A Different twist on an old charging question

[Timleech]

Here's the situation:-

 

24V electrics, dead simple one battery for everything, one alternator.

 

Alternator is an old Simms, big thing 9" dia., marked:-

 

217064

1750/58/2

 

External regulator, which I'm told is a standard modern Bosch item, 3-terminal.

 

The cable run from alt-battery is long, estimate about 12m, and too skinny. The regulator is about halfway along that run between the two.

 

I fully charged the batteries at home, then after a bit of a caning starting the engine from cold (no preheaters etc, BS5 starter working hard for maybe 20 secs) checked the charge rate at about 2A (digital clamp meter, probably not very accurate at that level). Battery voltage about 27.9v, alternator terminals around 28.1, so about 100mV per amp drop in the cables.

Alternator field voltage at that point about 21V.

 

I'm told 28V is about right for those regulators, but there is an adjustable version available.

What adjustment is available on those, and is 28.8V the best compromise to aim for?

Would the old CAV 3-position type of regulator work with this alternator? (I happen to have one) and if so what voltages do they give?

I'm wondering whether to splash out on a SmartGauge, as this can be incorporated into the future system and could maybe use that to add a float voltage.

 

Anyone (Snibble, Arnot?) know what the rating of that alternator might be? Based on that as well as voltage drops, what's the minimum size of cable I should aim for for decent results? It's all in flexi conduit, so I can't go mad without major restructuring, I'm not expecting perfection.

 

 

many thanks

 

Tim

[Sir Nibble]

My oh my! A Simms 1750. I would never have expected them to come up. Not seen one of them since I was an apprentice.

Its a 60A unit which comes in two flavours, +ve sensing and -ve sensing. Presuming you have the +ve sensing version, which your bosch reg suggests, then the CAV 440 will do the job and give options for 27, 28, or 29V.

Simms 1750, well I never.

[Nickhlx]

My oh my! A Simms 1750. I would never have expected them to come up. Not seen one of them since I was an apprentice.

Its a 60A unit which comes in two flavours, +ve sensing and -ve sensing. Presuming you have the +ve sensing version, which your bosch reg suggests, then the CAV 440 will do the job and give options for 27, 28, or 29V.

Simms 1750, well I never.

 

 

 

oooo aaaaaH - the don't make 'em like they used to ( thank God) - still, it's a tribute it's run this long I suppose

 

:lol:

 

Nick

[Arnot]

Just to add to what snibble has already said, my oh my! Talk about vintage...

 

It would also be a good idea to uprate the skinny cable, the voltage drop at high current might be a bit much.

 

There is a variable regulator the would probalby work, the butec three terminal jobby but on balance the 440 is probably a better bet.

 

Also I wouldn't bother with the float voltage thing unless you intend cruising at constant speed for more than 10 hours regularly.

 

I would love to see it some time.

 

Regards

 

Arnot

[Timleech]

Just to add to what snibble has already said, my oh my! Talk about vintage...

 

It would also be a good idea to uprate the skinny cable, the voltage drop at high current might be a bit much.

 

There is a variable regulator the would probalby work, the butec three terminal jobby but on balance the 440 is probably a better bet.

 

Also I wouldn't bother with the float voltage thing unless you intend cruising at constant speed for more than 10 hours regularly.

 

I would love to see it some time.

 

Regards

 

Arnot

 

Thanks for the answers, museum piece eh? Yes, visits by appointment

I'm not clear about this '-ve sensing vs +ve sensing' thing? The alternator has 4 connections, 2 for output & 2 for field, fully isolated, can I not just wire it to suit the regulator? I must admit I got confused by the way the present reg is wired, thought it was wrong but apparently it's not.

 

I'm just looking for a reasonably quick fix to improve things for the next 12 months or so, it'll probably all get changed then anyway, hence my comment about 'future systems'. I did put that in my original post but must have edited it out before posting.

 

I suppose a quick cheat would be to wire the alternator output direct to the starter motor & leave the reg on the end of the skinny wires, but the starter wiring doesn't have an isolator switch.

 

Thanks again

Tim

Edited November 25, 2009 by Timleech

[Sir Nibble]

If If remember, (no guarantees) the four terminals are, +ve, -ve, I+/V+ and F? It must be 35 years at least!

The difference is that for a +ve sensing unit there are 3 +ve "field" diodes, and for -ve sensing 3 -ve field diodes. you should be able to wire it like any other less eccentric design so long as it's not -ve sensing, which I believe we have established. Connect it to the starter by all means, but sort out the isolator, you shouldn't be leaving the starter live.

That's a very reliable slow speed unit but when you get around to sorting the system some old bus owner will bite your hand off!

What engine is this by the way?

[Timleech]

If If remember, (no guarantees) the four terminals are, +ve, -ve, I+/V+ and F? It must be 35 years at least!

