CTEK MULTI XS 7000 (12V) - Press Cuttings
The smartest battery charger in the world just got smarter - the MULTI XS 7000 CTEK, November 2002. by Ctek Sweden AB
Battery development never stops.
New types are introduced on the market and yesterday's wisdom becomes just history. Battery charger technology has had to adjust to this development to ensure that the advantages of new batteries can be utilised.
AGM batteries such as Optima and Exide Maxxima prefer slightly higher voltages in order to be properly charged. Another example is modern maintenance-free batteries. A boost charge using a higher voltage may be needed to regain full strength if a battery has been severely discharged several times.
All this and much more is built into the MULTI XS 7000 from CTEK SWEDEN AB ( former Coulombi Chargers AB).
Normal unregulated transformer chargers have thankfully all but disappeared from our marinas. These linear chargers are heavy, noisy and generate sparks when they are connected as well as giving off an odour and being generally unpleasant. Some people refer to them as "battery heaters" as the battery gets so hot. It's like choosing between a rock and a hard place when you charge. If you want a fully charged battery, you will get oxy-hydrogen gas and water loss. It is impossible for the low-end linear chargers to avoid gasses if you want to charge the battery 100%. Most models are not normally made for outdoor use and demand that the battery is disconnected from your boat when charging.
The transition from this type got underway in recent years to avoid these problems and unnecessary expense. A modern charger is usually switch mode, which is basically the same technology that is used inside a PC to fulfil the demands for compact design, high performance and, maybe most importantly, noise-free voltage and current. The clean current reduced temperature problems during charging and meant the battery lasted longer. A clean, well-controlled voltage meant the charger neither interfered with or damaged sensitive equipment in the boat.
CTEK introduced the diminutive CTEK MULTI XS 3600 earlier this year and its reception was phenomenal. A safe, flexible and easy-to-use charger seemed to be exactly what customers needed and it immediately captured a major market share in Scandinavia. Its big brother, the MULTI XS 7000, was introduced on the market at the boat show in Älvsjö, November 7-10, and follows the same design philosophy with a flexible and safe high performance charger in a compact format. The doubled performance is of course obvious but a lot more is hidden under the silver shell.
A modern maintenance-free battery guarantees its owner many years of trouble-free operation ay a modest cost if it is properly maintained. They are robust and lose almost no water due to the material used.
This means that the battery can be kept for a long time without losing capacity. Another advantage is that a significantly lower amount of gas is formed when charging which considerably reduces the need for topping up the water.
But if the battery is subject to over-discharging and defective charges several times over, this may cause the electrolyte to be stratified, i.e. the strength is high at the bottom of the battery and lower at the top.
Normal charging at 14.4V is insufficient if this stratification is to be reversed. The MULTI XS 7000 is unique as it has a boost feature that can be activated enabling the battery to be peak charged at 16V and 1.5A for four hours and then returned to normal maintenance charging. Everything is automatic and monitored by a microprocessor. The result is a battery without stratification that works at full power once again. These 16 volts normally represent an upper limit for high voltage that will not risk damaging any sensitive electronics.
A modern AGM battery such as Optima is virtually impossible to charge using a normal linear charger. These batteries are real workhorses when you need high current, but the flip side of that is that they demand a lot of current when they are charged. This high current during charging overloads most uncontrolled chargers. These batteries should also be charged at a higher voltage, providing that there are no voltage spikes. All chargers in the MULTI XS product line do all this as well as adjusting the current to the battery.
Maintenance charging can be done in two different ways. The most common method is to keep the battery at a constant float voltage of about 13.4-13.8V. This is perfect for alarm devices and electrical wheelchairs where you always need a battery that has a 100 % charge, and may sometimes be a solution for your boat as well. The alternative is pulse maintenance where the charge varies between 95% and 100%. This method results in considerably less water loss and prolonged service life for the battery and is the method CTEK has selected as standard for the entire MULTI XS range. However, you can select the float method for the MULTI XS 7000 if you so wish. In this case the 12V equipment also works without a battery being connected.
Have you ever heard of a battery that won't accept a charge? This is probably a battery whose inner resistance has been heightened. Chargers react by increasing the voltage way above the permitted value. The difference with a MULTI XS charger is that they send pulses of current and the charge often starts in a normal way. However, this is no miracle cure. The battery is damaged but can carry on working for a while at reduced power. You can ride out the emergency situation and have the time to plan your next battery purchase.
Other items in the specifications are obvious. Whichever way you connect, you cannot injure yourself or damage the boat, the battery or the charger. Reverse polarity protection, short-circuit-proof, watertight and galvanic insulation are the first things you notice. It is equally important that there are no sparks and that gas production is virtually eliminated. MULTI XS 7000 is electronic safe, as the battery does not normally need to be disconnected when charging and any plugs can remain in place. MULTI XS 7000 has been approved by SEMKO. (The Swedish Board for Testing and Approval of Electrical Equipment) Price around SEK 1,450 including VAT, and you will find most models in the shops from the middle of December
