Product Review : Lead Acid Battery Charger, Uni-Elektra Model 99411 (LIDL).

If you’re part of the group in our club that lay their bikes up over winter, then this review may be of interest.

The club has purchased a box of these chargers to give away as part of the raffle. These chargers are of the ‘one stage, switch mode, voltage regulated’ variety, and are not to be confused with the much cheaper and more dangerous unregulated units to be found on popular auction websites.
They’re capable of charging 2, 6 or 12 volt lead acid batteries (flooded cell or sealed lead acid), and most importantly of all, they hit the correct voltage for  permanent connection, also known as ‘float charging’.
The charger has two L.E.D. indicators. One lights up if you have the charging clips the wrong way round (avoid this), the other lights up while the unit is charging and extinguishes when the battery is full.
The charging light seems to switch off when the current drawn from the charger drops below a preset level.
One other thing to note about these chargers is that they automatically turn back on after a power cut. This may not seem important, but some of the newer multi-stage chargers have to be manually ‘started’ by way of a start button after they’re switched on. Short mains interruptions lasting 1 second or less are more frequent than you might think (especially at night). Uncovering your bike in Spring to find the charger reset itself months ago and let your battery die is a feature best avoided.

In addition to the charger pictured in this review, four other chargers with identical model numbers were also tested to get an idea of consistency Their no-load end point voltage was as follows (with the selector switch set to 12v – Fluke 185 DMM):

13.75v
13.78v
13.69v
13.77v

All within acceptable range for a 12v float charge.

NOTE: These chargers come with a voltage selection switch on the front of the unit. By default (from the factory), the selector switch is set to 2 volts. I don’t know of any motorcycle that has a 2 volt electrical system, so if you do manage to get hold of one of these, make sure you set the switch to the correct voltage for your bike. 12 volt systems are the most common on the larger bikes. Check your bikes manual if in doubt.

The Knowledge: Lead Acid Batteries
Lead acid batteries have been around since the 18th century, and have evolved into many different types. The two most common types to be found on bikes are:

·    The flooded cell.
·    The (sealed) valve regulated lead acid battery.

Flooded cell batteries tend to be used on bikes that don’t lean too far over (cruisers, and older bikes). This is because the acid in the battery leaks out if the battery is tilted too far from vertical (some manufacturers give you an overflow port which you can connect a pipe to, so the acid leaks onto the road rather than your bike). You can usually identify a flooded cell battery by the semi transparent exterior that allows you to see the acid level (min and max marks give the game away too). Flooded cell batteries require maintenance in the form of de-ionised water when the acid level drops below the minimum mark on the housing.

Sealed Gel VRLA batteries are very common on newer bikes and sports bikes because the acid doesn’t leak out when the battery is tilted. The acid is mixed with various compounds so that it forms a gel. VRLA batteries also contain valves that recombine the gas that’s produced during charging (hydrogen and oxygen). This is why these batteries are sealed. There’s no need to add de-ionised water, because the hydrogen and oxygen that’s produced during charging recombines to produce water.

There are many different types of sealed lead acid battery. Not all contain gel acid, and there are some which are sealed but don’t contain the recombination valves, so when the acid level drops below the min mark, you bin the battery. I make this point because if you’re looking to replace a battery on your bike with one from a mail order company (or an auction website), it’s important to know what your buying. Just asking for an SLA battery is not enough. Most bike shops refer to the newer Sealed Gel VLRA batteries as simply SLA batteries. If you buy from a bike shop or a website that specialises in direct replacement bike batteries, you should be fine, but ‘battery only’ websites might well hold you to the exact definition if you end up with the wrong type.

Some common questions:

Q) Why’s it important to keep a lead acid battery charged?
A) Leaving a lead acid battery in a discharged state slowly kills it. The longer you leave it discharged, and the greater the level of discharge determines how much damage you do. Leaving a lead acid battery discharged causes a process called sulphation, a condition that makes charging the battery difficult if not impossible. The process is gradual, and usually irreversible. Symptoms include reduced battery capacity (after a full charge) resulting in fewer and slower engine cranks, until there isn’t enough juice left in a fully charged battery to start your bike.
The other reason to keep your lead acid battery charged, especially over winter, is that the acid in a fully discharged battery freezes near 0 DegC. The freezing point of the acid in a fully charged battery is –40 DegC by comparison. If your battery acid does freeze, it will expand, and rupture the battery case.

