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It has been over a year since my last problem... knock on wood. Until yesterday.

We wanted to go for a boat ride on the evening of the 3rd (you will see relevance). However, the boat, on the mooring had a dead battery... I had left the radio on a few days prior. In my twisted mind the most reasonable means of getting it going was to pop the battery out of the Rover and take it to the boat for a jump start. Worked perfectly and enjoyed the ride. Anyway.....

I quickly put the battery back in and all worked well. Ran it on the evening of the 3rd until the after noon of the 5th. Probably started the car 6 to 8 times in that period. Went to the car on the evening of the 5th, and the battery was weak, and couldn't start the car. I got a jump start and drove 35 or 40 minutes home. Turned off the car and tried to restart immedialy and same condition... too weak to start the car. This morning, I wire brushed the terminals and clamps until they sparkled thinking maybe i didnt get a good connection when i put the battery back in. Jump started the car and ran 40 minutes to work. tried to restart, same thing.

My twisted logic... battery was fine 2 or 3 days ago, took a charge deep enough to jump a 280 hp boat and then start the Rover 6 or 8 times. However, it is no longer either getting a current to charge it, or not taking a charge. Seems strange that the battery would have the capacity for that many starts, and then absolutely nothing a couple of days later. The alternator is producing enough current to run the car. The connections between the battery and cables are good.

Thoughts? Could using the battery as a jumper have damaged it that dramatically and quickly? Could something else in the charging loop have gone coincidentally at the exact time I took the battery out and put it back in? Could the alternator be producing enough current to run the car but not enough to charge the battery? Is there anything else in the loop other than alternator or Battery that could be at fault? Fuses? Relays?

This evening, I will get the car running and disconnect the battery to see if the alternator is actually producing enough current to run the car. Then, I will put the battery on an actual charger over night to see if it takes a charge. Any other thoughts? The battery is about a year and a half old and the alternator is maybe 2 years old.

Thank you in advance.
 

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This evening, I will get the car running and disconnect the battery to see if the alternator is actually producing enough current to run the car.
whatever the reason [for your issue] you certainly don't want to do that, the battery effectively clamps the alternator down to a certain range of voltage, without it you could be putting high voltages through all the vehicles wiring/components.

If your Alternator is struggling [i think i'm right in saying] your main lights will dim/vary, i was ridding around recently with a multimeter on the cigar lighter, i've got no real issues (other than not using it everyday/week) and i was getting 13.95 volts pretty much consistently.

But go through the Sticky (this forum's home page) then everyone can see and comment.
 

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Good Advice, makes sense, thank you. I had the alternator go a few years back and am familiar with the simptoms of that. This "feels" like the battery but as I said, 2 days ago it was good enough to jump start a boat and then start the car at least 6 times before no longer taking charge.

It also "feels" like it is somehow related to taking the battery out and putting it back in... if nothing more than the timing of the issue.

I'll have all weekend to test and check. Maybe even just tighening the battery clamps put some stress on the wires and loosened one of the connections to the alternator..

We'll see.
 

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Survey says...... Battery. Had it tested. 88 Cold Cranking Amps. Hard to believe that it went from a good battery to a dead one in a matter of days but I'll take it. Battery is cheaper than an Alternator.
 

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Good stuff :thumb:, once a battery has gone too far [regardless of time] then that's it, they can sometimes still be brought back with a specialised charger to reverse the sulfation process (which is what kill's it).
 
D

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Following the usual 'conventional car wisdom' (although not always applicable for P38s..) " It is usually what we last did ourselves that caused the new problem "... it was probably your 'deep charging' routine that caused the battery failure (?).... Trying to force current into a nearly-flat battery (with an old-style charger or even just the alternator/charger/regulator on the car) can cause all kinds of problems.

A 'smart charger' (eg. a 3-stage unit) is a good investment, even though it takes several hours to charge a battery.

- this can do what your 'normal' alternator etc can't... it can switch from constant current to constant voltage... depending on the battery's needs.....
 

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