new batteries

[VidaliA]

My cape dory 28 needs new batteries. I have a single house bank and a starting battery. There is nothing out of the ordinary on board to consume energy. Just the basics. I have a 14 horsepower universal diesel. I am not sure what is the best type of battery for this application. I have had deep cycles on board and they seem to work ok. Any advice is appreciated..
Thanks

[Russell]

My cape dory 28 needs new batteries. I have a single house bank and a starting battery. There is nothing out of the ordinary on board to consume energy. Just the basics. I have a 14 horsepower universal diesel. I am not sure what is the best type of battery for this application. I have had deep cycles on board and they seem to work ok. Any advice is appreciated..
Thanks

You definately want deep cycle. Outside of that you have choices between lead acid, agm and gel. Considering what you said (just the basics) I doubt the expense of AGM or gel is worth it for you. I would recommend getting deep cycle lead acid batteries, and as far as though I would strongly recommend Trojans, considered by many cruisers to be the best bet. If your old batteries gave you plenty of power for your needs I would just stick with the same size you already had.

[Neil Gordon]

I've done well with two deep cycle lead acid batteries. I rotate their use as house bank (#1 in the odd months, #2 in the even months) and use both for starting.

Is there a reason you dedicate one to house and one to starting?

[VidaliA]

I guess I just use one for the starting battery out of habit. I see it is better to alternate them.

Question: If the house bank is down 50%, and I want to start the engine. Should I switch the battery switch to all or to just the other battery?? I was thinking that by switching it to all it was equalizing the charge, therefore wearing down my starting battery??
thanks for the help.

[Neil Gordon]

Question: If the house bank is down 50%, and I want to start the engine. Should I switch the battery switch to all or to just the other battery?? I was thinking that by switching it to all it was equalizing the charge, therefore wearing down my starting battery??
thanks for the help.

Conventional wisdom is to "age" your batteries equally. If you're using a 1/2/both switch, then pick a scheme to rotate usage for house needs. When starting, use both to start and recharge. Don't switch with the engine running.

It's common to use 1 or 2 for house based on day of the week, odd or even. I switched to months while living on board, since I wasn't recharging every day.

[Bob M.]

I guess I just use one for the starting battery out of habit. I see it is better to alternate them.

Question: If the house bank is down 50%, and I want to start the engine. Should I switch the battery switch to all or to just the other battery?? I was thinking that by switching it to all it was equalizing the charge, therefore wearing down my starting battery??
thanks for the help.

If this is the case it is a good idea to switch to "All" this way you use both batteries to start the engine then your house bank will also charge up. I do the same in using one battery as the house battery and one as the starter battery. I label them number 1 and number 2 and swap them each year when reinstalling them before the boat goes into the water. Using this method I have gone thru only 3 sets of batteries since 1985. Make sure to charge them up real good using a good battery charger rated for your battery capacity before installing them each spring. Charge them also when you remove them from the boat each fall before winter storage. I store mine on a shelf in the garage off the floor for the winter storage. Take care of your batteries and they will take care of you when you need them.

[Dan & Pat]

Contrary to common belief, most marine (or automotive) alternators are not designed to act as battery chargers, rather to maintain a charge while the motor is running. Although it will work, it is not good for the battery or the alternator.

A Starting Battery should be the one you use for starting and running your motor. (period!) It should be maintained at 95% charge at all times. These batteries are not designed to be drained and re-charged repeatedly. Starting puts a quick and powerful drain on these batteries, and once the motor is started, the alternator kicks back that charge into it. If or when the charge goes below 75%, the alternator will re-charge it, but it puts a tremendous strain on the electrical system and battery.

A Deep cycle battery, on the other hand, is designed to be able to handle being gradually drained and recharged, and not hit with a big discharge load like starting your motor. These should be re-charged gradually, using a charger not your alternator. The alternator will over-heat and most likely boil your battery.

A compromise is to use a dual-purpose Starting/Deep Cycle battery, but it is in fact a compromise. You don't really get the best of both worlds, you get the worst - a battery that is less expensive than a deep-cycle, but will have a shorter life span.

