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Reverse Engineering my Electrical System


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Hello, 

 

I could use some advice on reverse engineering my new-to-me narrowboat. The 230 system is fairly well installed but the 12v stuff looks pretty DIY and has given me a few headscratchers (tracing the wiring is a headache). For a bit of background, I'm not an electrician but I do a lot of site power work so I have a fairly decent electrical background, but mostly in 400/230v stuff. 

 

First off this is what I know: I've got an older Victron Phoenix compact multiplus 12v 1600 hooked up to 3x 110ah leisure batteries (Yuasa brand). I have two alternators, and from tracing the wiring it looks like the leisure batteries are charged directly from a fairly large alternator (which puts out 20a at 13v on idle - I'm not sure if this is good or not, it seems low to me but I was assured that it was fairly new). I also have a second smaller alternator attached to the starter battery. The previous owner of the boat wasn't particularly tech savvy but told me to watch the voltage meter (a Deep Sea single channel unit) to make sure I didn't discharge the batteries too much, which I have been doing for the last couple of months. 

 

I've recently been having issues with inverter cutting out after a few hours of use (initially I was getting a few days before the voltage dropped 1v down from the starting point, at which point I would charge them up). However, it turns out that the meter actually connected to the STARTER battery. What threw me was the second lead connecting to the leisure batteries, but it appears that that just powers the meter. I can only assume that this was a mistake during installation as that doesn't seem very useful to me - there's no way of monitoring the leisure battery voltage. 

 

Anyway, I suspect I've cooked my batteries by running them ridiculously low. They're currently reading 11v after 4 hours of charging and my 12v lights are dimming every time the water pump kicks in. 

 

So my questions are as follows:

Is it normal to put a V meter on the starter battery and not the leisure batteries? 

 

I'm not on shore power, but if I were to take the batteries to work one at a time and put them on a recovery charge for a few days, are they likely to come back to life? If so, will they balance themselves when I connect them again? If not...

 

Can I somehow connect to this older Victron Phoenix to change the charge profile to Lifepo4? I couldn't find the manual for it. I've built a few LifePo4 batteries for work and have a good source for cheap cells - I'd rather do that than buy more lead acids, but I also don't really want to drop £1k on a new inverter/charger on top of a new set of cells right now. I'll also be putting a few solar panels up at some point. 

 

Thanks for your advice as always!

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OK I'll go for starters... other opinions will be along in due course...

 

No it's not normal to monitor the starter (only) . Often there is a selector switch. Won't be hard for you to add. Personally I'd just get another voltmeter and have two.

 

In terms of the charger, so long as there are some settings that you can change on the phoenix then I would just find a setting or tweak it to match what you need for the lithiums. Although I have no more knowledge that you on that  charger.  Can you find a manual online or on the victron site? 

 

You really need to see what the alternator is pushing out at say 1200 revs rather than idle.  Lots of advice here on why you shouldnt try to charge flat or discharged batteries with an idling engine.

 

Hope that helps as a start.

 

Just to add if the 4 hours charging is with the engine idling I'd really try increasing the revs to see if the charge current increases and set the revs for max current. 

 

Further thought, if the 4 hrs charge is via the victron on landline then I think you might have a serious problem with one or more batts. Check electrolyte if you can, check for one gassing, being hot or ends bulging  in case a cell is shorting. 

Edited by jonathanA
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19 minutes ago, Quattrodave said:

I'd start by reading and understanding the battery charging primer:

 

https://www.canalworld.net/forums/index.php?/topic/95003-battery-charging-primer/

I did have a look through this but it's not wholely relevant as I don't technically have a charger, just an alternator. Although cont to think of it that answers my question re the lithium batteries - it doesn't matter if my inverter doesn't support lithium (I can't see any dip switches on it unless they're under the cover) as I'm not using it to charge at all, I would still need some kind of DC-DC charger to interface between the alternator and the lithium cells but that's certainly cheaper than a new inverter.

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9 hours ago, MixingWizzard said:

I'm not on shore power, but if I were to take the batteries to work one at a time and put them on a recovery charge for a few days, are they likely to come back to life? If so, will they balance themselves when I connect them again? If not...

 

You could try, also make sure the water levels are ok in the batteries. However 11v is a very unhealthy reading on a 12v battery after 4 hours charging so I also imagine they're toast.

 

Not sure about the Victron phoenix and Lithium compatibility.

