Jump to content

Featured Posts

I have a Smartgauge and a correctly set up Ah gauge. I find the SG tracks the Ah gauge remarkably well on discharge, often just a % or two difference. It does take a few % to settle down after charging (surface effect) but by 95% it is fine, more usually by 97%.

Link to comment
Share on other sites

9 hours ago, dmr said:

Its well known that Smartgage is not accurate during charging, its little better than a guess, though actually quite a good guess. !00% is a good "daily charge" but not the full "weekly or monthly charge".

I have not heard of this 80% limitation. After a charge Smartgage takes a while to sort itself out, thats surface charge, and those who advocate using a simple voltmeter have exactly the same problem, its just physics. The Balmar device does look good, if it really combines amp-hour counting with a Smartgage voltage algorithm  then it would be almost perfect, I'm surprised its not more popular.

 

......................Dave

The site I sent the link to which actually tested the Balmar said it was very accurate. It is very popular -- and very well thought of -- in lumpy water circles, but like many other new technologies hasn't made much impact on the UK narrowboat scene.

 

Same applies to almost anything to do with higher-power AC electrical systems like LiFePO4, BMS, charging, high-output alternators, generators, solar -- there are a few brave souls pushing these into narrowboats who might think they're doing something new, but in the cruising/RV/off-grid fields thousands of people have been doing all this for many years and already looked at all the issues, compared different bits of kit, blown up/set things on fire, and found out what does and doesn't work.

 

If you want to find reliable information about all this, the forums and companies who provide kit to these markets are the place to look, there's a wealth of information and experience out there -- even if a lot of it is American, that doesn't make it any less useful...

  • Greenie 1
Link to comment
Share on other sites

From reading this thread and others, I've got the impression that a good monitoring set up would be to have 2 meters.  A Victron/NASA type to tell you when to stop charging.  And a Smartgauge to tell you when to start charging.  This Balmar interests me, because it looks like it's a single unit which covers all bases (if it works as claimed).

 

Can anyone recommend someone who could fit one for me?  I had a look at the 'simple' installation instructions, and I might as well have been reading Russian!

Link to comment
Share on other sites

2 hours ago, IanD said:

The site I sent the link to which actually tested the Balmar said it was very accurate. It is very popular -- and very well thought of -- in lumpy water circles, but like many other new technologies hasn't made much impact on the UK narrowboat scene.

 

Same applies to almost anything to do with higher-power AC electrical systems like LiFePO4, BMS, charging, high-output alternators, generators, solar -- there are a few brave souls pushing these into narrowboats who might think they're doing something new, but in the cruising/RV/off-grid fields thousands of people have been doing all this for many years and already looked at all the issues, compared different bits of kit, blown up/set things on fire, and found out what does and doesn't work.

 

If you want to find reliable information about all this, the forums and companies who provide kit to these markets are the place to look, there's a wealth of information and experience out there -- even if a lot of it is American, that doesn't make it any less useful...

I had a look at the Balmar spec. and it does look good. The problem for me is that I have the shunt in the positive lead which is unusual  (I have the old Adverc monitor) and I don't want to move it to the negative, I the Balmar could work with a Hall sensor I would get it.

 

I have also thought about their alternators, 200amps from a small frame looks impressive, but they need a proper controller which again is not easily compatible with what I have now. I would also need a new pulley on the engine. It would likely be a £2000 to £3000 upgrade for me but I am thinking seriously about it.

 

...............Dave

Link to comment
Share on other sites

Link to comment
Share on other sites

15 minutes ago, dmr said:

I had a look at the Balmar spec. and it does look good. The problem for me is that I have the shunt in the positive lead which is unusual  (I have the old Adverc monitor) and I don't want to move it to the negative, I the Balmar could work with a Hall sensor I would get it.

 

I have also thought about their alternators, 200amps from a small frame looks impressive, but they need a proper controller which again is not easily compatible with what I have now. I would also need a new pulley on the engine. It would likely be a £2000 to £3000 upgrade for me but I am thinking seriously about it.

 

...............Dave

Same things I've spent a lot of time looking at (planning ahead) recently ?

 

What's stopping you adding the Balmar shunt in the negative lead and keeping the one you've got?

