SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

Start Battery

6K views 35 replies 14 participants last post by  haffiman37 
#1 ·
After reading a couple of books (Nigel Calder especially), I wonder if the argument could be made to make your starting battery a true "starting" battery. Given the short use and high amps, wouldn't the thin-plated batteries be a better battery than more traditional deep cycle?

I am not saying you cannot use one for another, but the thin plates on a true start battery and quick surface charge (not to mention a lot lower cost), might make a true start battery a better option.

THoughts?
 
#2 ·
I have two group 27 gel cell batteries in parallel for the house battery and a wet cell, no maintenance starting battery to start the diesel motor. I think this makes sense, except that in charging them both, it may be causing some issues, though I have the charger/inverter set for the more sensitive gel cell batteries and don't use the equalizing function (posted this on another thread on this topic.).
I think your basic premise of using a starting battery is sound.
Frank.
 
#3 ·
Dad, a lot of boats now use exactly that. One cheap and small starting battery for starting, and one larger battery/bank for house use. If you match the starter current draw to what a deep cycle battery can supply as a surge load (i.e. starter load) then you can certainly use deep cycle for both, but the new logic seems to be reserving that special dedicated starter battery JUST for starting, and that also makes sure it is available when you need it. And, that it is cheap and easy to replace.
 
#4 ·
We have a similar setup - 400Ah in deep cycle and a standard high-cranking amp starting battery. Keep them separated, monitor the charge states individually - works great for us.
We never put house loads on the engine battery.
 
#5 ·
Indeed, keeping a separate REAL starting battery is the preferred way to go these days.

Re: charging, one of the simplest and most effective ways to keep both the starting battery and the house battery bank charged is to connect all charging sources to the HOUSE batteries, and to use a simple device which senses a charging load on the house batteries and diverts a bit of it to keep the starting battery topped off.

I've used such a device for several years with great success. Mine is a Xantrex EchoCharger which puts up to 15A into the starting battery whenever it senses at least 12.9 VDC or so on the house batteries. It is cheap, simple, and maintenance free. There are other manufacturers who make such devices as well.

Bill
 
#6 ·
I went a step further and put in a second alternator, a simple automobile type that is old enough that it has a separate regulator, but if I were doing it now I would get one with a built-in regulator.

I highly recommend this approach - I have used the redundancy several times.
 
#7 ·
I agree the best bet is a separate starting battery dedicated to that one function. On Wave Dancer I have a separate G24 starting battery and two
G27 house batteries wired in parallel. Also have space for a third house G27 if I need the extra amp hours. The charging systems either shore power or engine based keeps the system topped off nicely. This the classic way to go although you see all kinds of arrangements and views out there on this.
 
#8 ·
I think maybe my thread was missunderstood, let me explain:

First, for those of you that may have read my threads in the past, I am a VERY STRONG ADVOCATE for a seperate, independant, out of the loop, starting battery. Period. If I am not mistaken, to meet ABYC, you MUST have it seperate. I think many manufacturers get around this by putting in a 1/2/both switch so that in theory one battery is a starter... whatever. Terrible setup. Terrible. And for those of you that are still doing what I did for many, many years (like switching your batts between 1 & 2 on even/odd days), you better read a few books about electricity. You exponentially (not linear) reduce the life of both batteries. Very bad idea. Go read Nigel Calders Boatowners Mechanical & ELectrical Manual, talk to a battery manufacturer, or any electrical engineer. Parallel is much, much better and will vastly extend the life of boat batteries. I guess the exception is if you do not have a starter battery... but I don't think I need to cover that ground again.

Now, my statment:

Deep cycle cells are built with heavier, thicker plates versus a typical start battery is built with a typical thin plate. We tend to (as cruisers) associate a thin plated battery as bad and a thick plated battery as good. This may not be the case at all. When you start your engines, there is a huge, but short (hopefully), amp draw which pulls the juice off the surface of the plates... but that is it. This can then be easily replenished with a quick charge. A deep cycle battery would also pull the surface charge off but then get deeper into the plate, requiring what we often assocaite with as needing a multi-state charge to replenish the "interior" of the battery, not just the surface.

