Battery expert please?? advice needed

[long512]

Hi All,

looking for some advice on car battery's. We have opened a clay pigeon shooting range at our farm, and my brother is paranoid about how long we can use these batteries before they start to loose the power to work the traps. they are just standard car batteries (new) some 40ah and some 70ah . we run the traps for about 3 hours and they pull around 5 amp max each time they fire but only for around 4 seconds. its hard to say how long in total they continually run but no more than 1.5 hrs i would say???

questions,

1. what is the best way to test/measure the batteries before we remove them to charge?

2. does it cause damage to the cells charging them to much ie after every time?

any advice would be greatly received, i probably need to give you more information, motor size power ect if so just ask i'll find out tomorrow!

also, we are thinking about supplying them from a 12v transformer ( a big one ) but i'm worried about cable size. we have a huge roll of mullticore 2.5 tri rated but when doing my calculations i fear its not big enough? there are 20 traps in total and at times would be 3-4 pulling supply at the same time.
the cable run will be at least 50m they say you cant have more than 3% vd over the run??? using an online cable sizing guide it recomends a cable 20mm to keep voltage drop bellow 0.036v??

what am i missing? my brother recons 2.5 will be big enough coz his mate says so??

cheers allister

 

[i=p/u]

He fits them lol

 

[ruston]

I was going to suggest leisure batteries as above, also if the batteries are kept in a shed, have you considered a PV (solar) panel on the roof to charge them?

Just to stretch the imagination , I know it's not ideal , but will give you the gist. Safe transportation too.
There will be better set ups but this was just a quick Google.

Electric Poultry Fencing - Solar Power Panel Energizer and Dolly Kit | Electric Poultry Fencing | Chicks and Game Birds from Stromberg's |

 

[long512]

thanks guys, i hAD a look lasat night and the majority of the batteries ARE leisure batteries, sorry my mistake in the original post.

thanks for the suggestions, we have a contact that owns a scrap yard and he's gave us some golf buggy batteries too so were on the right track.
with regards to the solar charging, i was thinking of the units that you can buy for your cars to keep there batteries topped up in the colder months. just about £20 each think its worth a look?