# Starter battery



## ezz (Nov 6, 2011)

Do I have a problem?
With help from this forum I have fitted a couple of solar panels and so now when at home I no longer hook up. But I do keep an eye on the leisure and starter battery voltages. I have noticed the starter battery quickly drops, a day or so, to 12.3 volts at which stage the system takes over and redirects some charge to it. 
The van, a Fiat base, is only 30 months old and so I would have thought that battery should hold its charge better. I have had no problem starting but do not want to but there again I do not want waste money on a new battery if I do not need to. 
What checks do you suggest I carry out, if any. 

Thanks
Eric


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## safariboy (May 1, 2005)

Fiat X250 cabs do tend to draw quite a lot of charge when stationery. This will be more so if you have an extra Thatcham 1 alarm fitted. Mine drew 170mA minimum.
The radio can also be a problem.
Despite this the solar panel should be able to cope in May. 12.3V seems a very low voltage but as I do not know how your system is configured someone else may no better. I use a dual output solar charger and despite the fact that only 10% of the charge goes to the cab battery only have a problem in December and January. (140W panel) I suspect that yours in a different system.
I hope that this bumps your problem up so someone who has a system more like yours can help
It should be passible to disconnect the cab battery (earth) and monitor the battery by itself.


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## Wizzo (Dec 3, 2007)

The battery voltage at rest and after a period of not charging should be more like 12.7v so it appears that your battery may be on its way out. It could be that it has at some point been allowed to go flat and has never properly recovered.

JohnW


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## cabby (May 14, 2005)

I would be inclined to disconnect the van battery and do an independent voltage check on it. However, you do not state if you have security etc. draining the battery, nor what size it is. If the charger notices the drop in voltage and charges accordingly then the system is working.

cabby


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## Techno100 (May 8, 2010)

What do you mean by "the system takes over"?


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## Penquin (Oct 15, 2007)

When you leave the MH, do you lock it and ALARM it?

If so then the alarm system will use current, I found that on ours the alarm drained the battery within a couple of weeks to an unacceptable level, so if yours is dropping to abut 12,3 then it sounds like the alarm is activated...

We have a Battery Master fitted (very easy as only 3 wires from memory and great instructions with the Battery Master. This automatically sends power from the solar panels to the leisure battery and then if that is full to the vehicle battery, there cannot be any current going in the opposite direction, so if the leisure battery is not fully charged the panels charge that.

That may be what you mean by "the system takes over", but do you have a BatteryMaster (or similar) fitted?

Once I fitted ours, I have never had to worry about the charges of either battery as long as there is sufficient sunlight to generate the charge required. I just check both batteries every 10 days or so to ensure all is working OK.

Dave


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## readyforoff (Dec 28, 2013)

If it starts ok then what's the problem ? X250 (and any other vehicle) should draw no more than 10ma when standing if it's as it left Fiat. Alarm about 30ma ditto tracker.


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## safariboy (May 1, 2005)

readyforoff said:


> If it starts ok then what's the problem ? X250 (and any other vehicle) should draw no more than 10ma when standing if it's as it left Fiat. Alarm about 30ma ditto tracker.


Fiat claim the discharge current is more than 50mA (given to me when I enquired because we were having problems) but from my experience it is larger even when the radio is disconnected. This is partly the alarm.
In the user manual Fiat suggest disconnecting the earth if the vehicle is o be unused for more than a short period.

The figures I gave were correct in 2007 they may have reduced the current in later models.


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## gaspode (May 9, 2005)

How are you measuring the battery voltage ezz?

From experience I can tell you not to rely on the M/H system panel to give you an accurate voltage. When we got our present M/H the system recorde the battery voltages at 0.5v lower that the actual terminal voltage, this due to a combination of poor calibration and voltage drop in the long runs of thin wiring between battery and meter. Some systems can be manually calibrated (CBE for instance) to compensate for voltage drop.

So firstly, note the reading your system is displaying, then measure the terminal voltage using an accurate digital meter across the battery terminals. Then remove the positive connection from the battery terminal and measure again when you can be sure that there is no voltage drop caused by a constant load. This will then give you a better indication of what's actualy going on.


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## rosalan (Aug 24, 2009)

Adding Gaspodes wisdom to the fact that when it reaches "12.3" whatever that really is, the charge is diverted to the van battery, all sounds to be working as it should.
From what you say, you already have a system for charging both batteries which should be set to cut in at an appropriate level of charge/discharge, I am curious as to why you assume it is the battery's fault that it is allowed to fall to 12.3. I would trust Ken's point that the true reading at the battery would be higher. If there were a question of which component is at fault, why not the the charging device for waiting until the battery's reserves fell beyond that which you expected.

Alan


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## ezz (Nov 6, 2011)

*Starter Battery*

Hi and thanks for the thoughtful and helpful replies. Yes there is a system within the vans existing electrics to top up the starter battery and that works from hook up. My forum inspired DIY solar is connected via a mppt controller directly to the leisure battery without any link to the starter battery which seemed the easiest way. None the less "the vans system" does appear to takeover and provide charge at the 12.3 volt level so long as the leisure battery is charged. 
I have checked the battery voltage with a meter and it compares well with the vans display but I have not followed Gaspodes constant load suggestion yet. There is additional current drain from Thatcham alarm but I do not think the after market radio is drawing anything as it has its own on/off switch. But I need to look closer at that.
The reason I am concerned about the starter battery is that even following a good charge from say being on hook up or following a good long run it still drops within 24 hours from 13+ to 12.3 volts. I hear the if it aint broke dont fix it point but it is not in my nature not to confront a problem.
So still some checks to do I think.

Eric


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## Penquin (Oct 15, 2007)

Surely 12.3 - 12.5 is the normal value for a 12 volt battery, it is NOT a 13v battery.......

The fact that initially it read over 13v is not relevant, the charging voltage is slightly higher and it takes time to settle down.

When it is charging from the EHU or the alternator the voltage reading at the battery is likely to be around 14.4 v AFAIK.

If it is static at 12.3v and does not drop lower for a considerable time then I would not worry and would simply monitor. A 12v battery that is NOT charged to 12v is one to start worrying about IMO.

I think your system is working normally and properly although it may well be worth looking at whether the voltage delivered via you MPPT controller would also charge the vehicle (starter) battery - if that is taking place then it sounds as if your entire system is working perfectly. So relax and enjoy it IMO.

Dave


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## safariboy (May 1, 2005)

The problem is that the battery voltage depends on an number of factors and so is not a very good way of measuring the state of charge. The traditional value for a fully charged cell is 2.2V which gives 13.2V. It then falls quite rapidly to 2.0V per cell for most of the discharge. However like all traditional views it is only partly valid. I still feel that I would like to see about 12.7V for a battery some time after charging has stopped.
If it reads about 13.4V just after charging the calibration is probably OK, but it is certainly a point to watch.
With everything off you should not see the leisure battery discharge at all.

This all matters because if your battery is in a permanent state of part discharge its life will be reduced.


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