Alternator Regulator

[amarf]

Hi,
I have 200ah service bank charged by 80A yanmar/hitachi alternator. I'm looking for smart multi stage charging, and I found this ctek 250 s dual smart charger http://www.ctekbatterychargers.com.a...250s-dual.html

Ctek claims that this is state of the art regulator but I'm worring about 20A limit since when batteries are empty my alternator should deliver Munch more, at leaset in theory.

Any inputs?

[djmarchand]

That CTEK device is essentially a charge controller like you would use with a solar panel. It accepts DC from multiple sources but only delivers 20 amps to the batteries.

Your Yanmar alternator has a simple internal regulator that regulates to a fixed voltage of about 13.5 V. At that voltage you don't need the CTEK device.

What you probably need if you are looking at charging faster from your alternator, is one with an external multistep regulator. That is not what the CTEK device is. Balmar and Ample Power make external regulators, but you will have to either modify your Yanmar alternator to have to proper connections or buy a high output alternator (from Balmar or others) which has them.

A good high output alternator and external regulator will charge at about 100 amps when the battery is near empty.

David

[amarf]

Thanks, it clears things a bit.... I guess that is the same situation with Sterlings BtoB 50A ?

[barnakiel]

There are also fine Sterling multi-stage regulators that do not require cutting into the alternator. Have a look at the red models.

Sterling Power Products: Alternator to Battery Charger

They deliver 80 or 130 amps. Separate start bat output. Digital remote panel etc. as optional extras. We had the 80 model on one of the boats I sailed last year. It did great job.

b.

[djmarchand]

That Sterling device is just a dual output charge controller. It converts the alternator's standard voltage to something different before it goes to the batteries. This tricks the alternator to put out more current by presenting a lower impedence load than the batteries otherwise would do.

The better way to affect an alternator's output is to change its field current. The standard Yanmar alternator (made by Hitachi) has an internal regulator, so it is not possible without modifications to bypass that regulator. You can have an alternator shop take it apart, snip the internal regulator wire and bring the field current wire out the back so that it can be connected to an external regulator. If you do that it will charge much faster because the output voltage will rise above 13.5 to keep the current flowing to the batteries.

But a better, but more expensive way is to buy a high output alternator. These have heavier windings and better cooling to deal with the high current output.

David

[amarf]

Hi David,

I'm aware of my options, however sterling and CTEK's have those dual charger controller and they claim that these are brand new technology and that they work very good. I'm trying to find a solution to optimize and shorten charging of my service bank (200aH) with 80A alternator, so the question is if they would do the job or is it waist of money?

[barnakiel]

Originally Posted by djmarchand

That Sterling device is just a dual output charge controller. It converts the alternator's standard voltage to something different before it goes to the batteries. This tricks the alternator to put out more current by presenting a lower impedence load than the batteries otherwise would do.

(1) The better way to affect an alternator's output is to change its field current. (...)

(2) But a better, but more expensive way is to buy a high output alternator.(...)

David

David,

Re (2) above: the OP has 80 A alt on 200 Ah bank. Not likely to need a high(-er) output alt unless there are any extra loads involved.

Re (1) : yes, it is a neat way - probably less loses too. The Sterling way is way simpler to install though - two wires in, two wires out, no changes to the alt.

Otherwise re CTEK : I would be careful and buy one only after I see their unit doing what is advertised. My attitude here is driven by using a 'top-new-technology' blahblahblah CTEK charger this summer. We found it to be IDENTICAL (sic) with a BILTEMA (cheap car-bike unit). It also took the same amt of time to charge the battery ... So, I say pay for CTEK only if you are damn sure you are not buying a re-branded, ordinary thing.

Cheers,
b.

[belizesailor]

Originally Posted by djmarchand

...

What you probably need if you are looking at charging faster from your alternator, is one with an external multistep regulator. That is not what the CTEK device is. Balmar and Ample Power make external regulators, but you will have to either modify your Yanmar alternator to have to proper connections or buy a high output alternator (from Balmar or others) which has them....

