Preserving and Restoring Your Car Battery

Noco Genius battery charger
The Noco Genius battery charger/restorer can extend the life of your car battery, and restore a failing battery to good health.

While much focus these days is on new battery types; generally the most expensive investment in batteries we currently make is with the decidedly old fashioned lead-acid battery in our vehicles.  The technology dates back to the very first ever rechargeable batteries in 1859, and while there have been modern-day tweaks such as the development in the 1970s of “sealed” or “maintenance free” type batteries that obviated the previous need to top up the individual cells with water on an occasional basis, the underlying basis of operation is unchanged.

There are two different styles of lead-acid batteries.  Car batteries are designed to give a very high current for a brief period of time (ie when starting your car).  This is not the same as a “deep-cycle” (sometimes generically referred to as a “golf cart” type) lead-acid battery which is designed to give a moderate flow of current for an extended time.  Car batteries do not like to be deeply discharged, whereas the deep-cycle batteries are happier to be taken much further down to almost a 0% state of charge.

The life of a car battery depends on several factors.  Some you don’t have much control over – for example, the temperature the battery is stored and operated at (over about 77° (ie 25°C) starts to harm/shorten battery life).  Some you have a limited degree of control over – for example, how the charging circuitry in your car recharges the battery.  But there are a couple of things you can do to enhance your battery’s working life.

The most important thing to do is not to overly discharge the battery.  Normally, this never happens if the vehicle is your daily driver, because if you’re not sufficiently charging it up each day to cover the outgoing charge used to start the car, then it will fail to start your car probably before the point at which it has been too extremely discharged to harm the battery.

But if you’re storing your car for an extended time, or if you leave electrical/electronic items running while the engine is off, there is a danger of depleting your battery down to an almost zero charge.  A typical car battery is only good for maybe 10 – 20 such events before it is no longer usable.  Each of those ten or so deep discharges will harm the battery, until cumulatively it is no good.

You might think the solution to this problem is just to leave the battery hooked up to a battery charger.  Yes and no.  A normal battery charger is likely to overcharge the battery and destroy it, because it lacks the built-in intelligence to adjust its charge rate as the battery gets close to full.  But a special “trickle charger” has built in functionality to manage the state of the battery and is hopefully less likely to harm it.

Of course, it is certain that sooner or later, your battery will fail, and the local battery store tells you to buy a new one.  They are usually correct about this, but not always.  It is possible that an intelligent battery conditioner can revive your dead battery and reverse some of the chemical wear and damage that has accumulated, giving your battery a new and extended life before it needs to be replaced.

These days a car battery seems to cost $100 – $200, and possibly another $100 or more for the fitting of it into your car and disposal of the old battery.  There’s also the hassle/inconvenience factor of when your battery dies that is best avoided – for sure such things never happen at convenient times and places.  (See also our article on emergency car jumper battery starters.)

We see most batteries with three year warranties, or sometimes 3 1/2 year warranties.  That suggests to us that a typical battery will last longer than three years, but not necessarily a great deal longer, depending of course on the factors that affect its life, and most “experts” seem to make similar claims.

So anything that can extend your battery’s life is potentially of value – even another six months of battery life is a significant improvement in convenience and reduction in cost.

We were about to replace the failed battery in one of our cars, eight and a half years ago, when we found an amazing product.  We bought it and now, 8.5 years later, the “failed” battery has still not been replaced and is working almost as well as a new battery would.

The Noco Genius Smart Battery Charger

Our “other” car spends most of its life in the garage, untouched, sometimes with six or more months passing between outings.  So it was always a struggle to keep the battery reasonably charged, and after going through batteries more regularly than we wished, we finally resolved to do something about it after what seemed to be yet another premature battery failure.  This caused us to discover the Noco Genius Smart Battery Charger – an amazing device that essentially does three different things.  It protects a battery and keeps it fully charged during extended periods of storage.  It refreshes and “exercises” the battery during its fully charged state.  And, thirdly, of special interest to us back in November 2010, it will usually “recover” and repair/restore a damaged overly discharged battery.

