Views on alternator to battery charging systems?

[Tranona]

If you currently get enough charge from your alternator to keep your batteries charged in relation to your usage, then you do not need a booster. Just a VSR in a BEP Marine switch cluster will do exactly what you need. Ensure the engine start battery is charged first - usually a very short period then switches charge to house automatically. The switches isolate each bank but the third switch parallels the two batteries for emergency starting.

You can get a package from Merlin www.power-store.com

No connection except satisfied customer - fitted them to two boats.

 

[mattnj]

The alternator is reasonably new and working - it's not the problem. Stupidity, lack of care, and poor memory are the problems I want to solve. I want to be in the position not to have to worry about batteries and always have a charged starter battery available (engine can't be hard started) an also not to have batteries being undercharged. My ideal system is one where I switch on the engine for a bit, it sorts out the batteries as required, and I don't have to think about switching switches between batteries etc.

I am coming to see that there are two Sterling approaches. Either you have a system which is wired into the alternator and controls it, or there is a system which controls the output from the alternator without actually having to add wires etc. to the alternator. The first is half the price of the second, so it's down to how much work I want to do.

Philip

Go for it, you wont regret it, they are the business and do exactly as you have described above, fit and forget (and enjoy more battery performance)

 

[snooks]

The alternator is reasonably new and working - it's not the problem. Stupidity, lack of care, and poor memory are the problems I want to solve. I want to be in the position not to have to worry about batteries and always have a charged starter battery available (engine can't be hard started) an also not to have batteries being undercharged. My ideal system is one where I switch on the engine for a bit, it sorts out the batteries as required, and I don't have to think about switching switches between batteries etc.

If that's all you want, save yourself £80 and get a VSR

When you get to the boat switch all the switches on (except the emergency parallel), and away you go, it charges your engine battery, when that reaches 13.8V it then charges your house batteries....when the batteries drop to something like 12.5V it separates them again, so your engine battery is always full.

 

[William_H]

If that's all you want, save yourself £80 and get a VSR

When you get to the boat switch all the switches on (except the emergency parallel), and away you go, it charges your engine battery, when that reaches 13.8V it then charges your house batteries....when the batteries drop to something like 12.5V it separates them again, so your engine battery is always full.

Yes I would tend to agree with snooks. A VSR will automatically do your battery switching and isolation.
Yes the Alternator to Battery charging system will sqeeze more amps into the house battery for a limited amount of engine running.
What you need is an amp meter so you monitor exactly what is happening with existing system of switching. This will probably show you that the alternator is putting in about 20 amps at first into the house battery (and engine battery) However this will diminish fairly rapidly to a mediocre but useful charge rate.
You may find however that in most voyages you have shut the engine down before it diminishes too much. At best the alternator to battery charger will give perhaps twice the current into the house batteries but if you only do a short engine run it will not improve current all that much. For longer engine runs it will however give more useful current into the batteries for a longer time.
Larger or more house batteries will also take more charge from the standard alternator in short engine runs.However you then have more batteries not fully charged.

You might find that in reality you don't have so much of a problem or that solar may give you a better outcome. A lot depends on your needs and sailing habits. good luck olewill

 

[stirlingtours]

I have used the Sterling setup with the remote panel and found it works well. No need for 1/2 switch or anything else. One problem during installation was the hefty cables to the shunts. I wanted to mount the unit vertically and the shunts horizontally but couldn't bend them. The only thing to watch out for is extra wear on alternator belts since it is doing more work, however when I did experience slip the remote warning lamp came on well before anything serious happened.

