Nigel Calder: Battery Book

[Windseeker]

I can’t remember the thread, but thanks for recommending this book. Completed the first chapter and now understand why my batteries pre-maturely died. It’s well organized, well written and has a good flow.

For the various reasons described in the book, I am better off joining my (2) 4D AGM batteries together as my entire house bank vs. alternating them. The question comes down to the starting battery. I can run on a single battery all night with a mast light, fridge, few lights etc. and still start my engine in the morning. I suspect that double bank will work as well or better. What about the emergency situation? Like when you are dragging anchor and the bowsprit on the boat behind you is about to make your transom look like a piece of meat on a shish-a-bob skewer?

I carry a charged jump pack and it is enough to start the boat with a dead battery. I also carry a portable generator. Do you think that is OK for the emergency situation? It would not be an instantaneous start, but certainly ok for an anticipated T-Storm for example.

I can add a separate starting battery, but not right now. That is a sizable project, and we are getting into the fun season. There is another question about this dedicated battery that I did not see in the book. If I don’t want this battery to die pre-maturely from sulfation by adding it to the House charging circuit, then why can’t I add 2 smart chargers in parallel off the same hot alternator? That was not an option presented. There must be a reason, but it escapes me???

[btrayfors]

Your best bet is to add a starting battery and to maintain that battery with a simple voltage follower device like the Xantrex EchoCharge. This little box sits between the house batteries and the start battery. Whenever it senses a charge on the house batteries (from the alternator or battery charger or solar panels or wind generator or whatever source), it bleeds off a bit of current -- up to 15A -- to charge the start battery.

Its operation is totally automatic. You don't need to flip any switches or do anything at all. It will maintain the start battery just fine all by itself. Mine has been doing so for over five years now, and the ones I've installed on client boats are all fine so far as I know.

Start batteries typically need VERY LITTLE CHARGING, since they are only in use to start the diesel. On a small cruising boat this usage is less than one amp hour (< 1AH); lots of amps for a few seconds! It only takes minutes to replace this amperage.

It's not such a big project. I do this for a living, inter alia; did one today on a smallish boat in Baltimore.

Give a shout if you need any guidance or help.

Bill

[cheoah]

Hi Bill, can you mix battery types here, ie: (2) Grp 31 AGM with a Grp 24 lead/acid for start? Boat came with big alternator and Balmar charge regulator but I guess it would not control anything beyond the echo.

Chase

[btrayfors]

Chase,

Sure, assuming:

1. the AGMs are the house batteries, and that all onboard charging sources go directly to the AGM's; and

2. the group 27 lead-acid battery you mentioned is a flooded battery and is the start battery, and is to be maintained with an EchoCharge.

BTW, AGMs and flooded batteries and gelled batteries are all lead-acid types, but I think I know what you meant.

No problem at all.

Bill

[Windseeker]

The echo charger sounds like a good solution. I'll look into it. Thanks Bill!

[Windseeker]

Well there it is on Page 41 of the book. I remember thinking the series regulator is the ticket, but then I also was thinking like Chase with having a flooded start. Since, you are "echoing" the charge cycle from the house bank, then you would need the same type battery. Xantrex also states this in their literature.

So, this is where I get hung-up. If I am bulk charging an AGM house bank, won't I be overcharging an AGM start battery? If I am charing an AGM house bank, won't I be undercharging a flooded start battery?

That's why I was thinking why not two smart chargers in Paralell. (two alternators is not an option) I'm not trying to over-think this, or spend money unnecessarily. I'm just frustrated having spent mucho dinero on batteries over the years only the learn that I have mis-treated them. They deserve better.

[btrayfors]

You're overthinking it.

AGM and flooded lead acid batteries have very similar charging requirements in terms of voltages at the bulk, acceptance/absorption, and float levels. In fact, most chargers are set very conservatively.

The EchoCharge will work just fine with AGM house batteries and a flooded start battery.

What you probably would NOT want to include in a mix of battery types is gelled lead-acid batteries; these are much more sensitive to high charging voltages.

Bill

[Windseeker]

Thanks Bill! You seem to have lots of knowledge in this area. This is what you do professionally?

[steve_hendry]

Note: Using the echo charge or the Balmar duo-charge, you can get away with a cheap automotive battery, since both current and voltage to the starter battery are limited. I feel kind of silly protecting a $50 battery with a device that costs significantly more, but the arrangement avoids the concern with the starting battery type having to match the house battery type.

[btrayfors]

Originally Posted by Windseeker

Thanks Bill! You seem to have lots of knowledge in this area. This is what you do professionally?

Yep. Inter alia.

See, e.g., http://www.qrz.com/callsign.html?callsign=wa6cca

[btrayfors]

Originally Posted by steve_hendry

Note: Using the echo charge or the Balmar duo-charge, you can get away with a cheap automotive battery, since both current and voltage to the starter battery are limited. I feel kind of silly protecting a $50 battery with a device that costs significantly more, but the arrangement avoids the concern with the starting battery type having to match the house battery type.

Steve:

No need to feel "kind of silly" :-)

The EchoCharge is not just to "protect a $50 battery".

Rather, it's a fully automatic way to keep the start battery (or any other auxiliary battery) charged, without worrying about hurting it, flipping switches (and possibly damaging other things), etc.

Peace-of-mind with your electrical system is worth a heck of a lot to most folks, including me!

Bill

[Windseeker]

Originally Posted by btrayfors

Peace-of-mind with your electrical system

That works for me!
Can you give me an opinion on Flooded Lead acid Batteries in the salon? My batteries are under a settee in the salon I changed them over from flooded to AGM but not because I knew better. I was advised they would perform better (and they have for what I was doing and how I was treating them). I have since learned that charging lead acid batteries can put off explosive, harmful vapors, etc. I was also told that it is against code. So why did my boat supplier put them in me boat when commissioned?