On the topic of using dual batteries and a switch: I recommend not using the "both" setting unless absolutely necessary for getting started in an emergency. When you jumper two batteries together, the stronger one discharges into the weaker one. Using this method also doubles the strain on your alternator, causing diodes to overheat and fail quickly.

Further, NEVER SWITCH FROM ONE TO THE OTHER OR BOTH WHILE THE KEY IS ON OR THE MOTOR IS RUNNING. (That's right I'm yelling!) Unless you have one of the newer digital switches, there is a momentary gap where there is no connection, then a spark when the contact is made. . . ZAP! There goes another diode, and chances are, you won't know it until your batteries are dead.

[Boyd]

Hi All:

A friend of mine, who cruised for 20 years, helped me set up my boat this way. Its been two years since my AGM's quit without warning and I couldnt be happier with this new setup. I take week cruises and plan on longer ones. I like simple. All that is required to keep things running is awareness of the battery charge condition.

I have a house bank of 440 ah using Trojan 105's (4 golf cart batteries) and a starting battery which is a standard sealed automotive group 24. I charge these with a 75 amp. automotive type internally regulated alternator. I have a Statpower 3 stage battery charger and a Link 10. The Statpower gives the batteries a good 3 stage charge when I am tied to shore power. No solar or wind power yet.

I use a standard 1-2-all switch. I run with the switch set to the house bank almost all the time. To start the engine in the morning I switch from the house bank to ALL. I run the engine (motoring out of the anchorage, set up sails, etc. )as long as needed till the charge rate falls to 15 amps or so. This usually takes an hour. The system usually initially charges at about 50 amps and tapers off. If I am motoring more than an hour or so I flip the switch to the house bank. YES I flip it while the engine is running because the switch is a "make before break" type. Just DONT flip it to "OFF" when the engine is running. Been doing this for years and have yet to lose an alternator. Verify your switch is that type before you fry the diodes.

My typical draw in 24 hours while living aboard with refrigeration, showers, lights, sterio, microwave, etc, no sacrifices here, Is about 50 amp hours so my bank will last conservatively 4 days to 50% discharge. The starting battery is theoretically fully charged at all times. My discharge/recharge pattern usually results in slowly diminishing the total house bank charge but rarely do I get below - 100 amp hours even after several days.

I dont have a complex 3 stage alternator regulator because it would take something like 24 hours motoring to float out the batteries. I work between 80% and 50% discharge at all times. The golf cart batteries are tough and are made for this type of situation.

Your type of sailing may not require the amount of battery capacity that I do so using a 200 ah bank may make more sense. I found that standard group 27 deep discharge simply didnt have the capacity to run anchor lights, and minimum loads over night.

Boyd
s/v Tern
CD30 MkII
Fort Lauderdale,Fla.

[Bob M.]

Contrary to common belief, most marine (or automotive) alternators are not designed to act as battery chargers, rather to maintain a charge while the motor is running. Although it will work, it is not good for the battery or the alternator.

A Starting Battery should be the one you use for starting and running your motor. (period!) It should be maintained at 95% charge at all times. These batteries are not designed to be drained and re-charged repeatedly. Starting puts a quick and powerful drain on these batteries, and once the motor is started, the alternator kicks back that charge into it. If or when the charge goes below 75%, the alternator will re-charge it, but it puts a tremendous strain on the electrical system and battery.

A Deep cycle battery, on the other hand, is designed to be able to handle being gradually drained and recharged, and not hit with a big discharge load like starting your motor. These should be re-charged gradually, using a charger not your alternator. The alternator will over-heat and most likely boil your battery.

A compromise is to use a dual-purpose Starting/Deep Cycle battery, but it is in fact a compromise. You don't really get the best of both worlds, you get the worst - a battery that is less expensive than a deep-cycle, but will have a shorter life span.

On the topic of using dual batteries and a switch: I recommend not using the "both" setting unless absolutely necessary for getting started in an emergency. When you jumper two batteries together, the stronger one discharges into the weaker one. Using this method also doubles the strain on your alternator, causing diodes to overheat and fail quickly.

