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Battery Management (yep, again....)
- Thread starter RobMcClain
- Start date
Roy & Dixie
New member
When the battery selector switch is in the #1 position for the starter battery I can still run everything from this battery, including all house items. Similarly, if I put the battery switch over to the #2 position for the house battery I can still run everything. Frankly, this confuses me. I always assumed the starter battery would just power the engine and nothing else, and that the house battery would then be used to power the electronics and house systems. I took the boat to a local dealer a few months ago to fix a leak in the hydraulic steering and while there I asked them to check the battery management. I specifically told them I wanted to assure the starter battery was only for the engine while the Group 27 house battery would be used to power everything else. When I picked up the boat they told me they had checked the configuration and that it was just the way I had said I wanted it. I know I should trust them, but I am still confused as to why I can power the house from the starter battery.
The motor home industry has, for many years, set up the start and house batteries as you state you expected them to be wired in your boat. My previous 1983 and my present 2008 motor homes (both class "A") have a wiring circuit where the start battery and house battery are not connected together when the engine is not running. The engine will be started only by the enging start battery. (they call it the "chassis battery). All house circuits are connected only to the "house battery". Thus, when a motorhome is parked, engine not running, there is no chance that the chassis battery will be run down by using interior circuits. The chassis battery is charged only when the engine is running. The house battery will power only the house circuits. It will be charged by a 12v converter (120vAC in, 12DC out) if "shore power" of 120vAC is available. This converter does not charge the chassis battery. The house battery will also be charged (along with the chassis battery)when the engine is running. All this is done without the user deciding on any switch positions. The element that allows this is a diode or relay circuit that allows power to flow into both batteries when the engine is running, but will not allow any power to flow from the chassis battery when engine is shut down. If everything is working as designed it is a fool proof system, and the user does not need to do anything toward power selection while motor homing.
I have never found the motorhome type circuit in the boats I've used. Most boats seem to have the circuit you describe, where the user decides which battery to use for what function. My CD is wired such that either or both batteries will power everything: (#1 or #2 or both).
So your original thinking and request of the local dealer is what the motor home industry uses as standard. Those involved in boating seem to have a better understanding of what is needed from our batteries and the decision is left up to us.
The motor home industry has, for many years, set up the start and house batteries as you state you expected them to be wired in your boat. My previous 1983 and my present 2008 motor homes (both class "A") have a wiring circuit where the start battery and house battery are not connected together when the engine is not running. The engine will be started only by the enging start battery. (they call it the "chassis battery). All house circuits are connected only to the "house battery". Thus, when a motorhome is parked, engine not running, there is no chance that the chassis battery will be run down by using interior circuits. The chassis battery is charged only when the engine is running. The house battery will power only the house circuits. It will be charged by a 12v converter (120vAC in, 12DC out) if "shore power" of 120vAC is available. This converter does not charge the chassis battery. The house battery will also be charged (along with the chassis battery)when the engine is running. All this is done without the user deciding on any switch positions. The element that allows this is a diode or relay circuit that allows power to flow into both batteries when the engine is running, but will not allow any power to flow from the chassis battery when engine is shut down. If everything is working as designed it is a fool proof system, and the user does not need to do anything toward power selection while motor homing.
I have never found the motorhome type circuit in the boats I've used. Most boats seem to have the circuit you describe, where the user decides which battery to use for what function. My CD is wired such that either or both batteries will power everything: (#1 or #2 or both).
So your original thinking and request of the local dealer is what the motor home industry uses as standard. Those involved in boating seem to have a better understanding of what is needed from our batteries and the decision is left up to us.
Roy,
A few comments on your RV thread. If there is a diode which blocks the house form the chassis battery/alternator, there will be about 1/2 volt drop between the charging source (alternator) and house battery--at times leading to undercharging of the house battery. The relay type of circuit is similar to what we are using on boats as the voltage sensitive relay. in fact many of the higher end RV's are using a similar circuit, with voltage sensing on both the chassis and house batteries. Many of the more expensive boats are now equipped the same way.
