Mastervolt Woes

[Greg Garrard]

Hi CBW users,

I have a Mastervolt Dakar Combi 2500/12V hooked up to five 135Ah deep cycle batteries. The whole kit and kaboodle is left connected to shore power 24/7, and used only when I take the boat out to Bath or Bristol, which is probably 2-4 times a year for no more than a day or two.

 

When I first got the boat, I didn't understand about batteries and so I ran them down accidentally on several occasions. I also found that the control panel showed a continuous decline from 100% even with AC attached - but after reading the Combi manual for about a day and making my brain hurt, I found a parameter I could change that stopped the number dropping all the time (but I can't remember what the parameter / value was - didn't write it down, doh). After having the boat for three years, I figured it was time to replace the batteries as they were giving well under 24 hours even if I 'powered down' (switched off everything bar the fridge). So I got a new set, took the old lot out - and found that the latter would hold a good charge anyhow. By then I'd already switched the very heavy batteries and was miles from the place I bought the new ones, and decided to sell on the old ones for a few quid, leaving the smart new ones in place.

 

When I put the new batteries in, the Combi reset itself, so the old problem of the % remaining value falling came back. Thinking it was only an irritation (after all, the charging V values on the control panel were all to spec) I didn't do anything about it. But now, after only two years, no deep discharges and (at a guess) no more than ten days total running on batteries, they seem to be near death again! I tested them, as per the manual, by disconnecting AC and leaving only a light on to check the real charge capacity. It was about 130Ah! So I tried disconnecting the batteries and recharging them individually with a car battery charger, but it quickly told me they were fully charged. I tried refilling them with distilled water, but they weren't depleted. And the little charge indicator on each one is either green (fine) or clear (ok).

 

Now, on a trip to Bath, with the fridge running, the AC started tripping out (10.5V or thereabouts) after only 70Ah!!! Where's my battery capacity going? Any idea how I should reset my Mastervolt so the % doesn't drop? Are these problems related?

Thanks,

Greg

[WotEver]

If the combi is fully functional and correctly wired then you should see no charge drop while connected to shore power. Quite the opposite - the Dakar should be continually charging the batteries and keeping them in tip-top condition.

 

So, either it's broken, or it's wired up incorrectly (can't imagine how), or the battery charger setting has been disabled. I think you need a decent boat electrician to tell you which one, although a read through the manual should assist you in confirming that the charger is enabled.

 

Tony

[Guest]

If the combi is fully functional and correctly wired then you should see no charge drop while connected to shore power. Quite the opposite - the Dakar should be continually charging the batteries and keeping them in tip-top condition.

 

So, either it's broken, or it's wired up incorrectly (can't imagine how), or the battery charger setting has been disabled. I think you need a decent boat electrician to tell you which one, although a read through the manual should assist you in confirming that the charger is enabled.

 

Tony

 

Bearing in mind as I have said on here before trying to understand the manual that comes with a Mastervolt product is akin to understanding the one that comes with a nuclear power station...

[WotEver]

Fairy Nuff. The manual is here and I do note that it shows the option of battery sensing (which may or may not be wired) and battery temperature sensing (which may or may not be wired and even if it is, it may or may not be faulty).

 

So I'll go back to my original advice of getting it looked at by a competant boat electrician.

 

Tony

 

Figure 3.4.1 in that manual shows the various Status LEDs - what are they doing?

 

Specifically, is LED #6 lit?

[by'eck]

Charge-efficiency-factor (CEF) is the parameter that most affects the accuracy of shunt driven battery monitors, which I believe the Mastervolt system uses. Its usually programmed in to the monitor & set to around 90% with new batteries. This means that they will require approx 10% more power put back into them compared with that taken out to reach a 100% state-of-charge (SOC). As they get older they will require more power to replace whats taken out, so the CEF will need to be programmed in at a lower value to maintain some degree of SOC accuracy.

 

Despite the above, if the monitor never reaches 100% SOC when on shore power 24/7 then something is amiss. It may be that the charge current is somehow not registering through the shunt, only discharge current. This would be likely caused by incorrect wiring. Note that the battery colour indicators although only crude devices, should always indicate green when charged, although they may need to be shaken to give a true indication.

 

From your problem description it appears you may have a more general charging issue as well. Does the low battery situation only occur when you go cruising? If so is the engine alternator working? It may be the charger if it happens when not cruising.

