justintime

Not all car alternators are internally regulated , particularly on some japanese vehicles which have an external voltage regulator mounted elsewhere on the vehicle, apologies for the contrary opinion John , but I agree with your other comments above.

The Green indicator on the battery usually gives an indication of electrolyte specific gravity if its a lead-acid battery . If you switched some loads eg lights, fan etc on you will see alternator charging amps rise. Take the belt to an engineering supplier though VS986 is a standard automotive alternator belt (986 is the length in mm) Presume the split charge relay coil is fed from the ignition swich so relay contacts connect starter & leisure batteries together when key is switched on . Does the voltage at the leisure battery increase with the engine running? If not , its possible the relay is not working.

A more expensive (and complicated) alternative to the two bulbs would be a blocking diode for split charging power from a single output battery charger to multiple batteries, and a normally closed relay in the circuit between starter switch and solenoid (terminal 50) with relay coil energised from charger output , so the starter would be prevented from operating with battery charger switched on.

Try this link for your marine and auto electrical supplies . It is well worth comparing the products as well as prices to some other suppliers . For example: Heavy Duty Battery Isolator Switch with 250 Amps continuos rating at £18.95 + £6 Delivery + Vat = £24.95 + Vat compared to over £30 +vat + delivery from other suppliers. Take note of the product you are buying , some other suppliers are distributing an economy version! Heavy duty copper tube terminal crimping tool as used to make up battery cables £49.50 + £6.00 delivery + Vat . As seen sold on ebay for around £80 ! The smaller low value items may work out slightly more expensive because of the minimum £6.00 delivery charge but the same delivery charge applies on orders up to £50 value. Order values above £50 are delivered free. For full product catalogue visit www.autoelectrics.smak.co.uk

198 amps seems more accurate . Part of Computerised bench test result from a new small diesel engine starter motor recently supplied is as follows: Rated Power : 1.20 kW Rated Voltage: 12.00 v Free Run Speed : 3352 Rpm Free Run Current : 41 amps Max of Power : 1.25kW Max of Torque : 14.07 Nm Max of Current : 566 Amp ( Presume the starter was stalled at this point as would happen if engine locked for some reason) Ripple : 18 Amp Hold Current : 11 Amp ( solenoid) The above figures were from a small japanese starter motor used on a two cylinder diesel engine.

http://docs-alliedelec.electrocomponents.c...cts_6770158.pdf

Problem with the bulb idea (as you quite correctly pointed out earlier) is it drains the batteries if it is left on without the charging system operating and also creates a voltage drop. I am sure an automatically resetting circuit breaker based on the bi-metal strip principle is available ( similar to the voltage regulator as used on fuel guage wiring on older vehicles)

If you must fit a switch make sure you also fit an in line fuse to the circuit ,so the fuse blows before the switch or wire insulation melts when the starter cranks and tries to draw current from both battery banks because you forgot to turn the switch off!

The following is a guide to automotive cable : Number & Diameter of strands (mm) Nominal CSA of core(mm)sq : Resistance/Metre at 20deg C 9/0.30 0.65mm 0.0294 ohms 14/0.30 1.00mm 0.0189 ohms 21/0.30 1.50mm 0.0125 ohms 28/0.30 2.00mm 0.0094 ohms 35/0.30 2.50mm 0.0075 ohms 44/0.30 3.00mm 0.006 ohms 56/0.30 4.00mm 0.00471ohms 65/0.30 4.50mm 0.0041 ohms 84/0.30 6.00mm 0.0031 ohms 97/0.30 7.00mm 0.0027 ohms 120/0.30 8.50mm 0.0022 ohms Thinwall automotive cable 28/0.3 2.00mm 0.0094 ohms 32/0.20 1.00mm 0.0195 ohms Starter cables** 37/0.71 15.00mm 0.0011 ohms 266/0.30 20.00mm 0.0010 ohms 336/0.30 25.00mm 0.0008 ohms 37/0.9 25.00mm 0.0008 ohms 61/0.9 40.00mm 0.0005 ohms 61/1.13 60.00mm 0.0003 ohms Highflex cable ** 195/0.50 40.00mm 0.0005 ohms Calculation for expected voltage drop on a cable run is calculated by: Current Flowing x Total Cable Resistance = Volt Drop not sure if the text formatting came out quite right on my post above as "20 deg C" should be next to "cable resistance at"

Try this website link which supplies direct from the manufacturer for battery terminals and starter cables up to 36" long. They also sell the proper crimping tools and cable terminals to make up your own specification of leads for heavier duty applications. http://www.autoelectrics.smak.co.uk/defaul...sultsperpage=10

If you need battery or cable terminals try this website http://www.autoelectrics.smak.co.uk/ The heavy duty battery cable crimping tool is much cheaper than most other suppliers!

1.When there are corroded or loose connections which cause high resistance. 2.Where the cable is not adequately secured in engine bays and subjected to vibration and movement which may cause chafing of the insulation eg on starter cables. 3.As already mentioned in a previous post, where the circuit is not fitted with a protection device (fuse or circuit breaker) of the correct current rating. 4.Where cable runs occur in areas subject to excessive temperature, eg close to exhaust pipes without heat shielding. 5. When starter motor cabling is subject to excessive current draw due to starter motor faults or engine problems. To name a few!