What Amp Hour Do I Need

[Snapperpaul]

After scrubbing the green acid stains of the engine bay and the floor of the passenger footwell i have decided to ditch the old battery off the donor and replace it, if i can afford a gel battery or something like a red top i will but i have no idea what amp hour i should be looking for, any ideas?

[Guest sparkt]

look for one that you would put on a nomal sierra 2.0l engine and that will be fine as you are only running the engine and not all those electric bits and peaces that other cars run

[Guest Dan_Beeston]

As your average RH runs much lower loads I would suggest you can get away with a much smaller battery than a standard Sierra, an OEM battery will be able to cope with all the standard tintop loads down to at least -20 degrees.

If the car is only going to be relatively 'fair-weather' it could be a good opoortunity for weight saving?

[Guest stu205]

according to an online calculator you only need 256A of cranking current for a 2.1 so you could get a TINY battery!!! or even 2x6v?????

 

http://www.bgsoflex.com/cca.html

[Snapperpaul]

Thanks for the calculator but i can't find battery manefacturers that qoute this, Varly red top quote for 5 secs.

I had a look in Halfrauds and can easily fit the smallest they do, i just don't want to go to low on the AmpHours. Any ideas what would crank the Pinto?

[Guest stu205]

TBH most VRLA batteries are fairly large cca (600-800A) Id imagine there would be a trade off between cca and Ah. There is a Red Top 15 which is 12v 14Ah with a cca of 400A and its only 5kg!!!!!

 

as for the Ah a good rule of thumb is 1.5x what your using

 

headlights 10-15 A?

side lights 3-5 A?

 

 

so 30-35Ah would probably do you

 

 

*edit* just re read your last question, as far as I understand the CCA is what the battery will deliver for a short length of time so say for arguments sake the starter is 100a and the OEM battery was 600A CCA that means if you use a 400A CCA you will just get less starting time once started the battery will recharge, this is when the Ah comes in, what you dont want is to have a situation where your using less than the battery can deliver whilst on charge (obviously) so with the original it would have to be capable of taking all the loads (less a diversity factor) but with the hood you wont be using half of those circuits so you can go for allot smaller battery, sorry if this is sucking eggs stuff!!!!!

[Snapperpaul]

Well i have sort of forced myself into a solution for the moment, my engine bay layout and a bit of bent metal as a battery support has meant, for the time being that the smallest battery that the local motorfactors do has been bought, less cranking amps than the next size up (063) but sits well in the engine bay.

I did contemplate mounting it low under the carbs between the bulhead and the engine mounts but once the carbs and air filter is on, i would never see it again. So for now or until i fork out for a RedTop, it will do.