 

The Balmar alternators -- especially the bigger ones -- are *very* expensive, as you say, and like any high-power alternator need an external controller and battery/alternator temperature monitoring -- Balmar do these, the newer Wakespeed WS500 is reportedly better (uses tail current to terminate charging and allows current pullback at idle to reduce engine load) but is expensive (about 700 quid in the UK!).

 

What engine do you have? You might be able to use a couple of "standard" (e.g. Iskra/Mahle) alternators configured for an external controller, this can be much cheaper than the Balmar ones.

Edited by IanD
Link to comment
Share on other sites

2 hours ago, IanD said:

Same things I've spent a lot of time looking at (planning ahead) recently ?

 

What's stopping you adding the Balmar shunt in the negative lead and keeping the one you've got?

 

The Balmar alternators -- especially the bigger ones -- are *very* expensive, as you say, and like any high-power alternator need an external controller and battery/alternator temperature monitoring -- Balmar do these, the newer Wakespeed WS500 is reportedly better (uses tail current to terminate charging and allows current pullback at idle to reduce engine load) but is expensive (about 700 quid in the UK!).

 

What engine do you have? You might be able to use a couple of "standard" (e.g. Iskra/Mahle) alternators configured for an external controller, this can be much cheaper than the Balmar ones.

Shunts are a necessary evil, more connections and volt drops in big cables, I would rather just remove the positive shunt and fit the negative but the layout of the batteries and cables makes it hard to do this neatly, and I do like tidy wiring ? A Hall sensor device would be good and I am thinking about this.

 

We have the Beta JD3 with a 100 amp Iskra, a 70 Amp Delco-Remy and a TravelPower, so its pretty busy. I dream of a dual battery bank, half lead acid, half lithium, and this would need more amps to charge it. Space dictates a small frame alternator so swapping the Iskra for a Balmar would be tempting. Trouble is the Iskra just runs off a single belt, anything bigger needs a new pulley on the engine, its about 13" diameter so I would likely have to get something made and thats big money.

Also the Balmar is a "positive" alternator so not a direct swap with the Iskra so I would need two Balmars as ideally I like to carry a spare.

 

.................Dave

Link to comment
Share on other sites

59 minutes ago, dmr said:

Shunts are a necessary evil, more connections and volt drops in big cables, I would rather just remove the positive shunt and fit the negative but the layout of the batteries and cables makes it hard to do this neatly, and I do like tidy wiring ? A Hall sensor device would be good and I am thinking about this.

 

We have the Beta JD3 with a 100 amp Iskra, a 70 Amp Delco-Remy and a TravelPower, so its pretty busy. I dream of a dual battery bank, half lead acid, half lithium, and this would need more amps to charge it. Space dictates a small frame alternator so swapping the Iskra for a Balmar would be tempting. Trouble is the Iskra just runs off a single belt, anything bigger needs a new pulley on the engine, its about 13" diameter so I would likely have to get something made and thats big money.

Also the Balmar is a "positive" alternator so not a direct swap with the Iskra so I would need two Balmars as ideally I like to carry a spare.

 

.................Dave

I don’t think a Hall effect sensor is viable for Ah counting (integrating), too much zero error. If it’s just for current measurement then fair enough.

Link to comment
Share on other sites

1 hour ago, dmr said:

Shunts are a necessary evil, more connections and volt drops in big cables, I would rather just remove the positive shunt and fit the negative but the layout of the batteries and cables makes it hard to do this neatly, and I do like tidy wiring ? A Hall sensor device would be good and I am thinking about this.

 

We have the Beta JD3 with a 100 amp Iskra, a 70 Amp Delco-Remy and a TravelPower, so its pretty busy. I dream of a dual battery bank, half lead acid, half lithium, and this would need more amps to charge it. Space dictates a small frame alternator so swapping the Iskra for a Balmar would be tempting. Trouble is the Iskra just runs off a single belt, anything bigger needs a new pulley on the engine, its about 13" diameter so I would likely have to get something made and thats big money.

Also the Balmar is a "positive" alternator so not a direct swap with the Iskra so I would need two Balmars as ideally I like to carry a spare.

 

.................Dave

Hmm, you're in a bit of a pickle -- carrying spare Balmars around is a money pit... ?