Yes, you can use a deep cycle... but the questions is, perhaps it really is not the best battery for that purpose (not to mention the cost)? Could the argument be made then, to use a true, NON deep cycle battery?? I would say it could. My logic off anywhere here?
 
#9 ·
Dad,

Exactly right. The thin plates are there to allow the manufacturer to stack more of them in the space. More plates = more surface area = more possible current (starting current or CCA, cold cranking amps) Starting batteries are optimized for short, high current discharges followed by short (relative) high current charges, as you would find starting an engine.

Can you use a deep discharge, yes, should you, probably not. If sufficient current is not available to the starter then the starter speed will be reduced causing harder starting. Compounding this the voltage available to the engine will also be less and if it’s a gasoline engine, harder starting (I’m not sure about diesels, never having worked on one).

Using a deep cycle battery for starting is as wrong as using starting batteries in your house bank.
 
#10 ·
This thread has gotten me thinking, which is a dangerous thing. If it is beneficial to use a high CCA, thin plate battery for starting, would it make any sense to use the same kind of battery as a dedicated battery for a bow thruster? You would use it infrequently, relatively speaking, and if it was mounted near the bow, you would reduce the length of heavy wire required. Since I know almost nothing about bow thrusters, I may be asking a silly question, and if so, I apologize.

I was looking at wire size tables and to carry 500+ Amps (746 hp/amp x 9 hp/12v = 559 A), it would take 4/0 wire (or better, depending on length of run and tolerable voltage drop).

Just asking.
 
#11 ·
Golux, I think the difference is that a starting battery in being asked to put out about one or one and a half kilowatt (for engines up to "car" size) for about 3-5 seconds, no more. With a bow thruster you may be wanting to use it for more than 3-5 seconds.<G> That puts you into deep cycle territory.
You also don't have to run monster cables up front, if there's a deep cycle battery up front. The battery can run the thruster, and the thinner cables will just recharge it a bit slower. Compromises.

Dave, I think the devil will lie in the details, as usual. If a single Group31 battery (large car battery) can suply 3500A into a dead short, it can certainly supply the kilowatt to run a starter motor for a few seconds without being drawn down much. A 50-100A load for four seconds still represents a tiny fraction of what the battery has stored--if you have a sufficiently large battery/bank. It's kind of like saying fleas can kill a dog by sucking all of its blood. Well, yes, they can. But one bite once a day, won't be intolerable much less fatal.
Carrying a totally isolated separate starting battery? Great if you can afford the dedicated inflexible resource, and the space and weight penalty, I guess. Since the engineering behind batteries hasn't really changed in the past decades, I have to wonder why "the norm" and the recommendations have shifted over the last 20-40 years, from having an A/B setup to having one house and one starting. Style, more than science, perhaps?
 
#12 ·
Hello,

Is a dedicated, seperate starting battery really that expensive? You can mount it fairly close to the engine(s) reducing the wire size. The lugs are not that much. Even if you put in a seperate charger and keep it totally independant, you are still out, battery and all, for a few hundred bucks or so(assuming you do it yourself). If you do not want the starter to have its own charger, put an echo on it.

What is a few hundred bucks if you know you can depend on starting your engine(s) when neccessary?? This is one of the few redundant systems that is not that expensive.

Just my thoughts.
 
#13 ·
You are right, bow thruster motors are similar to staarter motors although designed to allow somewhat longer run time. and the batteries that work well for starting, thin plate high output cranking types, also serve well as thruster batteries. AGMs are well suited for this service.Mount the bow thruster batteries near the thruster to minimize large wire run. again AGMs are convenient as they do not require maintainance although care must be taken with charging parameters to avoid thermal runaway. Especially if the batteries are in an enclosed area in warm climates. Most thrusters are 24 volts so a separate 24 volt charging source will be required. There are 746 watts in 1 HP 746 watts/24 volts =31 amps. In reality you should add 25% to account for inefficiency. If you have a 4HP thruster you will draw about 150 amps. Consult a voltage drop table and select the proper wire size for the run from the batteries to the thruster. Be sure to fuse the system close to the batteries. Since the charging current will be less than draw, the charging source, alternator, or AC powered charger can be located further away and smaller wire can be used.. Again consult a voltage drop table and be sure to measure both directions.
 
