Alternator Problem? Assistance needed

[acdbox]

Hi,

After ages of having charging problems I've hooked up an ammeter to try and find the cause of the issue.

Basically when the engine turns over it's starts off by putting out a high amperage... I spotted 30amps but could have been higher, before beginning to fall rapidly and hits zero with a minute or two.

Voltage is good, and it does put out army good amperage for a few seconds to possibly rule out connections/terminals.

 

There's a split charge replay and I know the leisure is far from flat and I'm pretty sure the starter could have done with at least a good few more minutes charging to be considered full????

So why the drop in charge????

 

I'm going to be installing a sterling regulator and wonder if this should remedy the matter or if anyone might have other inclinations as to the possible cause of the issue?

Oh the leisure is connected via a voltage sense relay.

 

Really appreciate any assistance.

Thanks

Andreas

That should have read the leisure is far from full.

[dmr]

Whats the voltage and where are you measuring it?.

 

Can you measure volts coming from alternator (big fat wire) and volts at batteries please.

 

Do you really mean the amps goes to zero after a minute or two, or is it just a few seconds? Is the fall in amps a slow reduction or does it stop suddenly?

 

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

[acdbox]

Hay DAVE thanks for replying

The voltage was in the high 14.2's on the ammeter whenever I check at the batteries directly it's around .05 less.

It's slightly difficult to measure voltage at alternator but if essential I will find a way.

As stated voltage at batteries when engine on around 14.22.

 

Yes, amps go to zero after a couple minutes but begin to tumble straight away. The fall is gradual in the sense it shows it dropping .01 amps at a time but quick in the sense it goes from 30+ amps to 0 in about 2 minutes.

Thanks again

[Paul C]

Read the voltages at the battery terminals - what's the voltage at BOTH the starter battery and the domestic battery bank?

 

Also....how are you measuring the amps?

 

I am wondering if its dropping quickly because its only charging the starter battery, which sounds like its in good condition and its possible that starting doesn't consume the amount of energy you think it does. I'd expect the domestic bank to be a bit lower state of charge than the starter battery and demand a few more amps than nothing.

[Loafer]

Hay DAVE thanks for replying

The voltage was in the high 14.2's on the ammeter whenever I check at the batteries directly it's around .05 less.

It's slightly difficult to measure voltage at alternator but if essential I will find a way.

As stated voltage at batteries when engine on around 14.22.

 

Yes, amps go to zero after a couple minutes but begin to tumble straight away. The fall is gradual in the sense it shows it dropping .01 amps at a time but quick in the sense it goes from 30+ amps to 0 in about 2 minutes.

Thanks again

 

I'll assume you meant 'on the voltmeter' not the ammeter.

 

It sounds to me like you're either close to fully charged anyway, or your batteries are shot. If they're 'shot', they'll behave like a much smaller battery and seem to charge very quickly.

 

That seems to be happening to your system.

 

What size are your batteries? How many of them are there? How old are they? How have they been treated?

 

Answers to the above would be more helpful to dead clever members here.

14.22V at batteries, with engine running, sounds a bit low, almost as if there's a resistive connection somewhere, or a diode in the alternator output cable.

 

Are you sure that your 'split charge replay' is actually a 'relay' and not a 'split charge diode'? That would account for a reduction in charge voltage down to 14.2.

 

Edited to add: I'm happy to be corrected here. I am three sheets to the wind and a bit squiffy after an excellent lunch.

Edited February 7, 2016 by Loafer

[acdbox]

Hi Paul,

Voltage at the batteries is around 14.2 when engine is running measured by a portable multimeter.

The amps are measured by an ammeter.

The starter is very new though has suffered from going flat already.

I would have assumed the starter would have been close to full already had it not taken me a few attempts to get her started.... At an assumption I would have thought she would have needed a charge beyond a few minutes to get her topped up once more?

 

Loafer, the ammeter is a battery monitor so displays voltage too. The leisure is a little worse for wear, but think it's got a bit more life in it.... As long as it gets some charge in it otherwise it will be going the way you say. It's also just the single leisure bat.

