Flat Eric Posted June 25, 2005 Share Posted June 25, 2005 Couple of questions about batteries 1) When power from battery needs to be disconnected. Should you disconnect both terminals (positive + negative) or Is disconnecting just the positive terminal sufficient (which could be done via a battery cut out switch) 2) Charging the battery - using household charger 240v Does this 'need' to be connected at the battery terminals or Can it be attached remotely - ie for positive on starter motor and for negative on earthing bolt on chassis 3) Consequences of using longer battery cables Thinking about mounting battery (red top 25) on rear bulk head (between bulkhead and boot box - using the unused inertia seat belt bolts. Any thoughts Quote Link to comment Share on other sites More sharing options...
grs Posted June 25, 2005 Share Posted June 25, 2005 what is your thinking behind mounting the battery on the rear bulkhead? Quote Link to comment Share on other sites More sharing options...
Flat Eric Posted June 25, 2005 Author Share Posted June 25, 2005 Wimbledon season... Just spotted your thread on same subject, and posted reply. Reason Move more weight to rear of car Clear some space in engine bay (V8) Quote Link to comment Share on other sites More sharing options...
Paul Ash Posted June 25, 2005 Share Posted June 25, 2005 1) When power from battery needs to be disconnected. Should you disconnect both terminals (positive + negative) or Is disconnecting just the positive terminal sufficient (which could be done via a battery cut out switch) Disconnecting positive alone is fine however if you intend the battery cut out switch to kill the engine if removed then you will need to purchase an FIA cut out switch with diode. arounf £20. As an ordinary battery cut out will not kill engine. 2) Charging the battery - using household charger 240v Does this 'need' to be connected at the battery terminals or Can it be attached remotely - ie for positive on starter motor and for negative on earthing bolt on chassis Not a problem 3) Consequences of using longer battery cables Thinking about mounting battery (red top 25) on rear bulk head (between bulkhead and boot box - using the unused inertia seat belt bolts. You may experience a small power drop over distance but not enough to worry about. have seen several westy's with the battery in the boot. Just use a good cable. Quote Link to comment Share on other sites More sharing options...
Gromit Posted June 25, 2005 Share Posted June 25, 2005 1) If your going to disconect the battery, your better off removing the earth (-ve) terminal as that way if the positive side of the battery shorts to the chassis there is no return circuit for the current to flow, wereas if you disconnected the positive (+ve) terminal, it possible to short circiut the battery back to earth. 2) You can pick up on the positive side of the battery as long as you havn`t got any fuses or breakers in between where you connecting and the positive. Earth side should be ok whereever as long as its a good connection. 3)If your going to mount the battery a long way away (ie rear of the car) your going to have to use much thicker cable for BOTH the positive and the negative feeds. If you use standard thickness cable the resistance of the cable will cause a noticable voltage drop at the starter motor and you could experience starting problems and charging trouble. On a remote mounted barrery you have to use a dedicated earth cable back to the engine earth mounting, if you rely upon the chassis to act as the return you might again get problems with volage drop. You will have to weigh up the benefits of moving the battery to the rear of the car against the weight gain of the much thicker battery cables (which can be considerable). I`ve done this on a few cars and have had some of the problems I mentioned before doing it this way. HTH and stands by to be told just how wrong I am. Quote Link to comment Share on other sites More sharing options...
Flat Eric Posted June 26, 2005 Author Share Posted June 26, 2005 Had not really considered extra weight of thicker cable. Another question - Mounting the battery - (if it does remain under bonnet). Can battery be mounted near the coil or does there need to be a distance between the two. If so what it acceptable. Quote Link to comment Share on other sites More sharing options...
Graham Posted June 26, 2005 Share Posted June 26, 2005 Westfield mounted them at the rear, for a while, on the V8 at least. I didn't think they ran an earth to the back, just earthed to the chassis at the rear, could be wrong... They used a reasonably slender positive cable too, still heavy though due to the length. I wouldn't do it, no problems starting but it was a PITA to get to! Graham. Quote Link to comment Share on other sites More sharing options...
grs Posted June 26, 2005 Share Posted June 26, 2005 It appears as though the battery in my car has been planned to be mounted on the rear bulkhead behind seats and there is an earth cable attached to the chassis at the rear. The live cable going up to the engine bay is about 5/16" Dia. I think the bloke that started the car I have may have thought of mounting the electricaly operated extinguisher on the front bulkhead because the extinguisher bottle is quite short in length but a fair bit wider than a standard car extinguisher bottle. Quote Link to comment Share on other sites More sharing options...
Gromit Posted June 26, 2005 Share Posted June 26, 2005 Can battery be mounted near the coil or does there need to be a distance between the two. If so what it acceptable. Can`t think of a reason why you shouldn`t mount it near the coil, theres nothing coming off a coil that would interfere with the battery and vice versa. Quote Link to comment Share on other sites More sharing options...
Flat Eric Posted June 26, 2005 Author Share Posted June 26, 2005 Thanks for your swift replies. Gromit - Don't know why but thought I read somewhere that there should be a reasonable distance between coil and battery. But, like yourself can not think of a good reason why. Think the battery will remain where it is for the moment. More than a little worried about using a small battery on my V8 (even if I know that Graham is not having problems with his). But I do not want to increase these fears with risk of voltage drop due to long cables. Also need to get car mobile again and up and running for trip to Nurburg. Quote Link to comment Share on other sites More sharing options...
Big R Posted June 26, 2005 Share Posted June 26, 2005 Hi FE Its normal practice to disconnect the +ve feed only. If you don’t attach directly to the battery, you won’t get the full charging current due to the voltage drop. I'd recommend only attaching directly to the battery. As per my earlier reply, you'll need heavier gauge cable if you're mounting the battery so far back. Let us know how you get on. Quote Link to comment Share on other sites More sharing options...
Barry Ashcroft Posted June 26, 2005 Share Posted June 26, 2005 Battery mounted in rear. On my new car the diff has cross bracings like on the new Sport2000s chassis which means the standard rear battery tray will not fit so westfield made me the seat belt cover in ally and we adapted a battery tray to it so the battery sits center instead of hanging off to one side which must be better. The battery is earthed at the rear and then a nice thick cable runs to the starter motor. Quote Link to comment Share on other sites More sharing options...
jeff oakley Posted June 27, 2005 Share Posted June 27, 2005 Looks like you will really be travelling light throught the states Barry. After all that lot is in the boot box area it will be more like a glove box Quote Link to comment Share on other sites More sharing options...
Barry Ashcroft Posted June 27, 2005 Share Posted June 27, 2005 Clean pair of shreedies and a credit card is all I will be carrying Quote Link to comment Share on other sites More sharing options...
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