Edited by booke23
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7 hours ago, MixingWizzard said:

I did have a look through this but it's not wholely relevant as I don't technically have a charger, just an alternator

 

That statement just shows how little you understand about batteries and their charging.

 

It is almost certain that you have been over discharging and badly undercharging your batteries, and now you have ruined them - even if they were good in the first place. A very, very common mistake by new boaters.

 

I lay odds that your voltmeter is one designed for the by's toys motorist market and nowhere near accurate enough or the job you need it to do, especially when you go to lithiums. It needs to show to 0.1 volt with a degree of accuracy. It also needs to monitor the domestic battery.

 

As you have been told, tickover is nowhere near fast enough for alternator charging, and only charging for 4 hours is not long enough either. Given a typical (50amp +) alternator and typical battery bank size and use, you need to charge at around the 1200 to 1500 rpm, but is you have an ammeter this can be gradually reduced to tickover as the batteries charge up and the current drops. You also need to charge for at least 10 hours and maybe 12 or more once a week, with the four hour charges every day.

 

You should try to NEVER let the battery voltage drop below about 12.25 to 12.3 volts before recharging.

 

My suspicion is that your batteries are now badly sulphated from persistent undercharging and now only have a fraction of their nominal capacity, and it is also likely that one or more cells are shorting and discharging the whole bank on their own. If you have cell caps you can remove take them off and start a very long charge at 1200 to 1500 rpm looking to see if any are  bubbling more than the others or the cell lids are getting hotter above individual cells. If any cells are dryer than the rest, that is also a tell-tale for shorting cells. Top them up with distilled/demineralised water to the level indicator or to about 3mm above what you call the plates before starting to charge.

 

In your situation, I don't think trying to charge them one at a time is a very good idea because, assuming no shorting cells, the freshly charged one would just discharge itself by trying to charge the others. They should even out eventually, but it may take more than just the three trips with a single battery, but it should not da nay harm unless they are shorting.

 

Please note that you can not know when the batteries are fully charges unless you also have an accurate ammeter.

 

You can buy battery to battery chargers with configurable charging profiles (I think Victron make one) and many use one, so the engine battery charges the domestic LiFePo4 battery, with the alternator augmenting the current flowing to the lithium bank.

 

You do not mention solar charging, so I would suggest that might be a better first action that changing to lithium domestic batteries. You may not have to run the engine for charging until around October. They are also excellent with lithium batteries.

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10 hours ago, MixingWizzard said:

Hello, 

 

I could use some advice on reverse engineering my new-to-me narrowboat. The 230 system is fairly well installed but the 12v stuff looks pretty DIY and has given me a few headscratchers (tracing the wiring is a headache). For a bit of background, I'm not an electrician but I do a lot of site power work so I have a fairly decent electrical background, but mostly in 400/230v stuff. 

 

First off this is what I know: I've got an older Victron Phoenix compact multiplus 12v 1600 hooked up to 3x 110ah leisure batteries (Yuasa brand). I have two alternators, and from tracing the wiring it looks like the leisure batteries are charged directly from a fairly large alternator (which puts out 20a at 13v on idle - I'm not sure if this is good or not, it seems low to me but I was assured that it was fairly new). I also have a second smaller alternator attached to the starter battery. The previous owner of the boat wasn't particularly tech savvy but told me to watch the voltage meter (a Deep Sea single channel unit) to make sure I didn't discharge the batteries too much, which I have been doing for the last couple of months. 

 

I've recently been having issues with inverter cutting out after a few hours of use (initially I was getting a few days before the voltage dropped 1v down from the starting point, at which point I would charge them up). However, it turns out that the meter actually connected to the STARTER battery. What threw me was the second lead connecting to the leisure batteries, but it appears that that just powers the meter. I can only assume that this was a mistake during installation as that doesn't seem very useful to me - there's no way of monitoring the leisure battery voltage. 

 

Anyway, I suspect I've cooked my batteries by running them ridiculously low. They're currently reading 11v after 4 hours of charging and my 12v lights are dimming every time the water pump kicks in. 

 

So my questions are as follows:

Is it normal to put a V meter on the starter battery and not the leisure batteries? 

 

I'm not on shore power, but if I were to take the batteries to work one at a time and put them on a recovery charge for a few days, are they likely to come back to life? If so, will they balance themselves when I connect them again? If not...