The difference is that for a +ve sensing unit there are 3 +ve "field" diodes, and for -ve sensing 3 -ve field diodes. you should be able to wire it like any other less eccentric design so long as it's not -ve sensing, which I believe we have established. Connect it to the starter by all means, but sort out the isolator, you shouldn't be leaving the starter live.

That's a very reliable slow speed unit but when you get around to sorting the system some old bus owner will bite your hand off!

What engine is this by the way?

 

The terminals appear to be marked +, -, and the lower of the two field terminals has a + stamped in the end and a dab of red paint.

When running, the + field terminal is at battery+ potential (actually fractionally higher than either battery or alternator, strangely) and the other is at around +7V. Does that compute?

 

Engine is kelvin R6, from the 1960s, I imagine the alternator is original equipment (gear driven from the timing gears) though most Kelvins I've seen from the period had dynamos or big CAV alternators.

 

Thanks

Tim

[Proper Job]

R6 Kelvin Nice lump.

 

There were a pair for sale on Apollo Duck not long back. IIRC one had a duff engine but good gearbox and the other had a good engine and duff gear box.

[Proper Job]

Found 'em..... Kelvin R6

 

They're still there. Need any spares Tim?

[Timleech]

Found 'em..... Kelvin R6

 

They're still there. Need any spares Tim?

 

Thanks, yes I knew about them & have the guy's phone number, debating whether I really want another 3 or 4 tons of rusting cast iron around the place though

 

Tim

[Sir Nibble]

When running, the + field terminal is at battery+ potential (actually fractionally higher than either battery or alternator, strangely) and the other is at around +7V. Does that compute?

Tim

That is precisely why I prefer battery sensing.

Arnot, check me on this. 440 regulator, A goes to D+, but the Hi-Med-Lo connections can be used for battery sense, yes?

[Tony Brooks]

That is precisely why I prefer battery sensing.

Arnot, check me on this. 440 regulator, A goes to D+, but the Hi-Med-Lo connections can be used for battery sense, yes?

 

 

My diagram shows the wander lead supplied by the main positive so yes if it is run right from the battery.

 

It also shows a trimmer so presumable the regulated voltage can be adjusted as well (as long as care is taken.)

[NB Alnwick]

Building on the topic title, one thing that I have never understood is why our 24v alternator (a CAV AC5 R) seems to produce a 'better quality' charge than when using our 240v AC Generator and our Sterling 25 Amp four stage charger? I know this all seems highly improbable but a couple of hours charge with the engine running will take the battery back up to 100% on the SmartGauge from around 80% and the batteries will then stay a t 100% for the rest of the day and, even with the inverter on, the battery state of charge appears to drop quite slowly. Charging from the generator to achieve the same jump of 80% to 100% takes about four hours but soon after the generator is switched of the batteries start dropping and drop back to 80% much quicker then when they have been charged off the alternator.

[Tony Brooks]

Building on the topic title, one thing that I have never understood is why our 24v alternator (a CAV AC5 R) seems to produce a 'better quality' charge than when using our 240v AC Generator and our Sterling 25 Amp four stage charger? I know this all seems highly improbable but a couple of hours charge with the engine running will take the battery back up to 100% on the SmartGauge from around 80% and the batteries will then stay a t 100% for the rest of the day and, even with the inverter on, the battery state of charge appears to drop quite slowly. Charging from the generator to achieve the same jump of 80% to 100% takes about four hours but soon after the generator is switched of the batteries start dropping and drop back to 80% much quicker then when they have been charged off the alternator.

 

 

I have a couple of suggestions.

 

If the 440 wander lead is set to high the regulated voltage is about 28.25 volts and perhaps your sterling charger is set to below this during acceptance. It also seems the MOD AC5 + 440 (I see no reason the civi version will be any different apart from not having a "nato plug" connection) is rated at 31 amps so it will be more effective that a 25 amp charger during the bulk phase as well.

 

Secondly is your charger doing adaptive charging? Now I do not understand all this but those who do seem to agree in does not work in may cases and drops into acceptance far to early (or is it drops into float?) either way it would take longer to reach a given state of charge.

[NB Alnwick]

I have a couple of suggestions.

 

If the 440 wander lead is set to high the regulated voltage is about 28.25 volts and perhaps your sterling charger is set to below this during acceptance. It also seems the MOD AC5 + 440 (I see no reason the civi version will be any different apart from not having a "nato plug" connection) is rated at 31 amps so it will be more effective that a 25 amp charger during the bulk phase as well.

