I have a single group 27 deep cycle battery on the "house circuit". It's about three years old. Anticipating an extended trip this summer, I'm thinking I probably need at least two group 27 batteries on that circuit.
Questions: I've heard that you can't connect a new battery in parallel with an old one due to differences in potential and the desire of the stronger one to try and "charge" the weaker. True? Second, I read in an old posting that the lead to the panel should come off one battery, and the lead to ground should come from the other. Correct?
My existing deep cycle (and the starting battery as well) shows 12.5 volts when fully charged. Does this sound high enough? The charger is a Guest 2505.
Larry, I know you're out there somewhere......
Kevin LeMans
CD30 Raconteur
lemans@gte.net
House Battery Bank
Moderator: Jim Walsh
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john
Re: House Battery Bank
12.5 volts is good. When charging should be 14.5.K. LeMans wrote: I have a single group 27 deep cycle battery on the "house circuit". It's about three years old. Anticipating an extended trip this summer, I'm thinking I probably need at least two group 27 batteries on that circuit.
Questions: I've heard that you can't connect a new battery in parallel with an old one due to differences in potential and the desire of the stronger one to try and "charge" the weaker. True? Second, I read in an old posting that the lead to the panel should come off one battery, and the lead to ground should come from the other. Correct?
My existing deep cycle (and the starting battery as well) shows 12.5 volts when fully charged. Does this sound high enough? The charger is a Guest 2505.
Larry, I know you're out there somewhere......
Kevin LeMans
CD30 Raconteur
John CD31 #18
redzeplin@yahoo.com
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bob loewenstein
Re: House Battery Bank
I would suggest you measure your electrolyte to give a better indication of your battery's health.
rfl@yerkes.uchicago.edu
rfl@yerkes.uchicago.edu
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Larry DeMers
Re: House Battery Bank
Hi Kevin!
Planning for a trip sure gets complicated, doesn't it? (We're planning a long one also). About your battery system. It depends on how much your budget will allow. A proper system with redundancy, will mean a bit of rewiring or rearranging your current system. If your budget is tight then a minimalist approach would be best. I'll shoot you some ideas on both. THis wil take a bit..I can't seem to describe well in few words, so I apologize if these run too long.
A. Minimalist Approach
THe idea here will be to concentrate on providing maximum security against loss of 12vdc availability while minimalizing new components and cost.
The downside is that your security is not as good as a full 3 bank system. Your charging will not be the required 3 stage protocol for deep discharge cells which means a shorter life between recharging because the cell is not getting a full charge ever, and shorter overall life due to the increased cycling of the cells, and intercellular buildup of crystal growth, which eventualy shorts out neighboring cells. But you can then buy cheap deep discharge batteries (~$45), and work them for their thre or four years of life, then start over...or upgrade.
This system consists at a minimum, of: 1 Group 27 or 31 (better) Deep Discharge battery in a case. This is the house battery, and is not for starting. It is wired to the houses own battery on-off switch.
Next, a truck starting battery..non-deep discharge, in a case. This is wired through a battery switch or 1-2-both-off switch to the starter circuit. If the 1-2-both-off switch is used, you can run the second input over to the house battery for emergency starting should the start battery fail (SECURITY).
You need a good quality digital voltmeter, preferably panel mounted, with which to monitor your cutoff voltage for charging (13.6v). More than probably, you will not see more than 12.8v or so from that charger. This means that the battery is not fuly charging. The difference between 13.6v and your reading is the amount of missing charge.
2. 3 Bank System
In this system, you have two house cells and a third cell for starting. Each cell has it's own 1-2-both-off switch, with the switches output going to the device it is meant for. House 1 & 2 banks are for that exactly. With a group 27, you have 65 AH to a flat battery. Since the idea is to use the battery more than once..you probably want to count on about a 50% discharge as the stop point..so a group 27 will provide roughly 33 AH. A group 31 has a rating off 90-100AH, with 50 AH useable to the 50% discharge point. So if you load up on 2 group 31's for the house 1 & 2 banks, you would have 100 AH available before recharging is needed..and still have a fresh starting battery to do it with.