 

Can I somehow connect to this older Victron Phoenix to change the charge profile to Lifepo4? I couldn't find the manual for it. I've built a few LifePo4 batteries for work and have a good source for cheap cells - I'd rather do that than buy more lead acids, but I also don't really want to drop £1k on a new inverter/charger on top of a new set of cells right now. I'll also be putting a few solar panels up at some point. 

 

Thanks for your advice as always!

Quite a lot to get through! Please let us know which engine you have, approximate age and if possible which alternators (at least in terms of output current). I would split the issue into 3 sections, in order of priority as there is no point in getting new batteries if the charging and monitoring isn’t there.

 

1/ Monitoring. It is not uncommon for an engine manufacturer or mariniser to include a voltmeter on the panel and this is the starter battery voltmeter. The domestic battery and alternator is an “afterthought”, often there is just a red warning light for the domestic battery alternator. Not very helpful as electricity is invisible and without adequate monitoring you have no idea what is going on. I would suggest installing a BMV712 or similar, this gives you domestic battery voltage and current, and State of Charge (SoC) estimation by counting amp hours out and in. This latter parameter is of course only accurate if you have set the actual battery capacity set up, which in the case of your batteries is probably way below the badged capacity. Monitoring voltage is useful to check things are working as expected and keep a rough idea of SoC, current is the only way to know when the batteries are fully charged (current falls to perhaps 2% of capacity). A BMV712 has a handy relay output which can be triggered by various things including SoC, which would be useful if you did go for Lithium batteries. 

 

2/ Charging. Please check the alternator voltage and current when running the engine a bit faster, say 1200 rpm. Depending on the engine setup, the domestic alternator probably isn’t spinning fast enough at idle to work properly. On face value the 13v and 20A sounds very poor unless the alternator is tiny and the revs way too low. If you find something similar happening at 1200rpm this points to an alternator fault such as a blown diode or diodes. Please get the charging side sorted before buying new batteries, otherwise you will knacker the new batteries in short time. 

 

3/ Batteries. Probably you need new batteries after this period of abuse, but get the above sorted first! Try to keep lead acid batteries above 50% SoC which is around 12.2v with zero load. Lead acid batteries are horrible things that refuse to charge quickly after the first brief flush, you have to charge them for many hours to fully charge them, and much of that time is with quite a small current going in for all the diesel burnt. If you don’t fully charge regularly (at least once a week) they sulphate and you are on the fairly rapid decline to knackered batteries.

 

Li batteries are fantastic but fraught with complicated issues. You have mentioned a dc dc charging source which is good although can be rather inefficient and costly. If you are going to build your own Li battery, please ensure you have a suitable BMS which is able to disconnect the cells before voltage or temperature issues cause damage or fire. Ready built batteries are getting quite cheap these days, probably there is little point in building your own when you can buy eg a Fogstar Drift well-made complete battery with heating. I did build my own but I wanted to make an integrated system including my own design of BMS to control charging sources.  A lengthy Covid lockdown project!

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11 hours ago, nicknorman said:

Quite a lot to get through! Please let us know which engine you have, approximate age and if possible which alternators (at least in terms of output current). I would split the issue into 3 sections, in order of priority as there is no point in getting new batteries if the charging and monitoring isn’t there.

 

1/ Monitoring. It is not uncommon for an engine manufacturer or mariniser to include a voltmeter on the panel and this is the starter battery voltmeter. The domestic battery and alternator is an “afterthought”, often there is just a red warning light for the domestic battery alternator. Not very helpful as electricity is invisible and without adequate monitoring you have no idea what is going on. I would suggest installing a BMV712 or similar, this gives you domestic battery voltage and current, and State of Charge (SoC) estimation by counting amp hours out and in. This latter parameter is of course only accurate if you have set the actual battery capacity set up, which in the case of your batteries is probably way below the badged capacity. Monitoring voltage is useful to check things are working as expected and keep a rough idea of SoC, current is the only way to know when the batteries are fully charged (current falls to perhaps 2% of capacity). A BMV712 has a handy relay output which can be triggered by various things including SoC, which would be useful if you did go for Lithium batteries. 