Edited August 31, 2011 by richardhula

[WotEver]

From your description of the problem it appears you may have a more general charging issue as well though. Does the low battery situation only occur when you go cruising?

Not according to the OP:

I also found that the control panel showed a continuous decline from 100% even with AC attached

 

That says to me that the charger ain't working.

 

Tony

[Keith M]

Hi CBW users,

I have a Mastervolt Dakar Combi 2500/12V hooked up to five 135Ah deep cycle batteries. The whole kit and kaboodle is left connected to shore power 24/7, and used only when I take the boat out to Bath or Bristol, which is probably 2-4 times a year for no more than a day or two.

 

When I first got the boat, I didn't understand about batteries and so I ran them down accidentally on several occasions. I also found that the control panel showed a continuous decline from 100% even with AC attached - but after reading the Combi manual for about a day and making my brain hurt, I found a parameter I could change that stopped the number dropping all the time (but I can't remember what the parameter / value was - didn't write it down, doh). After having the boat for three years, I figured it was time to replace the batteries as they were giving well under 24 hours even if I 'powered down' (switched off everything bar the fridge). So I got a new set, took the old lot out - and found that the latter would hold a good charge anyhow. By then I'd already switched the very heavy batteries and was miles from the place I bought the new ones, and decided to sell on the old ones for a few quid, leaving the smart new ones in place.

 

When I put the new batteries in, the Combi reset itself, so the old problem of the % remaining value falling came back. Thinking it was only an irritation (after all, the charging V values on the control panel were all to spec) I didn't do anything about it. But now, after only two years, no deep discharges and (at a guess) no more than ten days total running on batteries, they seem to be near death again! I tested them, as per the manual, by disconnecting AC and leaving only a light on to check the real charge capacity. It was about 130Ah! So I tried disconnecting the batteries and recharging them individually with a car battery charger, but it quickly told me they were fully charged. I tried refilling them with distilled water, but they weren't depleted. And the little charge indicator on each one is either green (fine) or clear (ok).

 

Now, on a trip to Bath, with the fridge running, the AC started tripping out (10.5V or thereabouts) after only 70Ah!!! Where's my battery capacity going? Any idea how I should reset my Mastervolt so the % doesn't drop? Are these problems related?

Thanks,

Greg

[Keith M]

Hi Greg,

 

I am assuming that you have a CSCP panel.

When the batteries were replaced the panel would have gone back to factory default, which means that the CSCP is now set for AGM or Gel batteries.

Is the battery capacity still correct

The CEF should be set to 90% as stated early.But if I read your OP correctly this set of batteries are over 2 years old.

And the float voltage needs to set at 13.2 volts.

 

Hopeful the batteries have been crossed wired.

If you require any more help please send me a PM

 

Sorry about the above posting hit the wrong button.

 

Keith

[nb Innisfree]

Remember only a Smartgauge will give accurate Percentage readings, ignore this particular reading on shunt based monitors.

[Gibbo]

It really does sound to me like the charger isn't doing anything.

[Greg Garrard]

Thanks for your posts!

 

I can rule out the charger not working at all. The unit goes through its regular bulk/absorption/float cycle fine (LEDs and on the CSCP), and the right voltages are reported for each phase. Unfortunately my multimeter doesn't give an accurate enough V figure to independently corroborate the CSCP, but it looks a bit *lower* than 14V. However, the batteries are fizzing properly. Oddly, though, the analogue voltmeter on the 12V board shows just *under* 14V (14.25V on the CSCP), whereas it shows the same level there as for the starter battery. I've had it from new for six years, too, so is it possible there has been a basic wiring mistake all this time?

 

Perhaps the CSCP is getting an inaccurate voltage reading all the time, and so shifting charge phase before the batteries are charged. I'll get an accurate multimeter and check that asap. Any other way of checking whether the Combi is getting accurate charge info? (And furthermore: why might the CSCP volt reading be *higher* than the real figure?)

 

According to the CSCP manual, the unit should set its own CEF 'after a number of cycles', but there is also a parameter which is 'set level full charge' which is 80% of C AHr (programmed total useable capacity, I think) by default. I presume that's related?

