Remote Battery Switch

Hi everyone!

Looking for a bit help on this Remote Battery Switch. I just finished upgrading my alternator to a Balmar 150A with an external regulator and of course all the extra stuff that goes along with an upgrade such as that. Along the way I decided to combine my thruster battery into my house bank. The theory on this was that the thrusters are only used leaving or coming back alongside (normally) and I wanted to increase my house bank so it seemed like a simple decision. The one thing I did not consider is the draw and subsequently the drop in voltage when using both bow and stern together. My voltage drops to the point where some of my electronics will shutdown and I get alarms on other systems, so... What I was thinking was to add a remote battery switch like the one in the link so I can isolate the thruster bank when I know I’m going to use them and then combine back to the house after I’m done. So I guess I’m just looking for some opinions on if this is a decent idea before I add something and regret it. Thanks, love the forum and have learned a lot.

Rob


https://www.bluesea.com/products/7700/ML-RBS_Remote_Battery_Switch_with_Manual_Control_-_12V_DC_500A

Are your thruster batteries close enough to the house bank to be combined? I know mine are not that close. Personally I like having them separate so that if I were to draw the thruster battery down the house bank would still be full. If you need more house bank I would probably just add more batteries to it.

Yes they are close enough and I used 4/00 cable so no line loss there. I know that just adding a battery would work but space is an issue as well as all the batteries are about 4 years old now so kinda did not want to start introducing new batteries. When they are done i would want to change them all at once.

Hi Diverrob,

The notion of having a seperate battery to power your bow and/or stern thruster is to buffer the house bank, and prevent the actual circumstance you have precipitated by tying the house batteries to the thruster batteries. As you have found, use of thrusters tied directly to the house bank, even with 4/0 wire, WILL cause your house bank to sag perceptibly. Those thruster batteries should be disconnected from the house bank entirely, and kept charged via an echo charger, or some other form of remote charging capability.

By attempting to "add" the thruster batteries to your house bank, in an effort to increase your house bank capacity, is counter-productive in other ways as well. Given the virtual impossibility of creating a "balanced" battery bank using remote batteries, you likely will exacerbate the rate at which one, or more of the batteries in your new enlarged house bank bears the brunt of discharge during use. This will prematurely age, and possibly kill one or more of the batteries in your bank.

Additionally, thruster batteries are typically start batteries, better able to provide the relatively high amperage draw and short duty cycle use of thrusters. Not so much for deep-cycle batteries used in a house bank.

Should you desire more house capacity, there is little alternative than adding additional batteries to the bank physically close aboard that bank, with careful consideration to proper wiring practices. These include not only ampacity, but cable resistances as well. Should space limitations preclude adding more batteries to the house bank, you may have to consider higher energy-dense battery arrangements, such as carbon-foam or lithium. All come at a price, of course!

It may well be money well spent to cruise over to Vancouver and commission an energy an energy audit from Pacific Yacht Systems (https://www.pysystems.ca/) before you throw more batteries, switches, and $10/ft. 4/0 wire at your boat. A well-respected crowd over there, with a wealth of information on their web site as well.

Regards,

Pete

There are also some well regarded people on Vancouver Island. Others on this forum could possibly recommend.

It’s worth learning all you can about your setup before engaging the experts, IMO. It’s worth testing the thruster at the dock, while off charge, using a clamp meter, to determine 1) the amperage of the thruster while in use and 2) the voltage drop while in use. These will be two separate tests. Ideally this should be done even temporarily with good starter batteries near the thruster. Then do the same with your system hooked up to see if you get the same results. If the thruster has lower voltage and amperage draw with your house bank, it’s not able to deliver properly and should be reconsidered at the very least and possibly reconfigured.

Jim

Hey thanks guys, all good points to consider and I’m going to run some tests on power usage as recommended. What are the thoughts on having your thrusters and engine start on the same battery? To me that seems like it may fix most of my issues. The boat is running 95% of the time when using the thrusters and then it’s topped up immediately from my new alternator (150A external regulator). Just trying to spitball here and see what the options are. Thanks

Rob

Diverrob said:

What are the thoughts on having your thrusters and engine start on the same battery? To me that seems like it may fix most of my issues. The boat is running 95% of the time when using the thrusters and then it’s topped up immediately from my new alternator (150A external regulator). Just trying to spitball here and see what the options are. Thanks

Rob

Click to expand...

