Club 80-90 Forums

Hey,

I have a leisure battery in my van and was wondering how I would find out whether or not its being split charged? I have used it a lot and I am currently running an 50w amp off it...just scared it might one day conk out cause its not being charged?

Cheers.
James.

oh and also my accelerator pedal came free yesterday, it was just flapping about. luckily on my driveway. It appears as if the screws that hold it to the floor have lost their thread...any suggestions on how to prevent this from happening again?

James.

Pop-rivet it back on?

Nuts and bolts?

check the voltage with the engine switched off. Start the engine and when the red light is out check the voltage again. If its being charged it will show the alternator voltage (14,4ish volts). If it hasn't changed its not being charged.

Leisure batteries need to be charged differently to starter or car batteries, I believe they need to be "deep cycled" you can get 3 stage chargers quite cheap nowadays that will electronicaly manage the leisure battery charging.
The difference is that the battery will give good amps for a lot longer than if it were alternator charged.

the "deep cycle" refers to the type of battery, not the way they are charged.

The two main types of lead-acid battery are leisure/deep cycle with has few, thick lead plates, or traction/starter with many thin plates. The LB gives low currents for long periods while the starter can give lots of current for a short period. Both should ideally be charged at a variable voltage from a 3 stage charger as you say. However they are both perfectly happy being charged on the alternator. And my post was in answer to "how to tell if the split charge is charging my LB"

The BIGGEST difference is that a deep cycle can withstand a deeper discharge more often than the other sort while trying to use one to start your van will render it useless in double quick time.

I stand corrected about "deep cycle" and apologise for "tangental topicing..tm"

however leisure batteries are as you say different beasts and I have found three stage chargers bring out the best in leisure batteries.

So, what would eb the best for a wind-turbine trickle-charged fridge battery - I would presume the Leisure battery configuration, as:-

a) it's never heavily drawn from current-wise;
b) needs to deep-cycle frequently waiting for some wind;

and might need to remain discharged throughout the winter without adverse effects.

and best buys? Charging power might be 500W to 1 KW at 14 volts (40 ~ 80A) maximum.

Thanks

not sure, but the answer might be in here.....

http://www.uuhome.de/william.darden/index.htm

Edited from a website................


BATTERY PERFORMANCE:
It's important to understand that, although batteries are described as 12-volt, in reality a fully charged battery should measure 12.6 volts after 24 hours of rest. A battery with a voltage of approx. 12.2V is only 50% charged and one reading 11.7V or less is, to all intents and purposes, fully discharged. Terminal voltages can be affected by various factors however, including the ambient temperature and cold weather will have a significant effect on a battery's voltage and its ability to take and hold a charge.
Bear in mind too that, even if the voltage at a battery is 12.6V for example, the reading at the end of the wire or at the socket where an appliance is plugged in is what matters and there the voltage may be substantially less.

A battery's performance is dependent on several factors including:
1) Temperature: both voltage and Amp/hour capacity will decrease significantly during cold weather. At freezing point a battery's capacity is reduced by approx. 25%. The optimum operating temperature for a lead-acid battery is 80°F/27°C.
2) Rate of discharge: the faster a battery is discharged, the less the power that it will supply. For example, a 100Ah battery discharging at 2 amps per hour should, in theory, deliver power for approx. 50 hours. The same battery, when discharged at 50 amps per hour, will only supply power for approx. 1 hour. (These figures are only for illustration)
3) Amount of discharge: The more a battery is discharged, the less efficient it becomes and the harder it is to charge it back up to its full capacity. To ensure good performance and long life, leisure batteries should not be discharged by more than 40% at the very most.

