Battery Crossover Switch

[Carsons_11]

New owner of a Cutwater 28. My boat is stored on the trailer under cover with no AC power available. With that, the solar panel will not provide any charging capability while stored. I am working on an externally wired Solar panel to use while stored. Looking at the wiring schematics, it seems that the engine alternator will only charge the engine battery unless the battery Cross Over switch is in the ON position.
Is that your understanding also?
Is it assumed that the solar panel alone can keep house batteries charged? Seems to me it may make sense the have the battery Cross Over switch in the ON position while the engine is running to help charge the house batteries with the engine alternator. Is anyone aware of any issues this may cause?

Also, what controls the Engine and Thruster battery charge relays?

Thanks,
Bob

 

[Nmontagno]

I have a new R23 and I was informed that the charging system works off a three bank system when the motor is running or when it is on shore power. It charges the house batteries first, then the engine battery, followed by the thruster battery.

My solar panel directs its charge at 90% to the house batteries and then 10% to the engine battery.

 

[BB marine]

I have a new R23 and I was informed that the charging system works off a three bank system when the motor is running or when it is on shore power. It charges the house batteries first, then the engine battery, followed by the thruster battery.

My solar panel directs its charge at 90% to the house batteries and then 10% to the engine battery.

This is not completely true. When on shore power depending on what type of battery charger you have will determine how the batteries are charged. A inverter/charger charging output goes to the house battery. Once the house battery is at 13.0 Volts for 90 seconds the ACR's (Auto charging Relay) closes and now charging output is to the thruster bank and engine bank. If the battery charger and inverter are separate units the charger has three outputs and charges each battery bank separately until one of the batteries reaches 13.0 volts for 90 seconds ACR's close and then the banks all become one and charge equally. When charging from the engine alternator the engine battery is charged first when it reaches 13.0V for 90 seconds the ACR's close and the house and thruster batteries are charged. The same happens with the solar panel 90% charge to the house and 10% to engine unless the battery voltage is 13.0 for 90 seconds then ACR's close and all are getting charged.You do not want to have the cross over switch on while running. The only time you want to use it in the on position is when a battery is dead. Think of the cross over switch as a built in jumper cable.

 

[TexasEye]

Then it doesn't matter where the Batt switch is set!

Where should the Batt switch be set for normal cruising, in slip and on trailer?

Thx

 

[BB marine]

Then it doesn't matter where the Batt switch is set!

Where should the Batt switch be set for normal cruising, in slip and on trailer?

Thx

The crossover should be off normal cruising,slip, trailer. If it is left on you have by passed isolation between engine and house batteries. The ACR ties them together as long as there is a charge. When there isn't a charge present the ACR opens. Think of the Cross over as jumper cables built in. When you use cables you attach them to the battery that is dead. Start the engine remove the cables. The cross over works the same. Turn the switch on excite the battery start the engine. Turn switch off.

 

[TexasEye]

Thx! Great info, easy to understand

 

[Cutwater28GG]

the thing that I think confuses a lot of boaters is

1. the cross over is as Brian says just a jump starter capability and shouldnt be used every day or left on.
2. that you shouldn't change the battery switches once the engine is running as it can voltage spike the alternator.

ive always been reticent to change the parallel switch when the engine is running (i.e. start engine with help from paralleled house battery due to low engine battery and then once running turn off the parallel switch)

Brian whats your take: ok to close the parallel switch once started?

 

[BB marine]

Yes it is ok. The engine battery is connected to the engine charging system so there is a path for alternator output. The crossover switch is jumping the house battery to the engine battery. When you disconnect the house from the engine battery you are not disconnecting any other connection. As I stated before if you jump a battery with cables once the engine is started you take the cables off. With the cross over switch you move to off position. Your engine battery is being charged by the alternator. The only battery switch that can not be turned to off position with the engine running is the engine battery switch.

 

[Carsons_11]

What prompted the original question was the fact that I lost all house 12vdc power last time out. I thought the batteries were just too low since the boat is not normally connected to shore power while on the trailer. I had to use the Cross Over switch to get house power to operate the Garmin, horn, etc. I had to leave the Cross Over switch in the ON position to maintain house 12vdc and thought this was so due to the low house batteries.

Today I went out to the boat to connect an external solar panel to keep the house batteries trickle charging while on the trailer. While making the connection, I discovered that the 100 amp battery terminal fuse was blown preventing 12vdc from getting to the house buss.

I replaced the fuse and will see what happens.

By the way, with all other switches off, I turned ON and left the Cross Over switch in that position to connect all batteries while the external solar charger is connected as I don’t see any issue with this.

Thanks for the information from all.

 

[asm777]

One other thing to be aware of.

Make sure inverter switch is ON.

I turned mine off while I was checking batteries and forgot to turn it back on. Battery charger will NOT charge the batteries even with shore power connected when the inverter switch is OFF!!

 

[Chimo]

Yes it is ok. The engine battery is connected to the engine charging system so there is a path for alternator output. The crossover switch is jumping the house battery to the engine battery. When you disconnect the house from the engine battery you are not disconnecting any other connection. As I stated before if you jump a battery with cables once the engine is started you take the cables off. With the cross over switch you move to off position. Your engine battery is being charged by the alternator. The only battery switch that can not be turned to off position with the engine running is the engine battery switch.

I always have shore-power connected so the batteries are topped up but when the weather is really cold or the engine hasn't been run for a while and will take a bit of extra juice I use the crossover to start. It avoids having the engine battery alone getting the big momentary draw down. I disconnect the crossover when the engine is running.

 

[jagizzi]

Make sure inverter switch is ON.

I turned mine off while I was checking batteries and forgot to turn it back on. Battery charger will NOT charge the batteries even with shore power connected when the inverter switch is OFF!!

This is only true for boats with a combination Inverter charger. The Cutwater 30 is the only Cutwater with this unit, the other boats have separate inverters and chargers. RT 31 Has the same I believe but I am not sure on the 29. This is something that we as boat owners should know about our boats so if you are not sure this thread should provide the inspiration.

Easy to check as the combo units are labeled as such. If you don't have a combo unit you should be able to find both an inverter and a charger located on the boat. In this instance you can, and should, leave the inverter off until it is needed.

 

[asm777]

Make sure inverter switch is ON.

I turned mine off while I was checking batteries and forgot to turn it back on. Battery charger will NOT charge the batteries even with shore power connected when the inverter switch is OFF!!

This is only true for boats with a combination Inverter charger. The Cutwater 30 is the only Cutwater with this unit, the other boats have separate inverters and chargers. RT 31 Has the same I believe but I am not sure on the 29. This is something that we as boat owners should know about our boats so if you are not sure this thread should provide the inspiration.

Easy to check as the combo units are labeled as such. If you don't have a combo unit you should be able to find both an inverter and a charger located on the boat. In this instance you can, and should, leave the inverter off until it is needed.

Thanks for that clarification and correction! I usually stay out of model related discussions as there are differences but wrongly assumed a C28 would be similar to a C30!