# Power management control panel (PMS3)



## Helzie (Jun 15, 2017)

Hi

We just bought a 20 year old Mazda Bongo. It has a PMS3 power management system. I've found the manual online and read various forum posts about how it works but I still have a few questions about it if anyone can help!

I've pulled together below what I've managed to work out and included questions about things I'm not sure about. I'd really appreciate it if anyone could answer my questions in italics below and also let me know if any of my instructions to myself are wrong!

Thanks very much. 

*Using the mains supply instructions:*

* Plug in to the mains supply. 
* Switch the CHARGER SUPPLY rocker to the ON position.
* The internal lights, fridge, water pump and 3-pin sockets will be powered by the mains.
* The leisure battery will be charged from the mains.  
* Switch the CHARGER SUPPLY rocker to the OFF position.
* Unplug from the mains supply. 

_Questions:

* Is the car battery also charged from the mains?
* Does the position of the BATTERY SELECTOR switch matter for charging (CAR, OFF, VAN)?
* How do you know when the leisure battery is fully charged (if charging at home, the cable will be across the pavement so I want to disconnect ASAP)? 
* Does the CHARGER SUPPLY rocker need to be in the ON position to draw power from the mains power supply or is it enough to be connected to the mains?_

*While driving instructions:*

* Switch the BATTERY SELECTOR switch to OFF. 
* The leisure battery will be charged while driving.
* The Indel B fridge will be powered while driving. 

_Questions:

* If the BATTERY SELECTOR switch is NOT turned to OFF while driving, will that cause any problems?
* Will both batteries be charged, regardless of the position of the BATTERY SELECTOR switch (CAR, OFF, VAN)?_

*While parked instructions:*

* Switch the BATTERY SELECTOR switch to VAN. 
* The lights, fridge and water pump will be powered by the leisure battery. 
* The 3-pin sockets won’t work. 
* In an emergency, switch the BATTERY SELECTOR switch to CAR to power the fridge and other DC appliances. This will use the car battery and may flatten it quickly.


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## izwozral (Jun 15, 2017)

Sorry I can't help but I am sure one of the more technically minded members will be along soon.


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## bobj808 (Jun 15, 2017)

Hi, we had a PMS3H in our campervan, it is just a bit more of an updated unit to yours but operates the same. Unless you have 240 lights or fridge which I doubt, then the only thing that happens when you plug in the mains is the 240 socket(s) will be live and the leisure battery will be charging if it needs it. Everything else, pump, 12 v lights, fridge (well dependant on model) will run off leisure battery.  The system doesn't allow the battery to be overcharged. I doubt if it will also charge the vehicle battery, certainly mine's didn't. Be careful with the caravan/off/car switch - if you use it on car it will use the vehicle battery - we never used (or had to) this function as we had 2 x 100 amp leisure batteries. We often used a Honda Generator to charge/top up the leisure batteries which has a floating earth which caused the red 240 mains switch to flash off and on but this is normal and nothing to worry about. Your alternator should charge the leisure battery while driving - we didn't have a lead from our alternator on our system, just a wire from the vehicle battery through a relay to the PMS which seemed to work fine. If you don't have LED lights, you should fit some as lights and the fridge are biggest consumers of power. I eventually took the electric fridge out, got some extra cupboard space and we used 12v cool boxes which were fine for a weekend. You'll know you divide your watts by your volts to get your amp hour consumption - our fridge certainly ate amps! You can travel with the 12v switch set to off or caravan - makes no difference. Hope this helps. Bob.


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## snowglowjoe (Aug 27, 2019)

*PMS3 Query*

Have had a problem with my PMS3 not charging. I discovered that the 10A aux fuse on the front panel had blown (I know not why?)
Replaced the fuse and discovered that now, when charging and the Car/Van rocker switch is in the mid position, the green charge indicator column is showing voltage. I'm sure it was not like this before the fuse change. Any thoughts?


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## Nesting Zombie (Aug 27, 2019)

Hi ya,
The Nest has got a very old ‘PMS4’,
I constantly leave the Battery charger rocker switch located on the top in the ‘Charge’ position.
This of course only produces charge when on hook up or Genny.
If I want the Leisure Battery charged I flick the power distribution panel rocker switch located in my galley area (Far Left of the panel) to ‘Aux’ if I want the Starter Battery charged I flick the SAME power distribution panel rocker switch to ‘Main’.
When driving I’m not getting 230v to the PMS4 unit so it doesn’t matter.
My Alternator is running my Fridge while pushing up to 15A to the Leisure Battery & of course charging my Engine Battery all at the same time.


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