The converter off 110 volts is a very low output "battery charger". These are often poorly regulated--and upgrades are available to allow them to allow a better regulation of the house battery charging circuit and also in some case to monitor and charge the chassis battery.
The higher end RV units no longer use converters, but rather large large inverters/ battery chargers (typically 100 to 150 amps on the charger circuits and use banks of golf cart batteries) These chargers are very sophisticated, and do charge both chassis and house batteries. I have been using this type of system on boats since the mid 1980's. Again, larger boats are also provided factory equipped with this type of system.
You did not mention the relays which allow the house and chassis batteries to be combined if the engine start is low, found on most RV's--and labeled as "Battery Boost"
Of course there are multiple differences with the RV and boat--in that you are safe in a parked RV you cannot start--and in a boat you cannot start, may be in danger, so the old fashioned back up is very important. In the RV or boat if you have already prepared satisfactory jumper cables it may allow starting when the electronics fail....Or you can have an 1/2/all switch in your RV...as boats now have.
The C Dory type of boat tries to keep the systems simple, and cheap. Many of us add on to these systems, based on our past practices and the latest technology.
A few comments on your RV thread. If there is a diode which blocks the house form the chassis battery/alternator, there will be about 1/2 volt drop between the charging source (alternator) and house battery--at times leading to undercharging of the house battery. The relay type of circuit is similar to what we are using on boats as the voltage sensitive relay. in fact many of the higher end RV's are using a similar circuit, with voltage sensing on both the chassis and house batteries. Many of the more expensive boats are now equipped the same way.
The converter off 110 volts is a very low output "battery charger". These are often poorly regulated--and upgrades are available to allow them to allow a better regulation of the house battery charging circuit and also in some case to monitor and charge the chassis battery.
The higher end RV units no longer use converters, but rather large large inverters/ battery chargers (typically 100 to 150 amps on the charger circuits and use banks of golf cart batteries) These chargers are very sophisticated, and do charge both chassis and house batteries. I have been using this type of system on boats since the mid 1980's. Again, larger boats are also provided factory equipped with this type of system.
You did not mention the relays which allow the house and chassis batteries to be combined if the engine start is low, found on most RV's--and labeled as "Battery Boost"
Of course there are multiple differences with the RV and boat--in that you are safe in a parked RV you cannot start--and in a boat you cannot start, may be in danger, so the old fashioned back up is very important. In the RV or boat if you have already prepared satisfactory jumper cables it may allow starting when the electronics fail....Or you can have an 1/2/all switch in your RV...as boats now have.
The C Dory type of boat tries to keep the systems simple, and cheap. Many of us add on to these systems, based on our past practices and the latest technology.
Roy & Dixie
New member
The C Dory type of boat tries to keep the systems simple, and cheap. Many of us add on to these systems, based on our past practices and the latest technology.
All you said is true concerning more upscale RV's. I did not mention the "battery boost" switch, which both of my RV's have had. I was afraid of getting too deep into the details. My latest motorhome is an Open Road model of Tiffin MH, the most basic of their models. It is a front engine diesel, but otherwise the same as their basic gas chassis. I have a 50a converter that has a jumper which will put a higher voltage to the house batteries for faster charge and to be used intermittently to lengthen battery life ( build up of something on plates?). And I have a cheap fused jumper to connect house batt/converter to chassis batt to keep it charged when not driven frequently. But it has a very basic electrical system. I generally "dry camp" (no shore power). I use the quiet diesel for micro oven power and run the A.C. if absolutely necessary, and to charge batteries every couple days if in one place for a while. But just like you said, C-Dory type boats, and some of us with R.V.'s like the economy and simplicity. Some motorhomes now have 4 banks of 2ea 6v house batteries just to run their residentual refrigator/freezers between 50a parks. Many must run their 8-10KW gens any time they are on the road.