 

I reset the battery capacity to 135AHr after I tested it using a small voltage lamp as per my OP. The only other parameter I could usefully mess with would be return amps (default 6% of C AHr) and charge voltage (default 14.25V). I think it was probably one of these I changed, which stopped the CSCP readout dropping gradually a couple of years ago.

 

There is also an 'advanced' option to set the CEF manually between 70 and 99, but I'd need to know that value accurately first, and I have no idea where to start.

 

Keep the suggestions flowing!

Cheers,

Greg

[Greg Garrard]

I haven't been able to check that the voltages on the CSCP correspond to those on the batteries - borrowing a digital multimeter tomorrow - but I'll check those, verify the mV reading across the shunt (once I find it!) and also check voltage drops throughout the system asap.

 

Right now the Mastervolt has switched into Float mode (13.20V on the screen) and is reporting *discharge* amps of about 2-4A all the time. Why (apart from possibly also getting the wrong current reading from the shunt) could this be?

 

I've set the capacity to 190 AHr, on the basis of the 35% useable capacity advised in the CSCP manual. The float charge is set to 13.25V, although that's not what's showing on the screen right now (see above). I've also set the Charged current % (parameter A04 - confusingly also referred to as 'return Amps') from the default 2 to 3.8 (because 3.8 is 2% of 190....) but I think this might be wrong. It's meant to be 'the current accepted by the full battery as a % of the declared battery capacity', but I have no idea what that means. The manual promises to reveal the ideal values in chapter 5, but never mentions it again. Any insights?

 

And finally there's that 'set level full charge' parameter (70-90%, def 80%) which sounds like it might be similar to CEF, but who knows...

All thoughts and suggestions gratefully received.

Greg

[WotEver]

All thoughts and suggestions gratefully received.

As has been previously mentioned, your CSCP will tell you lies about the batteries' SoC. You can optimise the settings so that the lies are smaller, but it will never be accurate for longer than a day. A Smartgauge will tell you the truth. Although the current model won't tell you what the total capacity of your bank is, it will at least tell you how charged it is as a percentage of its current capacity, and allow you to see how that charge depletes over time.

 

The constant 2-4A draw could well be the fridge.

 

Tony

Edited September 1, 2011 by WotEver

[Greg Garrard]

As has been previously mentioned, your CSCP will tell you lies about the batteries' SoC. You can optimise the settings so that the lies are smaller, but it will never be accurate for longer than a day. A Smartgauge will tell you the truth. Although the current model won't tell you what the total capacity of your bank is, it will at least tell you how charged it is as a percentage of its current capacity, and allow you to see how that charge depletes over time.

 

The constant 2-4A draw could well be the fridge.

 

Tony

 

Thanks Tony. The Smartgauge looks amazing, but I'm not too concerned about getting precise % charge values (and can't afford £160).

 

The important thing is that it's the CSCP that actually controls the charge profile on the Mastervolt, so if either (1) the shunt setup is giving the wrong V values or (2) the CSCP parameters I mentioned are badly wrong, the batteries will drain down continuously so that when I go away from shore power (as I just did) they'll *start out* with almost nothing in them. I'll look into (1) myself, but I'd appreciate advice about (2). [NB as of this morning with the new settings, Float V seems to have stabilised at 13.25, and SoC is not dropping. Maybe I did something right?]

Greg

[nb Innisfree]

Tony said the Smartgauge will tell the truth but actually it doesn't, what it does is make a guess as shunt monitors do but instead of that guess getting more inaccurate as time goes on the SG's guesses get more accurate with time until they are very near the truth,much more truthful than anything else.

 

Trying to set up a shunt based monitor to give accurate percentage readings is an impossible task as the parameters keep shifting, good to do though as it acts as a sort of training gadget to help you understand batteries and charging/discharging.

[Gibbo]

This is going to be a long one because I feel we are missing some vital piece of information.

 

Anyhoo, let's deal with this bit first...

 

The important thing is that it's the CSCP that actually controls the charge profile on the Mastervolt, so if either (1) the shunt setup is giving the wrong V values or (2) the CSCP parameters I mentioned are badly wrong

 

This isn't correct.

 

The CSCP is two completely separate, distinct, devices that just happen to be in the same box.

 

It is a remote control for the Dakar and it is a battery monitor. The two functions are completely independent and (with a few irrelevant minor exceptions) they do not cross over.