Further, NEVER SWITCH FROM ONE TO THE OTHER OR BOTH WHILE THE KEY IS ON OR THE MOTOR IS RUNNING. (That's right I'm yelling!) Unless you have one of the newer digital switches, there is a momentary gap where there is no connection, then a spark when the contact is made. . . ZAP! There goes another diode, and chances are, you won't know it until your batteries are dead.

Wow this post is interesting as I have never heard that putting both lead acid batteries on line with the alternator charging over heats the diodes? I do realize that when going to "All" position the higher charged battery will drain to the lower charged battery unless they are isolated. However, in the instance I am using the 'All" selector I am only starting the engine which is then going to charge both batteries. Once the engine is off I immediately go to the house battery. What is interesting is that I have been doing this for years and years and never over heated a diode.

Also I agree that you should never switch your battery selector while the engine is running to prevent frying your diode unless you have a switch which has been designed for switching while under load.

I would be interested in hearing from our resident electrical and battery expert Larry DeMers to see if this is consistent with what we have heard?

[Clay Stalker]

I guess I do approximately what Neil does....I have two group 27 deep cycle lead acid batteries on Yankee Lady. I start the engine on "both," and run it, charging, on "both" also. Have never worried about boiling over the batteries, sometimes motoring for 4-5 hours at a time. I do keep my eye on the electrolyte and replenish as needed, which is just occasionally. When I am at anchor, I either use battery 1 or 2, and don't really have a system, just try to alternate. I have an original equipment alternator, and don't run real high usage stuff like refrigerators etc....but the CD player does run a lot....never had a problem with batteries. Replaced the batteries when I purchased Yankee Lady in 2003 and am expecting (no, hoping) to get a run of 8-10 years with them.

Clay Stalker

[Russell]

Wow this post is interesting as I have never heard that putting both lead acid batteries on line with the alternator charging over heats the diodes? I do realize that when going to "All" position the higher charged battery will drain to the lower charged battery unless they are isolated. However, in the instance I am using the 'All" selector I am only starting the engine which is then going to charge both batteries. Once the engine is off I immediately go to the house battery. What is interesting is that I have been doing this for years and years and never over heated a diode.

Also I agree that you should never switch your battery selector while the engine is running to prevent frying your diode unless you have a switch which has been designed for switching while under load.

I would be interested in hearing from our resident electrical and battery expert Larry DeMers to see if this is consistent with what we have heard?

It is correct that you should never, except in an emergency put a load on two seperate banks tied together. The ussual method is to start with your battery on your start bank, then switch to both AFTER the engine is started, since now there is a charge on them. Then before cutting off the engine switch it back to engine. Of course your battery selector switch should be the "make before break" style to do this. An easier method is to use a battery combiner for starting and do away with switching batteries all together.

You wire your alternator and other charge sources directly to the house bank, wire your starter directly to the engine start bank. Then between the two banks put in an automatic battery combiner (about $60) which senses charge voltage and automaticly combines them when there is a charge coming in so everything gets charged. Then in the system you put in an emergency combine switch you can use to combine the house and start banks in an emergency when the engine bank is having trouble starting for some reason. So other then in an emergency you never have to worry about switches and switching or doing things the right or wrong way, its all automatic and very simple. Almost all marine electricians nowadays recommend this wiring setup and I switched mine to this awhile back and it works without a hitch.

[Paul D.]

I have a simple set up that has worked well for three seasons. I just installed the Link 10 that was given to me three years ago so I should have more accurate info on the state of the batteries this season.

House bank is two Trojan T-105's for 220 amps, start is a good high CCA group 24. I have a $100 echo charge between the two which keeps the starter battery charged when the house bank is getting charged. It disconnects them when the charge drops below 13.25 volts or so.

When warm, I can start the motor on either bank and switch to house. When cold, as it usually is up on the north shore of Lake Superior, I start on all. There is a 60 watt solar panel with regulator that stays attached all the time, even in winter when I shrinkwrap the boat.

