Another Battery Question... Help!

This is tom/terraplane...been wanting to check out some things for some time, and now that there are some battery gurus on line here....

22 cd, new in 2005. Sally's Sister..been great no problems. Standard factory setup. mostly, but.Guest 10amp Charge Pro, two Optima blue top batteries, Perko switch (1,2,all, off) Shore power...

l. Should shore power be used just spoadically,; does it harm batteries to leave it hooked up for longer periods..couple of weeks?

2.When starting, do i start always with just one battery, and use the other just for house use? Or do I start with both on.

3.Do I shut off batteries when i'm at the dock for several days.

4. My batteries on on the deck, secured, between the gas tanks, sitting in trays and strapped down, just in front of the second bilge pump in stern. Water tends to collect in the black plastic trays..is this harming the batteries.

Guess that's it...any comments welcomed.

tom
 
Tom,

Only one of your questions can I help you with, and that's the one about the location of your batteries. It's ok to have them on the deck (although not preferable), but they should be enclosed in battery boxes to protect them from water and the elements. The reason for having them off the deck is that in the case of a boarding sea flooding the cockpit, it won't drown out you power. The battery boxes are supposedly designed to trap iar under the lid to prevent this, but I'd not want to depend on it.
 
Tom - disclaimer, I am no expert, just repeating what folks have told me, and if I am wrong, well, I trust somebody here will straighten us both out.

1. There is nothing wrong with leaving the shore power and charger connected all the time. The charger shuts off the charge when it senses the batteries are fully charged. The Optima (and virtually all batteries except NiCads) are best maintainted at a full charge all the time.

2. One battery should be dedicated to starting and the other dedicated to the house - the batteries should not be connected in the "Both" position except when the starting battery is too low to start the motor(s)

3. You do not need to shut the batteries off, but shutting them off at the swithc protects against anything that might be drawing power and could run them down.


terraplane":xwd7bbse said:
This is tom/terraplane...been wanting to check out some things for some time, and now that there are some battery gurus on line here....

22 cd, new in 2005. Sally's Sister..been great no problems. Standard factory setup. mostly, but.Guest 10amp Charge Pro, two Optima blue top batteries, Perko switch (1,2,all, off) Shore power...

l. Should shore power be used just spoadically,; does it harm batteries to leave it hooked up for longer periods..couple of weeks?

2.When starting, do i start always with just one battery, and use the other just for house use? Or do I start with both on.

3.Do I shut off batteries when i'm at the dock for several days.

4. My batteries on on the deck, secured, between the gas tanks, sitting in trays and strapped down, just in front of the second bilge pump in stern. Water tends to collect in the black plastic trays..is this harming the batteries.

Guess that's it...any comments welcomed.

tom
Click to expand...
 
terraplane said:
This is tom/terraplane...been wanting to check out some things for some time, and now that there are some battery gurus on line here....

22 cd, new in 2005. Sally's Sister..been great no problems. Standard factory setup. mostly, but.Guest 10amp Charge Pro, two Optima blue top batteries, Perko switch (1,2,all, off) Shore power...

l. Should shore power be used just spoadically,; does it harm batteries to leave it hooked up for longer periods..couple of weeks?

If your charger is a proper three stage one and for marine use, it will reduce the charge given to the batteries automatically and there is no danger of overcharging them. On the contrary, the very small trickle or float charge protects them at their optimum state. The properly installed shore power system shouldn't be a problem if left turned on to do this.


2.When starting, do i start always with just one battery, and use the other just for house use? Or do I start with both on.

You can start with either one if the one you're using is fully charged. If they are both down a bit, use them both. If one is really down, leave it out of use as it will just drag the other battery and starting system down. You want to start with as much voltage as you can muster. Low voltage starts are hard on the starting motor because the low voltage doesn't produce as much torque, and as a result, excessive amperage flows through the starter, resulting in heat build up. If both batteries are weak and you can tell the starting motor is straining and not turning close to normal speed, charge the batteries before you try to start the motor again. Too much heat and you'll throw the solder out of the armature windings, ruining the starter.


3.Do I shut off batteries when i'm at the dock for several days.