 

The CSCP can be used to tell the Dakar what type of batteries are being used, to set the charge current limit, to switch the inverter and charger on and off etc. None of these functions rely on the battery data from the CSCP.

 

Once CSCP has told the Dakar what type of batteries are being used, what the charge current limit is etc, the Dakar deals with the current and voltage on its own. It is not instructed by the CSCP. Incorrect voltage measurements by CSCP, or incorrect current measurements will not affect what the Dakar charger is doing. They are dealt with completely seperately. All it will do is give the operator incorrect information. But the Dakar will continue to operate correctly. That is to say, if the monitor side of the CSCP (incorrectly) decides the batteries are fully charged this will not shut the charger off, or put it into float. The Dakar decides that for itself. And it uses a very simple algorithm for doing so which, effectively, is fool proof. It will not do the wrong thing just because the monitor is doing silly things.

 

The only setting which could be causing an issue is if the charger limit has been set so low that the charger simply cannot keep up with the DC loads which will result in a continual reduction in SoC. But that can't apply because OP says the voltage was up at around 14 volts whilst on charge. It would not have been if this was the case.

 

Now back to the first post.

 

You state that even plugged into AC the indicated SoC continued to fall. This could mean one of two things. Either:-

 

1. The actual SoC really was falling...

 

OR

 

2. The indicated SoC was falling but the real SoC was not.

 

If 1. applies then either the charger is broke, it was switched off, or the current limit is set too low and it cannot keep up with the DC loads (see above - this can't be the case). No other explanation is possible. It is that straightforward.

 

If 2. applies then there is something wrong with the installation. Maybe the shunt is incorrectly wired. This is an extremely common occurence with this type of monitor. In fact, from my experience in the field I reckon about 90% of them are installed incorrectly. Yes, that includes those installed by "professionals".

 

However, there is clearly something else going because not only does the battery monitor show the SOC falling at an alarming rate (when it should not be), the batteries themselves are massively underperforming in that after only 70Ahrs removed, they were at 10.5 volts.

 

As I said earlier, I believe we are missing some vital piece of information.

 

If absolutely everything that OP says is absolutely correct, then we need to have another loook at the laws of physics because this is actually impossible.

 

What has been missed? I am absolutely 100% certain that something has. That isn't me clutching at straws, that is me being utterly 100% certain that the description of the problem is wrong somwhere. It may be something that OP considers unimportant so it hasn't been mentioned. But some vital piece of info is not being given here and until we get it, the whole problem is pure guesswork, which is a sure road to get absolutely nowhere.

[WotEver]

The important thing is that it's the CSCP that actually controls the charge profile on the Mastervolt, so if either (1) the shunt setup is giving the wrong V values or (2) the CSCP parameters I mentioned are badly wrong, the batteries will drain down continuously...

This is the bit that I'm not understanding at all.

 

As far as I can make out, the charging settings on the CSCP set the float charge voltage, absorption charge voltage, absorption time, and maximum Charge current. Whilst wildy wrong settings could damage your batteries or cause them to charge slowly, none of those settings would allow the batteries to drain; the float voltage would ensure that didn't happen.

 

I'm confused.

 

Tony

 

ETA cross-posted with Gibbo

Edited September 1, 2011 by WotEver

[Gibbo]

Right now the Mastervolt has switched into Float mode (13.20V on the screen) and is reporting *discharge* amps of about 2-4A all the time. Why (apart from possibly also getting the wrong current reading from the shunt) could this be?

 

Here's part of your problem. If the batteries are being floated at 13.2 volts, and the meter is showing a 2-4A discharge all the time then either the meter is faulty or the shunt is incorrectly wired (the latter would be my guess). With the batteries on float at 13.2 volts there should be no discharge showing whatsoever. No matter what loads are switched on. This is an absolute certaintly. 100%

 

Though I should add that if it's showing 2-4A discharge just for an hour or so after it switches from acceptance/absorption to float this could be perfectly normal. But not if it's showing it "all the time".

 

I've set the capacity to 190 AHr, on the basis of the 35% useable capacity advised in the CSCP manual.

 

This is incorrect. The capacity should be set to the actual capacity of the batteries, not the capacity that you intend to use. If you want the SoC% to read down to a certain capacity (say you want it to read 0% when the batteries get down to (say) minus 200Ahrs) you use function M02 - discharge floor. M02 also affects time remaining in the correct manner.

