battery drain

[davehull]

Hi All

 

Since September last year when I fitted 3 new Numax 110ah batteries, I have managed to completely destroy them. This problem came to light when we cruised over the Christmas/new year holiday. The batteries would hold no charge, luckily we could use the genny to provide some power and get the engine started. Back on hook up in the marina this has not caused any problems, but I needed to sort it out.

 

I have since split the batteries into 2 banks and fitted a smartgauge/bank along with 3 new Varta 110ah batteries for the domestic bank, renewed all the cables. After fitting the smartgauge I started to monitor the batteries % I found that within 90 minutes the batteries had lost 25% of their charge.

 

I have led lights throughout and these draw just over 5 amps if I have them all on (which we don't) a Shoreline Fridge/freezer drawing 4.5 amps when the compressor kicks in (about every 10 mins for less than 30 seconds) water and shower pumps that draw 7ish amps when running. I didn't think that what I had used in that time should have drained the amount from a fully charged 330 ah bank.

 

I isolated the domestic batteries and fitted a power supply to run the 12v system to avoid killing the new batteries. Since isolating the battery bank it has remained at the same %. I assume I have a short somewhere inside the boat, any ideas on how I can find this? I had removed the battery charger and inverter from the set up before installing the new batteries and smartgauge and planned to replace these when I had proved the new system was working ok, obviously I have not replaced these yet.

 

I have bit the bullet and arranged an Electrician to come Friday to hopefully find the fault, anything I could do before then to find what's happening?

 

Dave

[b0atman]

Are these batteries being used to start the engine instead of a dedicated starter battery ?

[kevinl]

You could try turning everything off and taking out all the fuses then put then back one at a time monitoring the batteries, that might give you some idea which circuit has the short. It's hopefully a short in a fitting like a light or switch and not in the buried wiring.

K

[Nickhlx]

Surely if this much current / power was "disappearing" it should be obvious from where by the smoke / heat it is being converted to is appearing ?

[nicknorman]

Presuming the batteries were at rated capacity, 25% = 82.5AH which over 90 mins = 55A drain, which at 12v is 660 watts. So if your presumptions are correct, something will be generating 660 watts of heat and getting very hot!

 

More likely, I think, it is something else causing the indications you see. A good starting point would be to get a DC clamp meter such as UNIT UT-203 and measure the actual current drain. Even though you may not be able to get it in time for the electrician's visit, it will prove useful in the future and for around £30 is a no-brainer since, as I often say, electricity is otherwise invisible.

 

Other possible scenarios

 

Some equipment is on that is presenting a big drain (seems unlikely since you have disconnected the inverter)

The batteries are not at rated capacity, are badly interconnected etc

The Smartgauge is incorrectly fitted (ie not directly onto battery posts), set up incorrectly or mis-calibrated by the manufacturer.

The batteries were not fully charged, but you set the Smartgauge to 100% SoC when you fitted it.

Edited February 4, 2015 by nicknorman

[smileypete]

A 'clamp meter' that measures DC amps will find this sort of fault no problem.

 

£25 for Mastech MS2108A off Ebay, or £40 for Unitrend UT203 from Maplins, but beware not all measure DC amps, especially the cheaper ones.

 

Also there's numerous reports of sealed leisure batts underperforming, non sealed ones are far better for off grid.

 

cheers, Pete.

~smpt~

Edited February 4, 2015 by smileypete

[davehull]

Hi All

 

1- dedicated battery for starter 3 battery bank for domestics

2- could work, I have checked each circuit for amp draw with multi meter

3- no visible indication of heat that I can see, the interior is all white so I would think heat would show

4- was assured batteries were fully charged when bought (last Friday) but didn't check/charge them myself. I did set smartgauge to 95% All connections to battery posts. D C clamp meter on shopping list.

5- New batteries are Varta non sealed which I choose over sealed economy leisure batteries on advice from South Yorkshire batteries in Sheffield.