This depends on what you're doing, and what you mean by being at the dock for several days..occupied or unoccupied? As discussed above, if you leave the charger on, you're generally better off, as long as you regularly check on the system.

If you'll be periodically using the 12 volt system, you need to leave the charger on to replace the used capacity.

If, on the other hand, you'll be leaving the boat unoccupied and with no current drain, you can shut the batteries and charger off just for peace of mind, knowing that everything is at rest.


4. My batteries on on the deck, secured, between the gas tanks, sitting in trays and strapped down, just in front of the second bilge pump in stern. Water tends to collect in the black plastic trays..is this harming the batteries.

Answered just fine my Mike above!

Another common question regards leaving the shore power and charger systems on while you're away to be able to recharge the batteries which are being used by the bilge pumps.

For very small usage, the batteries will be just fine operating the pumps without recharging.

If it is felt or found out that they will need recharging during the absence period, the shore power and charging systems can be left on. I would, however, disconnect any appliances about which I had any misgivings about being left on line, even though they are turned off at the switch. This is done mostly for peace of mind, as we leave these things plugged in all the time at home with the switches off. I particularly unplug the electric heater and get it up off the floor where water could get to it if the bilge pumps fail.

Joe
Click to expand...
 
This is probably the best explanation I have found on battery wiring and use. http://continuouswave.com/whaler/refere ... ttery.html One other small note re charging. A few yrs ago at an aviation maint seminar I had a chance to talk with a battery rep. according to him it is the charge / discharge cycles that eventually kill a battery. (The lead sulfates sluff off of the plates and when they build up enough in the bottom they short out the cell) The more a battery can be kept topped off the longer it will last. some sort of a charger / maintainer is a good idea whenever the boat is where it can be plugged in. Just MHO
Norm
 
is there a way to see if a battery is leaking voltage?
Click to expand...
To check for external items that may be drawing current;

1. Make sure everything is off
2. Disconnect a lead to the battery. (doesn’t matter which one)
3. Hook a voltmeter in series with the battery lead and the battery terminal.
4. The voltmeter will have a voltage reading if you have anything drawing current.

Your question about my bilge pump. I can hear it when it cycles.
 
Norm,
Great find on the battery connection schematics reference. I use the "New" Dual Battery, dual engine setup. The engines are hardwired each to their own battery and the 1-2-BOTH-OFF switch common terminal goes to the cabin electronics. I alternate on trips between selecting battery 1 and battery 2, but try to always keep one battery at full charge at all times (I do not hook to shore power, rarely at dock except at get-togethers!).

Dave,
The voltmeter between the unhooked cable and battery will work, but if you have a multimeter, use the "amperage" function (connect the leads on the meter correctly), select a higher than you think range first then range down to avoid blowing the fuse in the meter (don't ask how I know this...). That will give you a measurement. I'd say 40 ma (0.040 amps) is too high as a steady current. When on a low range, be careful if/when the bilge pump cycles, could blow that fuse in the meter...

I run a very, very small trickle charger while boat is at home in between trips, usually 3-4 wks. It puts out a constant voltage, thus the amps (less than 1a max) goes down as the battery voltage goes up. It's the cheapest charger I think in the world, about $6.00 at Harbor Freight on sale. I put the battery switch in the BOTH position while it is hooked up to this charger, both batteries stabilize about 13.2-13.5 volts -- it is OK to connect in parallel as long as they're being charged. A bit higher than I'd like in voltage, but seems to be no harm. Solar panel(s) would also work fine. My batteries are nearly 4 yrs old now, still good energy capacity (where's that piece of wood...). I also run dual Link 10 monitors to keep an eye on everything.

Steve
 
Steve,

First, I found the Whaler site with those layout prior to my visit to the factory to work with the rigger. Took them with me, but he did not like them, saying, if I remember correctly, that the engine mfgs would not approve , and that they were for larger engines. As far as them being for larger engines, it is true that the BEP config for twin engines comes with a qualification that it only works for larger engines (over 200hp). That qualification is right on their site.