Q) If I charge the bike battery before leaving it for the winter, will this do?
A) No (depends on how long you leave it though). If your bike has an alarm fitted, then this will draw some power from the battery. Over a few weeks, you’ll not discharge the battery by much, but over 6 months, the drain can be substantial. In addition to this, all lead acid batteries suffer from what is known as ‘self discharge’.  This is a flaw common to all batteries in various degrees, but it means an unconnected battery will slowly loose charge, even if there’s nothing connected to it. The amount of charge loss is mainly dependent on temperature, but in warm climates, a lead acid battery can go dead in 6 months. Battery manufacturers compete to produce batteries that suffer less from this effect. Some of the best manufacturers publish data sheets for their batteries which state what the discharge rate is at various temperatures.

Q) How do I know if my lead acid battery is discharged?
A) There are many ways, but the easiest is to measure the battery voltage with a volt or multi meter with nothing connected to it (unloaded condition). This usually means having to unbolt one of the battery connections (to break the circuit), before taking the reading. Your battery manufacturer should publish a data sheet telling you what the fully charged and discharged voltages are. Typical fully charged voltages (for a 12 V battery) are 12.6 V to 12.8 V. Typical fully discharged voltages are 11.8 V to 12.0 V.

Q) What should I check when I buy a new battery?
A) If you’re buying a battery that already contains acid (some don’t – you have to add it yourself), check it’s at or near full charge. You can do this by measuring the no load voltage at the battery terminals. If you measure less than 11.8 V, then the shop owner is giving you a battery that’s been stored in a discharged state. The chances are it will be sulphated, and difficult to charge. Hand it back if this is the case. Use a shop that has a high turnover of batteries. Manufacturers charge their batteries before they leave the factory, but all batteries will start to self discharge (parasitic discharge) from this point on. Shop owners are meant to charge them as per the manufacturers instructions if they’re left on the shelf for too long.

Q) Do I have to keep measuring the battery voltage while my bike is laid up?
A) You could periodically measure the no load voltage, and charge with a charger, this method would work, but there are easier ways: Float charging.

Q) What’s ‘Float Charging’?
A) This describes a method of charging lead acid batteries whereby the charger is left connected to the battery permanently. The voltage set by the charger is important, because if it’s too high, you’ll over charge the battery (causes hydrogen gassing and plate corrosion: bad), too low, and you’ll under charge the battery (causes plate sulphation: also bad). Over and under charging a lead acid battery will slowly kill it.

Q) Can’t I use any lead acid battery charger to float charge my bike battery?
A) No. You have to use one that’s designed for float charging. Lead acid battery chargers fall into two categories; float charge and cyclic charge. If you’re constantly draining and recharging a lead acid battery (called cyclic use), then the voltage set by the charger is much higher than if you’re going to leave it continually connected (float or standby charging).
You can fully charge a LA battery using a float charger, but it takes much longer than if using a cyclic charger, because the voltage is lower. This poses a problem for charger manufacturers, because the average punter on the street doesn’t care about battery life, they buy the charger that will give the fastest charge (thank advertising for this).

Q) How do I know if the charger I’m buying \ I’ve bought is float or cyclic?
A) Good question! You buy a charger from a reputable manufacturer, and read the instructions.
·    The cheaper chargers will cyclic charge a battery and wait for you to unclip the charging terminals. If you don’t do this, you over charger the battery.
·    Float chargers will slowly charge a battery to capacity and keep it there, without overcharging.
·    Some of the more expensive (multistage) chargers start off by cyclic charging, and then fall back to a float charge when the battery is full (Optimate version 4, Datatool and Accumate).
·    Some multi-stage chargers do a cyclic charge and then turn off altogether when the battery is full. Your battery starts to self discharge from this point on. If you want to re-start charging, you have to turn the charger off and on. These types of charger are no good for float charging.

If your charger came with instructions (some don’t), and they tell you to charge the battery for a fixed number of hours, and then remove the charging leads, you’ve almost certainly got a cyclic charger.

Unfortunately, it’s becoming common to find many chargers with instructions that don’t clarify what type of charging method is employed (it’s very difficult to sue someone over a charger being out of specification, if they never tell you what the specification is in the first place). If this is the case, ring the manufacturer and ask them. If they don’t know or don’t want to tell you, take the charger back \ buy a new one. Leaving a cyclic charger permanently connected to a battery is a very bad idea. At best you’ll kill the battery. In the worst case, you’ll burn your house down. Overcharged batteries vent hydrogen which is explosive.