The starting battery is isolated from it's buddies as before, and never ever used for anything else but starting. It is a truck starting battery, not a deep discharge battery. Immediately, the first benefit will be noticed. The engine spins over a lot faster with the true starting battery (due to the internal construction of the two types of batteries, the starting battery gives up current easier and faster than a deep discharge battery, which can put out current continuously for far longer than the starting battery).
Now for recharging these banks. West Marine and Heart Interface make a device called a Battery Combiner. You probably remember the combiner diodes that Guest sold/sells still, and the reason not to ever use them..so won't repeat that now. The Battery Combiner for THREE BATTERIES, has two relays and some controlling logic on a small metal frame, and sells for around $150. It's well worth it! It is connected to all three batteries at it's output, and to the alternator and charger (and solar regulator, windmill, nuclear generator, fuel cell whathaveyou..)at it's input. It's function is this, and the Heart unit I have works fabulously. It notes when the charger is on, compares the incoming voltage to the individual battery voltages and consults the preset voltage that you ascribed to that battery. If the incoming voltage is higher than the battery, then the appropriate relay is closed, and that battery is charged. Once it reaches the preset max. charge voltage (13.6v), the relay opens, stopping the charge. This same action occurs for the two house batteries, while the start battery will recharge based on it's internal resistance...all off of this little relay frame called a Battery Combiner. I highly recommend this for you.
Lastly, the don't's with batteries:
Don't Hard-Wire your house bank in parallel with another battery, regardless of their individual size, weight, age, group, sex or national origin..ever. The higher voltage battery will discharge into the lower voltage battery, until they are equalized. So if one cell fails in bank one, shorting to it's neighboring cell, dropping that batteries voltage by 2v, there will be a quite strong effort on the part of bank 2's cells to output their voltage into bnak 1 until their voltages are equal. This could take on interesting symptoms, like profuse bubbling etc..caps going blam...generally, this is viewed as a problem. Use the 1-2-both-off switches that came with your boat, or up grade, and enjoy better operations.
Don't let the cell separators ever show above the electrlyte line. As soon as this happens, sulphation starts to occur in that cell, and that is the beginning of the end for that cell.
This is way too long.. I hope it helps a bit. Wrtie me if you have anything else..be glad to give it a swack..
Cheers,
Larry DeMers
s/v DeLaMer
Cape Dory 30 We're actually on the boat again!
demers@sgi.com
Planning for a trip sure gets complicated, doesn't it? (We're planning a long one also). About your battery system. It depends on how much your budget will allow. A proper system with redundancy, will mean a bit of rewiring or rearranging your current system. If your budget is tight then a minimalist approach would be best. I'll shoot you some ideas on both. THis wil take a bit..I can't seem to describe well in few words, so I apologize if these run too long.
A. Minimalist Approach
THe idea here will be to concentrate on providing maximum security against loss of 12vdc availability while minimalizing new components and cost.
The downside is that your security is not as good as a full 3 bank system. Your charging will not be the required 3 stage protocol for deep discharge cells which means a shorter life between recharging because the cell is not getting a full charge ever, and shorter overall life due to the increased cycling of the cells, and intercellular buildup of crystal growth, which eventualy shorts out neighboring cells. But you can then buy cheap deep discharge batteries (~$45), and work them for their thre or four years of life, then start over...or upgrade.
This system consists at a minimum, of: 1 Group 27 or 31 (better) Deep Discharge battery in a case. This is the house battery, and is not for starting. It is wired to the houses own battery on-off switch.
Next, a truck starting battery..non-deep discharge, in a case. This is wired through a battery switch or 1-2-both-off switch to the starter circuit. If the 1-2-both-off switch is used, you can run the second input over to the house battery for emergency starting should the start battery fail (SECURITY).
You need a good quality digital voltmeter, preferably panel mounted, with which to monitor your cutoff voltage for charging (13.6v). More than probably, you will not see more than 12.8v or so from that charger. This means that the battery is not fuly charging. The difference between 13.6v and your reading is the amount of missing charge.