Since I am on a mooring I did not spend money on a good AC charger. the panel keeps things full when away and I just tip it away from the sun in winter and it trickle charges till spring. I have added water to the T 105's only last fall. The batteries can stay in the boat and we have plenty of power for our needs. About 50 amps/day more or less.

This set up was suggested to me by Ferris Power systems and it has worked well. For the 33, I just had to build a shelf for the larger 6 volt dual batteries and run the wiring. I like the simplicity of one battery switch, leaving the switch on house and not worrying about overcharging. Now with the link 10 I hope to really see how much we use when the fidge and autopilot are both running.

Anyway, I recommend the T-105's and a group 24 if you can fit them all in the 28.

Best of luck,

Paul

[rtbates]

You wrote

Further, NEVER SWITCH FROM ONE TO THE OTHER OR BOTH WHILE THE KEY IS ON OR THE MOTOR IS RUNNING. (That's right I'm yelling!)

You SURE about that?? I'm not. All the battery switches(The big RED 1/2/ALL type) that I've come across have been MAKE BEFORE BREAK for that very reason. Now IF you switch to OFF while running you may have trouble.

[Larry DeMers]

There is a lot going on in this post, so will handle this one statement at a time.

[quote="DanPat"]Contrary to common belief, most marine (or automotive) alternators are not designed to act as battery chargers, rather to maintain a charge while the motor is running. Although it will work, it is not good for the battery or the alternator.
.................................
This I take exception to. Alternators are certainly intended to act as a battery charger. Balmar has made a good business of just this fact. And they work. The diodes are rated for the current that they will pass, and they are heat sinked, so should not be damaged by battery charging under normal conditions.
........................................


A Starting Battery should be the one you use for starting and running your motor. (period!) It should be maintained at 95% charge at all times. These batteries are not designed to be drained and re-charged repeatedly. Starting puts a quick and powerful drain on these batteries, and once the motor is started, the alternator kicks back that charge into it.
........................................
True
.........................................


If or when the charge goes below 75%, the alternator will re-charge it, but it puts a tremendous strain on the electrical system and battery.
.........................................
Not true. The alternator will start charging when the battery internal resistance allows it. That usually is at a very small level. It just trickles the charge in if that is what is needed. It will not put any straqin on the alternator or electrical system..this is just silly.
.........................................


A Deep cycle battery, on the other hand, is designed to be able to handle being gradually drained and recharged, and not hit with a big discharge load like starting your motor.
........................................

Somewhat true, although the deep discharge batteries will start the motor, they will not spin as fast as when a proper starting battery is used.
........................................


These should be re-charged gradually, using a charger not your alternator. The alternator will over-heat and most likely boil your battery.
........................................
Not true at all. What is the regulator for anyway?
...........................................



A compromise is to use a dual-purpose Starting/Deep Cycle battery, but it is in fact a compromise. You don't really get the best of both worlds, you get the worst - a battery that is less expensive than a deep-cycle, but will have a shorter life span.

On the topic of using dual batteries and a switch: I recommend not using the "both" setting unless absolutely necessary for getting started in an emergency. When you jumper two batteries together, the stronger one discharges into the weaker one. Using this method also doubles the strain on your alternator, causing diodes to overheat and fail quickly.
. .........................................
You must have lost an alternator to overheating. You are overcautious unnecessarily.
..........................................


Use a battery combiner, and you will be a happy sailor!

Cheers,

[mahalocd36]

You wrote

Further, NEVER SWITCH FROM ONE TO THE OTHER OR BOTH WHILE THE KEY IS ON OR THE MOTOR IS RUNNING. (That's right I'm yelling!)

You SURE about that?? I'm not. All the battery switches(The big RED 1/2/ALL type) that I've come across have been MAKE BEFORE BREAK for that very reason. Now IF you switch to OFF while running you may have trouble.

I think there are some old switches that didn't 'make before break' while switching. But modern ones can handle this just fine. We switch between them when the engine is running, it's just fine.