That's what I have on Sandpiper with a single Ford Lehman. It has two Group 31 batteries in parallel for a start battery.

The start battery starts the engine and generator plus powers the bow thruster and windlass.

I don't use a 120 VAC battery charger on the start battery. Not needed.

The engine is always running when using the windlass and thruster and it's 100 amp alternator provides additional power to the windlass/thruster by keeping the voltage up and tops the battery up.

I reconfigured the start battery system to this in 2000 and it's been working fine without issues.

I do have a second 160 amp alternator/external regulator on the engine for charging the house battery.

Thanks for the info and I think I will give that a shot to see how things work. My alternator charges both banks through an automatic battery combiner so in theory this should work.

I installed two of those remote switches on Stella, one for the house and one for the starter bank. Besides serving as the primary cutoff between the batts and everything downstream, They allow me to instantly disconnect either bank from the main panel in the saloon. Not having to enter the ER during an electrical fire might be advantageous ?. They work perfectly, but if I trip them, or they trip on their own (which has never happened), I do have to go down to the ER to manually reset them.

My experience; 2x4D house batteries plus 1x4D for start battery. The bow thruster was also on the start battery. Incident.... a nice easy docking.... The CumminsQSB 5.9 (380HP at 3000RPM) would shut down when I used the bow thruster. Turns out, bad battery.... voltage dropped below 10.6Vt (?)
Solution; replaced all 3x4D batteries, added 3rd 4D to house bank. Moved bow thruster to house bank. Priority, keep the Cummins at all cost.
Alternative TEMPORARY solution, bring all the batteries on line, dock the boat, split the batteries and investigate the cause.

Yes I will need to do a test along side to see if this will cause the engine to shut down. Thanks again for the advice

I think your idea of running the bow thruster from the start battery has merit because the engine will already be running and you'll isolate the BT load from the house bank. I don't have a thruster but I put my windlass on my Group 31 start battery to shed load from the house bank and it's worked great for 10+ years.

I only have a single bank 55A shore charger connected to the 660AH house bank but have a helm-switched Yandina 160A Combiner to share the charge with the start battery when desired.

Normally the start battery needs no shore charge since its dedicated alternator normally keeps it topped off. It often sits uncharged for a week or two at a time with no load and without a problem. When I board in prep for departure, I can simply flip the helm COMBINER switch to top off the start battery (normally ~12.5V) with the house charger while I remove canvas.

PS. I use my windlass ALOT since I fish regularly for sturgeon in 25-60 ft of water. I'll often set the anchor 3-5 times per day for 3-5 days in a row typically a couple of times per month. It gets a heck of a workout.

High current dc brushed motors are electrically noisy. I would want both windlass and bow thruster on their own cranking battery, near the bow. A somewhat smaller charging cable running to an isolated charge lead. I don’t favorite stressing either an electronic prime mover motor or nav electronics with the transients that these hi amp motors make.

diver dave said:

High current dc brushed motors are electrically noisy. I would want both windlass and bow thruster on their own cranking battery, near the bow. A somewhat smaller charging cable running to an isolated charge lead. I don’t favorite stressing either an electronic prime mover motor or nav electronics with the transients that these hi amp motors make.

Click to expand...

I believe that’s what I’m trying to do by separating the thrusters from the house and keeping them on the same battery as the starter. Thanks for your thoughts, I did not consider the electric noise (a bit above my knowledge at this point).

I could see where an modern electronic controlled diesel might be sensitive to voltage dips from the start bank, an older mechanical diesels like a FL or Perkins should not suffer from that, I would think.

Maybe an expert like Ski in NC can chime in here.

