BLUE SEA SYSTEMS: Battery Charger and ACR Combined Unit

Electrical and electronic topics for small boats
jimh
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BLUE SEA SYSTEMS: Battery Charger and ACR Combined Unit

Postby jimh » Mon Dec 28, 2015 7:16 pm

Blue Sea Systems has a very interesting new product for 2016, an AC-operated battery charger with internal automatic combiner relay for DC charging. The combination of two products into one housing should appeal to small boat owners who want to conserve space for electrical gear and simplify the primary power distribution wiring.

blueSea7605BatteryLink.png
blueSea7605BatteryLink.png (34.66 KiB) Viewed 3674 times

The battery charger is called the 7605 BatteryLink Charger and is expected to be available in February 2016. A sales flyer gives details. When operated from 120-VAC, the maximum charging current is 10-Amperes. A temperature sensor monitors battery temperature to provide temperature-compensation during charging. The charger is described as "a three-stage" charger. Generally this is understood to mean the charger modulates the charging current and voltage in three steps, usually an initial charging rate, an absorption charging rate, and a floating charging rate, but Blue Sea Systems does not describe this in specifics.

There is a bit of confusion in the present literature regarding how the charger operates. The literatures says: "Use AC shore power to charge two isolated battery banks with the 3 Stage 10 Amp battery charger." The crucial word is "isolated" battery banks. But it also says: "When AC power is present, the ACR will combine both batteries and the AC charging will charge them as one bank." That seems to rule out the banks being isolated when the charger is operating from AC power. Of course, away from the dock, when the charging current comes from the outboard engine, the ACR switches the batteries into parallel for charging, and up to 65-Amperes of charging current can be handled by the ACR. Recall that if one battery is significantly discharged and placed in parallel with a fully charged battery, some of the charging current could come from the full-charge battery, so 65-Amperes could be flowing.

I like the concept of integrating the battery charger and the combiner relay, as the amount of primary power distribution wiring should be reduced significantly compared to wiring a separate charger and ACR into the circuit. The proposed schematic diagram is shown below. [Note: this circuit diagram has since been revised; see second article below]

batteryLinkSchematic.png
batteryLinkSchematic.png (30.48 KiB) Viewed 3675 times

One curious aspect of the suggested circuit is the fusing of the battery positive lead to the main power switch. Typically that is not done because the current in that branch of the circuit could be several hundred amperes during engine cranking. The fuses for currents of several hundred amperes are disproportionately expensive compared to the other components in the circuit.

jimh
Posts: 11672
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: BLUE SEA SYSTEMS: Battery Charger and ACR Combined Unit

Postby jimh » Mon Sep 04, 2017 9:41 am

Blue Sea Systems has published more information about their 7605 Charger-Combiner product since my initial comments above. The user manual now clarifies the charging profile used: "The BatteryLink® Charger uses a three stage automatic charging profile. The three stages are referred to as bulk, absorption, and rest/float."

Blue Sea Systems has also revised the wiring diagram supplied with the 7605, relocating the fuses which seemed to be in the wrong place in their earlier diagram; the fuses are now only in the circuit between the batteries and the charger, not in the circuit between the batteries and the engine. Here is the corrected wiring diagram:

blueSeaSystem7605SimplifiedWiring.png
From the installation instructions for Model 7605
blueSeaSystem7605SimplifiedWiring.png (138.75 KiB) Viewed 2797 times


The 7605 also has the nice feature called Start Isolation; this prevents combining of the Cranking battery and House battery during engine starting by the ACR. This prevents a voltage sag on the House battery. Avoiding a voltage sag on the House battery prevents all the electronic devices powered by the House battery from rebooting when the voltage sags. I would certainly install the optional Start Isolation circuit if I installed the 7605. Here is the complete wiring diagram with options shown:

blueSeaSystem7605FullInstallationDiagram.png
From the installation instructions for Model 7605
blueSeaSystem7605FullInstallationDiagram.png (139.53 KiB) Viewed 2797 times