The main point I was trying to make was the difference between the bassic R.V. house/chassis battery system and the basic boat selector switch.
All you said is true concerning more upscale RV's. I did not mention the "battery boost" switch, which both of my RV's have had. I was afraid of getting too deep into the details. My latest motorhome is an Open Road model of Tiffin MH, the most basic of their models. It is a front engine diesel, but otherwise the same as their basic gas chassis. I have a 50a converter that has a jumper which will put a higher voltage to the house batteries for faster charge and to be used intermittently to lengthen battery life ( build up of something on plates?). And I have a cheap fused jumper to connect house batt/converter to chassis batt to keep it charged when not driven frequently. But it has a very basic electrical system. I generally "dry camp" (no shore power). I use the quiet diesel for micro oven power and run the A.C. if absolutely necessary, and to charge batteries every couple days if in one place for a while. But just like you said, C-Dory type boats, and some of us with R.V.'s like the economy and simplicity. Some motorhomes now have 4 banks of 2ea 6v house batteries just to run their residentual refrigator/freezers between 50a parks. Many must run their 8-10KW gens any time they are on the road.
The main point I was trying to make was the difference between the bassic R.V. house/chassis battery system and the basic boat selector switch.
One comment which does apply to most battery types, and that is plate sulfation. I recommend using a technology such as "Pulse Tech":
http://www.pulsetech.net/Content/Our-Technology/Pulse-Technology.aspx
To prevent sulfation of battery plates. These are less destructive to the battery plates than periodic high voltage application, and work all of the time to prolong battery life and efficiency. The devices are powered off the battery and left permanently attached. There are some pulse devices which also include chargers.
http://www.pulsetech.net/Content/Our-Technology/Pulse-Technology.aspx
To prevent sulfation of battery plates. These are less destructive to the battery plates than periodic high voltage application, and work all of the time to prolong battery life and efficiency. The devices are powered off the battery and left permanently attached. There are some pulse devices which also include chargers.
Roy & Dixie
New member
One comment which does apply to most battery types, and that is plate sulfation. I recommend using a technology such as "Pulse Tech":
I had never heard of this product or technology. Very interesting infomation. For some reason I could not think of "sulfation" term when I was posting the earlier post. I take at least one long trip each month in the R. V. so the house batt is charging at 13.9-14v for the duration of each trip. I have heard that this is better than the house batteries having only the float charge from the converter applied while plugged in at home or in a seasonal park. But the product you noted seems the best of all methods.
I had never heard of this product or technology. Very interesting infomation. For some reason I could not think of "sulfation" term when I was posting the earlier post. I take at least one long trip each month in the R. V. so the house batt is charging at 13.9-14v for the duration of each trip. I have heard that this is better than the house batteries having only the float charge from the converter applied while plugged in at home or in a seasonal park. But the product you noted seems the best of all methods.
The pulse technology can also bring back deeply discharged batteries. I won't say it is as "good as new", but I have gotten several years of service out of batteries which I thought were shot.
A lot depends on the charger and what may be running in the RV. Boats are different, and I completely disconnect all cables when leaving the boat--don't leave a charger on, and they are fine months later.
The other option is the solar charger, as many have done when leaving the boats in storage.
A lot depends on the charger and what may be running in the RV. Boats are different, and I completely disconnect all cables when leaving the boat--don't leave a charger on, and they are fine months later.
The other option is the solar charger, as many have done when leaving the boats in storage.
The desulphation feature is also present on some of the DC to DC chargers like I mentioned in my post above. They also feature float ability to safely have your bank of batteries topped off in storage given that you also provide a primary multistage charger for the source battery.
These are not common on boats yet, but I think we may begin to see them more as the power requirements grow in complexity and required capacity. Gotta keep all those screens lit and toys running!
These are not common on boats yet, but I think we may begin to see them more as the power requirements grow in complexity and required capacity. Gotta keep all those screens lit and toys running!