 

[Ian_Edwards]

Hi,
I fitted one two years ago to a 110 amp alternator (130amp model) and 500 amp hrs of battery (100 amp hrs starter, 400 amp hrs domestic). It works well and well worth the effort, it fully charges both the starter and domestic batteries very quickly, it stops charging the starter battery when it’s fully charged (which doesn't take long).
I regularly see 100amp+ going into the domestic bank, the alternator runs hot, but was already fitted with a cooling fan, if the alternator isn’t cooled, you may need to fit fan. I got the remote control box which measures the temperature of both a battery terminal and the alternator and switches off the boost charge (reverting to a simple split diode configuration) if either the alternator or battery gets too hot.
I had four issues with the unit:
1. I found it quite difficult to fit, stiff heavy duty wires, shunt, lack of space, it took quite while to shoehorn it into the space.
2. The connectors on the circuit board for the temperature sensors are very poor.
3. When the starter battery is fully changed and the unit stops charging it, the Volvo engine control unit thinks the alternator has failed and sounds an alarm. (I can probably cure this by repositioning the sense wire …. But haven’t got round to doing it yet)
4. It charges the batteries at over 14 volts at times and that has “blown” my Blackberry phone, when charging it through the cigarette lighter socket, using the 12volt connector supplied with the phone.
We also have a solar panel and a 30amp mains charger connected and they all seems to work quite happily together.

 

[Mistroma]

Similar dilemma

I'm considering a similar setup and have supplied some information below to help anyone able to advise.

Daily usage is approx. 100Ah and alternator is 80Ah. However, I have "parasitic" loads of around 8 Amps (fridge, engine fan, misc. losses) and usually don't run engine flat out. According to specs. normal cruising at

2200rpm produces more like 66Ah and taking off 8Ah leaves 58Ah for charging.

This sounds fine but I think I need around 120Ah to recharge every 100Ah used. Without a smart charger I might need up to

3-4 hours running each day to keep batteries 80% charged.

Batteries are: 1x110Ah engine start, 3x110Ah domestic, 1x50Ah Bowthruster.

I've pretty much decided that I need to have 4x110Ah domestic batteries and a larger alternator to stand a chance of charging with only a couple of hours running each day. Still to decide on alternator and will need to use twin belts or serpentine belt because of the load.

I can add water to all batteries except the 50Ah one in bows and would like to avoid cooking that one on long runs.

But that still leaves me with some choices (none ideal):

1) Smart charge regulator (prob. Sterling) and larger diode or VSR (3 way)
Cheapest but not familiar with how well VSRs work. I know that my existing 100A diode just distributes the charge and so sealed battery would get same voltage as other banks (so likely to cook).

2) Sterling alternator to battery charger and larger 2 way diode or VSR (Because charger has 2 outputs not 3)
Expensive but sounds as if it gives better control when charging 2 banks. Still needs diode or VSR but perhaps slightly less chance of cooking the sealed battery.

3) Driftgate combined 3 way charge splitter (XSP120/1/3) and regulator
Also seems expensive and I haven't worked out how the splitter actually operates (description seems to indicate that it has 3 charge regulators).

My aim is to maintain good charge of 80%-85% from 55%-60% discharged state with 1-2 hours on engine each day. I'd also like to get 95%-100% charge from time to time with 4-5 hours running.

Perhaps I'm worrying too much about the differences between the battery banks:
100Ah engine start usually 90-100% most of the time
50Ah bowthruster battery 90-100% most of the time (but sealed maint. free)
440Ah domestic cycled from 60-80% regularly

I can keep the engine start and domestic banks topped up. I suppose it might be cheaper to replace the bowthruster when needed and just buy a cheaper charging setup.

I'm also considering a Smart battery monitor at around £120-£160 (where do you stop, fuel cell, generator).

 

[snooks]

But that still leaves me with some choices (none ideal):

1) Smart charge regulator (prob. Sterling) and larger diode or VSR (3 way)
Cheapest but not familiar with how well VSRs work. I know that my existing 100A diode just distributes the charge and so sealed battery would get same voltage as other banks (so likely to cook).

2) Sterling alternator to battery charger and larger 2 way diode or VSR (Because charger has 2 outputs not 3)
Expensive but sounds as if it gives better control when charging 2 banks. Still needs diode or VSR but perhaps slightly less chance of cooking the sealed battery.

3) Driftgate combined 3 way charge splitter (XSP120/1/3) and regulator
Also seems expensive and I haven't worked out how the splitter actually operates (description seems to indicate that it has 3 charge regulators).