2. 3 Bank System
In this system, you have two house cells and a third cell for starting. Each cell has it's own 1-2-both-off switch, with the switches output going to the device it is meant for. House 1 & 2 banks are for that exactly. With a group 27, you have 65 AH to a flat battery. Since the idea is to use the battery more than once..you probably want to count on about a 50% discharge as the stop point..so a group 27 will provide roughly 33 AH. A group 31 has a rating off 90-100AH, with 50 AH useable to the 50% discharge point. So if you load up on 2 group 31's for the house 1 & 2 banks, you would have 100 AH available before recharging is needed..and still have a fresh starting battery to do it with.
The starting battery is isolated from it's buddies as before, and never ever used for anything else but starting. It is a truck starting battery, not a deep discharge battery. Immediately, the first benefit will be noticed. The engine spins over a lot faster with the true starting battery (due to the internal construction of the two types of batteries, the starting battery gives up current easier and faster than a deep discharge battery, which can put out current continuously for far longer than the starting battery).
Now for recharging these banks. West Marine and Heart Interface make a device called a Battery Combiner. You probably remember the combiner diodes that Guest sold/sells still, and the reason not to ever use them..so won't repeat that now. The Battery Combiner for THREE BATTERIES, has two relays and some controlling logic on a small metal frame, and sells for around $150. It's well worth it! It is connected to all three batteries at it's output, and to the alternator and charger (and solar regulator, windmill, nuclear generator, fuel cell whathaveyou..)at it's input. It's function is this, and the Heart unit I have works fabulously. It notes when the charger is on, compares the incoming voltage to the individual battery voltages and consults the preset voltage that you ascribed to that battery. If the incoming voltage is higher than the battery, then the appropriate relay is closed, and that battery is charged. Once it reaches the preset max. charge voltage (13.6v), the relay opens, stopping the charge. This same action occurs for the two house batteries, while the start battery will recharge based on it's internal resistance...all off of this little relay frame called a Battery Combiner. I highly recommend this for you.
Lastly, the don't's with batteries:
Don't Hard-Wire your house bank in parallel with another battery, regardless of their individual size, weight, age, group, sex or national origin..ever. The higher voltage battery will discharge into the lower voltage battery, until they are equalized. So if one cell fails in bank one, shorting to it's neighboring cell, dropping that batteries voltage by 2v, there will be a quite strong effort on the part of bank 2's cells to output their voltage into bnak 1 until their voltages are equal. This could take on interesting symptoms, like profuse bubbling etc..caps going blam...generally, this is viewed as a problem. Use the 1-2-both-off switches that came with your boat, or up grade, and enjoy better operations.
Don't let the cell separators ever show above the electrlyte line. As soon as this happens, sulphation starts to occur in that cell, and that is the beginning of the end for that cell.
This is way too long.. I hope it helps a bit. Wrtie me if you have anything else..be glad to give it a swack..
Cheers,
Larry DeMers
s/v DeLaMer
Cape Dory 30 We're actually on the boat again!
K. LeMans wrote: I have a single group 27 deep cycle battery on the "house circuit". It's about three years old. Anticipating an extended trip this summer, I'm thinking I probably need at least two group 27 batteries on that circuit.
Questions: I've heard that you can't connect a new battery in parallel with an old one due to differences in potential and the desire of the stronger one to try and "charge" the weaker. True? Second, I read in an old posting that the lead to the panel should come off one battery, and the lead to ground should come from the other. Correct?
My existing deep cycle (and the starting battery as well) shows 12.5 volts when fully charged. Does this sound high enough? The charger is a Guest 2505.
Larry, I know you're out there somewhere......
Kevin LeMans
CD30 Raconteur
demers@sgi.com
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Joe Cioffi
Re: House Battery Bank
Hello Kevin,K. LeMans wrote: I have a single group 27 deep cycle battery on the "house circuit". It's about three years old. Anticipating an extended trip this summer, I'm thinking I probably need at least two group 27 batteries on that circuit.
Questions: I've heard that you can't connect a new battery in parallel with an old one due to differences in potential and the desire of the stronger one to try and "charge" the weaker. True? Second, I read in an old posting that the lead to the panel should come off one battery, and the lead to ground should come from the other. Correct?