 

What pulleys do you have on the JD3 for the two alternators and the Travelpower? Have you asked Beta if they have anything else available that could be swapped in?

 

They were very helpful when I wanted information about this kind of thing, I'll send you the contact info if you want, but there might be a lot fewer options (polyvee etc) for the JD3 than the Beta 43.

 

If the hardware already exists and is known to fit the cost is quite cheap, as are new Iskra alternators -- for the Beta 43, for 2 x 24V 100A Iskra with brush boxes (for external regulator) plus pulleys (2 x 180mm polyvee on crank + 2 x 65mm freewheeling on alternators) they quoted me about 800 quid (fitted on a new engine), plus 700 for the Wakespeed means 1500 quid total (inc. VAT) for around 5kW DC.

 

Unless you can drive it with a polyvee belt a single high-power alternator is going to be difficult, you could replace the Travelpower with one but this certainly wouldn't be cheap -- also most high-output ones are 24V or 48V which means a new battery bank, so you might as well keep the Travelpower and feed it into the AC input of a charger/inverter to charge the batteries.

Edited by IanD
Link to comment
Share on other sites

2 minutes ago, IanD said:

Hmm, you're in a bit of a pickle -- carrying spare Balmars around is a money pit... ?

 

What pulleys do you have on the JD3 for the two alternators and the Travelpower? Have you asked Beta if they have anything else available that could be swapped in?

 

They were very helpful when I wanted information about this kind of thing, I'll send you the contact info if you want, but there might be a lot fewer options (polyvee etc) for the JD3 than the Beta 43.

 

If the hardware already exists and is known to fit the cost is quite cheap, as are new Iskra alternators -- for the Beta 43, for 2 x 24V 100A Iskra with brush boxes (for external regulator) plus pulleys (2 x 180mm polyvee on crank + 2 x 65mm freewheeling 65mm on alternators) they quoted me about 800 quid (fitted on a new engine), plus 700 for the Wakespeed means 1500 quid total (inc. VAT) for around 5kW DC.

 

Unless you can drive it with a polyvee belt a single high-power alternator is going to be difficult, you could replace the Travelpower with one but this certainly wouldn't be cheap -- also most high-output ones are 24V or 48V which means a new battery bank, so you might as well keep the Travelpower and feed it into the AC input of a charger/inverter to charge the batteries.

The current engine pulley takes two A profile belts. The TravelPower runs on a polyV pulley on a taperlock on a stub shaft.

Beta do or did have a pulley that takes an A and a  B belt, I think this is what they use when they fit a 100amp Iskra. I see this as quite a lot of money for only a small gain.and the B won't go round a small alternator pulley. One option is a brand new custom pulley to allow either a polyV or a twin A drive to new alternator. This would really have to be a small frame so a Balmar or equivalent. If I did this it would be tempting to include the Travelpower on the same pulley.

A possible option might be to machine off the the second pulley groove and use two polyV pulleys on taperlocks on the stub shaft, I don't think there is a twin polyV taperlock available. I don't really like this idea though it might be a lot cheaper.

 

The Travelpower has to stay, its a really good thing, it drives the washing machine, and it drives the immersion heater to get a faster engine warm up. It also drives a 30 amp charger to help the alternators during bulk charge.

 

I can just about keep 100amps going into the batteries, a bit more would be really good but its an expensive jump.

 

.................Dave

Link to comment
Share on other sites

1 hour ago, nicknorman said:

I don’t think a Hall effect sensor is viable for Ah counting (integrating), too much zero error. If it’s just for current measurement then fair enough.

Its a challenge but I have some ideas, but just too many other projects going on to get it done. Might get something done this winter.

Some of the popular Chinese amp hour meters use Hall effect but I suspect they are not too good. Our case is particularly difficult as for a lot of the time we only draw 1 to 3 amps.

I don't know what the problem is, zero drift, non linearity or hysteresis? One option is to have a high current sensor for charge and a low current sensor for discharge but not sure how Hall sensors handle big overloads, can't find anything on the www.

 

.................Dave

Link to comment
Share on other sites

1 hour ago, dmr said:

The current engine pulley takes two A profile belts. The TravelPower runs on a polyV pulley on a taperlock on a stub shaft.