4) use less power

 

[Mistroma]

Option 4

Already considered using less power but couldn't find anything I'd want to reduce. Fridge and then instruments are biggest drain. Fridge gives a lot of freedom for cruising (& Ice blocks are hard to get). Lights are used so little that LEDs might save 4Ah per day.

I have found another option now Merlin do a SmartBank ADVANCED - 3 Battery (Full Package). But I need more information on how that performs to do any sensible comparison.

Seems to be a tricky balance between cost vs. performance (as always).

 

[pvb]

Batteries are: 1x110Ah engine start, 3x110Ah domestic, 1x50Ah Bowthruster.

I've pretty much decided that I need to have 4x110Ah domestic batteries and a larger alternator to stand a chance of charging with only a couple of hours running each day. Still to decide on alternator and will need to use twin belts or serpentine belt because of the load.

There's no point having a larger alternator unless you dramatically increase the size of your domestic bank. The alternator can only supply as much current as the batteries will accept, and even 400Ah of batteries won't accept much more than 50A or 60A in most circumstances. I have a 90A alternator, Adverc booster and 660Ah domestic bank, and I rarely see much more than 60A or 70A max charge rate.

A bigger domestic bank will accept charge more readily, thus minimising engine running time and, for a given usage, will have a lower depth of discharge (thus prolonging battery life).

Although I have no experience of it, I think the Sterling Alternator to Battery Charger is a neat idea, especially as it doesn't boost the voltage to the engine start battery. And it includes a diode splitter.

The easiest charging solution for the bowthruster battery is a "shadow charger" type device, such as this one. The big problem with charging remote bowthruster batteries is that when you use the thruster with the engine running (ie most of the time) there can be a big current drawn through the charging cables, which need to be appropriately sized. A shadow charger won't allow a high current to be drawn, so the cables can be lighter.

If I were you, I look at these steps:-
* add 2 or 3 more domestic batteries
* fit a Sterling Alternator to Battery Charger
* fit a shadow charger for the bowthruster battery.

 

[snooks]

Already considered using less power but couldn't find anything I'd want to reduce. Fridge and then instruments are biggest drain. Fridge gives a lot of freedom for cruising (& Ice blocks are hard to get). Lights are used so little that LEDs might save 4Ah per day.

I have found another option now Merlin do a SmartBank ADVANCED - 3 Battery (Full Package). But I need more information on how that performs to do any sensible comparison.

Seems to be a tricky balance between cost vs. performance (as always).

The fridge will be the big one, as will anything using an inverter. If your lights are tungsten/halogen then they will also suck up electricity when they are on. An oil lamp adds atmosphere and doesn't use electricity

If you have a big plotter or display (laptop etc), turn the brightness down, this will also save you power. Don't turn the radar (if you have one) on if you are not using it and don't need it, and switch the instruments off at night.

If your fridge has good insulation it doesn't have to be running all of the time, and you don't need ice (it doesn't need to be sub zero ), keep it as full as possible and minimise the amount of air in it, even if it's with beer or bottles of fresh water, and minimise the amount of time you open it. The less cold air you have the less the cold it looses when you open it, the less the cooling unit has to work to get the air cold again, the less electricity you'll use.

Most of the time it's cold at night so you can save 8 hours of fridge use straight away.

If you're going down to the boat put a couple of 5 lt water containers in the freezer the night before and take them with you to cool the fridge right down when you get there, this will also help you save power.

Most boats you can get away with running the fridge for a couple of hours a in the morning, when motoring and a hour or two the evening when you arrive or charging/cooking or when you come back with a load of shopping.

Get any meat vacuum packed from your local butcher, it keeps for longer, Keep things in boxes in your fridge, cold meats/cheeses/salad all in separate boxes. This makes a number of items easy to take out quickly, so you close the lid asap.

Non of these measures effect the quality of life on board, and they are free, with the exception of a few tuppaware pots

Btw. We have a 80ah alternator, 2 x 110ah batteries + 1 engine start battery and a rutland wind charger (which more or less just powers out ultrasonic antifouling)

I'm not saying you can't get get the toys, it's your boat and you can do what you would like, but 100ah seems a lot to be using in 1 day.

