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You can calculate the correct capacity for your Energy Bull as shown in the following example:
You need a battery for an electrically powered boat. A 600W e-motor is used with a 24V electrical system. In addition, a radio, various navigation lights and a depth sounder have to be supplied with power (total 50W). Five hours of autonomous operation are required.
These values are now used in the following equation:

Wattage: Volt = Ampere x Hours x Safety Factor = Battery Capacity in Ah i.e. 650 : 24 = 27 x 5 x 1.7 = 230Ah (k20)


A safety factor of 70% should be used for wet batteries (30% for AGM and gel recombination batteries). In the case above, two Energy Bull 968 01 batteries (230Ah each) used in sequence would be advisable.

Finding the right battery for use in a motor caravan is not that simple. The text below is intended to provide some explanations regarding the Energy Bull and shed some light on alternative possibilities. 


Pay close attention to the appropriate dimensions of the feed cable (in order to minimise voltage loss).

The charging voltage for Energy Bull batteries should amount to 14.2 – 14.4V. In order to achieve suitable battery life, the charging current should not amount to more than five times the rated current* (see subsequent calculation).  

All in all, the Energy Bull is a good cyclical battery, which forgives a great deal (as opposed to gel or AGM batteries).  The “disadvantage” of Energy Bull batteries as compared to AGM or gel batteries relates to maintenance. For when an Energy Bull battery is employed, it is imperative that the electrolyte level is checked regularly. During intensive use (camping operation) this should take place on a monthly basis, otherwise quarterly and half-yearly inspections are sufficient.

Gel and AGM batteries are maintenance-free. 

A reasonable price, insensitivity to high temperatures and higher charging voltages are all positive factors in favour of the Energy Bull. 


Solar cells
In the case of solar cells make certain that you have a “good“ regulator. Ideally, this should have pulse-width modulation (PWM), temperature compensation and freely selectable parameters (charging voltage...). 


Inverters require a sizeable amount of discharge current from the battery.
In principle, Energy Bull and gel batteries are unsuitable for high current discharges (>40 times the rated current* for >1min).
Should you require increased amounts of discharge current, we recommend the use of an AGM battery (Running Bull).  
*--> Calculation of the rated current follows!


It is preferable that the batteries are only operated with low discharge depths.
A lead-acid battery can withstand a certain degree of capacity conversion (= number of conversions of the rated capacity).
The flatter the cycle, the higher the number of possible repeats.
As far as cyclical capability is concerned, if handled with care the gel battery offers roughly twice the service life of an Energy Bull.


Should the battery be installed inside the vehicle, it must be fitted with a degassing hose with an external outlet. When selecting a battery please choose a type that has a central degassing connection.
--> This allows the gases created during charging (hydrogen and oxygen) to be conducted out of the vehicle.

In a normal operational condition, AGM and gel batteries do not generate any gas (exception: a charger or battery defect). However, for safety reasons a degassing hose must be employed.

Energy Bull batteries generate gases during standard operation and therefore it is essential that a degassing hose is used.

*Rated current calculation

Example: 100Ah (K20) Energy Bull 95751
Rated current (In) = 100 Ah: 20 h = 5A
Maximum charging current = 5 x In = 25A

As a result of our experience, we know that sufficient charging of the battery when driving is unfortunately only possible to a very limited extent. Particularly in summer (air conditioning running at high power, lights on, radio playing, refrigerator running,...) there is very little residual current for the complete recharging of a battery. In some cases, the living area battery must even support the on-board supply ...


The use of a B2B charger represents a sensible approach. At the very least, these devices serve to raise the charged voltage to a reasonable level. 


If, for example, your batteries are approximately 50% discharged (95A are missing) some 105 Ah have to be recharged in order to bring the battery up to full power.

At best, 15A (on average) remain for the living area battery and this means that you would have to drive your vehicle for at least 7h in order to achieve full charging!


In order to obtain the maximum service life from your battery, please ensure complete separation from the on-board supply when the vehicle is not in use (>7 days).
--> Appropriate full charging of the battery should take place beforehand. 

In principle, the AGM battery is not foreseen for use on its side. However, owing to the battery’s design it is nonetheless possible to employ it in this position. See image Menzi Muck walking excavator. In spite of this fact, a degassing hose should be fitted (for safety reasons). In an unfortunate situation (damage to the charger or the battery), acid can escape more easily when the battery is in a lateral position. 


Moreover, depending upon the application (starter battery,...) this installation position may lead to slight limitations on service life.

Menzi Muck Schreitbagger mit Banner Running Bull AGM Batterien

– Before charging a wet battery, check the electrolyte level and top up if necessary with de-ionised or distilled water to the maximum acid level mark, or 15mm above the upper edge of the plates.


Should the battery be removed prior to recharging in order to prevent damage to the vehicle?
Please note the charger type. The operating instructions of the vehicle or the charger manufacturer frequently contain valuable tips regarding battery charging in the vehicle.
In general, a fully automatic charger (charging voltage limitation of 14.8V) is well suited to the charging of a battery installed in a vehicle.

Should your charger have an automatic mode with voltages  >15.9V, it is vital that the battery be separated from the in-board electronics and removed from the vehicle.
In a worst case scenario it is possible that the installed control devices can be destroyed due to overvoltage and the resulting damage would be enormous. Warning! Follow the vehicle manufacturer’s instructions when disconnecting the terminals.

– Batteries may only be charged with direct current. Connect the positive (+) battery terminal to the positive (+)   terminal of the charger, and the negative (-) battery terminal to the negative (-) terminal of the charger.
– Do not switch on the charger until the battery has been disconnected. When charging is completed, switch off the charger before disconnecting the battery.
– It is recommended that the charging current be equal to one tenth of the capacity (e.g. 44Ah divided by 10 = 4.4A charging current).
– The temperature of the acid may not exceed 55°C during charging. If the temperature rises above 55°C, the charging process must be discontinued.
– The fittings must not be opened.
-  Ensure that recharging amounts to 1.2 times the consumed capacity (e.g. consumed capacity 30Ah, recharge 36Ah)
– Charging must be performed in a well-ventilated room.
– Charging is finished when the current drops to 0 or stops falling, or if the automatic charger switches off.

For deep discharged flooded batteries we recommend a charging voltage of 16V (separate the battery from the onboard electronics)!


Warning! Oxyhydrogen gas is formed during charging! It is essential that fires, sparks, open flames and smoking be prevented!


Running Bull AGM/BackUp: only recharge with a voltage controlled charger (max. 14.8V)! The use of standard, non-voltage controlled chargers will dest­roy the battery through overloading and cause the electrolyte to escape!