Help Please - Seawolf Battery..

periscope · 28-10-2005

Plodding on with the tray assembly, but it's not quite finished yet. (Photo att)
Reading ahead in the instructions it appears that the Robbe battery for this sub just sort of hangs in the hole from a couple of fittings which slide into the battery slots. I think the battery is a bit expensive and I want to use my own batteries which are then interchangeable if one goes flat. I generally use Titan sealed lead acid batts 6v 4ah - they give me quite a good running time - I was thinking about making a box or cradle for the Titan batt out of scrap to hang inside the battery hole - or maybe even just lay the battery on the tray above the hole secured with Velcro ( maybe glue a couple of bits of scrap across the hole to prevent any accidents) - or would this be top heavy? Any advice or suggestions would be really appreciated.

Ian

Nigel.D · 28-10-2005

worthless post one! Id love to help but its all greek to me ask Richard he will know (probably)

adzam · 28-10-2005

i beleive an SLA is an option ian, although ballasting may be diiferent, i personally used the recomended robbe unit.

as long as teh battery is stationary and cannot move then just aadjust any ballast as required when teh model is complete.

ajg141 · 28-10-2005

Ian

Chris is right (again!). The Robbe battery is the one I use and it's proved very reliable and didn't require much in the way of re-ballasting. The important thing to remember is that those little brackets attached to the battery sides allow the battery to sit low in the hull thus keeping the centre of gravity low. This is an important consideration in a sub as the motor torque will cause a high degree of roll if you raise it the c.o.g too much. You could use your preferred set up but try and keep it low!

Andrew

**Bunkerbarge** · 29-10-2005

If this is your first submarine kit I would strongly recommend that you stay with the kit batteries. You can fit anything you want but reballasting a sub if you have never done it before takes a bit of getting your head around.

A ship has to sit in the water at the correct attitude and be stable, which is a function of the difference between the centre of bouyancy and the centre of gravity. That is pretty straightforward, all you need is a bath and some weights.

A sub has to have this trim and stability at whatever depth it is at, so ballasting when on the surface may not match the requirements when submerged. Get it wrong at depth and the boat may change trim and end up surfacing or, worse, diving. I am not saying it is too difficult but to prevent unecessary headaches I would suggest you fit the Robbe batteries for now and experiment at a later date when you have gained experience and confidence.

Coming along nicely though, I look forward to the sea trials! Don't forget there are only two types of water craft, Submarines and targets!!

periscope · 29-10-2005

Thanks Everyone - all points noted. I'll decide what to do as the model progresses - I did look at a battery rack to keep the centre of gravity low - I made it from a coathanger, it just wants a strip of something glueing across the base - but I'll decide later. Thanks again.

Ian

periscope · 29-10-2005

Thinking things over I've decided ''why spoil the ship for a pennyworth of tar' - it does make sense to use the correct fittings. Can someone please tell me the Robbe part number of the battery - there are not many places to get supplies from round here, I'll probably have to send for one. Also I already have a Robbe 5R multi charger, just wondered what the battery capacity is, my charger will do 60, 140, 180 or 500mA charge - will this do the trick or will I need another charger?

Thanks Guys

Ian

adzam · 29-10-2005

hello ian,

i beleive the battery is a 6v 5 Ah
you can order direct from robbe www.robbe.com
http://www.amodelworld.co.uk/ may be able to sort you out also, if you drop them an email, their prices are very reasonable.

Adz..

periscope · 29-10-2005

Thanks Chris - I'll contact 'A Model World' Later - I got my surface model Paula from them last year at Doncaster, and I got my Seawolf from them this year at Blackpool. They are very good and their prices are very keen. If the battery rating is as you say I'll be able to use my Robbe charger on 500 mA I'll give them a ring after the weekend. Thanks again Chris.

Ian

periscope · 30-10-2005

The story so far ......