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TravelPower 5kw and Multiplus II


MrFish

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I am looking for guidance how to best use a TravelPower 5kw fitted onto a Beta 43. I want be be able to charge a 48v Battery bank (Leoch Lead Carbon 800ah 24 x 2v batteries in series) and put power into the Multiplus II 48/8000.  Will this be possible? I would prefer not to have to buy a separate battery charger to connect the TravelPower to the batteries if it can be avoided.

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23 minutes ago, MrFish said:

I am looking for guidance how to best use a TravelPower 5kw fitted onto a Beta 43. I want be be able to charge a 48v Battery bank (Leoch Lead Carbon 800ah 24 x 2v batteries in series) and put power into the Multiplus II 48/8000.  Will this be possible? I would prefer not to have to buy a separate battery charger to connect the TravelPower to the batteries if it can be avoided.

In theory you should be able to connect the TravelPower into the AC input of the Multiplus. The problem is setting the Multiplus maximum current limit which determines how much power it can draw from the AC source, because it doesn't have any way to know how fast your engine is turning -- for the TravelPower to put out 5kW the engine needs to be running at well above tickover, probably at least 2000rpm (see attached plot).

 

If you set the MPII AC current limit to 22A this. will be fine if the engine is running fast enough, but if not and it tries to take more power than the TravelPower can generate (at lower rpm) the TravelPower output voltage will collapse. What happens then is guesswork, maybe the TravelPower shuts off entirely, maybe the MP II drops its current demand or stops charging if the voltage drops too much, maybe the TravelPower voltage then recovers and the MP II then loads it again until it drops out again...

 

The MP II AC input is really intended for a source -- mains or generator -- which can always provide up to the set current limit without collapsing, the TravelPower isn't like this.

 

You'll have a similar problem with any other battery charger.

 

 

alternators.PNG

Edited by IanD
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One of the reasons i wanted the Multiplus II is the access to ESS via the Cerbo GX so it makes it easier to both monitor and change the settings. I will set up the AC input as a generator and start trying different levels of max current input. So far i have been unable to find any data for the Travelpower which shows a graph of voltage drop against current draw. In theory the TravelPower 5kw can provide 25A at 230v. However i am guessing that in practice the voltage will dip.

 

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8 minutes ago, MrFish said:

One of the reasons i wanted the Multiplus II is the access to ESS via the Cerbo GX so it makes it easier to both monitor and change the settings. I will set up the AC input as a generator and start trying different levels of max current input. So far i have been unable to find any data for the Travelpower which shows a graph of voltage drop against current draw. In theory the TravelPower 5kw can provide 25A at 230v. However i am guessing that in practice the voltage will dip.

 

 

The curves I showed give TravelPower output power and current (assuming constant voltage) vs. engine rpm -- for a Beta 43 as it happens. The output power is the limit, it will try and maintain the voltage as you draw more current until it runs out of power, then I believe the voltage will drop while maintaining constant power (set by rpm).

 

If you continue to take the more power (or lower rpm) then when the voltage hits the AC low voltage threshold of the MP II it will stop charging. Then the voltage will go back up to 230V, at which point the MP II will turn on and start charging again, at which point the voltage will drop again...

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Just been reading this in the multiples manual for using the VE configuration software:   

 

2.2 AC Input Current Limit

The charger on the Multiplus is very powerful. If you have an existing generator that is not able to supply the maximum charging current of the Multi, you will need to adjust the AC Input Current Limit in the General Tab of VEConfigure.

A reasonable starting point for the AC Current input limit is 80% of the generator capacity in Watts. For example:

a 5kVA generator typically provides about 4 kW

80% of 4 kW is 3200 W

3200 W / 230 V volts = 13.9 A

Set the AC Current Input Limit to 13 A

If you find the generator is still overloading, or running too hard, you may lower this further. It can also be increased if you find the generator easily handles the load (though this can be difficult to test as it requires a flat battery to maximise charging demand and a large load).

There is another additional setting in the Charger Tab for DC current limiting.

The AC input current should be adjusted first, as it also takes into account the PowerAssist functionality.

The Multi is able to synchronise the generator waveform with it's own and provide power to the loads from the generator as well charging the battery. This means it still possible to overload the generator with a low 'DC Charger current limit' if the AC input limit is not also set correctly to the size of the generators output.

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We’ve got a 3.5kw travelpower on a Beta 43. It makes about 2kw at idle, but that is very bad for the engine. By about 1200rpm it can make full output, although a bit higher rpm is better in order to reduce belt tension / crankshaft side load. If I was expecting 5kw output I think I’d want around 1400rpm. If you let the revs get too low the voltage dips at first, then I think eventually it would trip off though I’ve never had that happen.

 

To organise the source of power to the Victron you could use a manual ac changeover switch, or do as we do and have an automatic changeover such that shore power gets connected if it’s available, otherwise the travelpower is connected.