I've used a couple of generations of the Ample Power Next Step regulators. Good product. Technically one of the best external multi-step regulators on the market. Supports lots of different installation configurations/options. Good support too.

If you choose to go with a Next Step then be aware that there are a number of different options which can be factory installed/configured. Be sure and talk to them before you order and get their recommendation on the configuration to order.

[btrayfors]

amarf,

You've got several answers from well-intentioned folks, but you failed to provide enough information to start with to allow a proper response.

What type of battery bank do you have? Flooded? AGM? Gelled?

That's a critical point to know.

Bill

[djmarchand]

b. has got my curiosity piqued. If anyone has one of the Sterling charge controllers, could you post your experiences.

I would be particularly interested in:

1. Type of engine alternator it is installed with.
2. Current that the alternator puts out into 25% discharged batteries. Also type and capacity of battery bank.

FWIW a Yanmar 80 amp alternator will only output about 20 amps into a 25% discharged 440 AH flooded cell bank.

David

[amarf]

Bill,

I have two 100 ah closed batteries,(ordinary flooded bat) calcium+ somthing, they are two years old...my 80A alternator is powered by 2gm20 yanmar, which is also the only source of power, no solar/wind. My boat is in Greece and I motor quilte a lot on calm days, so I'm interested to top up battery bank while motoring, but also on hook, when I need electricity.

[btrayfors]

Originally Posted by djmarchand

b. has got my curiosity piqued. If anyone has one of the Sterling charge controllers, could you post your experiences.

I would be particularly interested in:

1. Type of engine alternator it is installed with.
2. Current that the alternator puts out into 25% discharged batteries. Also type and capacity of battery bank.

FWIW a Yanmar 80 amp alternator will only output about 20 amps into a 25% discharged 440 AH flooded cell bank.

David

David,

There are a number of factors which in combination determine how many amps a given battery bank will accept, including:

- state of charge (SOC);
- type and chemistry of batteries;
- type and condition of jumpers and connectors;
- battery balancing condition (are cables connected in right place?);
- age and condition of batteries;
- temperature;
- capacity of charging source;
- size and condition of charging cables (both positive and negative); and
- voltages at charging source and at battery bank.

Other things being equal, by far the most important of these is the voltage level at the battery bank.

I would expect a 440AH flooded battery bank @75% SOC to accept way more than 20 amps, provided the charging voltage were high enough (i.e., 14.8VDC). At lower voltages, the battery bank would accept less amperage.

Do you know what the voltage at the battery bank is when you are reading only 20A from that 80A alternator?

Bill

[btrayfors]

Originally Posted by amarf

Bill,

I have two 100 ah closed batteries,(ordinary flooded bat) calcium+ somthing, they are two years old...my 80A alternator is powered by 2gm20 yanmar, which is also the only source of power, no solar/wind. My boat is in Greece and I motor quilte a lot on calm days, so I'm interested to top up battery bank while motoring, but also on hook, when I need electricity.

David,

OK, one would expect your 200AH flooded battery bank to accept a maximum of 50A even when severely depleted.

So, your 80A alternator is more than capable of outputting that much amperage.

As the battery's SOC rises, they will accept less amperage and when they get to 80-85% SOC they'll accept much less amperage. And, above 80-85% SOC the charge efficiency goes way down, so that it will take a minimum of 25% extra AH to charge them all the way to 100%. That will take a long time, no matter the size of the charger/alternator.

Given your situation, you might be better off increasing the capacity of your battery bank rather than worrying about additions to your existing alternator setup.

First thing to do, though, is to investigate what's going on with the charging next time you're aboard. Be sure to have on hand a good digital multimeter and, if possible, a decent clamp-on DC ammeter. With these two instruments you can tell rather precisely what your alternator output really is at varying states of charge.

Bill

[amarf]

Sounds reasnoble, thank you fornyour help...I was just investigating if there are any smart solutions around in ordre to optimize charging, Without to much hastle...Anyway

[amarf]

By the way, I have a battery monitor installed with a shunt, so i Can see what is going in and out. What would those 200 ah batteries should accept at 50% discharge