We were cautious as to whether it truly would work as well as promised, and so we waited 8 1/2 years before reporting back to you!  Well, that was sort of the reason.  We were reminded about this unit and the whole subject of protecting/extending care battery life after our several articles about the emergency jump starting devices and how we relied on the Noco unit to “save” the battery again after we literally killed it with our emergency charger testing.

So, what have we learned over the 8.5 years?  The battery that needed replacing way back then is still working today, and – get this – it even holds a charge for a week or more between vehicle starts when we take it off the Noco unit and have it available as a (sort of) daily driver.  The Noco unit not only repaired the damaged battery, but took a battery that was at the end of its life and has added another 8.5 years to it – so far.

We’re not saying it will do this for your battery in your vehicle too, but we are saying it did so for us, and if you have vehicles that you store for extended periods, or batteries that are dying on you, maybe you should try one of these units.  At a cost of $36 – $60, there’s precious little downside and a huge upside.

What the Noco Genius Does

The unit first runs diagnostic tests on any battery it is connected to.  If it senses problems or low voltage, it first runs through a series of voltage spikes to reset and restore some of the chemistry on the battery plates.

At that point, or if the battery is in good condition, it proceeds through a regular slow charge cycle up to 80% of capacity, then it switches to a different slower charge rate to take it up to 90% charge, so as not to risk the battery “gassing off” – electrolysing its liquid and possibly losing it entirely outside of the closed battery system.

After the Noco has got the battery to 90%, it then steps through a series of states indefinitely.  Some of the time it is simply trickle-charging to keep the battery at almost fully charged, at other times it varies the current so as to stop the battery from getting over-conditioned and to simulate some usage to (in non-technical terms) keep it “exercised”.

You can use the Noco unit as a regular battery charger too, but probably you’ll buy a unit that has a slow rate of charge, so if you’re in a hurry and need to be able to start your car quickly, it would not be a good choice for that.  We have a regular charger that will charge at a rate of 50A for when we’re in a hurry, and the Noco (the model we chose charges at a max of 1.1A) for all other times.

Noco Genius Model Choices

There are a number of different models of the Noco Genius intelligent smart charge units.  The main difference is the rate at which they will charge, rather than their features and capabilities.

Of course, Noco would like you to buy a big powerful and expensive one.  But truly, there’s no need for this unless you expect to always be in a hurry to recharge a battery.  I chose the G1100 unit (the number implies that it charges at a rate of 1100 mA, ie 1.1 amps), because it seemed to offer the best compromise between cost and charge speed.  Amazon sells it for $37.15 currently.  There is a smaller G750 unit which is probably adequate for most people and uses, but it is only a couple of dollars cheaper than the G1100, and so there’s little point in getting the G750 instead of the G1100.

The next size up is the considerably larger G3500 (ie 3.5A) which is $59.57 on Amazon.  Is it worth spending another $22?  Only if there are times when you need the faster charge rate.  It does claim to have more sophisticated repair functions, and that might be worth $22 more.  We don’t think that option was available when we purchased our G1100 in 2010.  But the G1100 has worked perfectly well for us, so we’re not complaining.

Using a Noco Unit with a Daily Driver Car

There’s little chance to have a Noco Genius charger “work its magic” if your car is out and about most of every day.

But if you know there’ll be a weekend or a week when you’ll not be using your car, it might be occasionally worthwhile to connect it up to a Noco unit and let it work at some reconditioning of your battery.  Indeed, if you’re not going to be using it for more than a couple of days, particularly if you have the slower G1100, we’d probably discharge the battery much of the way towards dead and let the Noco work its magic for an extended time.

How do you know how much charge remains in your battery?  Easy.  Get a decent digital voltmeter, (by “decent” we mean one with four or more digits on its display and ideally 0.5% accuracy, and some imprecision in the last displayed digit) and when the battery voltage (with everything switched off) drops to 12V on a normal 68° day, it is probably about 20% or so charged.  Don’t go much below that.


A Noco Genius charger is ideal for cars you seldom drive, or sometimes store, or for vehicle starter batteries that are failing.  They restore old batteries to “almost new” condition, and extend the life of all batteries that they have a chance to occasionally charge and condition.

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