Beta do or did have a pulley that takes an A and a  B belt, I think this is what they use when they fit a 100amp Iskra. I see this as quite a lot of money for only a small gain.and the B won't go round a small alternator pulley. One option is a brand new custom pulley to allow either a polyV or a twin A drive to new alternator. This would really have to be a small frame so a Balmar or equivalent. If I did this it would be tempting to include the Travelpower on the same pulley.

A possible option might be to machine off the the second pulley groove and use two polyV pulleys on taperlocks on the stub shaft, I don't think there is a twin polyV taperlock available. I don't really like this idea though it might be a lot cheaper.

 

The Travelpower has to stay, its a really good thing, it drives the washing machine, and it drives the immersion heater to get a faster engine warm up. It also drives a 30 amp charger to help the alternators during bulk charge.

 

I can just about keep 100amps going into the batteries, a bit more would be really good but its an expensive jump.

 

.................Dave

If you can only fit one big alternator in, you really need another polyvee pulley as well as the one that drives the Travelpower.

 

If you can control the total load somehow (which might be tricky...), you could use a bigger 230Vac battery charger connected to the Travelpower output to get more into the batteries -- assuming you haven't got a combo like a Multiplus 12/3000, in which case you could put the Travelpower into this.

 

Actually if you're looking at a bigger battery bank anyway, a decent combo like this would solve your problem. You can get more AC power out (Travelpower + inverter in power assist mode) when needed, or charge the batteries fast when the washer isn't using all the power (120A/12V to batteries from Multiplus=1.5kW from Travelpower), without having to touch your alternators.

 

Travelpower ==> Multiplus AC input (3kW power in)

Batteries <==> Multiplus DC port (120A charge/250A discharge)

Multiplus AC output ==> appliances (up to 6kW power out)

Link to comment
Share on other sites

3 hours ago, IanD said:

If you can only fit one big alternator in, you really need another polyvee pulley as well as the one that drives the Travelpower.

 

If you can control the total load somehow (which might be tricky...), you could use a bigger 230Vac battery charger connected to the Travelpower output to get more into the batteries -- assuming you haven't got a combo like a Multiplus 12/3000, in which case you could put the Travelpower into this.

 

Actually if you're looking at a bigger battery bank anyway, a decent combo like this would solve your problem. You can get more AC power out (Travelpower + inverter in power assist mode) when needed, or charge the batteries fast when the washer isn't using all the power (120A/12V to batteries from Multiplus=1.5kW from Travelpower), without having to touch your alternators.

 

Travelpower ==> Multiplus AC input (3kW power in)

Batteries <==> Multiplus DC port (120A charge/250A discharge)

Multiplus AC output ==> appliances (up to 6kW power out)

I actually suspect the current setup is pretty optimum for what it does which is why any improvements would be so expensive.

I'm and engineer so looking at all the options interests me.

We have the little Victron 30 amp charger, more amps would be good but bigger chargers are physically a lot bigger and space on the wall is running out. The Victron stops when the washing machine is heating, not sure why as the spec on input voltage range is good. Even with the big polyV pulley I suspect the TravelPower is a long way off full power, we normally do battery charging runs at about 700rpm. In winter when not moving we can just about get away with an engine run every other day, but probably not if it gets much colder. 

What I would really like is a little Lithium bank, about 200Ah to supplement the lead acids and make everything a bit easier, and try to charge this without increasing our engine run times. A slightly bigger alternator (and a quite complicated Arduino project?) could maybe do this but it would not be easy and is all looking very expensive. A second mains charger dedicated to the lithium bank would be good, and I would love to keep the alternator working harder once the lead acids go into absorption.

Just getting more charging amps is not cost effective unless they have somewhere to go which really does need some lithiums.

I am not sure about a combo, we don't really need a big inverter, but something that could charge the batteries but still prioritise the washing machine/immersion heater would be good. Can they do things like that?

 

Due to Covid we have done much less moving this year, and much more engine running just to charge batteries which has made me realise just how inefficient it all is.