I only ask this because the best place for the starting battery in in the adjacent settee in the salon. I don't mind buying a small AGM for this spot, but, as Nigel stated, for starting, a starting battery with thinner plates is better. Quick, powerful discharge and easy surface charge replacement.

What do you think?

[btrayfors]

Originally Posted by Windseeker

That works for me!
Can you give me an opinion on Flooded Lead acid Batteries in the salon? My batteries are under a settee in the salon I changed them over from flooded to AGM but not because I knew better. I was advised they would perform better (and they have for what I was doing and how I was treating them). I have since learned that charging lead acid batteries can put off explosive, harmful vapors, etc. I was also told that it is against code. So why did my boat supplier put them in me boat when commissioned?

I only ask this because the best place for the starting battery in in the adjacent settee in the salon. I don't mind buying a small AGM for this spot, but, as Nigel stated, for starting, a starting battery with thinner plates is better. Quick, powerful discharge and easy surface charge replacement.

What do you think?

I think that the "explosive, harmful vapors, etc." is true but overstated. Flooded batteries are often placed under salons, berths, etc., and I have never seen or heard of any real troubles with such placement. On my own boat, I have a total of eight T-105s and a start battery...all in living spaces, and no problems in the past 20+ years.

The "thinner plates" argument is a good one. There is no question that a real start battery is preferable to start your diesel, even though it's true that a big house battery bank of deep-cycle batteries CAN start the engine, too. IMHO.

The "easy surface charge replacement" is true. On average, it takes less than 1AH to start your diesel (unless there's a problem which requires long cranking times), and this amperage is quickly replaced when the engine starts. Most alternators in do this in a few minutes, and then loaf along for the rest of the time. This is why it makes much more sense to have the alternator set up to charge the house batteries, and to use a device like the EchoCharge or Balmar's DuoCharge to maintain the start battery.

Bill

[billr]

Really good information here. Though the "peace-of-mind" for me includes redundant systems as much as possible, ones in which the failure modes can be contained. When we bought our current boat, which is now in our 6th year of re-fitting on the hard, the battery charger system (which was on to maintain the batteries) had sustained a failure. It was trying to initiate a battery charging cycle every 2 hours. Consequently, it destroyed the four 8-D flooded batteries, which resulted in battery acid condensing all over the battery compartments, etc. What a mess. And replacing the batteries with AGMs was a $2000. excercise. My concerns on the failure modes is based on the fact that today's electronics are more prone to failure (ie. they have many more failure modes) than the older electronics. For those of us in electronic manufacturing, these failure modes are a continual headache. From a boat application standpoint, it always seems logical to the ask the question of "what capability will I have left when this electronics assembly fails". Then you think of the analogy of having 2 Racor filters running in parallel for your engine fuel.
Bill, any thoughts on this from you?

Billr

[btrayfors]

billr,

Excellent points and excellent question.

It used to be the case that mostly what you had to worry about was "infant mortality", i.e., failures to electronic devices in the first hours of their operation. If they made it past the first few days or weeks, it was likely they'd work for a very long time with no trouble.

It's different now, though, with the insidious presence of substandard components. A good example is the case of the leaking capacitors, which very nearly put the huge computer firm, Dell, out of business. And these were sourced in Japan, not China!

With miniaturization and with "smart" devices, today's electronics are a lot more complex than those of the not too distant past, with thousands and even millions of more solid state devices (some computer chips have an unbelievable number of components). All this doesn't make for more reliable electronics; rather, it makes them more susceptible to failure, especially from heat, from electrical transients, and from stray RF or EMF.

What to do?

On my boat...and my client's boats...I try wherever possible to:

a. choose high quality gear which has a good track record and comes from a trusted manufacturer;

b. keep system designs as simple as possible;

c. avoid unnecessary complexity as, e.g., in networked devices (see below);

d. pay close attention to the power train, i.e., try to ensure that electronic devices get plenty of clean power, regulated insofar as possible; and

e. keep the equipment clean, protected from the elements, and well treated.

None of these is a sure thing; just a way to stack the odds in your favor.

Re: networking, I have a strong preference for standalone devices. I see little reason for most of them to be networked (exception: GPS and VHF/DSC). This is partly out of a concern for reliability and simplicity, but also for redundancy and to avoid unnecessary dangers. One of my pet dislikes is linking autopilots to GPS's or chartplotters. I won't do it for my clients, as I believe that for many boaters today this is downright DANGEROUS. I don't want my radar overlaid on my chartplotter. When I look at the radar screen I want to see what the radar sees, nothing else. For similar reasons I don't overlay other things like AIS or charts on the radar screen.

I believe that you should always have a backup when a system fails, i.e., more than one way of doing things. If the alternator fails, you should have another way to charge the batteries (solar, wind, generator, etc.). If the GPS fails you should be able to fix your position by other means (meaning that you should be proficient with radar, charts and dead reckoning, RDF, celestial navigation, etc., depending on where you are cruising). If the VHF radio fails you should have a backup unit or, at the very least, a good handheld VHF which can be attached to your main antenna). If your EchoCharge fails, you should have a way to charge the start battery (either by jumper cables or a switch to interconnect the batteries). If a bad cell develops in your house battery bank you should know enough to be able to identify the offending battery and remove it from the bank. Etc., etc.

A prudent mariner will have thought about many of the possibilities of electronic gear failure and how they might be mitigated, just as he/she would plan for mechanical and other failures on the boat.

There will always be unforeseens which will test your preparedness. After all, Murphy still lurks aboard somewhere, ready to pounce when you least expect it :-)

Sorry for the long-winded response.

Bill