I just went and skimmed the detailed data sheet on that Sterling product. I have a VSR, so I think I'm set up already, but I was still curious - especially after you mentioned it again. I have to admit that I have not completely got my mind around how it is different than a VSR, except that I guess a VSR is more like a smart switch, and this Sterling unit is a sort of charger? But... it's just passing the charge along from the engine alternator and through the start battery, right? Because, I mean it can't "make power" on its own, and there is no other power source going into it (like there is on a 110 charger).
I couldn't tell if this "meant something" or was just normal for any similar device:
"Precautions against Gas Explosions. This equipment includes cables which may cause arcs or sparks on installation. In order to avoid fire or explosion do not install the unit in a room which contains batteries or highly inflammable materials or in a location that requires ignition protected equipment. This includes any space containing gasoline-powered machinery, fuel tanks or joints, fittings or other connections between components of the fuel system."
Not being able to put it with the batteries, or in any space that contains fuel tanks or joints (cockpit) would be a bit of a bummer. On the other hand, they say "Fit it as close to the primary (starter) batteries as possible."
Maybe I'm misunderstanding, or taking a "CYA/and don't be stupid" too seriously.
Here is where I read the more detailed info:
http://www.defender.com/pdf/259317.pdf
Sunbeam
I couldn't tell if this "meant something" or was just normal for any similar device:
"Precautions against Gas Explosions. This equipment includes cables which may cause arcs or sparks on installation. In order to avoid fire or explosion do not install the unit in a room which contains batteries or highly inflammable materials or in a location that requires ignition protected equipment. This includes any space containing gasoline-powered machinery, fuel tanks or joints, fittings or other connections between components of the fuel system."
Not being able to put it with the batteries, or in any space that contains fuel tanks or joints (cockpit) would be a bit of a bummer. On the other hand, they say "Fit it as close to the primary (starter) batteries as possible."
Maybe I'm misunderstanding, or taking a "CYA/and don't be stupid" too seriously.
Here is where I read the more detailed info:
http://www.defender.com/pdf/259317.pdf
Sunbeam
The Sterling is really just a sophisticated charger that simply uses the start battery as a energy source. It can do so in an automatic method where it senses activity and activates or de-activates itself as needed or it can be wired to only come alive when the ignition is on.
I run it in full auto so that it can activate for AC charging at home on the trailer.
All most users would need is a small (5 amp) multistage AC charger connected to the start battery which in turn would charge the second bank as well when the Sterling unit senses an excess of power at the start battery. Of course it will not allow the start battery to go below a set voltage but there is no manual switching for that protection. This small charger would mean your recharge time on AC would be slow if deeply discharged but most cruisers are connected to AC for overnight periods. Also, the increased effectiveness of house bank charging while running the engine means you are much less likely to arrive at that dock in a deeply discharged state.
Instead of spilling a relatively unregulated stream of overflow amps/volts to your house bank like a VSR setup, the Sterling can be set to best charge your house bank with correct voltage for the battery type in a smart/multistage fashion. I would not use a VSR system to pass an AC charge to any bank for an extended period such as during storage but with the Sterling or similiar units, no problem.
A larger AC charger up to 30amps could also be used if someone was often in a charging hurry or trying to top off with a generator.
The warning about installation and avoiding proximaty to fuel tanks and other explosive environments is pretty common in the literature for installed electronics and common sense should be exercised.
I use AGM batteries only so the worry about battery gasses is minimized.
waterproof, smarter charging, less wiring, no manual switching, smaller/simpler AC charger required, similar cost to VSR setup, simple install.....these reasons obviously swayed me
Greg
I run it in full auto so that it can activate for AC charging at home on the trailer.
All most users would need is a small (5 amp) multistage AC charger connected to the start battery which in turn would charge the second bank as well when the Sterling unit senses an excess of power at the start battery. Of course it will not allow the start battery to go below a set voltage but there is no manual switching for that protection. This small charger would mean your recharge time on AC would be slow if deeply discharged but most cruisers are connected to AC for overnight periods. Also, the increased effectiveness of house bank charging while running the engine means you are much less likely to arrive at that dock in a deeply discharged state.