#14 ·
DC starting, thruster, and windlass motors can draw high currents.

It is probably better to power these intermittent loads with batteries that are designed to deliver such amperage.

Deep cycle types, as I understand them, are optimized to deliver more modest current over a long interval between charges.
 
#15 ·
Hellosailor does make a valid point that seems to get right to Dad's point. If you can crank your engine over, in cold weather, with one of your house batteries why even carry a conventional battery for engine cranking? I would say that this is a good example of: as a general rule, but each situation differs, consult your electrical engineer.<G>
Now if you have a high compression engine, and you can hear each and every one of those little juice cans hit top dead center, all the while praying for just one little controlled explosion. you might want a conventional discharge battery. I would.
On the other hand, if you are in warm environs, and little denny diesel or atomic adam spin easily, probably well broken in. why not use a deep cycle?

We used to jump start an old Ford 8-N tractor with an electric golf cart. The Ford was a 6 volt system and the golf cart ran on 36 volts. We could never get enough juice out of one of the 6 volt batteries to crank her over. Jumping uo to two batteries, 12 volts, helped somewhat but we usually ended up going the full monty-all 6 batteries! That starter motor sounded like a jet turbine when it engaged! In the interest of staying alive I should note that this is very hazardous, a two man job, and we only jumped long enough to spin her over. And, of course, it wasn't our tractor!<G>
 
#16 ·
I think this is an issue of "the very best" vs. "good enough". A lot depends on your specific situation and where you want to put your money. I have separate starting and house batteries (and separate alternators) and really like the setup. But they were installed by a previous owner - would I install this system on a new(er) boat, I don't know.
 
#17 ·
I love theese theoretical disussions about batteries that seems o be a never ending story during off season.
What I have never seen is the yearly costs of all the different solutions.
Add up the costs of the batteries, 'superchargers', regulators etc, divide by lifetime and what is the result?
I dropped 4 70Ah 'cheapest' type into my SO 37 (came in fact from factory) in 2002. The boat was lying more or less unused for a couple of years, then went 20.000 miles from Norway to Malaysia. One month ago it was time to replace the 'package' .
Close to 5 years 'lifetime', no extra gadgets, no 'super++++', just ordinary wet cell 'leisure' batteries. No problems, original factory charge set up.
I do no deny that there are systems and setups that may be more 'technical' correct, but sometimes I find the simpliest the eaysiest, and when it works at low $$$ why not?
 
#19 ·
My experience. I bought my boat in 1993. It had a house bank of 4 Surrette 6v batteries that were installed in 1974. But they died a few years later. With a history like that I decided to replace with new Surrette batteries. But by then the company had changed hands (and quality). I only got 4 or 5 years before they stopped holding charge. This time I replaced them with generic golf cart batteries and they have been working ever since. Early on I did install an Ample power monitoring system and one of their regulators. I think careful monitoring and care is critical to battery life.
 
#22 ·
Just read an article in Lats & Atts. A couple just got done sailing around the world with a few auto batts and no worries. Just throw 'em away and buy new I guess. Perhaps this is another case of perfection getting in the way of acceptable?
 