 

The float charge is set to 13.25V, although that's not what's showing on the screen right now (see above).

 

It's close enough. Well withthin the expected error.

 

I've also set the Charged current % (parameter A04 - confusingly also referred to as 'return Amps') from the default 2 to 3.8 (because 3.8 is 2% of 190....) but I think this might be wrong. It's meant to be 'the current accepted by the full battery as a % of the declared battery capacity', but I have no idea what that means. The manual promises to reveal the ideal values in chapter 5, but never mentions it again. Any insights?

 

It's one of the functions the battery monitor side uses to make the decision that the batteries are fully charged. If the charge current is below the return amps and the battery voltage is above the "charged voltage" and all the removed amp hours have been returned and these conditions remain met for five minutes, the monitor resets the amp hour counter to zero. The idea of this is that if these conditions are all met, then the batteries must be fully charged. No other condition exists that would meet these parameters.

 

(You're right, it is a silly phrase - return amps is used by everyone else to mean something completely different - Mastervolt have a habit of doing this - look what they mean by equalisation - then look what almost everyone else means by it).

 

And finally there's that 'set level full charge' parameter (70-90%, def 80%) which sounds like it might be similar to CEF, but who knows...

All thoughts and suggestions gratefully received.

 

That setting is just for the low SoC alarm. If this alarm triggers, when you later start to recharge, the alarm will "detrigger" when the "full charge" setting is reached.

[Greg Garrard]

Thanks for your helpful replies. I've now checked the battery voltages and the CSCP voltages - they're the same to within 0.01V. I've also checked that the shunt mV value is 10% of the CSCP amp value (as per Mastervolt instructions), and that's fine too. I've also reset the battery capacity for the real 550AHr and changed the discharge floor to 50% (its highest possible value). So...

 

With the CSCP showing 13.25V-ish and all AC stuff running directly off the mains (the Dakar just feeds it through when it's plugged in, yes?), the charge level still seems to be dropping - perhaps more slowly than before. I can't tell from your replies whether the CSCP has *no* effect on the Dakar's charger, or only a minimal effect. There are just two parameters that *might* have some effect: A05, the float V, and A04, the return amps. The MV manual is ambiguous regarding the first of these (in one place it says the ideal value is 13.25V, but elsewhere 13.5V - I've set it for 13.6V to see if that helps).

 

Gibbo has helped me understand the second of these a bit better, but how do I know the right value? Increasing it from 2 to 3.8 *seemed* to help, but was a random value, more or less. I'm pretty certain that it was changing this value, years ago, that stopped the charge level dropping, so I'd like to get it right.

 

BTW, I was also working on the Eberspacher at the same time (the actual bane of my existence), and noticed, not for the first time, that when it's running, the batteries start to charge - presumably to compensate for the DC drain. But the charge level seems to end up *higher* overall than when I started running the heater. I had thought maybe the warmth given off by the heater was helping the batteries charge, but that can't be right because it's not *&*^^%*(^ working (again).

 

Also Tony - I can't control absorption charge V or time, only float level V and 'return amps'.

Cheers,

Greg

[ditchcrawler]

 

BTW, I was also working on the Eberspacher at the same time (the actual bane of my existence), and noticed, not for the first time, that when it's running, the batteries start to charge - presumably to compensate for the DC drain. But the charge level seems to end up *higher* overall than when I started running the heater. I had thought maybe the warmth given off by the heater was helping the batteries charge, but that can't be right because it's not *&*^^%*(^ working (again).

 

Also Tony - I can't control absorption charge V or time, only float level V and 'return amps'.

Cheers,

Greg

Is the shunt connected up back to front, IE Showing discharge while charging and then the high load of the eby starting showing as a charge and not discharge

[Gibbo]

Right, your latest post now gives the missing information that we needed.

 

Your shunt is (not might be, but is) wired up wrong. Absolute certainty.

 

See here...

 

 

I guarantee your shunt is not wired up like that.

 

PS. The MV manual is terrible. The float level is nothing to do with the charger. It doesn't affect it in anyway. It's what everyone else calls the "charged voltage". It's purely for the amp hour counter resynching.

Edited September 3, 2011 by Gibbo