Instead of spilling a relatively unregulated stream of overflow amps/volts to your house bank like a VSR setup, the Sterling can be set to best charge your house bank with correct voltage for the battery type in a smart/multistage fashion. I would not use a VSR system to pass an AC charge to any bank for an extended period such as during storage but with the Sterling or similiar units, no problem.
A larger AC charger up to 30amps could also be used if someone was often in a charging hurry or trying to top off with a generator.
The warning about installation and avoiding proximaty to fuel tanks and other explosive environments is pretty common in the literature for installed electronics and common sense should be exercised.
I use AGM batteries only so the worry about battery gasses is minimized.
waterproof, smarter charging, less wiring, no manual switching, smaller/simpler AC charger required, similar cost to VSR setup, simple install.....these reasons obviously swayed me
Greg
I’ve been trying to deal with kind of the same issue. I would like to actually isolate one of my two batteries as the house battery and also have it available as a backup, just in case I need the extra juice for a both engine start. I currently have a BEP Bidirectional VSR which will always charge the non-selected battery, once the selected batter is fully charged. It has the integrated VSR and the 1, 2, both and off switch settings.
My thoughts are to run a live power cable from the hot switch side of what I want to be the house battery. I would then put an inline on-off switch, which in turn would go to the 50 amp house breaker The 50 amp breaker then connects to the house breaker panel.
Anyone got any comments or see any issues with this approach? As with many of us, I don’t have a lot of room in the aft starboard locker, so just the additional switch, is going to be a tight squeeze.
Thanks Jim
My thoughts are to run a live power cable from the hot switch side of what I want to be the house battery. I would then put an inline on-off switch, which in turn would go to the 50 amp house breaker The 50 amp breaker then connects to the house breaker panel.
Anyone got any comments or see any issues with this approach? As with many of us, I don’t have a lot of room in the aft starboard locker, so just the additional switch, is going to be a tight squeeze.
Thanks Jim
Tim & Dave Kinghorn
New member
Hi Jim-
I am assuming you are referring to the #2 post of the 4-way switch to which your house battery is connected.
Instead of a switch in the starboard, aft compartment, why not use the Blue Seas Thermal Breaker and switch combination (BlueSeas series 187 @59.99. See Defender on-line catalog). This gives you the circuit breaker protection and an on/off switch in one. You could see put a switch forward at the house panel if you wish (I would probably run #6 wire forward for minimum voltage drop).
Tim & Dave Kinghorn
I am assuming you are referring to the #2 post of the 4-way switch to which your house battery is connected.
Instead of a switch in the starboard, aft compartment, why not use the Blue Seas Thermal Breaker and switch combination (BlueSeas series 187 @59.99. See Defender on-line catalog). This gives you the circuit breaker protection and an on/off switch in one. You could see put a switch forward at the house panel if you wish (I would probably run #6 wire forward for minimum voltage drop).
Tim & Dave Kinghorn
That is kind of what I have today. I have an intergrated breaker/switch with #6 wire that goes to the main house block, but the battery swicth also controls power to the breaker/switch. I just want the battery switch to control which battery i use to start the engine with. The VRS will keep both batteries charged. I want to directly connect what I call the house battery to the breaker/switch and then on to the main house breaker/block.
Does this make sence?
Thanks Jim
Does this make sence?
Thanks Jim
Use the breaker switch you have now. It should be within 7" (by ABYC standards) of the battery. However doing this, you do not have the option of running the start battery as a house battery, without some re-wiring.
The advantage of having the house separate, is that you don't subject the electronics to voltage surges during engine start--and that is a plus.
The advantage of having the house separate, is that you don't subject the electronics to voltage surges during engine start--and that is a plus.