#23 ·
Sailaway...I wouldn't say that standard batts are a "bad" way to go...just require a lot of care AND will fail sooner even with that care. For a one or two year trip...no problem with anything you buy as long as you keep the water topped up and don't fry em or completely deplete em. As for the bum-fuzzlers.. a lot of things "worked" for them that I wouldn't care to test over time. Some people are just damn lucky!! Great adventure and log though and they'll probably give seminars on how to go around the world now!! <G>
 
#24 ·
camaraderie said:
Sailaway...I wouldn't say that standard batts are a "bad" way to go...just require a lot of care AND will fail sooner even with that care. For a one or two year trip...no problem with anything you buy as long as you keep the water topped up and don't fry em or completely deplete em. As for the bum-fuzzlers.. a lot of things "worked" for them that I wouldn't care to test over time. Some people are just damn lucky!! Great adventure and log though and they'll probably give seminars on how to go around the world now!! <G>
From Your avatar pic You seems to be sailing in a differen 'class' than most of the cruisers I met on my way, and most probably have different needs and recoursces than a lot of cruisers. Calling those who goes for simplier and less costlier solutions for 'bum-fuzlers' and Your ending remark would have earned You a '-' in credability, had it been possible.
Not exactly what one would expect from a 'moderator' of a board!
 
#25 ·
Haffiman...You are out of Malaysia so perhaps that explains the mis-understanding...the name of the boat in question is "bumfuzzled" and I have NO problem with those who choose to sail in a well prepared but smaller and much simpler boat. I was referring to the logs of their trip...their total lack of preparation and some of the really questionable decisions they made along the way that did not manage to kill them.
Read their logs at http://www.bumfuzzle.com/ and see if you don't feel the same way. Very entertaining and I give them full credit for what they have accomplished which is way more than I have. But...I'll stick with the Pardey's or Beth Leonard for ADVISE on cruising round the world. BTW...the bumfuzzlers are NOT cruisers on a budget...they had lots of bucks to throw at stuff as it broke and had all the "toys" on their boat from a watermaker to a George Forman grill so please don't accuse me of elitism in this case. The only reason they had auto batteries was because the didn't KNOW any better. As to LUCK...let me just include this one direct quote from their website:
"Now let me tell you about our problems with our charts. First let me explain that we only use electronic charts,"

In this specific case I was responding to Sailaways thought that a couple of automotive batteries had worked for bumfuzzle. My thought about the topic was that any battery should work for a couple of years if you don't mis-treat it but that over time auto-batteries would not be a good choice. There are any number of citations for this supporting my own experience mainly because of plate thickness. My comments about the bumfuzzler couple do not change the accuracy of that thought.
BTW...my role as moderator is simply to weed out spam and make sure the cat fights don't get out of hand. It does not confer upon me any special knowledge or insight or make me the "oracle". Feel free to disagree and I'll feel free to post as I see fit with my own opinions. In this case...I stand by them.
 
#26 ·
I browsed Your link of the 'bumfuzlle' travel and they might be a bit off the normal in some aspects, but I think everyone that does a trip like that are, including me.
However this thread started as 'starter battery' and to my knowledge that is excact what the old lead-acid batteries are. Either You run the thick plated 'solar' type or thin plated for max start/discharge amps.
What most yachters know or should know as basic rules are that You do not mix types and sizes in the same charge circuit, and is the main reason I stayed with them. What a lot of around the world sailors does not quite realize is that what You may get at the local market back home is not available all over the world. Everything may 'break' and at sea Murphy's laws rules: it breaks at the least convenient spot and time!
I would not claim that the simpliest is always the best in any situation, but it may pay off to give it a second thought.
One small question I put in my original posting was the amp/hour consumption cost of the different solutions that are given. The 'old' lead acid costs around 1/3-1/4 of the gels, lasts perhaps 1/2 to 1/3 of the time of gels, needs no super chargers, may be bought almost everywhere.
Cruising You have plenty of spare time to check the level and clean off the tops. One thing however that is to be warned about is vapors when charging which means that the battery compartments must be well ventilated!
Yachters are individuals and very often with different opinions about the most. Theese kind of forums are great as it gives the possibilities of getting different opinions. To disagree with other posters taking part in the discussion is natural and keeps perhaps the board alive, but to bash down on someone not involved I find a bit out of the ethics.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top