 

Dave

[nicknorman]

Hi All1- dedicated battery for starter 3 battery bank for domestics2- could work, I have checked each circuit for amp draw with multi meter3- no visible indication of heat that I can see, the interior is all white so I would think heat would show4- was assured batteries were fully charged when bought (last Friday) but didn't check/charge them myself. I did set smartgauge to 95% All connections to battery posts. D C clamp meter on shopping list.5- New batteries are Varta non sealed which I choose over sealed economy leisure batteries on advice from South Yorkshire batteries in Sheffield.Dave

4. Is probably the issue. They probably were at a low state of charge when you set the Smartgauge's SoC to 95% and over the next 90 mins, it adjusted itself accordingly.

[davehull]

Nick

 

Would the smartgauge react that quickly, I thought it took 3 re charging cycles to find its level?

 

I understand that the setting that I put in was/is incorrect, but the voltage started at 12.70 and fell to 12.35 in the 90 mins.

 

I am not fully up to speed with this and after destroying 3 batteries panicked.

 

Dave

[nicknorman]

NickWould the smartgauge react that quickly, I thought it took 3 re charging cycles to find its level?

I'm not sure, and it certainly isn't as simple as "3 cycles" since if set up correctly, it is pretty good from the outset. It does refine itself as time progresses of course. In the case of installing it with an exaggerated SoC I think how it reacts will depend on a few things, for instance if the batteries had just come off a brief charge but we're only at say 75% SoC, the voltage would initially be "correct" for 95% SoC but would then fall off to the true value as the surface charge dissipated, and the SG reading would presumably drop rapidly as this would be indistinguishable from a rapid discharge.

 

Anyway, perhaps the answer is to fully charge the batteries and try again, before you spend money on an electrician chasing a phantom fault?

[davehull]

Nick

 

I think your right about charging the batteries and trying again, but it's still in the back of my mind that there must be a fault to fry the 3 new batteries fitted late September, or am I over thinking this and should forget what's happened previously.

 

Dave

[nicknorman]

NickI think your right about charging the batteries and trying again, but it's still in the back of my mind that there must be a fault to fry the 3 new batteries fitted late September, or am I over thinking this and should forget what's happened previously.Dave

Well I think you should bear in mind what happened, but be checking the state of the system as it is now, rather than what it was previously. TBH it is pretty unlikely that there is some inexplicable drain of 55A, and there are plenty of other reasons why the old batteries might have died, typically to do with charging.

[davehull]

Nick

 

I agree the previous charging was iffy at best and with no way of checking......

 

Will charge batteries tonight and start over monitoring from then, thanks for your help.

 

Will let you know how I fare over the next few days.

 

Dave

[Naughty Cal]

Hi All

 

1- dedicated battery for starter 3 battery bank for domestics

2- could work, I have checked each circuit for amp draw with multi meter

3- no visible indication of heat that I can see, the interior is all white so I would think heat would show

4- was assured batteries were fully charged when bought (last Friday) but didn't check/charge them myself. I did set smartgauge to 95% All connections to battery posts. D C clamp meter on shopping list.

5- New batteries are Varta non sealed which I choose over sealed economy leisure batteries on advice from South Yorkshire batteries in Sheffield.

 

Dave

We get out batteries from South Yorkshire Battery Services. They are good lads and know their stuff.

 

ETA: When we fitted our new Varta sealed batteries last year they took a few cycles before they seemed to pick up. We were a bit disappointed at first as they didn't appear very good and seemed down on capacity but after some use they seemed to improve vastly. Ours also seem to charge better from the alternator then they do from the shoreline and battery charger.

Edited February 4, 2015 by Naughty Cal

[matty40s]

I bought a new set of 6 x 120ah batteries in October. Fitted them, and then paid for a mooring for two days so I could fully charge the batteries. I let the smart gauge find its own level, cycling the batteries using washing machine or microwave with land line unplugged.

Just because you buy batteries from a shop/ supplier doesn't mean they are new, they may have been stood for months.

 

Being stood on concrete also causes battery problems, I don't know the theory behind this but it happens.

[dmr]

I bought a new set of 6 x 120ah batteries in October. Fitted them, and then paid for a mooring for two days so I could fully charge the batteries. I let the smart gauge find its own level, cycling the batteries using washing machine or microwave with land line unplugged.

