Pearson 303 is adding BLUE SEA SYSTEMS SI-Charging Relay

[StargazerP303]

Hi All! After much research, reading, you-tube vid's and phone calls to Blue Sea Systems.. I think I somewhat understand how this works and it sure sounds great. However, does anyone have one installed? and - Did you change the selection switch out to the on-off one they supply? Thanks Capt.Rob

 

[Maine Sail]

Hi All! After much research, reading, you-tube vid's and phone calls to Blue Sea Systems.. I think I somewhat understand how this works and it sure sounds great. However, does anyone have one installed? and - Did you change the selection switch out to the on-off one they supply? Thanks Capt.Rob

Selection switch? The 7610 ACR, which is appropriate for your boat, is a simple three wire hook up, unless you want to use the SI (start isolation) feature.

The 7610 will work with any battery switch set up you have. You do not need the "Dual Circuit Plus" battery switch. The "Dual Circuit Plus" is an easy ON/OFF but lacks the ability to properly isolate a bad battery bank and only leaves you with the "COMBINE" option in an emergency..

An ML-ACR uses a Contura switch, an industry standard switch, but the ML-ACR would be overkill for a P303.

The ACR simply sits between the house and start banks and charges both, by paralleling them, whenever charging is present. It isolates the banks when there is no charging.

#1 Run all charge sources to the house bank or preferably its always on busbar, solar, alternator, battery charger, inverter charger, wind etc.. For a cruising boat you don't want to feed charge current to the start battery first or you can suffer from relay cycling.

#2 Install ACR between house and start banks using the correct gauge wire and fuses within 7" of each battery banks positive terminal using an (ANL, MRBF or Class T fuse.

#3 Run a negative wire to the negative bus with a fuse in its lead.

#4 Run an SI wire to the ignition switch, if you have a dedicated/isolated starting only bank. No need if you have a 1/2/B switch.

#5 Done

Making Sense of Automatic Charging Relays

 

[StargazerP303]

Thanks Maine Sail! Yes, the battery selection switch. My current configuration is the standard (1/both/2/off) with 1 being my Start and 2 being house. Reading here on SBO there is a lot to digest..lol with great insight on configuring electrical connections to meet the needs. So if I'm understanding what I've read here on SBO in-a-nut-shell. 1. Move the 35amp alternators output wire (currently to starter post area) and connecting directly to the starting battery POS+ post to protect the diodes from while engine running and selector switch goes into the OFF position. 2. Install the ACR where (lug A) goes to POS+ of one battery and (lug B) goes to POS+ of the house battery. The 3 tabs on the ACR the one marked GND (ground) is connected to ?? electrical bus ground or engine ground ? The middle tab will be connected to starter solenoid POS+ position to make while starting engine ACR (opens) allowing the ACR to drop the connection of both start and house batteries. Now after the engine starts, the charging will be to the starting battery first and then when starting battery is completed then the ACR adds the house battery to be charged. This is great its like putting your switch into BOTH position without actually physically doing it. So leave the switch on position 1 (start) and go. Do I understand how this operates? Regards, Capt. Rob

 

[StargazerP303]

Selection switch? The 7610 ACR, which is appropriate for your boat, is a simple three wire hook up, unless you want to use the SI (start isolation) feature.

The 7610 will work with any battery switch set up you have. You do not need the "Dual Circuit Plus" battery switch. The "Dual Circuit Plus" is an easy ON/OFF but lacks the ability to properly isolate a bad battery bank and only leaves you with the "COMBINE" option in an emergency..

An ML-ACR uses a Contura switch, an industry standard switch, but the ML-ACR would be overkill for a P303.

The ACR simply sits between the house and start banks and charges both, by paralleling them, whenever charging is present. It isolates the banks when there is no charging.

#1 Run all charge sources to the house bank or preferably its always on busbar, solar, alternator, battery charger, inverter charger, wind etc.. For a cruising boat you don't want to feed charge current to the start battery first or you can suffer from relay cycling.

#2 Install ACR between house and start banks using the correct gauge wire and fuses within 7" of each battery banks positive terminal using an (ANL, MRBF or Class T fuse.

#3 Run a negative wire to the negative bus with a fuse in its lead.

#4 Run an SI wire to the ignition switch, if you have a dedicated/isolated starting only bank. No need if you have a 1/2/B switch.

#5 Done

Sorry Main sail didn't see you added to your posting here. Question here! Lets say its all installed and working fine. sel-sw in position 1 for starting engine and I'm cruising along and the starter battery is full and ACR kicks in to charge the house thus, combining start and house batteries and now I stop to eat..lol so I stop the engine what will the ACR do? Will it stay in the linked state or will it drop out or disconnect/disengage the connection between the batteries ? I know the SI connection to will do this once I hit the start button to start engine.

 

[Maine Sail]

Sorry Main sail didn't see you added to your posting here. Question here! Lets say its all installed and working fine. sel-sw in position 1 for starting engine and I'm cruising along and the starter battery is full and ACR kicks in to charge the house thus, combining start and house batteries and now I stop to eat..lol so I stop the engine what will the ACR do? Will it stay in the linked state or will it drop out or disconnect/disengage the connection between the batteries ? I know the SI connection to will do this once I hit the start button to start engine.

You may want to re-read what I wrote.

On a cruising boat the charge sources go to the house bank not start. For a center console with equal size banks it can go to start but not for a cruising boat with different sized banks, unless you want to suffer from relay cycling.

Myth #1 - "Batteries can drain into one another.":
The ACR relay OPENS at slightly above the voltage of a fully charged battery. No "draining"of any quantifiable capacity, of one battery into another, can occur at disconnect/open voltages above full charge.

Myth #2 - "The ACR charges the start battery first then house."
The ACR is nothing more than an electrical BOTH switch. It is activated (closed/parallel) and deactivated (open/unparalleled) by VOLTAGE set points. If it measures 13.0V for 90 seconds or more, on either the "A" or "B" terminal, it parallels the banks. If it sees 13.6V for more than 30 seconds, on either "A" or "B" terminal, it parallel's the banks. If it sees 12.75V for more than 30 seconds, on either "A" or "B", it opens or unparallels the banks. If it sees more than 12.35V for more than 10 seconds (eg: high current voltage sag due to thrusters, windlasses, inverters etc.) it also unparallels the banks.

With a 1/2/B switch there is no need to use the SI feature as you don't have an "isolated & dedicated start battery" anyway. With a 1/2/B you just have two banks that serve both house and starting at the same time.

If you had three ON/OFF switches (House Switch>Emergency Switch>Start Switch) or a Dual Circuit Plus switch or a 1/2/B with separate ON/OFF for a cranking battery, then SI would be a good feature to use.

 

[StargazerP303]

Thanks Maine sail, I have read your write up on this matter. I understand now where when the voltage drops after being turned ON or combined, It will turn off/open to separate the combining of the starting battery from the house battery. However, once you try to start the engine it to deactivates the connection too because your SI is connected to start/key. After reviewing all your great write-ups on this subject I feel so much better and educated on this now! Thanks so much Maine Sail. Capt. Rob