 

I think the civilian version is supposed to go to an initial 45 or 55 Amps but I rarely see much more than 30 Amps on the ammeter and when the batteries are in a well charged state this soon drops. I failed to mention that I have an Adverc controller in the alternator charging circuit and that in the early part of the year this was properly set-up to match the alternator output with considerable help from the Adverc technical advisers. It does make a difference and I wasn't previously a fan of Averc but then I didn't realise that the one fitted to our boat had been altered (incorrectly) by the previous owner. It now works and does just what it says in the advertisements.

 

Secondly is your charger doing adaptive charging? Now I do not understand all this but those who do seem to agree in does not work in may cases and drops into acceptance far to early (or is it drops into float?) either way it would take longer to reach a given state of charge.

 

Although the Sterling charger has separate feeds to both engine start and cabin batteries, I think the rate of charge may be dropping to acceptance and float mode earlier that it should because the engine batteries (the engine having not been started) are in a fully charged state.

[Sir Nibble]

Ac5 alternators come in a number of flavours. 12V 60A. 24V 45A. 24V 55A, are perhaps the most common. AC5R is the same bit of kit with a regulator built on. AC5 HER is the same with a different reg, and I am frankly not sure of what the difference is.

Perhaps a 55A alternator set at 28.5V is better than a 25A charger set to 29V. Shorter bulk charge for one thing.

Still, Simms 1750, well well well.

[Timleech]

That is precisely why I prefer battery sensing.

Arnot, check me on this. 440 regulator, A goes to D+, but the Hi-Med-Lo connections can be used for battery sense, yes?

 

Can I confirm how I should connect a 440 reg to my alternator please?

From the Left:-

- to battery -ve

A to field +ve

WL to warning light from ign switch (I think A and WL are connected internally)

F to field -ve

+ Hi-Med-lo to battery +ve

 

We used to use these with AC5 alternators, but the field terminals on those are marked with the same labels as the reg

 

If there is a trimmer it's not accessible externally, I've got one here of dubious parentage so I'll take it out of the case to have a look, fairly sure I've also got a new one in case I break this one.

 

Thanks

Tim

[Arnot]

That is precisely why I prefer battery sensing.

Arnot, check me on this. 440 regulator, A goes to D+, but the Hi-Med-Lo connections can be used for battery sense, yes?

Absolutely correct!

 

The early 440's had a trimmer inside the case but the later ones and the clones don't, this was because most of the failures were due to the poxy quality of the trimmer...

 

Regards

 

Arnot

 

Can I confirm how I should connect a 440 reg to my alternator please?

From the Left:-

- to battery -ve

A to field +ve

WL to warning light from ign switch (I think A and WL are connected internally)

F to field -ve

+ Hi-Med-lo to battery +ve

 

We used to use these with AC5 alternators, but the field terminals on those are marked with the same labels as the reg

 

If there is a trimmer it's not accessible externally, I've got one here of dubious parentage so I'll take it out of the case to have a look, fairly sure I've also got a new one in case I break this one.

 

Thanks

Tim

That should do it...

 

Regards

 

Arnot

[Timleech]

That should do it...

 

Regards

 

Arnot

 

Thanks. I'll try that at the weekend, with battery sensing and some 120/030 cable (because I have it, & it's bigger than what's on at present) direct to the starter terminals, & report back.

 

Tim

[Sir Nibble]

Thanks. I'll try that at the weekend, with battery sensing and some 120/030 cable (because I have it, & it's bigger than what's on at present) direct to the starter terminals, & report back.

 

Tim

I,m sure that will noticeably improve your charging. Out of interest, how much higher than battery was the voltage at the F+ terminal?

[Timleech]

I,m sure that will noticeably improve your charging. Out of interest, how much higher than battery was the voltage at the F+ terminal?

 

Don't remember/didn't record.

If I'm not pushed for time, I'll check before making the changes.

 

Tim

[nb Innisfree]

Ac5 alternators come in a number of flavours. 12V 60A. 24V 45A. 24V 55A, are perhaps the most common. AC5R is the same bit of kit with a regulator built on. AC5 HER is the same with a different reg, and I am frankly not sure of what the difference is.

Perhaps a 55A alternator set at 28.5V is better than a 25A charger set to 29V. Shorter bulk charge for one thing.

Still, Simms 1750, well well well.

 

Not the Simms 1750 surely? I just cannot believe it

[Sir Nibble]

Not the Simms 1750 surely? I just cannot believe it

Extracting the proverbial there?

Anyway, it's not THE 1750 it's A 1750, this one is called Nigel and collects dinky toys.

[Proper Job]

Is that the Dinky version of the 1750 Maxi?

 

I believe the Dinky version was more reliable than the real thing

[WotEver]

Is that the Dinky version of the 1750 Maxi?

 

I believe the Dinky version was more reliable than the real thing

But did it have that satisfying 'clunk' when you shut the doors?

 

The door close was the best thing about the Maxi...