Alternator upgrade
 

Is it possible to upgrade the alternator on my 940 Celebration estate.I have recently replaced the voltage regulator which has made a massive different,but a bit more current would help,too.
Do the ones fitted to the V90 or 850 fit.??

TIA

Shaun

Depends what alternator you've already got. Assuming it's the original alternator, there should be a green sticker on it if it's a Bosch (some late cars had Nippon Denso alternators) detailing the part number (0 120 abc xyz) and the output 14V and the current at that voltage.
First thing to do is find out what you've got already and then i'll have a look to see what options there are. If memory serves the FWD Volvos you suggest as a donor have totally different brackets so won't even think of bolting onto your red block.

The short answer is "yes".

The long answer includes a "why"?

Even the high output alternators in the same pattern (and I've seen them up to 90A in the same frame) still have to cope with physics. More output = more heat, more drive requirements, and often overlooked - more current through the B+ cable.

IIRC, the standard unit is a 55A unit. Its under stress with everything on - heated seats, headlights, driving lights, heated rear screen, stereo cranked, and the cooling fan cuts in. But in real world conditions, its a pretty capable unit and at least won't melt your B+ lead!

My Celebration Estate currently has a 100 amp alternator,which,after replacing the Voltage regulator works well.,giving a good 14 volts .Trouble is,I only tend to use the car about town,so the draws are going to be more than the top up,so which means regular help from an external maintenance charger.This is frustrating when it catches me out....
Maybe the 960 or V90 alternator would fit better than the 850 one?

My existing alt.is Bosch .....

If you've already got a 100A alternator, upgrading it to even bigger won't help. Either you are having to recharge the battery because there's another problem (perhaps more faults in the alternator than just the voltage reg) such as the belts not tight enough, bad earth, battery on its way out or you haven't given it a decent runsince renewing the voltage reg toput some decent charge in the battery.

I've got a 120A on mine and use it mainly for short runs (about a mile each way) with the occasonal run further afield. I've not had a problem with recharging the battery!

The 960 and V90 both use the same faimly of engines (white blocks) as the FWD Volvos so the same answer applies. It's possible they might be compatible but it's a 50/50 guess and without knowing what alternator you've got (i've already asked for the number) it's impossible to try cross-referencing to a bigger one, not that it's likely to help you any.

Take it for a blatt up the A27 once a week to put some charge back into the battery if you really think all your town use is killing the battery. I really don't think it's only that causing your problem though and i'm sure Ash would agree with that.

What are you trying to achieve, what was the problem before that changing the regulator made a massive difference?

Most people have poor charging issues, this is usually caused by voltage drop across various crimp connections. Putting in a bigger alternator won't help with this, unless you are already consuming close to 1kw of electrical power, which would be unusual.

According to Volvo by 1990 Bosch alternators were fitted as follows:

100A - B230FT/GT
90A - B204GT
80A - B234F, B200E/F, B230E/F, B204E
55A - B230K

Bob :)

The problem I had (and still have but to a lesser degree) is this:
Somewhere on the vehicle I have a parasitic drop.I have been trying to remedy it for years,without success.Changed the alternator to another used one without any change in the situation.So to monitor the battery voltage more accurately I installed a voltmeter wired direct to the battery via an ignition controlled relay.I was horrified to learn that the alternator/battery reading was only just over 12 in all circumstances.Instead of spending loads on a new alternator I simply replaced the part which was most likely to fail-the voltage regulator.Bingo,the voltage is restored to an amazing13.5volts.I have also replaced the big three cables- battery+ to alternator,battery(earth)to body and onto engine block near alternator.I have also added another ground wire from alternator to body for good measure.
Still the parasitic drain remains,though.......?

See what I am up against!!!!

I get through batteries every three years as the discharge cycle harms them.I frequently have to use a maintenance charger.And my holiday in September this year was the first year I haven't had to recharge the battery mid way through,after the longjourney to get there.
I have removed the siren which is a known battery drainer when knackered,and I have exhausted my options,so far.

Thanks for reading,

Shaun

disconnect the clock.

Or, invest in a solar panel charger.

Moomin (940 Classic so very similar) has the same issue. I just use it as an excuse to drive him regularly.

Your battery isn't charging, the alternator is knackered. It should e 14.4V on a cold regulator dropping to 14.0V on a warm one.

Somewhere you're losing a bit of voltage and that suggests to me that the rectifier in the alternator is FUBAR. Common problem on those Bosch alternators, it loses one or both diodes on one phase, dropping the output by about 1/3 and also introducing a parasitic drain.

If you put the headlamps, HRW and heater fan on doe the charge warning light glow dimly, getting slightly brighter as the engine speed rises?

Also what sort of battery is it? As in, is it one of the new, "Calcium Technology", "Silver Calcium" or similar batteries? If so, your alternator won't charge it properly. They need a higher charging voltage of a minimum of 14.7V to 15.1V so if that's what sort of battery you've got, it could be what killed your alternator.