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4 hours ago, MrFish said:

One of the reasons i wanted the Multiplus II is the access to ESS via the Cerbo GX so it makes it easier to both monitor and change the settings. I will set up the AC input as a generator and start trying different levels of max current input. So far i have been unable to find any data for the Travelpower which shows a graph of voltage drop against current draw. In theory the TravelPower 5kw can provide 25A at 230v. However i am guessing that in practice the voltage will dip.

 

Victron categorically state that ESS should not be used for off grid install such as boats. ESS relies on a permanent grid connection and at times can feed energy back into the grid, especially if a large load is turned off. I do not know if the travel power electronics would like being back fed. I believe ESS also needs a grid code to be set on the inverter so the system knows the rules. I am not sure you needs ESS, you just needs the AC  current limit setting so you do not draw too much power. If you have a Cerbo GX connected to the inverter then you can set the AC current limit from one of the Cerbo screens very quickly and easily without needing to reprogram the inverter.

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55 minutes ago, nicknorman said:

We’ve got a 3.5kw travelpower on a Beta 43. It makes about 2kw at idle, but that is very bad for the engine. By about 1200rpm it can make full output, although a bit higher rpm is better in order to reduce belt tension / crankshaft side load. If I was expecting 5kw output I think I’d want around 1400rpm. If you let the revs get too low the voltage dips at first, then I think eventually it would trip off though I’ve never had that happen.

 

To organise the source of power to the Victron you could use a manual ac changeover switch, or do as we do and have an automatic changeover such that shore power gets connected if it’s available, otherwise the travelpower is connected.

The curve I posted was for 5kW Travelpower as fitted to a Beta 43 (actual pulley sizes used by Beta), about 2.8kW at 1200rpm (minimum recommended speed for charging) but it needs 2000rpm to reach 5kW. The 3.5kW one has a curve which is higher at idle and flattens off at lower rpm, it's all to do with the winding ratios.

Edited by IanD
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6 minutes ago, IanD said:

The curve I posted was for 5kW Travelpower as fitted to a Beta 43 (actual pulley sizes used by Beta), about 2.8kW at 1200rpm (minimum recommended speed for charging) but it needs 2000rpm to reach 5kW. The 3.5kW one has a curve which is higher at idle and flattens off at lower rpm, it's all to do with the winding ratios.


I am a bit sceptical about that graph. It says zero output for the travelpower at idle. If that really is the case it’s poor design. There must be a very big difference in the pulley ratios compared to the 3.5kw - if it’s correct. And if it is correct, why?

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2 hours ago, MrFish said:

Thank you. Out of interest what do you use the second alternator for on the beta 43?

How many alternators have you got two or three?

 I thought Beta engines set up with travel power were fitted with 3x alternators?

1x Starter battery charging.

1x Domestic Battery charging.

1x Dedicated Travel Power.

 Do Beta do a 48v alternator option or not? Hence the OP’s question on charging.

Edited by PD1964
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Just received this reply from Beta Marine when I asked about engine speed required for full power generation. 

 

Please refer to page 12 on the attached manual. The ratio would be 3.6:1. So around 1200 RPM engine speed you get full power out of the travel power (alternator speed od 4320 RPM)

 

8 hours ago, PD1964 said:

How many alternators have you got two or three?

 I thought Beta engines set up with travel power were fitted with 3x alternators?

1x Starter battery charging.

1x Domestic Battery charging.

1x Dedicated Travel Power.

 Do Beta do a 48v alternator option or not? Hence the OP’s question on charging.

The first alternator is used for the starter battery as you have stated.  The second alternator is 175A but is not currently used. 

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Note what Nick said about belt tension and side loads at low speed. Some older Betas destroyed the front of the crankshaft by excessing alternator/Travelpower loading at low revs, so I would always try to run at higher rather than lower revs. Maybe, even if it meant fitting a smaller prop.

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11 hours ago, nicknorman said:


I am a bit sceptical about that graph. It says zero output for the travelpower at idle. If that really is the case it’s poor design. There must be a very big difference in the pulley ratios compared to the 3.5kw - if it’s correct. And if it is correct, why?

 

The power output vs. rpm came straight from the data sheet for the 5kW travelpower, and the pulley ratios/sizes used came straight from Beta (for travelpower on the Beta 43) so I'm confident that they're correct.

 

As I said, the 5kW unit has different windings (fewer turns of thicker wire) to allow higher maximum power (at higher rpm) but at the cost of reduced power at low rpm, like many high-power alternators. It's not really bad design, it's physics... 😉

 

And given that Beta recommend not running below 1200rpm for heavy-load battery charging -- which the Travelpower certainly qualifies as -- and it puts out 2.8kW here, I don't see a problem. Admittedly if you do want to run at 1200rpm for charging the 3.5kW unit (which reaches full power) is a better choice, only those with a very well-silenced engine would want to run at 2000rpm (to get 5kW) for any length of time.