Great, thanks. I'm OK with not having a backup for the House that I can switch to. If I have to later, i'll see if i can fit another switch, so I can flip between them in an emergency. It's just so tight in the locker, that anything you want to add is a chore. Yes I wanted to get the House off the start battery for the very reason you mentioned. My electronics shut down every time I restart the engine, which can't be good for them.
Jim
Jim
Tim & Dave Kinghorn
New member
Hi Jim
I'm guessing the start battery is connected to terminal 1 of the switch; the house battery is connected to terminal 2, and the engine and the house circuit are connected to the common terminal.
If this is true, when you select the start battery (terminal 1) the house circuit is still connected through the common terminal along with the engine.
And when you select the house battery (terminal 2), you can start the engine as the engine and the house circuit are still connected to the common terminal, and the start battery is out of the circuit.
It would then suggest that the solution would be to move the house circuit from the common terminal to terminal 2. If your circuit breaker/switch is now connected to terminal 2, you would have the ability to disconnect the house circuit via the circuit breaker switch. Your VSR still connects to both batteries.
Now, when you select position 1 on the switch, the start battery is connected to the engine, but the house circuit is connected to position 2 and is not affected by the starting load. When the start battery is charged, the VSR will automatically switch the charging load to the house battery.
If you wish to have an additional on/off switch, you could install it forward where the #6 house lead attachs to the housing distribution fuse panel.
if you go to our photo page, you can see a similar set-up on our boat (An Electrical and Voltage Control Module for our Venture).
I'm guessing the start battery is connected to terminal 1 of the switch; the house battery is connected to terminal 2, and the engine and the house circuit are connected to the common terminal.
If this is true, when you select the start battery (terminal 1) the house circuit is still connected through the common terminal along with the engine.
And when you select the house battery (terminal 2), you can start the engine as the engine and the house circuit are still connected to the common terminal, and the start battery is out of the circuit.
It would then suggest that the solution would be to move the house circuit from the common terminal to terminal 2. If your circuit breaker/switch is now connected to terminal 2, you would have the ability to disconnect the house circuit via the circuit breaker switch. Your VSR still connects to both batteries.
Now, when you select position 1 on the switch, the start battery is connected to the engine, but the house circuit is connected to position 2 and is not affected by the starting load. When the start battery is charged, the VSR will automatically switch the charging load to the house battery.
If you wish to have an additional on/off switch, you could install it forward where the #6 house lead attachs to the housing distribution fuse panel.
if you go to our photo page, you can see a similar set-up on our boat (An Electrical and Voltage Control Module for our Venture).
Hi, I like your setup and wish I had the room to do anything close to what you have. When I was looking at buying a CD, I always liked the Venture for the extra room and layout. The extra foot and the bigger beam helps a lot. Unfortunately, there was not Venture close to me on the east coast when I was looking and I think CD was in bankruptcy. So I bought a 2007 CD 22 from stock in 2008. Still love the boat, but you know how it is, sometimes you just wish things were just a little bigger.
In any case, what you mentioned is exactly what I am going to do. As my second battery is between the two gas tanks on the floor, I will probably upgrade that to a group 27 and make that the house battery. I will then go with your idea and flush mount a switch at the helm, as I have room there.
Thanks again for your comments and help.
Jim
In any case, what you mentioned is exactly what I am going to do. As my second battery is between the two gas tanks on the floor, I will probably upgrade that to a group 27 and make that the house battery. I will then go with your idea and flush mount a switch at the helm, as I have room there.
Thanks again for your comments and help.
Jim
Anyone ever try to use these types of Battery Switches and VSR combos? They seem to imply that this is a dual VRS, with an emergency high capacity override that duals the batteries for an engine start. In looking at the diagrams, I can’t see any way that they can duals the batteries, unless they use the VRS wire connections, which I think would fry if you put that amount of Amps thru them.
Here is the link to the units
http://www.bepmarine.com/home-mainmenu- ... ery-switch
Thanks Jim
Here is the link to the units
http://www.bepmarine.com/home-mainmenu- ... ery-switch
Thanks Jim