50 amps. I have been very happy with mine for running lights and using as a charger.

As for the connections, you should be fine with a good crimp and quality connectors. If the connection doesn't get warm/hot then you should be good. The cheap amazon connectors are likely to give you issues. Menards/Home Depot carry decent ones.
Thank you so much!
 

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