 

................Dave

 

Link to comment
Share on other sites

A combo like the Multiplus will connect the Travelpower, batteries and mains loads, the Travelpower and batteries can both act as power sources. It the AC load exceeds what the Travelpower can provide, the inverter will provide extra from the batteries. If the batteries need charging and the AC load is less than the Travelpower can produce, the spare power will top up the batteries. A Multiplus 3000 can charge batteries at up to 120A (1.5kW out of Travelpower) and the inverter can provide up to 3kW (240A out of batteries) on top of what's coming in from the Travelpower -- so even if the engine's not running you have 3kW of AC available (until the batteries go flat).

Link to comment
Share on other sites

On 13/11/2020 at 22:58, dmr said:

I actually suspect the current setup is pretty optimum for what it does which is why any improvements would be so expensive.

I'm and engineer so looking at all the options interests me.

We have the little Victron 30 amp charger, more amps would be good but bigger chargers are physically a lot bigger and space on the wall is running out. The Victron stops when the washing machine is heating, not sure why as the spec on input voltage range is good. Even with the big polyV pulley I suspect the TravelPower is a long way off full power, we normally do battery charging runs at about 700rpm. In winter when not moving we can just about get away with an engine run every other day, but probably not if it gets much colder. 

What I would really like is a little Lithium bank, about 200Ah to supplement the lead acids and make everything a bit easier, and try to charge this without increasing our engine run times. A slightly bigger alternator (and a quite complicated Arduino project?) could maybe do this but it would not be easy and is all looking very expensive. A second mains charger dedicated to the lithium bank would be good, and I would love to keep the alternator working harder once the lead acids go into absorption.

Just getting more charging amps is not cost effective unless they have somewhere to go which really does need some lithiums.

I am not sure about a combo, we don't really need a big inverter, but something that could charge the batteries but still prioritise the washing machine/immersion heater would be good. Can they do things like that?

 

Due to Covid we have done much less moving this year, and much more engine running just to charge batteries which has made me realise just how inefficient it all is.

 

................Dave

 

If you can fit one it, a combo can kind of do what you're looking for by running the washer and charging batteries -- but...

 

You program the combo with the maximum allowable 230Vac input current from the TravelPower (e.g. 15A is 3.5kW) -- which isn't that simple because it depends on rpm. If the batteries are low and the washer takes less than this, the excess power will be used to charge the batteries. If the washer isn't running, all the power up to the programmed limit will be used to charge the batteries, up to the limit of what the charger can support (120A for Multiplus 3000, which is about 1.5kW). Would work great with lithiums which like fast charging and don't need long absorption times.

 

The problem is that there's no communication between the Travelpower and the Multiplus, which is expecting a "stiff" AC source. If the TP is overloaded (more power demand than it can provide at the given engine revs) then I assume it drops its output voltage to maintain constant power -- do you know if this is correct? The maximum load of the Multiplus on the AC input is defined as a current limit, but I think the inverter shuts down if the input voltage drops below a set limit (180Vac?) -- I don't know if it then restarts automatically or not.

 

So say you set the MP input current limit to 15A (3.5kW) but the engine revs are only high enough the generate 2kW. If the AC load (washer etc) exceeds 2kW the TP output voltage will either drop (if it maintains constant power) or it will shut down (if this is what happens in an overload). If the voltage drops below the MP input limit then the MP will shut off; if the TP voltage then goes back up the MP will restart, drawing load again, which pulls the voltage down by overloading the TP, so the MP shuts off, so the voltage goes back up...

 

You could end up with a ding-dong battle between the TP and MP turning on and off, possibly leading to something dying -- TP, MP or washing machine ?

 

I think you're right that what you have now is the best you can do without a complete rip up and start again e.g. replace TP with a big expensive alternator with external controller and a combo to use a lithium house bank. If you want to get lithiums in there in a useful way without doing this the only real option is a bigger (or another) alternator (externally regulated), the problem is the mechanics of driving it.

Link to comment
Share on other sites

I have been thinking about this a bit.  I can see the attraction of the combi, but it is physically big which is a problem, space is limited, and there are other downsides. Can the combi be set to only work when the engine is running? We have a few mains chargers and an immersion heater and its really good these only run off the TravelPower. I know so many people who have got flat batteries by accidentally leaving the immersion on. We only use our little inverter once or twice a week so checking that the imersion is off is no big deal.

