Bow thruster electrical installation - battery spec and charging cables

[picardy]

I am about to have a side Power SE40 bow thruster installed by a trusted "one man band" but he won't do the electrics. This is fine as I will get someone else to to do this professionally. Spec says thruster needs a battery capable of providing 300 CCA www.side-power.com/public/templates/default.php?id=74

I do however want to buy many of the electrical bits myself (can get trade) and have some questions which I wonder if you could help me with

1. battery - I intend to have a dedicated battery next to the thruster and run charging leads. Current set up is 2 house battery and 1 engine all conventional wet cells. Is it a case of bigger is best for batteries or am I wasting my money? I was wondering about an Optima AGM to give max power at Thruster as they give 800CCA. Alternatively I could use a Varta professional wet cell with a CCA of 570.

2. Charging cables - will 10mm2 be large enough over an 8-9 metre run or should I go for 16mm2

3. Charging - I am told if I use one of these http://www.bepmarine.com/home-mainmenu-8/product-714/digital-voltage-sensing-relay-dvsr I can connect charging cables to existing charging source and this will take care of it all. Is that right?

Comments gratefully received. Thank you

 

[Carduelis]

I used one of these slave chargers. Much easier than running thick cables the whole length of the boat. It's been in for 3 years so far and worked perfectly.

http://www.powerstore.co.uk/view-item.asp?itemid=1270&id=209&

 

[Boathook]

Use a Adverc? 12/12dc charger. This takes power from the main batterys once they are charged. It also controls the amount of charge, etc like a smart charger. You would possibly only require to use 2.5mm CSA cable for this. It's the set up I have.

 

[nigelmercier]

Strange they only specify the CCA, the similar Vetus model specifies the capacity, see page numbered 14 of their excellent manual: http://www.vetus.com/media/magentominds/sasdocument/20121113021208_0.pdf