Merlin's kit is very good, and their support on the phone is great too.

 

[dt4134]

The fridge will be the big one, as will anything using an inverter. If your lights are tungsten/halogen then they will also suck up electricity when they are on. An oil lamp adds atmosphere and doesn't use electricity

I used to think a fridge would be a big current draw, mainly because countless skippers told me that was the biggest problem. But now I've got a boat with a decent battery monitor I've found it's not as clear cut as that. The fridge takes 3A about 50% of the time, so 1.5Ah per hour, well below lighting levels - although I've also reduced the drain for lights (nav & domestic) by fitting LEDs to mitigate that.

The diesel heater was the biggest shock as it takes a fair current when it is running not just when starting.

 

[Mistroma]

Minimising Power

All snooks suggestions are very sensible and I've implemented both one way or another.

e.g. When going down to the boat I take a pile of freezer packs and keep as many as possible in freezer compartment.

I have something like 22 lights on board. LEDs aren't high on my priority as my total domestic lighting use is around 4-5Ah (I'm really stingy with lights). External lights are a different story but again low priority as I'm rarely sailing at night.

I have a list of amount of power everything uses and you are correct about radar being a real hog. Fortunately, I've rarely used here on West Coast (only once off Mull of Kintyre). Nothing like the fog I used to get shuttling back & forth between Scotland and Holland.

Big killer is the freezer as my wife keeps that stocked. Perhaps I can investigate vac. packing. Thanks for that suggestion. Depends on storage time and ease of getting meat packed. I like to have plenty to eat on board and choice is limited on some of the Scottish Isles.

PS I also have a Rutland 913. It keeps the batteries up on the mooring even with the Yacht Sentinel alarm running. However, I think I only average about 8-10Ah/day when living on board. Sounds as if Snooks gets similar amount of output (certainly not enough to cancel out a fridge).

 

[Mistroma]

Thanks for real life figures

There's no point having a larger alternator unless you dramatically increase the size of your domestic bank. The alternator can only supply as much current as the batteries will accept, and even 400Ah of batteries won't accept much more than 50A or 60A in most circumstances. I have a 90A alternator, Adverc booster and 660Ah domestic bank, and I rarely see much more than 60A or 70A max charge rate.

A bigger domestic bank will accept charge more readily, thus minimising engine running time and, for a given usage, will have a lower depth of discharge (thus prolonging battery life).

Although I have no experience of it, I think the Sterling Alternator to Battery Charger is a neat idea, especially as it doesn't boost the voltage to the engine start battery. And it includes a diode splitter.

The easiest charging solution for the bowthruster battery is a "shadow charger" type device, such as this one. The big problem with charging remote bowthruster batteries is that when you use the thruster with the engine running (ie most of the time) there can be a big current drawn through the charging cables, which need to be appropriately sized. A shadow charger won't allow a high current to be drawn, so the cables can be lighter.

If I were you, I look at these steps:-
* add 2 or 3 more domestic batteries
* fit a Sterling Alternator to Battery Charger
* fit a shadow charger for the bowthruster battery.

Just what I was looking for. Pretty certain I've seen figures quoting Smart chargers putting 90-110 Ah back into a 400-440Ah sized bank starting around 50-60% discharged.

Always suspicious of data supplied by person selling something. Could you confirm charge level you are starting from though? With a 660Ah domestic bank you might only be discharging 20-30% and keeping batteries near 100% so bulk charge phase might be skipped or be short. That might explain 60-70A max charge. Also, might need to subtact parasitic loads to get alternator output.

I'll look at the shadow charger, not one I'd spotted. Thanks

 

[snooks]

All the local butchers we found around Scotland this year were more than happy to vac pac the meat we bought from them. Mince does tend to turn into a big burger though!

Oban, Gairloch, Lochinver, Stromness, Lossiemouth all have good local butchers, but the odds are they will Vac Pac if you ask them.

We managed without a freezer, but we did eat a lot of Lloyd Grossmans Thai Green Curry and boil in the bag rice!

