New Build Electrical setup advice

[nicknorman]

13 minutes ago, IanD said:

2.7:1 for alternators (180mm crank/65mm alternator -- info from Beta), 3.3:1 for Travelpower (guesstimate based on pulley sizes in photos, look ~20% bigger ratio)

 

All the kind of stuff that's not easy to find out, neither are the current vs. rpm curves, for some reason manufacturers seem to want to hide this. Maybe because it looks better to say just "100A" or "5kW" without saying that you don't get this until a noisy 2000rpm which is far more than most people charge at...

These graphs are on the Iskra website. Well it covers up to the 150A one. Idle at 850 x 2.7 = 2295 rpm so already fairly well up the curve at idle.

 

[IanD]

14 minutes ago, nicknorman said:

These graphs are on the Iskra website. Well it covers up to the 150A one. Idle at 850 x 2.7 = 2295 rpm so already fairly well up the curve at idle.

 

 

Yes that's where I found the Iskra info, once I was sure which model Beta used. The problem is that they're *too* far up the curve at idle, they'd pull about 7bhp (more than half of the full-throttle engine torque at idle and just below for the Beta 43) which would drag the revs right down. Beta also don't recommend charging under heavy load for long periods below 1200rpm otherwise there is risk of damage according to the manual, possibly to the drive plate (my speculation).

 

The new Balmar 48V/100A alternator has less of a problem but costs over £3000 (for an alternator!!!!!!) together with the hardware to fit it, which makes the TP look like a bargain ? And the thought of the problems of replacing this if it fails (cost and delay) didn't make me happy -- same with the TP, some people have had problems with these too, either with the alternator itself or the control box letting out magic smoke, and that's a single point of failure.

 

That was the drive behind the dual 100A/24V idea -- the alternators themselves are cheap and widely available, the belt/drive is standard and proven, the controller might be new to narrowboats but is well-known/proven (and well thought of) in marine/RV circles -- and if it dies, in an emergency the internal regulators can be fitted back in place of the brush boxes.

Edited November 9, 2020 by IanD

[nicknorman]

Just now, IanD said:

Yes that's where I found the Iskra info, once I was sure which model Beta used. The problem is that they're *too* far up the curve at idle, they'd pull about 7bhp (more than half of the full-throttle engine torque at idle and just below for the Beta 43) which would drag the revs right down. Beta also don't recommend charging under heavy load for long periods below 1200rpm otherwise there is risk of damage according to the manual, possibly to the drive plate (my speculation).

No I think the problem is the crankshaft to pulley joint under low rpm high belt load and high torsional oscillation, in part because the pulley sticks out so far beyond the front bearing. There is history of pulleys falling off having first chewed up the end of the crank. Beta modified the setup to no longer cut off the end of the crank, sometime in the 2000s. However I have heard of people having this problem even with later engines. So we are careful to avoid high loads at low rpm other than very briefly.

[IanD]

5 minutes ago, nicknorman said:

No I think the problem is the crankshaft to pulley joint under low rpm high belt load and high torsional oscillation, in part because the pulley sticks out so far beyond the front bearing. There is history of pulleys falling off having first chewed up the end of the crank. Beta modified the setup to no longer cut off the end of the crank, sometime in the 2000s. However I have heard of people having this problem even with later engines. So we are careful to avoid high loads at low rpm other than very briefly.

I knew about the problem with older engines but I thought the splined shaft had fixed this -- I also read somewhere that premature drive plate failure was the problem with the newer engines, not the pulleys falling off, but you could of course be right about this -- none of this is the kind of thing engine suppliers like to admit to or talk about for obvious reasons, so avoiding high loads at low rpm is obviously A Good Thing ?

[ditchcrawler]

45 minutes ago, IanD said:

2.7:1 for alternators (180mm crank/65mm alternator -- info from Beta), 3.3:1 for Travelpower (guesstimate based on pulley sizes in photos, look ~20% bigger ratio)

 

All the kind of stuff that's not easy to find out, neither are the current vs. rpm curves, for some reason manufacturers seem to want to hide this. Maybe because it looks better to say just "100A" or "5kW" without saying that you don't get this until a noisy 2000rpm which is far more than most people charge at...

So almost 6000 rpm and 7000 rpm for max output and cooling

[IanD]

1 hour ago, IanD said:

They are the same under the skin. You only need 1 to control 2 identical alternators on the same engine, as you say this costs around £500. But this isn't an extra cost, you need it anyway with lithiums -- or lead-acids like gel/AGM/lead-carbon if you want to charge quickly and get anywhere remotely close to the quoted cycle lifetime, internal alternator regulators are terrible for this.