My existing deep cycle (and the starting battery as well) shows 12.5 volts when fully charged. Does this sound high enough? The charger is a Guest 2505.
Larry, I know you're out there somewhere......
Kevin LeMans
CD30 Raconteur
First I want you to know that I am and have been a marine certified electrian for the past 18 years.
Yes you do not want to connect in parallel a weak battery with a new one it will drain the new one down to the same level.If you are connecting the two in parallel it does not make a difference because the positives will be connected together and than the negitives will be connected together so you end up with one of each.
My suggestion would be to first see if you can load test the first and see how it is taking a charge.Better yet replace it.And install two 27's and install a paralleling switch inthat way you can equally use one than the other and incase you have a problem you can always parallel the two together.
12.5 volts after it has sit off charge for a while is very border line.A fully charged battery voltage is 12.6 - 12.8.And the true fact is 12.4 is just about a fully DISCHARGED battery,so those few 10's of a volt is very critacal.
If you need any help in the wiring of a switch let me know and I can help you.
Good Luck
JGC2@PRODIGY.NET
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Ken Cave
Re: House Battery Bank
More thought to add to the confusion of batteries! Have you measured your needs?!!? I had a Catalina 25 with just one gel battery that would last me on a seven day trip without the worry of recharging. Why? I had a stereo, an Autohelm, and a portable GPS.
On my Cape Dory 28 (which is equipped with four six volt batteries for the house system as well as one large 12 volt battery for the engine ) the former owner installed a radar, frig, windless, TV and VCR, inverter, microwave, etc.
Now, with the Adler Barbour running while at dock, I can safely rely on the house batteries for about four days without charging.
Also, when you measure your system for use, also think of keeping your batteries up to snuff with a decent monitor (Link 20) and an in-charge regulator.
Yup, you are either gonna pay the money now, or later!! Better be safe than sorry!!
Ken Cave
bcave@whidbey.net
On my Cape Dory 28 (which is equipped with four six volt batteries for the house system as well as one large 12 volt battery for the engine ) the former owner installed a radar, frig, windless, TV and VCR, inverter, microwave, etc.
Now, with the Adler Barbour running while at dock, I can safely rely on the house batteries for about four days without charging.
Also, when you measure your system for use, also think of keeping your batteries up to snuff with a decent monitor (Link 20) and an in-charge regulator.
Yup, you are either gonna pay the money now, or later!! Better be safe than sorry!!
Ken Cave
bcave@whidbey.net
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Larry DeMers
Re: House Battery Bank -addendum to previous post
I should have added several more elements to the epistle that i published above..I added a large charger/inverter (Heart), Link 2000 for the two house banks, and a LINK 10 for the starter bank. Then we get into the alternator and 3 stage regulator which is where I am at now.
This is now a fairly robust, self-charging system with redundancy and security from catastrophic cell failure.
Larry
demers@sgi.com
This is now a fairly robust, self-charging system with redundancy and security from catastrophic cell failure.
Larry
demers@sgi.com
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Warren Kaplan
Re: House Battery Bank -addendum to previous post
Mind you Larry had to take all the berths out of DeLaMer to fit all this stuff!!Larry DeMers wrote: I should have added several more elements to the epistle that i published above..I added a large charger/inverter (Heart), Link 2000 for the two house banks, and a LINK 10 for the starter bank. Then we get into the alternator and 3 stage regulator which is where I am at now.
This is now a fairly robust, self-charging system with redundancy and security from catastrophic cell failure.
Larry
Warren
Setsail728@aol.com
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Patrick Turner
Re: House Battery Bank
You might check the Ample Power web site. I'll try and include it in this post, otherwise do a search. They have a lot of information re: this sort of thing. I believe their current philosophy is to have a single starter battery and one house bank, which of course can be comprised of mulitple batteries in parrallel to form a large house bank.
http://www.amplepower.com/
Pat
patrick.t@home.com
http://www.amplepower.com/
Pat
patrick.t@home.com