I did measure some TP voltages a while ago, I really should fit a proper voltmeter. Its always a bit low, about 230v, maybe due to its Swedish roots? The voltage does fall quite a bit under load which I suppose is in effect a constant power. I think I have seen less than 200v (I wrote it all down but cant find my notes). The washing machine copes with all this very well. Does this mean that the combi would be taking a lot of power from the batteries much of the time even though we could actually manage with the lower voltage? So its likely that the power assist mode for us has more cons than pros. The idea of using any excess mains to charge the batteries is a big attraction, does the combi do this and do it well?

 

I did a couple of engine measurements yesterday and putting a second big PolyV pulley on the stub shaft on a taperlock would not be good, and would likely involve moving the TravelPower pulley out a bit, biggish job and increased side load on the crank nose, so a big new combined custom pulley is the only way to fit a bigger alternator.

 

I think this is all just dreaming right now, but I might ditch the Alde and get a diesel heater which would free up the perfect spot for a combi.

 

A bigger issue now is making decisions that might last ten years when there is so much uncertainty about fuels, maybe diesel will get so expensive that gas will be better, or maybe improving charging is a shorter term thing and fitting an electric motor and huge lithium bank is the way forward?, but maybe not in my lifetime.

 

................Dave

 

 

Link to comment
Share on other sites

4 minutes ago, dmr said:

I have been thinking about this a bit.  I can see the attraction of the combi, but it is physically big which is a problem, space is limited, and there are other downsides. Can the combi be set to only work when the engine is running? We have a few mains chargers and an immersion heater and its really good these only run off the TravelPower. I know so many people who have got flat batteries by accidentally leaving the immersion on. We only use our little inverter once or twice a week so checking that the imersion is off is no big deal.

I did measure some TP voltages a while ago, I really should fit a proper voltmeter. Its always a bit low, about 230v, maybe due to its Swedish roots? The voltage does fall quite a bit under load which I suppose is in effect a constant power. I think I have seen less than 200v (I wrote it all down but cant find my notes). The washing machine copes with all this very well. Does this mean that the combi would be taking a lot of power from the batteries much of the time even though we could actually manage with the lower voltage? So its likely that the power assist mode for us has more cons than pros. The idea of using any excess mains to charge the batteries is a big attraction, does the combi do this and do it well?

 

I did a couple of engine measurements yesterday and putting a second big PolyV pulley on the stub shaft on a taperlock would not be good, and would likely involve moving the TravelPower pulley out a bit, biggish job and increased side load on the crank nose, so a big new combined custom pulley is the only way to fit a bigger alternator.

 

I think this is all just dreaming right now, but I might ditch the Alde and get a diesel heater which would free up the perfect spot for a combi.

 

A bigger issue now is making decisions that might last ten years when there is so much uncertainty about fuels, maybe diesel will get so expensive that gas will be better, or maybe improving charging is a shorter term thing and fitting an electric motor and huge lithium bank is the way forward?, but maybe not in my lifetime.

 

................Dave

 

 

The combi will take power from the batteries only if the AC demand on the output (washer etc) is bigger than the available AC on the input (TP). If you did have a decent-sized battery bank (lithium or not) with fast charging from the engine it would mean you could run the washer without having to run the engine all the time, and recharge by running the engine for a much shorter time (which is when lithiums help, don't need hours of absorption charging).

 

This would greatly reduce engine running hours from what you have now, especially if you did run it fast enough to get the full 3.5kW out of the TP when charging. But for this to be effective you need to find a way of getting plenty of charging current when the engine is running, either TP into AC input of combi (could be tricky, see above) or a big alternator.

 

For example, a typical washer uses less than 1kWh per cycle (average figure is 0.6kWh) -- peak demand (motor, heating) is higher than this, but not average. So today if your wash cycle lasts 2 hours you have to run the engine with TP for 2 hours, at maybe 700rpm. With a lithium bank and a combo, depending how fast you can charge the batteries the engine running time would be much lower, the issue now is how to get all that power into the batteries since a Multiplus 3000/12 can only charge at about 120A which is 1.5kW (but it can pass AC power through to the output).