Voltage dips on vessels with electronically controlled engines are not good. Voltage drops can fault out navigation equipment but the greater danger are to engine controls. I once followed a Mainship into a lock that lost control of its throttles at a most inopportune moment. The boat was at just above idle speed and contacted the lock wall at an angle, bounced off and into the swim platform of a boat already tied to the lock wall, bounced again and lodged its pulpit underneath a steel pipe railing. It was later found that the engine controls were wired to the thruster battery which had been being used heavily. The voltage drop resulted in the controls defaulting to the last known command. It all happened very quickly in that command was lost very close the lock wall.

So, if it were I, whatever wiring scheme I were choosing for a boat with electronic engine controls, it would be one that ensures against voltage drops to those controls.

i went thru so many balmar regulators, that balmar had to replace them abt 8 times, gave up on them, and went and to a 165 amp leece neville alternator, internally regulated, shoulda been a 200, etc, it only goes to 14.1 volts, at that voltage, uses very little water, put a 3+ inch double pully on, so it would charge at low speed when we were trolling up by bella bella, and the price was right!...i think the balmar stuff is over rated and way to expensive, as far as i`m concerned it`s not reliable!...clyde

Yes we have these Blue seas remotes in both our boats and they work like a charm

we do not use them to combine batteries.

Awesome, thanks!

Batteries

Need new ones, any ideas on brands,
I've been using Interstate 8D's but their getting to expensive. I live in Wa state. I hate shopping at West Marine, nobody their can answer questions or even been in a boat. Anyway thanks for any ideas. Ms.Glenda

If you're going to stay with flooded lead acid give Dyno Batteries a try. Buy direct from them, they're in Ballard near Fisherman't Terminal. Not the cheapest but very high quality. There are options to 8Ds. You don't need to wrestle those heavy batteries out and back in again.



Dyno Battery - Premium Quality Battery Manufacturing - Made in the USA

Diverrob said:

Hi everyone!

Looking for a bit help on this Remote Battery Switch. I just finished upgrading my alternator to a Balmar 150A with an external regulator and of course all the extra stuff that goes along with an upgrade such as that. Along the way I decided to combine my thruster battery into my house bank. The theory on this was that the thrusters are only used leaving or coming back alongside (normally) and I wanted to increase my house bank so it seemed like a simple decision. The one thing I did not consider is the draw and subsequently the drop in voltage when using both bow and stern together. My voltage drops to the point where some of my electronics will shutdown and I get alarms on other systems, so... What I was thinking was to add a remote battery switch like the one in the link so I can isolate the thruster bank when I know I’m going to use them and then combine back to the house after I’m done. So I guess I’m just looking for some opinions on if this is a decent idea before I add something and regret it. Thanks, love the forum and have learned a lot.

Rob


https://www.bluesea.com/products/7700/ML-RBS_Remote_Battery_Switch_with_Manual_Control_-_12V_DC_500A

Click to expand...

My solution would be to UNcombine the thruster batt bank from ANYTHING. Once it is isolated place a Blueseas ACR between the thruster and house bank. Running the alternator output to the thruster bank will ensure that you don't disconnect from alternator power by running the voltage of the thruster bank below 12.75 volts (the disconnect setting for the ACR). If you like the alternating current battery charger can be run to the house bank which will run charging current to the thruster bank when on generator shore power once the house bank is charged.

mermaidgigi said:

Need new ones, any ideas on brands,
I've been using Interstate 8D's but their getting to expensive. I live in Wa state. I hate shopping at West Marine, nobody their can answer questions or even been in a boat. Anyway thanks for any ideas. Ms.Glenda

Click to expand...

If they are house batteries, switch to golf cart batteries (2 per 8D). Lot less weight to wrestle.

Costco has Interstate GC batteries for $99

If starting batteries, a pair of Group 31's.

i had a problem with my port engine to mutch compression and needs sometime to start with both battery (port and starboard) together i had made this automatic by placing a starter relais from a big gm starter that is operated bij the starter relais from the the port engine,

You could try the same, put a big starter relais (small cost) to switch the banks together and power it by power from your thuster motor

(sorry for the bad englisch)