 

2/ Charging. Please check the alternator voltage and current when running the engine a bit faster, say 1200 rpm. Depending on the engine setup, the domestic alternator probably isn’t spinning fast enough at idle to work properly. On face value the 13v and 20A sounds very poor unless the alternator is tiny and the revs way too low. If you find something similar happening at 1200rpm this points to an alternator fault such as a blown diode or diodes. Please get the charging side sorted before buying new batteries, otherwise you will knacker the new batteries in short time. 

 

3/ Batteries. Probably you need new batteries after this period of abuse, but get the above sorted first! Try to keep lead acid batteries above 50% SoC which is around 12.2v with zero load. Lead acid batteries are horrible things that refuse to charge quickly after the first brief flush, you have to charge them for many hours to fully charge them, and much of that time is with quite a small current going in for all the diesel burnt. If you don’t fully charge regularly (at least once a week) they sulphate and you are on the fairly rapid decline to knackered batteries.

 

Li batteries are fantastic but fraught with complicated issues. You have mentioned a dc dc charging source which is good although can be rather inefficient and costly. If you are going to build your own Li battery, please ensure you have a suitable BMS which is able to disconnect the cells before voltage or temperature issues cause damage or fire. Ready built batteries are getting quite cheap these days, probably there is little point in building your own when you can buy eg a Fogstar Drift well-made complete battery with heating. I did build my own but I wanted to make an integrated system including my own design of BMS to control charging sources.  A lengthy Covid lockdown project!

Many thanks for your excellent reply. To follow up: 

 

The engine is a beta38. I have just fired it up to test the alternator. Of course my rev counter has decided to stop working (sods law) but at what sounds like roughly 1200 it is in fact putting out 50 amps at 14v - much better! Irritatingly one of the few pieces of information I got from the previous owner was to never run the engine higher than idle without it being under load - I'm assuming this is also incorrect. 

 

I've only just got back from work and it's too late to do a full charge, but if I ever get home before 8 I'll have a go at bringing the batteries back to life.

 

I think I need to bump solar up by considerable list of boat maintenance tasks. Running the engine to charge is not really feasible for me as I'm rarely home from work before 7/8pm. 

 

I just had a look at the prebuilt lithium offerings, they have come down considerably since I built mine so that seems like the better option. 

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20 minutes ago, MixingWizzard said:

I've only just got back from work and it's too late to do a full charge, but if I ever get home before 8 I'll have a go at bringing the batteries back to life.

 

To get a 12 hour charge and stay within the rules you'll need to fire the engine up at 08:00 and leave it running until 20:00

 

Just doing an odd hour here or there is a waste of diesel.

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19 minutes ago, MixingWizzard said:

I've only just got back from work and it's too late to do a full charge, but if I ever get home before 8 I'll have a go at bringing the batteries back to life.

 

I think I need to bump solar up by considerable list of boat maintenance tasks. Running the engine to charge is not really feasible for me as I'm rarely home from work before 7/8pm. 

Remember, on Canal River Trust waters, there is a ban on running engines/generators from 8pm to 8am for charging, so others can get some sleep.

Enough solar will work fine in summer, but at some point in the winter months it isn't going to be enough. How are you going to keep your batts charged then, if you aren't around when you can run the engine? You'll be limited to weekends only, which isn't ideal for lead acid battery life.

 

22 minutes ago, MixingWizzard said:

I just had a look at the prebuilt lithium offerings, they have come down considerably since I built mine so that seems like the better option. 

These are not a drop in replacement for lead acid, despite how they are often marketed. Sudden automatic disconnection from the alternator when they are fully charged can wreck the alternator. There are various ways round this of varying cost, complexity and engineering elegance, but these need to be understood to make an appropriate decision and can add a lot to the cost.

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6 minutes ago, Alan de Enfield said:

 

To get a 12 hour charge and stay within the rules you'll need to fire the engine up at 08:00 and leave it running until 20:00

 

Just doing an odd hour here or there is a waste of diesel.

 

When I lived aboard the lithium bank was an excellent fit with getting home late in winter and only being able to do the odd hour or two of charging here and there. They soaked up everything the alternator or the genny could throw at them and didn't care if they stayed only partially charged for days (or weeks) on end. 

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3 minutes ago, MtB said:

 

When I lived aboard the lithium bank was an excellent fit with getting home late in winter and only being able to do the odd hour or two of charging here and there. They soaked up everything the alternator or the genny could throw at them and didn't care if they stayed only partially charged for days (or weeks) on end. 

 

 

Just a reminder that the boat under discussion has LA batteries.