There's also solar going into the leisure... Whatever may be going in this time of year? Definitely not enough to be keeping them full.

 

No diode... Definetly a voltage sensing relay not diode.

 

again, any insight very much appreciated.

[WotEver]

If the voltage is remaining at 14.2V when the ammeter is showing 0A then I suspect that the ammeter is telling lies.

 

Either that or both batteries are full, which you feel is unlikely.

 

Whereabouts is the shunt for the ammeter wired?

 

Tony

[mickp]

Solar has been very good ish today and may have charged the battery if you have only one

[acdbox]

Hay Tony...

The Shunt is right before the battery on the negative cable.

Ok, will have to do a manual test so to speak and give the batteries a good charge and monitor the voltage after if

It reflects a battery with charge or not?

[acdbox]

Hay Mickp, I have a solar setup 260w MPPT, but my leisure was knocking on 50% this morning.... Can believe my starter was topped up Just not my leisure... Or maybe it's what loafer says and they're just not holding charge? Will have to test to find out.

 

Coming back to sterling external regulators, does anyone have any experience to know if this could also solve a matter like this?

[mickp]

With the engine running and no amps turn somthinking on a bit juicy and see if it goes up or goes into neg amps

[Loafer]

Hay Tony...

The Shunt is right before the battery on the negative cable.

Ok, will have to do a manual test so to speak and give the batteries a good charge and monitor the voltage after if

It reflects a battery with charge or not?

 

I'm not quite sure what you're asking there, but but if you are monitoring ANYTHING during charge, you need a charge voltage of 14.8V for (wet-cell batteries) for about 2 hours to get near to 100% charge, and charging current then should be down to 1% of your battery bank total capacity as it is NOW. Unlikely to be as it was when your batteries were 'new'.

[acdbox]

Ok will have to test tomorrow, as its late for the neighbours to run it now. Will report the findings tomorrow

[Paul C]

What kind of battery monitor, does it monitor both battery banks and can it store the lowest recorded voltage of the starter battery? (A BMV702 can)

 

Other than that, you could try measure the starter battery voltage during starting, or just "listen" to the starting to see if the engine spins nicely or whether it appears sluggish etc.

 

Another option might be to do a traditional "load test" - a very basic test which puts a large load on the starter battery and measures the voltage for a piece of time - to assess its condition.

[Loafer]

Regarding alternator 'boosters', I would avoid them unless you live off-grid and never go anywhere, in your boat.

 

They are useless if you cruise regularly. They're good at trying to charge quickly, but they can also be the cause of alternator failures (by providing high currents for longer).

 

I've had them, and removed them, and added them back again, and then removed them. No real difference with continuous cruising, and definitely not required if you spend most of your time connected to a shore power source.

 

Most boat engineers poo-poo them, unless they're selling them in their shops.

[acdbox]

I'm not quite sure what you're asking there, but but if you are monitoring ANYTHING during charge, you need a charge voltage of 14.8V for (wet-cell batteries) for about 2 hours to get near to 100% charge, and charging current then should be down to 1% of your battery bank total capacity as it is NOW. Unlikely to be as it was when your batteries were 'new'.

To isolate if the fault is with the ammeter not picking up the charge, to run the engine for 1-2 hours so theoretically even if not full it would have had a decent amount of amps go in and by keeping an eye on voltage drop after over a period of time to see if the battery behaves like it has taken a charge even though the ammeter hasn't registered it? Hope that makes sense?

[Loafer]

To isolate if the fault is with the ammeter not picking up the charge, to run the engine for 1-2 hours so theoretically even if not full it would have had a decent amount of amps go in and by keeping an eye on voltage drop after over a period of time to see if the battery behaves like it has taken a charge even though the ammeter hasn't registered it? Hope that makes sense?

 

It makes sense, but isn't necessarily good practise.

 

Quick example: If you had a 500 amp-hour (Ah) battery bank, and you take half of that out (250Ah) over a couple of days, it will take at least 8 hours of charging to have any hope of putting it all back. At LEAST 8 hrs.

 

Similarly, if you have a 100Ah bank, and take out 50Ah, it will STILL take 8 hrs to put that back to full charge.

