Is my battery charging?

[saviller]

Took my Sumo out for a long drive yesterday as it was legal at last. After stopping to pick something up at dusk (so headlights had been used), I came out to find a flat battery. Some kind souls gave me a push to jump start it so I could get home.

I have an Edelbrok carb (fitted to a RV, but need a heat shield fitted so that it will start when hot - the petrol in the float bowls evaporates, and this shield prevents the carb getting too hot - but thats not the problem - though cranking the engine over a few times until the bowls fills up seems as though the battery is starting to die after about 5 cranks.
I have a Halfords battery with 620 cranking amps, and 110 reserve amps - brand new at the start of the build.

When driving, I have no red light showing, the volt meter sits at 10 - 12 amps with the engine running.
Coming home after the bump start with the engine running, there was no change in the brightness of the headlights when revving.

But after arriving home and stopping, then trying to crank the engine over straight away, the battery was dead - enough power to continue to drive the fans, but not to turn the engine over.

My questions are:
Is the battery up to the job ? I chose the code for an old rover sd1 so I would have thought so.
How can I check if the battery is being charged when the engine is running?

This is a standard Pilgrim loom with the usual wires to the alternator (2 large brown, one thin brown and yellow)

[tonym]

if it's any help, my volt meter reads at 14 when the engine is running :thumb:

[neil still building it]

hi richard
12 volts is the real MINIMUM for a battery ..constantly below this and you'll cream it!!
over 14 volts running is going to cook it so it needs to be 13.8 volts ideally when running
so if you're outside these parameters you have a problem ..is your voltmeter accurate...? try an electrical test meter to confirm..
if you had no warning lamp ..did this light when you switch on the ignition?if there's a dodgy bulb the charging won't work at all this bulb must work and glow at the right time-this is the LOAD the alternator sees to start charging ,alter the wattage and you vary the cut in rpm...so you can see from that it MUST WORK!!
NEIL

[kitcarman]

Hi Richard,
I agree with all the others – in normal running the voltage should be a minimum 13.8 volts.

The problem isn’t with the battery - of that I’m certain from what you’ve said. That leaves the alternator and the wiring.

Question – did you use a Pilgrim wiring loom?

Den.

[saviller]

Hi Guys, thanks for the replies so far...
When I turn the ignition on, I have both the red and orange light on, when the engine starts, both go out.
I have the standard Pilgrim loom, brand new alternator. The wiring connections on the alternator are 2 large brown cables, and 1 thin brown and yellow wire.

I shall go out and check that these are all connected securely, plus I'll check the cable connections to the starter motor.

When the ignition switch is turned, prior to starting, the voltmeter sits at 10 but that was prior to me taking it off to recharge it.

[neil still building it]

another thought...can you please: hook up an accurate voltmeter(or at least we assume the dash one is wrong!) across the battery before starting.turn on the lights and a few things to load the battery-whats the volts?.turn off the lights etc.then with the hood up ,start your engine check whats the volts as you crank it below 8 volts is no good.now with the engine running whats the volts,switch on the lights again ,volts again ...so now you have an out line of whats happening and when.
now diagnosis time...... 12volts ,down to 8 volts,up to 13.8 volts +stays at 13.8 (or very near you may need to up/tickle the tickover -thats ok)with loads,stop the engine ,12.5 volts will resume (it may be 13 to start but will slowly drop to 12.5)
if not its likelt to be that pilgrim loom again...look at the links in the pilgrim /alternator problems lnks at the bottom of this page the answer is there......
cheers
NEIL

[neil still building it]

i seem to remember relays going bad ??connected to the alternator (though why they are i can't fathom -every other install never uses relays ...i wonder why....?):angel:
NEIL

ps i suppose if the volts drop below 10 the relay won't LATCH.....so no hope of ever charging once the volts drop this far...!....good idea ...-NOT
:angry: :angry:

[saviller]

Hi, I hooked up the voltmeter, and it seems as though there is no/little charge going into the battery... I charged the battery, and have been out on a few trips before doing this test.
At rest, meter reads 11.4 V
With lights on, meter reads 11.2V
At crank over, meter reads 9.3 V
When running, meter reads 11.6V, raising up to 12.0V with revving quite hard
When switched off, meter reads 11.2 V again

Any ideas as to how to track this fault down further? I have checked the alternator connections, the distributor connections, and the connections to the starter motor

[saviller]

I fully charged the battery and everything is OK now - I had a few tips from JRV8, and it seems that over the course of building the car, I kept taking charge out, but never running enough to put charge back in. It got so low that there wasn't enough in to excite the alternator charging circuit.

After a full charge, the voltmeter reads about 13.7 at 2000 rpm

Thanks for all the help/pointers

[neil still building it]

hi richard
i'd still keep checking i don't think you're out of the woods yet..!
why wouldn't ti charge before..i still think this will re-occur..
are you able to bypass some of this loom and wire the alternatro 'NORMALLY' ie how all the other mainstream manufacturers do
wire the sens. wire to the ignittion switch via the tell tale bulb(so in series) then both larger spades go to the solenoid(and to the battery)
if you have relays in circuit between this lot than thats where you r problem lies.......drop below 10 volts and they drop the connection and result in no charge and no warning lamp....
NEIL