Perko Battery Switch

[somekevinguy]

I just bought my first boat and I am wondering how my Perko battery switch works. The boat has a dual battery setup with a Perko dual battery switch. I think the boat was converted to a dual battery setup after new. It was a factory option and the owners manual says that if you have the switch in the 1 position the alternator with still charge battery number 2 also but I am not sure if my switch is same switch the factory uses. Do all the Perko dual battery switches work this way. I am wondering if mine works this way or do I have to switch to All to charge both batteries.

Mine looks just like this one. I read the instructions for that switch on the Perko site and it doesn't say anything about this.

 

[burp]

Re: Perko Battery Switch

The Perko switch if connected without any other electronic gadgets, will result in the alternator only charging the battery which is selected by the Perko switch.

Any chance the owners manual was referring to an onboard battery charger? With AC power applied to the boat, the charger will charge whatever is connected to it, regardless of where the Perko switch is positioned.

 

[Silvertip]

Re: Perko Battery Switch

People - and boat manufacturers -- do creative things when wiring a boat and especially a dual battery switch. My suggestion is to go to the Perko site and check the "standard" wiring diagram and compare it to what you have. If installed in the "standard" configuration, the negative terminals of both batteries will be tied together and then connected to the engine block. The positive cable from each battery will go to the BAT 1 and BAT 2 terminals on the switch. Every accessory on the boat should then be connected to the COM terminal on the switch. That doesn't mean there is bunch of wires connected there. It means the main power feed to the fuse/breaker panel gets connected there rather than at the battery. As for operation, OFF = all power is disconnected. BAT 1 = the engine charges BAT 1 only and BAT 1 only is running all accessories. BAT 2 = same as BAT 1 except BAT 2 is being used. BOTH = both batteries are being charged by the engine and both are powering everything. How you use the switch is up to you. If your boat has an automatic bilge pump, it must be connected directly to the battery.

 

[somekevinguy]

Re: Perko Battery Switch

Yeah I looked at the boat and it was wired just as you described except the bilge pump was on the BAT1 terminal so it always had power. It also had individual wires for the radio memory and the mercathode wired straight to the COM terminal along with the main positive buss wire and starter.

The manual said the radio memory, mercathode system and bilge pump stay connected to the battery when you switch the battery switch to off. This is the way I though it should be too so I moved the radio memory wire and mercathode wire to the BAT 1 terminal along with the bilge pump wire that was already there. Now I don't loose all my radio presets every time and I don't only have mercathode protection when I am running the boat.

As far as the manual here is the exact text.

"To start the engine place switch in Number 1 position. With this setting, power will now be supplied to your boat from the number 1 battery. This will allow the engine to charge both batteries."

In another spot it says if the number 1 battery is low switch over to Number 2 position to start and then switch back to Number 1 and this will allow the engine to charge both batteries.

I though maybe the switch had a built in battery isolator function with diodes which only blocked the power one way but let it charge both. So this isn't the case? Do they make one like that? So I guess run in BOTH and then run the radio on the shore in either BAT 1 or BAT 2.

 

[convergent]

Re: Perko Battery Switch

Seems like you could test this by running the radio for a couple of hours on battery 2, then switch it to battery 1 and start the boat. Measure the voltage on battery 2 and compare with battery 1. You should be able to tell if its charging or not.

 

[somekevinguy]

Re: Perko Battery Switch

Yeah I guess I could. I wouldn't even have to run the radio first. Alternator voltage is like 14 so I should be able to tell the difference even with the battery fully charged. I doubt the switch has an isolator function built in though. Seems like it would need a big heat sink like a normal isolator. I am thinking the owners manual is just a typo or wrong and it should have read ALL where it said BAT 1.

 

[Silvertip]

Re: Perko Battery Switch

Post the catalog number of that switch. I need to check with the manufacturer.

 

[somekevinguy]

Re: Perko Battery Switch

It is an 8501. I am sure it doesn't. It would have to have heat sinks to have an isolator function. Maybe the optional factory setup uses a different switch. I think more likely the manual was just wrong though. I saw a setup for sale here that had a relay setup that charged the primary battery only until it reached a certain voltage and then connected both batteries so they would both be charged. I think it automatically disconnected the primary battery when the voltage dropped too. That would be sweet to have automatic switching so you don't have to remember to switch when you are beached with the stereo running. Not worth the trouble and expense to me to get one of those though.

 

[Silvertip]

Re: Perko Battery Switch

If what the instructions say is true, another device (such as an ACR) would be needed and be built into the switch or included in the wiring. I seriously doubt the switch itself included an ACR function. The Perko 8501 is a basic switch and does not have an ACR function. It simply connects BAT 1, BAT 2 or BOTH to the charging system and charges ONLY the battery(ies) that are selected. Check the wiring for another device (probably an ACR - automatic charge relay).

 

[somekevinguy]

Re: Perko Battery Switch

Yeah I didn't see anything. Like I said I think the second battery setup was added after the fact. Maybe the factory setup had one.