Am frustrated in not being abel to go down to the boat to solve this problem due to rain. Problem with shore power battery charger is that it takes an expensive adapter to mate it to a standard extension cord for charging while on it's trailer. Marinco is $50; I found one for $35.
 
Hi Folks,

I have two batteriess, and both are the same. (I have to look up what type they are.) I heard that you should have both batteries the same, and use only one at a time. I have no problem starting with the batteries I have. I have them on a three way switch, Battery A, Battery B, and both. If one battery gets used to much, like reading all night, I can start the engine with the good battery, and then switch through both batteries to the bad one, and let the engine charge it. I have a meter that, with a push of a button, can tell me the condition of the battery that I am presently using.

The reason for the same batteries. I have heard that you might have problems when you switch from one battery THROUGH both batteries to the second battery if they are not the same.

This has worked very well for me.

Fred Heap
 
Mike,

Not sure where you read the engine mfr's would not approve of each engine being directly connected to their own battery. My local Yamaha dealer said it was fine, but then again, they didn't know as much about their engines than I did...hmmm. Maybe it depends on engine make/model for their susceptability to switching glitches. My Perko battery switch is definitely a make-before-break type as most all are. That's essential to make sure the engine charging systems ALWAYS see a load. But I did install a 50 (or 100?) amp fuse in series with each engine connection to prevent an electrical fire in the event of a short.

Raining cats and dogs here now (Simi).

Steve
 
The problem with using batteries in parallel is that a strong one will discharge through the weak one, since it it putting out more electrical pressure, or voltage, or is in a higher state of charge, which is all the same thing.

This means that if you connect a fully charged battery with one that is discharged, a current will flow from the charged battery into the discharged one. The amount of curent or amperage flow depends on the voltage difference between the batteries.

A smaller difference and all that hapens is you have a moderate current flow and wind up with two batteries with their voltage readings and storage capacity averaged out as they seek equilibrium.

But as the condition of the two batteries gets greater, bad things can happen. The current flow can be so great as to cause the electrolyte in the weak battery to boil and explode in extreme cases.

Another problem occurs when one of the batteries has an internal condition which results in its self-discharge. In this case, paralleling the batteries will drain the good one right down into the condition of the self-discharged one.

So there's ample reason right here not to be connecting batteries in parallel, let alone the ones that center on keeping one battery in a fully charged state to start the engine(s).

Because of these reasons, we come up with the general rule for most applications to not use the batteries in parllel unless necessary.

However, it is possible to parallel two or more batteries if they are in the same age, general condition, and state of charge. If you are very sure that your two, three, or four or more batteries are of very equal condition and thus can avoid the pitfalls above, they can be connected in parallel to supply great amounts of amperage and/or simply to keep their states of charge equal. And they can also be charged as one big battery in this same simple way. Parallel usage and charging is much simpler than engaging in the constant switching batteries on and off as they are used, and then facing the same problem when trying to charge them equally.

To practice this, start out with all new batteries of the same make, capacity, etc., and monitor their independent voltage periodically to see that they are still in equal condition. When one starts to show variation, replace it immediately. If they are near the end of their expected life, replace them all. I'm currently doing this with four group 27 deep cycle marine batteries and have had no problems doing it over the years with first two, then four batteries.

Joe.
 
Joe,

Thanks for the reminder on paralleling batteries and "their condition". Common thinking when hooking up and using batteries in various applications is that they're NEW -- what could go wrong? I think we've all been there and experienced a premature battery failure or some other anomoly that comes along (Murphy comes to mind..). I'd rather not buy 2 batteries is one goes killing the good one, or worse, to see my CD go up in flames -- hmmm, bad picture... Paralleling is for short-duration, emergency stuff if you don't have isolators. BTW, any voltage imbalance between parallelled batteries is quickly transferred, limited only by the internal resistance of each battery (2 ft, 2-4AWG cables are VERY LOW resistance)!

That's it. I'm going out TODAY and spring for another $6 trickle charger at Harbor Freight so I can 'independently' maintain my batteries 'without' paralleling them. It'll double the current going into them, but hey, 2x0.01 amps ain't all that much!

Steve
 
Steve-

Thanks for the refinement of ideas regarding the paralleling of batteries and the caveat about paralleling!