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1 minute ago, Alan de Enfield said:

 

 

Just a reminder that the boat under discussion has LA batteries.

 

Just a reminder I was encouraging 'im to go lithium!

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24 minutes ago, Jen-in-Wellies said:

Remember, on Canal River Trust waters, there is a ban on running engines/generators from 8pm to 8am for charging, so others can get some sleep.

Enough solar will work fine in summer, but at some point in the winter months it isn't going to be enough. How are you going to keep your batts charged then, if you aren't around when you can run the engine? You'll be limited to weekends only, which isn't ideal for lead acid battery life.

 

These are not a drop in replacement for lead acid, despite how they are often marketed. Sudden automatic disconnection from the alternator when they are fully charged can wreck the alternator. There are various ways round this of varying cost, complexity and engineering elegance, but these need to be understood to make an appropriate decision and can add a lot to the cost.

I'm aware of the engine restrictions, which is why I was saying that solar will be needed! 

 

I was aware they have a different charging profile but I didn't know about disconnection from the alternator - I'll look into it. 

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1 hour ago, MixingWizzard said:

Many thanks for your excellent reply. To follow up: 

 

The engine is a beta38. I have just fired it up to test the alternator. Of course my rev counter has decided to stop working (sods law) but at what sounds like roughly 1200 it is in fact putting out 50 amps at 14v - much better! Irritatingly one of the few pieces of information I got from the previous owner was to never run the engine higher than idle without it being under load - I'm assuming this is also incorrect. 

 

I've only just got back from work and it's too late to do a full charge, but if I ever get home before 8 I'll have a go at bringing the batteries back to life.

 

I think I need to bump solar up by considerable list of boat maintenance tasks. Running the engine to charge is not really feasible for me as I'm rarely home from work before 7/8pm. 

 

I just had a look at the prebuilt lithium offerings, they have come down considerably since I built mine so that seems like the better option. 

Beta 38 probably has a 100A domestic alternator. Obviously 14v / 50A is not too bad but if that is with the batteries pretty flat, it still isnt great. I would expect full output from the alternator (100A) at least for the first few minutes. I suggest checking the voltage at the alternator (between fat cable on back of alternator, and alternator or engine casing) vs the voltage between + and - posts on one of the domestic batteries when the engine is running at 1200 or whatever - ie a fairly high charge current. I suspect you might find that a fair bit of voltage is being lost between the alternator and the batteries, and 1/2 volt can make quite a difference to charge current.

 

If you do find a significant voltage difference, try to locate it firstly by checking alternator positive to battery positive voltage (to see if it is in the positive wiring) and again by checking alternator casing to battery negative - in order to see if it is mostly in the positive or negative wiring. Most likely it would be in the positive with eg the isolator switch and any connections being most likely culprits. Eliminating excessive voltage drop in the wiring can make quite a big difference to charging speed, at least in the first 1/2 of the charging process.

 

But if you find no significant voltage drop, it could just be that the batteries are getting very tired.

 

Running the engine above idle at no load /neutral - well, not really an issue within reason. Not flat out for sure, but charging at say 1000-1300 is better for the engine than at idle. Don’t forget that when the alternator is working hard this is putting load on the engine anyway.

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2 minutes ago, booke23 said:

Most Beta engines (including the Beta 38) include the following advice in the manual about battery charging out of gear:-

 

image.png.5bb782c2a50938626002273875c98d4b.png

Obviously it depends on the load, ie how far along the charging process you are. 1200 to start with, for sure. But 6 hours in when the current is 15A (and hence the mechanical load is very small), you can reduce the rpm to the point just before the current starts to decrease. It’s all about avoiding a heavy belt load at low rpm, and worth remembering that belt pull (force) is electrical load divided by engine rpm.

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11 hours ago, nicknorman said:

But if you find no significant voltage drop, it could just be that the batteries are getting very tired.

 

To amplify this:

 

The higher the alternator charging current, the lower the charging voltage, so a low voltage at the batteries could mean a faulty alternator, volt drop in the wiring or batteries demanding a high charging current. Lucas said that the charging voltage should be checked with 10 amps or less charging current AND sufficient revs, so the lack of revs is not limiting the current to 10 amps or less.

 

Hence, Nicks comment about tired batteries, either because they have shorting cells drawing a high charging current or they are so sulphated they were way below 50% charged when you took the measurement.

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