The Fordson Tractor Pages Forum

What size battery can i fit under the bonnet of my dexta. Is there a code for the optimum battery?

A suitable battery would be:
Power: 74Amp Hours
Power: Cold Cranking Amps (CCA) 680
Typical Dimensions: Length x Width x Height: 278mm x 175mm x 190mm
Eg see Varta 574 012 068 Battery: http://pmd.varta-automotive.com/pmd2/sh ... 0120683132

However, you need to check your terminal type/size and also your hold down arrangement.

In theory according to the manual, we should have 74AH for a standard Dexta and 80AH for Super D. However modern 80AH batteries are too long to fit the battery bay and the consensus is the 74AH is quite adequate. Note that if you run too big a battery, say >700CCA, there is a risk of overloading the starter.

A relevant link from the Fordson website.
http://www.fordsontractorpages.nl/phpbb ... ht=battery
Search also the old website:
http://www.fordsontractorpages.nl/bbs/
All the best

Bensdexta wrote:A suitable battery would be:
Power: 74Amp Hours
Power: Cold Cranking Amps (CCA) 680
Typical Dimensions: Length x Width x Height: 278mm x 175mm x 190mm
Eg see Varta 574 012 068 Battery: http://pmd.varta-automotive.com/pmd2/sh ... 0120683132

However, you need to check your terminal type/size and also your hold down arrangement.

In theory according to the manual, we should have 74AH for a standard Dexta and 80AH for Super D. However modern 80AH batteries are too long to fit the battery bay and the consensus is the 74AH is quite adequate. Note that if you run too big a battery, say >700CCA, there is a risk of overloading the starter.
A relevant link from the Fordson website.
http://www.fordsontractorpages.nl/phpbb ... ht=battery
Search also the old website:
http://www.fordsontractorpages.nl/bbs/
All the best

A larger battery of the correct voltage will not overload the starter, as the larger the capacity of the battery the smaller the volt drop resulting in less amps being drawn by the starter motor!

Gerald

Tubal Cain wrote:

Bensdexta wrote:Note that if you run too big a battery, say >700CCA, there is a risk of overloading the starter.

A larger battery of the correct voltage will not overload the starter, as the larger the capacity of the battery the smaller the volt drop resulting in less amps being drawn by the starter motor!Gerald

Perhaps a loose statement on my behalf, which I read somewhere on the old site

I think the starter will take what power it can, given by Ohms law. Nonetheless more CCAs means more potential to do harm if something's wrong, eg a short somewhere, given that the starter circuit has no protection. So it seems sensible to not to fit a larger battery than is necessary, say 700CCA?
Happy to be corrected

The bigger the battery, the better. Providing it will fit.

The bigger battery will just crank the engine for longer. Batteries were always rated in Ampere Hour Capacity which is a better guide to battery power than the Cold Cranking Amps now used. The same type of battery from different manufactures will perform differently as far as AH is concerned but may still be rated the same CCA.

This use to come up a lot when we were selling Ford Batteries against other makes. The Ford always had a higher AH than the competition and would last twice as long.

Thanks for all the advice. So basically i need the biggest that will fit under the bonnet with the highest AH rating. I did wonder if anyone knew of the battery code (I.e. 067) that batteries seem to get these days. I did buy one for this tractor a long time ago but it was slightly too big to fit under the bonnet but it worked well. Unfortunately i used the battery for another machine which has since gone so can't find out what code it is.

Are the dimensions that Ben gives the max size that will fit under the bonnet?

Bensdexta wrote:Nonetheless more CCAs means more potential to do harm if something's wrong, eg a short somewhere, given that the starter circuit has no protection. So it seems sensible to not to fit a larger battery than is necessary, say 700CCA?
Happy to be corrected

I think that it doesn't matter very much if the short circuit current is 600 A or 700 A or something else. It is a whole lot of current and the damage will be done in every case.

Hello
I guess Brian is correct here. What about us here in the cold north. We have all our Dextas supplied with 2 batteries. One under the bonnet and one by the left fender. That means !2V, 140Ah and at least 1200 CCA. We still have the same starter.