The temperature factor is difficult to control but the other two can be dealt with by using a sophisticated charging regime. Ordinary chargers and on-board charging systems are not usually capable of providing this regime and, as a consequence, most batteries are never fully charged.
On-board chargers will charge the battery at around 13.8 - 14.2 volts and, although they will keep the battery in a reasonable condition, they won't charge it up to the maximum. With a starter battery this isn't a problem but, with a leisure battery, every Amp/hour wasted means less TV viewing time, less lighting or less water pumping. To achieve the maximum power from a 12V battery it's necessary to look at additional pieces of equipment.
Multi-stage battery chargers:
As previously mentioned, a charge of 13.8 volts is enough to maintain a battery at a reasonable level. It's the voltage which most basic chargers work on and is low enough to avoid overcharging and consequent damage to the battery's plates. It's also safely under 14.4 volts which is the point where “gassing"| occurs. This is the result of the water in the electrolyte breaking down and splitting into hydrogen and oxygen gas which is, of course, potentially explosive. In reality, the amount of gas given off is very small and, if the battery compartment is properly ventilated, should not present a risk. As previously explained, the problem with charging at a constant 13.8V is that the battery will only be charged to around 75% of its capacity. As a fully charged 100Ah battery will only provide around 50Ah of usable power, it follows that the same battery, if charged to 75% of its capacity, will only be able to supply around 35Ah.
This is the main reason why so many caravanners and boaters run out of battery power after as little as one day without mains.
When in a discharged state, a battery's plates become “sulphated"|. This is caused by leaving the battery in a discharged state and results in it being even less able to provide as much power as it should. The only way to get rid of the sulphation is to charge the battery at a higher rate, 14.3 volts being the optimum for a wet lead-acid battery. If a battery is charged at this voltage for too long though, it will be overcharged and, again, the plates will be damaged.

The solution to this apparent paradox is the multi-stage charger, a sophisticated piece of electronic equipment which will charge a battery as quickly and efficiently as possible, ensuring not only maximum performance but also a long life. The charger achieves this by monitoring the battery and then supplying exactly the right amount of current at the most appropriate voltage. This is done in several stages as follows:

Stage 1: The bulk stage is where the charge current (Amps) is constant and the battery voltage increases. The battery can be charged at any rate up to 20% of its Amp/hour rating. This stage is maintained until the gassing voltage (14.4V) is reached.
Stage 2: The absorption stage limits the voltage to between 14.4V-14.8V and the current decreases according to the battery's demands until it is fully charged. The actual duration of this stage is controlled by a timer in the charger. This stage also provides an equalising charge which helps to reverse the effects of sulphation, clearing the plates and increasing their ability to supply power.
Stage 3: The float stage maintains a reduced charge voltage of approx. 13.8V-14V, avoiding gassing and keeping the battery in a fully charged condition.
Stage 4: When the battery is full, the charger monitors its condition and, in the event of the battery being discharged to below 11.5V, the sequence starts all over again.

Some chargers are designed for occasional use and can be simply hooked up to the battery as required, with the battery in or out of the vehicle. Others, such as the Sterling Marine range, are intended to be mounted in the vehicle and used, not only as chargers but, when connected to mains power, as 12V power supplies too. This helps to conserve battery power and ensures that, when connected to the mains, 12V appliances always have sufficient power to operate correctly.

Thanks chaps, food for thought...

Kev, I take it that is from the Sterling site?

If you really want to talk about batteries I suggest you have a look on the SBMCC forum where the subject comes up often. Also if you are considering purchasing Sterling (or Advec) advanced chargers I would suggest joining the club as both companies offer discounts.

I only skimmed that article but I know an advanced charger is needed if you want more energy put in you battery. An alternator is a constant voltage device so overcharges a flat battery but as the battery voltage gets within 1 volt of the alternator it can no longer push enough power in. So a split charge system can never fully charge your batteries. Add the fact that you shouldn't run your batteries flat and your 110AHr battery really becomes a 55AHr (at most) one if charged from an alternator.

Whats SBMCC?

sorry, Self Build Motor Caravan Club
http://www.sbmcc.co.uk
the forum is linked from the front page. The vehicles range in size from Double Decker buses down (once included an artic) but most have simple panel vans. There are a couple of T25 (including me) on there too. As a guest you won't be able to search but you will find batteries are one of the most discussed topics.