Those who practice frequent and or long term paralleling of batteries definitely do run the risk of one of the batteries going bad and causing one of the problems mentioned.

The odds on having a problem are somewhere between those in Russian Roulette and those on winning the PowerBall Lottery, but where exactly I'm not sure. Determining those odds would take some investigation we would probably find they would depend a lot on the quality of care and supervision given the batteries.

Joe.
 
Dan-

Thoughtful and very true points on battery use! We all learn and sharpen our ideas from these discussions. Thanks for the ideas and additions! Joe.
 
A lot of good points about batteries and switch positions. A point of caution for us with twin engines. The use of "both" position on the battery switch is much different with twins.
 
years back having fried a new battery first trip out i than did a library thing if i read it right:

a regular battery will die if it is drawn lower than 10.3 new or other wise. it may still lite things up but when you hit the starter cross your fingers . first nite out i let the fridge run it down it was toast after that. the numbers may not be right on but a 12 volt battery runs between 10.3 and 12.7

battery's sitting for long periods ?? the plate's coat over this also shortens the life .. coats over with what?? can't remember but it's in the book. i think the trickle charge cure's this

another thing is my battery charger will show the green lite my little float in the tube thingy floats in the green, lites, spot lite every thing lites up but hit the starter which needs apox 200 amps its fried despite the OK readings

i think a separate starter battery and a separate house battery is a must. murphys law, things will catch up on you. i always switch off the starter battery when under way. have the three way switch

the last i read on deep cycle batters they can be drawn down 4-5 times but they also will fold if drained completely ... like a fridge running away no battery alarm ..

i'm into intergraded navigation items etc. but i think a starter battery should be on its own, separate from any other electrical thingy
 
I learned a few things about batteries when I bought my first Link 10 monitor. It's really a small computer that tracks and integrates current usage over time to calculate how much 'capacity' (amp-hrs) you've used. My batteries are combo deep/starting rated at 110 amp-hrs. According to the Link 10 literature, you can draw down a battery to a maximum of 50% of it's capacity. I shoot for about 70% maximum down just to add a little buffer.

For example, if you burn your 1 amp anchor light for 12 hrs overnight (actually the C-Dory standard (Perko) bulb draws slightly less), it will consume 12 amp-hrs. The % capacity remaining is then (110-12)/110 = .89 or 89%. If you also ran your stereo (assume 1 amp), 2 interior lights (1 amp each) and your Wallas heater (assume 1 amp) for 4 hrs before going to bed, that would be (1+2+1)*4 = 16 amp-hrs more used. % capacity remaining would be (110-12-16)/110 = .74 or 74%. The Link 10 does all this calculating in real time. Add a refrigerator, inverter, microwave, etc, well, better get more batteries to boost your capacity (amp-hrs).

All this is fine, good and accurate when the batteries are 'new'. The Link 10 doesn't take into account reduced capacity as the battery ages. But you can plug in a lower 'capacity' number say after 2 yrs to approximate that.

Notice the battery voltage doesn't come into play, just the current! There are more complex interactions that must be accounted for to accurately calculate capacity remaining, the Link 10 does that too. The faster you pull current out, the more rapid your capacity reduces (non-linear). Likewise when recharging, you have to put more back into the battery to bring back to the same charged capacity (Perkert's Law pronounced "Purr-cay" or "Purr-care" I forget).

Now I forgot the point I was trying to make other than voltage alone is not a good indicator of condition, depends on surface charge accumulation, temperature and several other factors. Lesson over, sorry if got carried away...

Steve
 
Batteries, electrical circuits, electronic devices, appliances, and the like are indeed complex topics with many facets and facts.

Read as much as you can and as often as you can. Some people find the topic more interesting and understandable than others.

No one will comprehend everything they read the first time through. The more you learn over a period of time, the more you gradually understand and can utilize in working on your boat.

Knowledge and skill in this subject is just like any other aspect of boating and seamanship: competency develops over a period of time with experience and shared knowledge.

You won't become an electrical engineer or a master mariner overnight, but patience and diligence will go a long way towards helping you become a better boat owner and skipper through the years.

Joe.
 
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