Blue Sea ML-ACR

Blue Sea ML-ACR

Information

The Blue Sea Ml-ACR 500 Amp magnetic latching (bi-stable) relay automatically combines batteries during charging and isolates batteries when discharging and when starting engine.

It uses the charging voltage to decide when to connect truck batteries to camper batteries and when to disconnect.

There is an override switch to force disconnect batteries during maintenance. There is also an optional remote function available as an add-on. 

  • Manual override knob provides an added level of safety allowing control with or without power and offering LOCKED OFF capability for servicing
  • LED output to remotely indicate switch state -requires optional LED
  • 3.8″-16 tin-plated copper studs for maximum conductivity and corrosion resistance
  • 7/8″ (22mm) stud length accepts multiple cable terminals
  • Silver alloy contacts provide high reliability for switching live loads
  • Waterproof – rated IP66 from water projected in powerful jets

blue sea ml-acr

 

Problems

None Reported

No problems reported yet

Tips

TROUBLESHOOTING PDF

Blue Sea have produced a flow chart trouble shooting guide for the ACR. Click the button below.

(James Young)

TROUBLESHOOTING with a Multimeter

In most cases, ACR issues can be diagnosed by a few tests with a multi-meter.

mc-acr wiring diagram

mc-acr multimeter test

Step 1: Check all fuses and/or circuit breakers connected to the ACR.” There could be up to (3): (1) on each battery positive wire to the ACR, and (1) on the ACR Ground wire.

Step 2: Unplug the SI (Start Isolation) wire if one is connected.

Step 3: Check battery voltage with charging OFF and batteries at rest”

 

Test 1: Voltage of Battery A at the battery terminals

Voltage reading: _____________

Test 2: Voltage of Battery B at the battery terminals

Voltage reading: _____________

Test 3: Voltage between the ACR ground wire (-) and Terminal A (+) of the ACR.

Voltage reading: _____________

Test 4: Voltage between the ACR ground wire (-) and Terminal B (+) of the ACR

Voltage reading: _____________

 

Step 4: Check battery voltage with a charging source, or engine, ON one battery. Wait 2 min after applying the charging source before taking readings

 

Test 1: Voltage of Battery A at the battery terminals

Voltage reading: _____________

Test 2: Voltage of Battery B at the battery terminals

Voltage reading: _____________

Test 3: Voltage between the ACR ground wire (-) and Terminal A (+) of the ACR. Test 4: Voltage between the ACR ground wire (-) and Terminal B (+) of the ACR Test 5: Voltage between the ACR ground wire (-) and Start Isolation wire (+).

Voltage reading: _____________

 

During charging, battery terminal voltage of at least one battery MUST be above 13.0 VDC, and the second battery must be above 9.5 VDC, for the ACR to Combine. The battery readings should be the same as the ACR terminal to ACR ground voltage readings. The ACR will stay combined until the voltage at the A or B terminals goes below 12.75 VDC. If any voltage is present on the Start Isolation terminal the ACR will “Lock Out” until that voltage is removed. If any battery voltage is below 9.5 VDC the ACR will “Lock Out”, and the battery must be charged before ACR will combine

 

(Markus)

Circuit Protection

Circuit Protection

Information

SmartPlug Connector

The camper attaches to shore power via a 30a SmartPlug connector.

If you have the Magnum Charger / Inverter then you are only wired for 110v. Do not plug into a higher voltage outlet like you might find in South America or Europe for example.

In truth, this plug is not very smart. Previous iterations had a breaker, which was removed. The ‘smart’ seems to be the fact that there is a clip which holds the plug in place and that the connection is tight and waterproof. That’s about it.

To that end it is recommended that you obtain extra circuit, voltage and surge protection. 

smartplug

Problems

Reverse Polarity Warning

The XP has an issue (not XP’s fault) whereby it loves to make your rig / camper live with electricity. Shocking! (sorry!)

As you head south, a lot of the shore power plugins have a) no ground and b) reverse polarity.

I would say reverse polarity is at least 50% of shore power sockets we have tried. Open ground is probably up to 80 or 90% (We have a circuit analyzer)

Because of the way it is wired, if you plug the XP into a reverse polarity socket, with open ground, then it can make the truck live. You will get a buzz of the truck / camper. If you are using a faulty high powered device this could be quite dangerous.

I think this is because US / Canadian code dictates that the Camper neutral needs to be connected to earth in the truck. (I think! – maybe someone electrically minded can assist?) Euro vehicles use a separate arc breaker instead I think.

Marcus Tuck gave me a fix (and some education, which I may or may not have relayed correctly here). If you are heading south, carry a short ‘reversed’ extension lead. Basically, a short extension cable that has has one end rewired the wrong way round. This ‘flips’ the reverse polarity shore power back to correct polarity.

Doing this up north will likely mean you can do it with some nice chunky wiring and decent male / female plugs at either end.

(James Young)

 

 

Tips

CAMCO DEFENDER

This small plugin device allows you to check a shore power socket prior to plugging in your camper.

It uses a 30amp connector, same as your SmartPlug. Just plug it in prior to plugging in your SmartPlug and it displays either an ‘all good’ or an error code – for example: if there is no ground, reverse polarity or similar. It also has surge protection.

If there is an error then it still works. The downside is that you could create an issue, the upside being that if you decide the issue is ok to live with you can still get power. Visit their website > CAMCO POWER DEFENDER

I would consider this a ‘minimum’ level device. There are a lot sturdier and more proficient (and more expensive) options on the market.  

(James Young)

camco power defender