Hi, where about's in Derby are you? Trying to work out if i drive past you on the way to / from work... (i pass at least 1 light weight)
wrt to your issue, what exactly is the problem? you have a 24V system and your alternator gives you 24.7v... i know on 12v the alternator normally delivers nearer 14v ish when running, but, it can all work on just 12v from the alternator...
wrt to your issue, what exactly is the problem? you have a 24V system and your alternator gives you 24.7v... i know on 12v the alternator normally delivers nearer 14v ish when running, but, it can all work on just 12v from the alternator...
dr pepper
New Member
Depending on the state of the battery that might be ok.
The alty will limit the voltage if the current is high to protect itself.
What you need and probably wont have is a clamp meter, to measure the output current of the alty, if the output current is nowhere near the max, and the volts is that low then theres a problem with the charging system or alty.
Run the engine a while and 'feel' around all the connections, a bad connction tends to get hot.
Try cleaning the battery terminals, clean the engine earth strap both ends, clean the terminals to the starter solenoid, take off the alty and clean up where it bolts to the engine, and if that doesnt work then you could see if you can get a spare brush set for the alty, failing that your gonna have to get another or have it fixed.
The alty will limit the voltage if the current is high to protect itself.
What you need and probably wont have is a clamp meter, to measure the output current of the alty, if the output current is nowhere near the max, and the volts is that low then theres a problem with the charging system or alty.
Run the engine a while and 'feel' around all the connections, a bad connction tends to get hot.
Try cleaning the battery terminals, clean the engine earth strap both ends, clean the terminals to the starter solenoid, take off the alty and clean up where it bolts to the engine, and if that doesnt work then you could see if you can get a spare brush set for the alty, failing that your gonna have to get another or have it fixed.
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oxides
Well-Known Member
Are both batteries the same type/make/age? If the batteries are in good condition you should see just over 25v (12.6v each) across them both. Put the lights on with the engine stationary and check the voltage of each battery. they should be near 12v and both the same. If they're not you might have to replace both batteries. The charging system should deliver about 27/28 volts, shared equally across each battery. Much lower than this and the batteries won't charge properly. Low volts can be caused by:-
Alternator running at maximum current - you'll need an ammeter to check this. Can be caused by faulty battery.
Poor contact between alternator and battery.
Alternator producing insufficient voltage, possibly worn brushes.
Alternator regulator failed.
Is yours the full FFR wiring setup? 'cos there's a lot of wiring to chase through and lots of places where it can go wrong.
Alternator running at maximum current - you'll need an ammeter to check this. Can be caused by faulty battery.
Poor contact between alternator and battery.
Alternator producing insufficient voltage, possibly worn brushes.
Alternator regulator failed.
Is yours the full FFR wiring setup? 'cos there's a lot of wiring to chase through and lots of places where it can go wrong.
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fenby1976
New Member
Do the 24V systems have the rectifier and regulator mounted on the alternator or are they remote? I had a mini digger which didn't have these bits on the alternator itself. If the regulator was somewhere else, then that might explain why changing the alternator didn't have any effect
BULLDOG01
New Member
Hi
Have a 88" lightweight 24v, it is charging but stedily, goes upto 25.4v, after a short while,but does not alter when lights/wipers etc. are on, have a recon altenator but still the same?.
is this usual or is there a common problem, as it is ex military.
thanks
Paul. checked the shunt box, its o.k.
Have a 88" lightweight 24v, it is charging but stedily, goes upto 25.4v, after a short while,but does not alter when lights/wipers etc. are on, have a recon altenator but still the same?.
is this usual or is there a common problem, as it is ex military.
thanks
Paul. checked the shunt box, its o.k.
ratty
I'm not special I'm limited edition
Are you worried it's undercharging or overcharging? A 24v charging system can go as high as 28v.
ratty
I'm not special I'm limited edition
What are the battery voltages showing if you measure the voltage across each of them individually?
mystery
Well-Known Member
try Land Rover Lightweight may give some info
fenby1976
New Member
This diagram should help shed some light on what the problem is:
The diagram shows that the rectifier is contained within the alternator, but the regulator is located within what is known as the 'Generator Panel'. The diagram also shows that there are a pair of ammeters in the system: one for the pair of batteries for the vehicle electrics and one for the extra pair of batteries for powering the radio. One of the ammeters should be telling you how much current is flowing into or out of your batteries. I'd suspect the regulator, but it's possible some voltage could be dropped over some bad connections somewhere between the alternator and the battery. I think that the Generator panel and shunt box are located behind the seats. All the shunt box does is produce output voltages for the amperage meters (which actually measure voltage accross a pair of resistors in the shunt box), and house a fuse for the radio charging circuit.
The diagram shows that the rectifier is contained within the alternator, but the regulator is located within what is known as the 'Generator Panel'. The diagram also shows that there are a pair of ammeters in the system: one for the pair of batteries for the vehicle electrics and one for the extra pair of batteries for powering the radio. One of the ammeters should be telling you how much current is flowing into or out of your batteries. I'd suspect the regulator, but it's possible some voltage could be dropped over some bad connections somewhere between the alternator and the battery. I think that the Generator panel and shunt box are located behind the seats. All the shunt box does is produce output voltages for the amperage meters (which actually measure voltage accross a pair of resistors in the shunt box), and house a fuse for the radio charging circuit.
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ed.poore
Active Member
Since I've been doing a little reading up on this subject - you'll typically need ~14.4V per battery to begin to charge the batteries so that would equate to ~28.8V for an FFR, if the voltage drops below 10.5 then start worrying (will begin destroying the battery).
Typical open-circuit voltage of a lead-acidic battery is ~12.7V.
Typical open-circuit voltage of a lead-acidic battery is ~12.7V.
