I wish I had a Euro for every battery I have replaced, I am sure that by this time I would be anchored somewhere beautiful and not in a bilge somewhere hulking around heavy batteries. The subject of the post today, batteries, chargers and why so many get replaced too early.
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| Batteries awaiting to be collected for recycling, in a large boatyard you could fill this box twice in a busy week, but it doesn't have to be that way. |
Batteries are nothing new, electric cars using batteries came about before combustion engines were mainstream, batteries are in our cars, bikes, phones, computers, everywhere. When they are installed in boats they are being used in the harshest of environments, salty air, movement, banging, crashing, is it surprising they fail and, what can we do to get the maximum life out of them?
Right tools for the job
I am not going to go through all the different types of batteries, there are so many articles on this subject, written by experts in the field. I want to explain some of the most common issues I see and help boaters to avoid and overcome them.
Cheap or old chargers
The older style of battery chargers are called ferroresonant chargers. Inside there is a transformer than turns mains voltage into DC current to charge batteries, there are no electronics that regulate the charge process. This type of charger might have worked well a long time ago with normal lead acid type batteries that could be topped up with distilled water, but not with newer sealed types. These chargers have a tendency to overcharge batteries (due to their very basic charge circuit design), creating that well know bad eggs and acidic odor. If you have a boat with one of these, then now is the time to upgrade.
Whilst we are on the subject of upgrading battery chargers, may I please remind you, not all chargers are created equal. If you have petrol / gasoline engines in your boat, only certain chargers are built to the standards (ignition proof) that makes installing them in the engine room acceptable, automotive chargers are not built for installation in engine rooms (or boats at all).
Smart or dumb chargers?
Lets call them smart chargers, really, they are multi stage chargers, this means unlike the old style ferroresonant type, they can charge according to need, battery type, compensate for temperature, some advanced units can recoup batteries that might otherwise need replacing and, the best feature, a lot can be programmed specifically to the batteries being charged, these types of chargers are a huge, night and day upgrade for your boat, its not all plain sailing however....
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| Modern battery charger with selectable charge profiles for different battery chemistries, including Lithium Ion. Note the white cable, that's a temperature sensor that goes on the battery negative post, reduces battery overcharging due to overheating. |
Several things that immediately come to mind;
Size matters, how many amps is the charger capable of putting into charging the batteries? I see far too many chargers that are undersized, I would recommend a minimum of ten percent charger output to the size of the batteries being charged, a quick example, two batteries of say 95 ampere hours (Ah), that's 190 Ah in total, ten percent is about 19 amps, not a common size of charger, so 20 amps minimum.
Too much "stuff", I deal with a lot of smaller sports and day boats, these seem to be the category for me at least that have the greatest problems with their batteries, there are many reasons for this, firstly, more and more higher demand devices are installed in smaller boats, high demand stereos with power hungry amplifiers, electric anchor winches, bow thrusters, fridges, flashing party lights, underwater lights, multiple electronic screens, digital switching, the list goes on, all of these items require battery power to function properly, sometimes a lot of battery power.
Quite often there is an option of a factory installed charger and I would say in at least nine of ten cases it is undersized, it takes a great deal of time to recharge heavily depleted batteries and, although a modern charger with some electronics to control the charge, the output is split between the batteries, a typical example is a 20A charger connected to two separate batteries, but in reality it battery will only get a maximum of 10A as the total charge is split between the two batteries. The problem I have to deal with a lot is fridges, obviously in summer when out boating you need plenty of drinks, these drinks are nicer when cold, so when in port, one battery or the house bank of batteries is left on to power the fridge and the charger connected to keep the battery charged, unfortunately, the undersized charger cannot keep up with the fridge which will be working at full power in the Mediterranean in Summer and charge the battery too, the result, a battery that is permanently undercharged and dies a premature death.
There are solutions, that in the case of sports boats or day boats are reasonably straightforward, one is change the battery type for a more appropriate type that can be discharged more often and to a deeper degree of discharge.