Q) What if I don’t have a float charger, can I still use my cyclic charger to keep my battery fully charged?
A) Yes, but it depends on the charger you have.
·    Basic 1 stage cyclic charger: These chargers are designed to charge depleted batteries. If you throw a charger like this across a battery that’s only very slightly discharged, for the full 12 – 14 hours, you’ll over charge the battery. How long you leave it connected should depend on how discharged it is. You could measure the charge state as described above, then use timed trial and error.
·    Multi stage charger (Optimate \ Accumate \ Datatool) If you’ve got a smart charger that goes into a battery maintenance mode (float charge) when the battery is fully charged, then there’s no problem. Just keep the charger connected to the battery and the mains supply on.

Q) Is fast (boost) charging bad?
A) Depends how fast. Best answer is to avoid it if you can. Your battery will last longer. Fast charging causes the battery to heat up and acid is lost in the process. Some manufacturers specify the conditions under which you can fast charge your battery (so many amps for so many hours etc). This reduces the life of your battery, but not by much if you adhere to their details. Unless you bough a charger that states it does meet these criteria, then the boost button is best left off. Many car chargers have boost button, and if you boost a bike battery with a car charger, it’s a good bet you’ll damage your battery.

Q) Can I use my car charger to charge my bike battery?
A) As Scotty might say; ‘possible, but not recommended’. Car chargers are designed for much larger batteries than what you might find in a bike. They will in turn allow a very large current to flow when charging begins. This will cause your battery to over heat. The battery will charge, but you’ll do some damage. Bike chargers differ from car chargers in this respect by keeping the total current that’s allowed to flow to a value that considered safe for a bike battery, to stop it over heating. One to two amps is typical. Car chargers by comparison can supply anything from 5 to 10 amps and beyond.

Q) I’ve got a spare backup lead acid battery, how should it be kept?
A) Permanently on a float charger. If you can’t manage this, keep it away from heat sources. Self (parasitic) discharge increases with temperature.

Q) What’s the best method of recharging a dead motorcycle battery?
A) Charge it, but slowly (don’t boost charge or use a car charger). Use a bike charger. Fast (boost) charging a completely dead battery is one of the worst things you can do. The large boost current that flows causes the battery to over heat.
If ambient temperature conditions are at or near freezing, do not charge a fully discharged battery. The acid in a dead lead acid battery has a freezing point near 0 DegC. The freezing point of the acid in a fully charged battery is –40 DegC by comparison. Frozen battery acid does not charge properly. If you have to charge it, remove the battery from the bike, let it thaw indoors, and then overnight charge it.

Final word on charging Lead Acid batteries:

The only correct way of safely charging a battery, is to follow the manufacturers instructions. This may sound like an evasive way to end this review, but it’s very true. Battery manufacturers add all sorts of exotic chemicals to their batteries to improve one characteristic or another, and these subtle alterations can change the optimum charge voltage and current. Any reputable manufacturer will publish charging data for their batteries. The large problem with this, is that many of the cheaper batteries, are no name copies of something more reputable. Cheap bike batteries often have no charging instructions on the case, or even a manufacturers stamp. The charger discussed at the beginning of this review  was measured at 13.8 volts (rounded up from 13.76). This is a very common float charging voltage for 12v flooded cell and sealed VRLA batteries.

Most lead acid batteries don’t have one optimum float or cyclic charging voltage, they have a narrow range over which it’s considered acceptable to charge.

For Yuasa NP SLA batteries (http://www.tahoeinternational.co.uk/PDF/NP_Series.pdf) we see at 15 degrees Celsius, a float voltage of 13.8v is quite acceptable, but at 20 degrees Celsius we’d be just out of the optimum range.

Some other bike chargers and charging info:

Accumate: Multistage charger. 14.3v cyclic charge, dropping to 13.8v float charge.
http://www.accumate.co.uk/accuMate_instructions.pdf

Optimate: Multistage charger. 14.3v cyclic charge, dropping to 13.6v float charge.
http://www.accumate.co.uk/OptiMate%203sp%20instructions.pdf

Datatool: Multistage charger. 14.3v cyclic charge, dropping to 13.6v float charge.
http://www.datatool.co.uk/pdfs/battery_conditioner_ug.pdf

Hi

Would it be possible to get hold of a longer, more complicated and more boring version of this by any chance?