 

The Multiplus 12/3000 (assuming you stay with 12V) has the following limits:

 

Inverter output power : 3000VA/2400W continuous (6000W peak) -- DC from batteries to AC for washer

Charge current : 120A = 1500W -- AC from TP to DC for batteries

 

So with the TP running at 3.5kW the combi can provide 120A charging current to the batteries (1.5kW) while also powering the washer. If you add the ~100A you can get from the alternator and battery charger this gives 220A (3kW) into the batteries, which will charge them up pretty damn quick if they're lithiums. *BUT* you need to be careful about controlling all the charging sources (including alternators) to stop your lithium cells getting damaged or at the least having their lifetime reduced.

 

The advantage now is that instead of running the engine for the length of a wash cycle (maybe a couple of hours?) you only need to run it for long enough to replace the <1kWh used up which is maybe 20 minutes, and you can do this anytime -- or not at all if you recharge when cruising.

 

Link to comment
Share on other sites

1 hour ago, IanD said:

 

The advantage now is that instead of running the engine for the length of a wash cycle (maybe a couple of hours?) you only need to run it for long enough to replace the <1kWh used up which is maybe 20 minutes, and you can do this anytime -- or not at all if you recharge when cruising.

 

A washing machine only takes significant power when it’s heating the water for the main wash, maybe about 20 minutes. After that it doesn’t use much, it is quite happy to run off batteries without taking much our of them.

Link to comment
Share on other sites

3 hours ago, IanD said:

If you can fit one it, a combo can kind of do what you're looking for by running the washer and charging batteries -- but...

 

You program the combo with the maximum allowable 230Vac input current from the TravelPower (e.g. 15A is 3.5kW) -- which isn't that simple because it depends on rpm. If the batteries are low and the washer takes less than this, the excess power will be used to charge the batteries. If the washer isn't running, all the power up to the programmed limit will be used to charge the batteries, up to the limit of what the charger can support (120A for Multiplus 3000, which is about 1.5kW). Would work great with lithiums which like fast charging and don't need long absorption times.

 

The problem is that there's no communication between the Travelpower and the Multiplus, which is expecting a "stiff" AC source. If the TP is overloaded (more power demand than it can provide at the given engine revs) then I assume it drops its output voltage to maintain constant power -- do you know if this is correct? The maximum load of the Multiplus on the AC input is defined as a current limit, but I think the inverter shuts down if the input voltage drops below a set limit (180Vac?) -- I don't know if it then restarts automatically or not.

 

So say you set the MP input current limit to 15A (3.5kW) but the engine revs are only high enough the generate 2kW. If the AC load (washer etc) exceeds 2kW the TP output voltage will either drop (if it maintains constant power) or it will shut down (if this is what happens in an overload). If the voltage drops below the MP input limit then the MP will shut off; if the TP voltage then goes back up the MP will restart, drawing load again, which pulls the voltage down by overloading the TP, so the MP shuts off, so the voltage goes back up...

 

You could end up with a ding-dong battle between the TP and MP turning on and off, possibly leading to something dying -- TP, MP or washing machine ?

 

I think you're right that what you have now is the best you can do without a complete rip up and start again e.g. replace TP with a big expensive alternator with external controller and a combo to use a lithium house bank. If you want to get lithiums in there in a useful way without doing this the only real option is a bigger (or another) alternator (externally regulated), the problem is the mechanics of driving it.

In practice this isn’t a problem because the power demand can be set to what the TP can supply at idle, ie around 2kw. It is however very handy to have a quick and easy means to adjust the max ac current input, in our case we have a Mastervolt masterview panel, or for Victron they do a remote panel with a knob to adjust it. So it takes just a few seconds to change it.

I suppose if I’m going to be clever I could use my homemade BMS to adjust the Mas Combi current limit according to engine rpm. Something to add to the list anyway!

Edited by nicknorman
Link to comment
Share on other sites

2 minutes ago, nicknorman said:

A washing machine only takes significant power when it’s heating the water for the main wash, maybe about 20 minutes. After that it doesn’t use much, it is quite happy to run off batteries without taking much our of them.

True, but if a TP is your only 230Vac source (which it is for Dave going by his description) you have to run it for the entire wash.

 

If you have an inverter/charger then you only need to run the engine to put the required energy back into the batteries; the faster you can do this, the less time you have to run the engine for.