Second, upgrade the charger to a more powerful one and better still, a really smart one that can detect which battery needs the most amperage.
Third, if the boat has a mains electrical panel installed, change the fridge for a dual voltage type that can run on mains or battery power or, install a transformer that will turn mains into battery power for when at the dock, this is a common upgrade and is quite economical when compared to upgrading batteries and chargers.
Common misconception, alternators fitted to most production engines are not really intended to charge batteries, especially large battery groups. Before you all run for your boathooks to chase me, I would like to explain. For the most part, alternators are there to keep up with electrical demand of the boat once the engine is started, I have noticed a trend of alternators progressively getting more powerful, Mercruiser fit 65A alternators, Volvo Penta have considerably larger cased more powerful alternators, so they obviously recognize the trend. Also remember that modern diesel engines are full of sensors and can be very sensitive to voltage, especially when batteries are low, they can throw all sorts of fault codes.
Sailboats seem much more up on charging schemes using alternators, as typically engine run time is more limited, so they need to make the most out of the charging time.
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Victron Energy Phoenix 50A charger, https://abuxboater.blogspot.com/2024/04/victron-energy-phoenix-50a-battery.html |
Dumb chargers, there are a few chargers that do something that drives me insane, even though I understand exactly why they do it, it causes a lot of telephone calls seeking assistance as to why the house or service bank of batteries is not charging. Some chargers if they do not detect enough voltage, such as the case of a really discharged battery will not start the charging process. It is completely understandable, its a safety issue, the charger assumes the battery is damaged and so refuses to go to work, thereby potentially stopping a problem.
Volts do not mean battery is good, this is a common misconception, just because the voltage showing is correct, it is no indication that the battery has any "juice" left in it, even technicians get this wrong. The best ways to actually check the capacity left in the battery is using a battery monitor to meter the state of charge or, use a battery tester. This issue is very common, thinking the batteries are okay when in reality they are not capable any longer of starting engines or being used for house service.
A few of the newer multi function displays can display battery voltage, alarms can be configured so if the voltage drops below a certain level, an alarm or on screen message is displayed, this does help a lot, the idea is to warn before the level gets too low and may cause a problem, it also helps to reduce helps to reduce cycling of the batteries and shorten their life.
Cheap batteries
I do not mean inexpensive batteries, I mean cheaply constructed from strange name companies. Having recently had a delivery of batteries from our supplier, we changed up our usual ones, I was very surprised at how the price had dropped, these were known brand high CCA (Cold Cranking Amps, a measure of battery ability to start a motor) sealed lead acid types.
What really surprised me is if you look even briefly, there are a few online stores that can supply batteries at really low prices, especially if you wait for delivery, so really no excuses for not using quality batteries.
Don't be fooled, boat dealers are equally as guilty as end users in this, they use batteries that will barely make it past the warranty period, sometimes out of ignorance, they simply haven't been informed that the industry has changed, a sort of "we´ve always done it this way" mentality.
Upgrades and solutions
Changing the mindset
I love classic boats, classic cars, bikes, basically I find myself drawn to more vintage and traditional things than new, modern and sleek, I find the visual appeal, design and nostalgia is far more interesting than any of the latest slick and smooth line designs, but, just like anyone who has restored anything will tell you, modern technology has its place.
Batteries and their associated installation are for me, one of the best upgrades you can make, forget about big stereos and new upholstery, get one of the basics right first.
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| You don't just replace the batteries or charger without also looking at the other parts of the installation. |
Batteries and their basic associated components, such as battery terminals, battery cables, disconnect switches and chargers that are installed properly and correctly sized will save you hours of aggravation in the future, trust me on this, all too often its easy to think of the final touches rather than the beginning, along with through hull fittings, seacocks and hoses, batteries are a fundamental part of boat function, I know they're not exactly sexy and there is no "look at me" potential but its better to be out boating in a boat that works than stuck in the marina on a hot day, sweating as you wrestle with flat batteries.
Summary
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