 

Which is probably why the 3.5kW travelpower is more popular, and shows the pitfalls of just looking at a headline power number like 5kW and assuming this must be better than 3.5kW because it's bigger... 😉

 

It's also why -- before I decided to go hybrid -- I was planning to use 2 of the Iskra 24V alternators with a Wakespeed controller, cheaper and can output 4kW at 1200rpm -- and with lower side/belt load than a single high-power alternator or Travelpower. I spent a lot of time discussing all this with Beta and they were very helpful, and agreed that this was the best solution 🙂

Edited by IanD
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1 hour ago, Tony Brooks said:

Note what Nick said about belt tension and side loads at low speed. Some older Betas destroyed the front of the crankshaft by excessing alternator/Travelpower loading at low revs, so I would always try to run at higher rather than lower revs. Maybe, even if it meant fitting a smaller prop.

 

That's why they brought in the warning about not charging below 1200rpm, and changed the crankshaft nose/pulley attach by stopping cutting off the splined extension.

 

They did say that the multi-vee belt loading for the travelpower (or a single high-power alternator like the Balmar 48V 100A) was pretty high, that a freewheeling pulley was strongly recommended (that's what they fit), and that any heavy loading below 1200rpm was a really bad idea. They were happier with the dual alternator setup, because the belt/side loading is smaller (two belts, alternators fitted on opposite sides of the engine).

Edited by IanD
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1 hour ago, MrFish said:

Just received this reply from Beta Marine when I asked about engine speed required for full power generation. 

 

Please refer to page 12 on the attached manual. The ratio would be 3.6:1. So around 1200 RPM engine speed you get full power out of the travel power (alternator speed od 4320 RPM)

 

 

39 minutes ago, IanD said:

 

The power output vs. rpm came straight from the data sheet for the 5kW travelpower, and the pulley ratios/sizes used came straight from Beta (for travelpower on the Beta 43) so I'm confident that they're correct.

 


Well these two posts can’t both be right!

Edited by nicknorman
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28 minutes ago, nicknorman said:


Well these two posts can’t both be right!

 

Beta told me that the pulley ratio was 3.3:1 (they gave actual diameters). Even if I change it to 3.6:1 I get this -- output at 1200rpm (4320rpm alternator) goes up from 2.8kW to 3.2kW. The alternator power vs. speed curves came from the 5kW travelpower data sheet, so I don't understand where Beta got theirs from, the 5kW doesn't reach full output until 6500rpm...

 

(unless they used the 3.5kW curves which are different, I don't think the OP told them which one he had...)

 

And with a 3.6:1 pulley ratio the alternator will spin at 10000rpm at maximum engine speed of 2800rpm, which exceeds the specified 9000rpm limit... 😞

 

alternators travelpower 3p6.png

tpcurves.png

Edited by IanD
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14 hours ago, nicknorman said:

We’ve got a 3.5kw travelpower on a Beta 43. It makes about 2kw at idle, but that is very bad for the engine. By about 1200rpm it can make full output, although a bit higher rpm is better in order to reduce belt tension / crankshaft side load. If I was expecting 5kw output I think I’d want around 1400rpm. If you let the revs get too low the voltage dips at first, then I think eventually it would trip off though I’ve never had that happen.

 

To organise the source of power to the Victron you could use a manual ac changeover switch, or do as we do and have an automatic changeover such that shore power gets connected if it’s available, otherwise the travelpower is connected.

 

I've just realised there's a major problem with the OPs idea of using the Travelpower to feed into the AC input of the Multiplus II... 😞

 

The travelpower output is split-phase with 115Vac on live and 115Vac antiphase on the neutral, which means it can't be connected to a mains input which expects 230Vac on live and 0Vac on neutral.

 

The most likely result if this is tried is damage or destruction of the Travelpower and/or the Multiplus -- if you're lucky the MP will just refuse to connect to the input, but I certainly wouldn't want to rely on this... 😉 

Edited by IanD
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1 hour ago, IanD said:

 

I've just realised there's a major problem with the OPs idea of using the Travelpower to feed into the AC input of the Multiplus II... 😞

 

The travelpower output is split-phase with 115Vac on live and 115Vac antiphase on the neutral, which means it can't be connected to a mains input which expects 230Vac on live and 0Vac on neutral.

 

The most likely result if this is tried is damage or destruction of the Travelpower and/or the Multiplus -- if you're lucky the MP will just refuse to connect to the input, but I certainly wouldn't want to rely on this... 😉 

No this is not correct. We connect our travelpower to our Combi no problem. It doesn’t care whether the neutral is 0v or 115v. And it’s quite happy to provide “power support” by merging the TP supply with inverter output.

Edited by nicknorman
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17 minutes ago, nicknorman said:

No this is not correct. We connect our travelpower to our Combi no problem. It doesn’t care whether the neutral is 0v or 115v. And it’s quite happy to provide “power support” by merging the TP supply with inverter output.

Done the same on a boat with a failed domestic alternator.

Just switched over to travelpower/combi charging-thought it was a rather handy quick fix. I think if there was anything much wrong with it would have shown up after a week I did it and a week or so  the owner did it on the way back!

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