 

[Amazon8mCat]

Simplest is a 1-2-OFF switch with your brain as controller, next a diode splitter - drops some voltage but your smart charger covers it - and stops one battery discharging into the other, then comes a VSR (voltage sensing relay) that charges one battery first then switches to the other.
I manage quite happily with a 1-2-OFF switch (actually separate switch for each battery), a voltmeter and a smart alternator controller. Boat is on a mooring and, since adding the controller, battery charge has been no problem.

I like that simple solution - for 12 years with just a 20hp outboard engine battery and matched domestic battery we did likewise but with just one switch (1, Both, 2 and Off) to the instrument panel. Now with two inboard engines on a similar boat I am looking for something equally simple. Maybe that's not possible? Any ideas welcome if it would avoid a splitter. Did you use just a 1,2, Off on each battery or was there a Both option? Many thanks for any ideas.

 

[VicS]

Views on alternator to battery charging systems

I am thinking of installing an alternator to battery charger . Has anyone any experience of these?

All the local butchers we found around Scotland this year were more than happy to vac pac the meat we bought from them. Mince does tend to turn into a big burger though!

Oban, Gairloch, Lochinver, Stromness, Lossiemouth all have good local butchers, but the odds are they will Vac Pac if you ask them.

We managed without a freezer, but we did eat a lot of Lloyd Grossmans Thai Green Curry and boil in the bag rice!

Now thats what I call thread drift!

 

[Keith-i]

I've read through the thread but I haven't seen mention of one other alternative to charging up to 3 banks. A MOSFET splitter works very much like a diode splitter but without the voltage loss. I fitted a Stirling Pro Split-R. It will charge all three batteries simultaneously although gives priority to the start battery and isolates all batteries to stop one bank pulling any other bank down. So far so good. No extra load on the alternator and slightly more advanced than a VSR which I previously used until I wanted a third bank in the mix

 

[d4raffy]

I've read through the thread but I haven't seen mention of one other alternative to charging up to 3 banks. A MOSFET splitter works very much like a diode splitter but without the voltage loss. I fitted a Stirling Pro Split-R. It will charge all three batteries simultaneously although gives priority to the start battery and isolates all batteries to stop one bank pulling any other bank down. So far so good. No extra load on the alternator and slightly more advanced than a VSR which I previously used until I wanted a third bank in the mix

I fitted both - an A2B and a MOSFET splitter - all good so far.
The A2B does the Start and splitter. The splitter the House and Thruster.
http://www.cruisersforum.com/forums/f14/alternator-hitachi-to-prestolite-swap-out-130609.html
My Hitachi alt gets hot so adding cooling next

 

[William_H]

At the risk of repeating what has already been said. Firstly what is the OP problem regarding electrical power as peculiar to his personal usage style?
The only prolem a smart charger be it alternator to battery charger or alternator regulator replacement controller is that it will reduce engine run time if engine is run just for battery charging. Either could reduce engine charging time by around 50%.
However if this is what OP does he needs an amp meter to clearly show what charge current he is putting in so he can estimate the worth of fur ther engine running.
He might start at a high charge current into the batteries but this will diminish soon to relatively low current. A smart controller or charger will maintain higher current for longer by charging at a higher voltage.
However higher charge current can be acheived by adding more capacity to domestic bank. The batteries won't be fully charged but the total AH put in and hence available for use later will be more for a given short charge engine run. Plus you might start with fully charged batteries ie from shore power for longer time befre charge needed.
A larger capacity alternator is only needed if your controller and batteries result in a charge rate that is near to the rating of the alternator. The alternator will get hot and have a shorter life. It may become the limiting factor in charge current. However I think for most boats a larger alternator will be the last thing to add and least likely to aid charging.

So to the OP don't rush to change anything unless you know you have a charging problem with your usage style. You don't have to spend lots of cash to have the best just to keep up with modern trends. Strangely around here I have looked at many boats some with 12v refrigeration (surprisingly few considering hot weather we get), I have never actually seen an alternator to battery charger or smart charge controller. The old (originally supplied) charge systems can be quite adequate for most people. good luck olewill