Just because you buy batteries from a shop/ supplier doesn't mean they are new, they may have been stood for months.

 

Being stood on concrete also causes battery problems, I don't know the theory behind this but it happens.

 

I have read that the concrete floor thing is no longer true, and comes from the old days when battery cases were made of some sort of hard rubber or similar.

 

A few years ago I bought a set of batteries from a motor factor and found they were heavily sulphated. The shop returned then to their supplier who initially refused a refund because the batteries were sulphated !!!!!!

 

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

[matty40s]

 

I have read that the concrete floor thing is no longer true, and comes from the old days when battery cases were made of some sort of hard rubber or similar.

 

 

It still stands, we inadvertently tested it the other week over 5 days.

[smileypete]

Probably more to do with the floor being cold rather than the material it's made of.

 

A cold battery will perform less well including charging, and the acid may stratify if the bottom is colder than the top.

 

cheers, Pete.

~smpt~

[Sir Nibble]

heard of the concrete floor thing. Also heard it extended to steel. 35 years an auto electrician and convinced it's rubbish and almost certainly always has been. Do you have a separate domestic alternator?

Edited February 4, 2015 by Sir Nibble

[davehull]

Just one alternator, split charging to be sorted by smartbank fitted at along side the newly installed smartgauge.

 

I asked when I bought the batteries, if I should charge them before fitting, they assured me they were fully charged, still lesson learned.

 

Fully charged batteries last night, will connect to load tonight and see what happens.

 

One thing I noticed was an E11 fault code on the smartgauge, any ideas?

 

Dave

[nicknorman]

One thing I noticed was an E11 fault code on the smartgauge, any ideas?

 

Dave

From the manual:

E11 SmartBank, (either by its own decision in the case of SmartBank Standard or under the control of SmartGauge in the case of SmartBank Advanced) has attempted to operate the split charge relay but SmartGauge is measuring different voltages on the 2 batteries. This would indicate either a faulty relay or faulty relay wiring. In either case, split charging is probably not taking place.

 

It goes on to say:

 

Disabling the SmartBank error codes in the SmartBank setup menu will disable E11, and E13. Note that E10 and E12 cannot be disabled.

The reason E11 can be disabled is to prevent nuisance error reports in poor installations where the cabling between the 2 battery banks is insufficiently sized. Also, some professional installers use the SmartGauge/SmartBank combination for purposes other than split charging and in some of these instances, the closure of the relay does not necessarily mean that both battery banks should be at the same voltage.

Edited February 5, 2015 by nicknorman

[davehull]

Am I totally stupid or just not getting this. I thought the smartbank would only split the charge when using the alternator, not with the battery charger which is only connected to the domestic bank. Should the battery charger positive lead be connected to the same place as the alternator input (starter battery isolator)

 

Dave

[Boredrider]

Am I totally stupid or just not getting this. I thought the smartbank would only split the charge when using the alternator, not with the battery charger which is only connected to the domestic bank. Should the battery charger positive lead be connected to the same place as the alternator input (starter battery isolator)

 

Dave

No, the smartbank will join the banks together when charge is received from any source.

[nicknorman]

Am I totally stupid or just not getting this. I thought the smartbank would only split the charge when using the alternator, not with the battery charger which is only connected to the domestic bank. Should the battery charger positive lead be connected to the same place as the alternator input (starter battery isolator)

 

Dave

I don't have a SmartBank but isn't the general idea to connect the two banks together when one is being charged? Whether that charge is coming from a charger or an alternator doesn't matter, and how could the SB know anyway? The electrons all look the same!

[trackman]

What Nick said. However, depending how it's all wired up, turning off your isolators may cut off the relay from one or both battery banks, often both.

The solar panels or other charge source may then only charge one battery bank. This will cause a difference in voltages between the 2 banks even when the Smartbank has closed the relay. Hence it gives error the code described on the Smartgauge display.

I get this error code for this reason when I isolate my batteries. Not a huge issue for me as it's the starter bank that isn't charged, but that one doesn't need it for short periods. If it should become a problem I can use the Smartbank emergency facility to connect together the 2 banks temporarily and start the engine from the fully charged domestic bank.