Just got a quote from the UK importers (Merlin), the WS500 is about £700. Damn that dollar-to pound exchange rate... ?

[nicknorman]

26 minutes ago, IanD said:

Just got a quote from the UK importers (Merlin), the WS500 is about £700. Damn that dollar-to pound exchange rate... ?

Ouch! It’s only $500 retail in USA, how can they add such a huge cut! I think I’ll stick with my 50 quid version!

Edited November 9, 2020 by nicknorman

[TheBiscuits]

1 minute ago, nicknorman said:

Ouch! It’s only $500 retail in USA, how can they add such a huge cut!

 

Import duty, VAT and carriage, followed by UK distributor markup.

[nicknorman]

36 minutes ago, ditchcrawler said:

So almost 6000 rpm and 7000 rpm for max output and cooling

We find that we get pretty much full output at normal cruising rpm of 1300 (3500 alternator rpm). One might get slightly more at higher rpm but not noticeably so.

[IanD]

45 minutes ago, TheBiscuits said:

 

Import duty, VAT and carriage, followed by UK distributor markup.

Also don't forget the "non-optional" extras...

 

Part No!	Description	Price inc Vat
05-4001	Wakespeed Advanced Alternator Regulator	£       546.17
05-4002	Wakespeed Advanced Wiring Harness (Positive)	£       75.78
05-4004	Wakespeed 15ft Cable w/ Waterproof Connector	£       39.68
05-4005	Wakespeed Data Terminator Kit	£       21.61
	Carriage (UK)	£       14.40

47 minutes ago, nicknorman said:

We find that we get pretty much full output at normal cruising rpm of 1300 (3500 alternator rpm). One might get slightly more at higher rpm but not noticeably so.

That makes sense for the 12V/175A, I'm not so sure for the TP (didn't look at the curve for that but would probably be better (proportionally) than the 5kW at low revs)

[nicknorman]

37 minutes ago, IanD said:

Also don't forget the "non-optional" extras...

 

Part No!	Description	Price inc Vat
05-4001	Wakespeed Advanced Alternator Regulator	£       546.17
05-4002	Wakespeed Advanced Wiring Harness (Positive)	£       75.78
05-4004	Wakespeed 15ft Cable w/ Waterproof Connector	£       39.68
05-4005	Wakespeed Data Terminator Kit	£       21.61
	Carriage (UK)	£       14.40

That makes sense for the 12V/175A, I'm not so sure for the TP (didn't look at the curve for that but would probably be better (proportionally) than the 5kW at low revs)

Yes the $500 isn’t really the actual price it seems!

 

The TP will produce 2kw at idle but we try to avoid that. Not sure at what rpm it will produce 3.5kw because we don’t really use more than 2kw.

Edited November 9, 2020 by nicknorman

[IanD]

For anyone still interested, this shows the effect of the Wakespeed WS500 pulling back alternator drive at low revs.

[nicknorman]

Oooh look, it’s now quite similar to the unmodified TP!

 

It’s probably adjustable but it does look a bit OTT on the graphs. I find 85A or so at idle is a good compromise (12v 175A)

 

Anyway, I think we’ve frightened the OP away!

Edited November 10, 2020 by nicknorman

[IanD]

1 hour ago, nicknorman said:

Oooh look, it’s now quite similar to the unmodified TP!

 

It’s probably adjustable but it does look a bit OTT on the graphs. I find 85A or so at idle is a good compromise (12v 175A)

 

Anyway, I think we’ve frightened the OP away!

It's not similar to the 5kW TP in the 1200rpm-1400rpm range which is crucial for narrowboats, output here is >50% higher (1200rpm = minimum for charging recommended by Beta, 1400rpm = typical cruising for a Beta 43). Most people would say that >50% more usable charging current (shorter charging time and fewer engine hours) for <50% of the cost is A Good Thing, but I know you don't...

 

It's adjustable, I just put in one setting to show the effect. Your 85A/12V at idle is a slightly higher engine load than the 20A/48V shown on the plots (2 x 24V in series, remember), load will be heavier still with the TP on.

 

The OP has probably gone away because of the bad news that it's going to be a lot more difficult than he hoped and cost a lot more to support all the 230Vac appliances he wants to have...

Edited November 10, 2020 by IanD