 

I THINK I'm right in saying that - but wait for Nicknorman, Wotever, dmr, bottle, PaulC etc, (apologies for those wise men whom I've forgotten to mention) to add their more knowledgeable opinions.

[acdbox]

Regarding alternator 'boosters', I would avoid them unless you live off-grid and never go anywhere, in your boat.

 

They are useless if you cruise regularly. They're good at trying to charge quickly, but they can also be the cause of alternator failures (by providing high currents for longer).

 

I've had them, and removed them, and added them back again, and then removed them. No real difference with continuous cruising, and definitely not required if you spend most of your time connected to a shore power source.

 

Most boat engineers poo-poo them, unless they're selling them in their shops.

Oh... Sounds like the hope of the external regulator helping resolve the matter maybe a miss.

Yeah I'm a cc'er and reckon if my70amp put out 70aamps to the batteries things would be smooth sailing or should I say cruising? Just haven't had that joy since I've had the boat.

 

And Paul, just a basic shunt based battery monitor currently have one mostly connected to the leisure and swap it over to check the starter... Have another waiting to be installed so can monitor both simultaneously. That monitor you have sounds impressive, may have to aim for one, one day. The voltage of the starter/leisure tend to be the same due to the voltage sense relay having been at play with solar in the day for when I get home. Until the leisure gets put under a little load and starts to drop to reveal where it's really at.

Always shows 12.7ish maybe more until a loads put on, quickly levels out.

[Loafer]

Keeping an eye on voltage drop during discharge is exactly what Merlin's SmartGauge does. With time and attention, you can judge that for yourself, as I do.

 

Don't ever let them go below 12.0V with the telly on, or 12.2V with NO load for a few hours.

 

12.2V rested voltage is a generally-accepted '50%' state of charge (SOC).

[acdbox]

Sorry yeah, the starters a 70ah and the leisure a 110ah. Don't understand the mathematics on that one loafer but don't discredit your workings...

[Loafer]

Sorry yeah, the starters a 70ah and the leisure a 110ah. Don't understand the mathematics on that one loafer but don't discredit your workings...

 

Forget your starter battery, if it starts your engine ok. It'll generally stay at a good SOC.

 

One single 110Ah battery is a very small bank indeed. It is probably down to half that now, if it's a cheap one more than 12 months old.

 

That battery will charge in no time, and be flat again in no time.

 

It sounds to me like you have a duff leisure battery, and the reason it's duff - probably undercharging over a long term.

 

If your charger is capable, then increase the charging voltage to 15.5 or so for a couple of hours, but with ALL your circuits isolated. Some stuff won't like 15.5 volts, but your battery might like it.

 

Be sure to check the electrolyte level too.

 

If your leisure battery is sealed, so that you can't take the top caps off, then don't do the 15.5V charge. That's only for batteries where you can add distilled water to make up the loss of fluid caused by high volt charging.

Boys, I need some verification here. I don't want to be the only one advising acdbox!

[acdbox]

Thanks Loafer, gotten do some testing. Like said... Appreciate your input and everyone too. Will come back with news in few days.

Andreas

[Loafer]

Thanks Loafer, gotten do some testing. Like said... Appreciate your input and everyone too. Will come back with news in few days.

Andreas

 

If you don't get the 'Battery Masters' on here soon, then please PM me in a few days' time, in case your thread has gone to about page 4 and I miss it! I am keen to help where possible, as long as it doesn't go much beyond 2+2=4!

Edit: Don't ask Nicknorman what 2+2 is. He might tell you it's 11! (True, to base '4'!)

[smileypete]

Sounds like the existing leisure batt has lost capacity...

 

How old is it and is a sealed type? They sometimes don't do so well on slightly lower charge voltages and liveaboard (ab)use.

 

If getting another batt, look for a non sealed one. Also can the make and model of the alternator be determined? It might be possible to source a higher voltage internal regulator for it which should be cheaper than a sterling external regulator.

[Iain_S]

 

(snip)

Edit: Don't ask Nicknorman what 2+2 is. He might tell you it's 11! (True, to base '4'!)

 

10, shirley