Link to comment
Share on other sites

7 minutes ago, nicknorman said:

In practice this isn’t a problem because the power demand can be set to what the TP can supply at idle, ie around 2kw. It is however very handy to have a quick and easy means to adjust the max ac current input, in our case we have a Mastervolt masterview panel, or for Victron they do a remote panel with a know to adjust it. So it takes just a few seconds to change it.

I suppose if I’m going to be clever I could use my homemade BMS to adjust the Mas Combi current limit according to engine rpm. Something to add to the list anyway!

If you set the combo input current limit to what the TP can provide at idle (e.g. 2kW) then you can't use the other 1.5kW at higher revs, unless (as you say) you change it either manually or automatically -- maybe possible with a home-brewed BMS if it talks to the combi over CANbus or similar and reprograms the setting, I don't know if anything commercially available can do this as standard or be programmed to do it, using a TP this way isn't a "normal" setup.

 

Not an ideal solution, but probably all that Dave can do without ripping everything up and starting again...

 

And he still has to decide between an expensive commercial LiFePO4 solution and a much cheaper homebrewed one using secondhand cells that needs a lot more knowledge -- though he did say he's an engineer... ?

Edited by IanD
Link to comment
Share on other sites

5 minutes ago, IanD said:

If you set the combo input current limit to what the TP can provide at idle (e.g. 2kW) then you can't use the other 1.5kW at higher revs, unless (as you say) you change it either manually or automatically -- maybe possible with a home-brewed BMS if it talks to the combi over CANbus or similar and reprograms the setting, I don't know if anything commercially available can do this as standard or be programmed to do it, using a TP this way isn't a "normal" setup.

 

Not an ideal solution, but probably all that Dave can do without ripping everything up and starting again...

 

And he still has to decide between an expensive commercial LiFePO4 solution and a much cheaper homebrewed one using secondhand cells that needs a lot more knowledge -- though he did say he's an engineer... ?

I already have the home made BMS talking to the Combi over CANBUS and can change settings. The original idea being that when charging on shore power, the BMS would be able to adjust the charge voltage to prevent a cell over voltage and or reduce to a float voltage to stop charging at some specified SoC. Quite easy with a micro with built in CANBUS hardware, once you have “cracked” the communication protocol. Which is fairly simple.

Link to comment
Share on other sites

39 minutes ago, nicknorman said:

I already have the home made BMS talking to the Combi over CANBUS and can change settings. The original idea being that when charging on shore power, the BMS would be able to adjust the charge voltage to prevent a cell over voltage and or reduce to a float voltage to stop charging at some specified SoC. Quite easy with a micro with built in CANBUS hardware, once you have “cracked” the communication protocol. Which is fairly simple.

If your BMS can read engine rpm -- and Dave builds his own, or you build one for him ? -- this would be a good solution, it's effectively customised to his needs. It's a shame that the TP is an old design which doesn't include any communication to the outside world, this would make things much easier.

 

If we wants to buy a system which does all this then I suspect he'll be out of luck, as well as out of pocket... ?

Edited by IanD
Link to comment
Share on other sites

1 hour ago, IanD said:

If your BMS can read engine rpm -- and Dave builds his own, or you build one for him ? -- this would be a good solution, it's effectively customised to his needs. It's a shame that the TP is an old design which doesn't include any communication to the outside world, this would make things much easier.

 

If we wants to buy a system which does all this then I suspect he'll be out of luck, as well as out of pocket... ?

Yes the BMS can read engine rpm. Or rather, it can get it over CANBUS from the alternator controller which gets it over LIN from the alternator regulator chip. Well, alternator rpm anyway, so you have to do a sum to get engine rpm. Anyway, Dave is quite capable of building this stuff, he just needs to get his act together!

Link to comment
Share on other sites

1 hour ago, nicknorman said:

Yes the BMS can read engine rpm. Or rather, it can get it over CANBUS from the alternator controller which gets it over LIN from the alternator regulator chip. Well, alternator rpm anyway, so you have to do a sum to get engine rpm. Anyway, Dave is quite capable of building this stuff, he just needs to get his act together!

Sounds like your system can do what he needs -- all he needs to do is build one, add a combo and externally controlled alternators and a lithium battery bank and he's away ?

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.