Battery drainage, urgent problem

[steveghoward]

Hi all, we have two 180 watt solar panels charging a single vetus 145 amp battery bought 12 weeks ago. We did have two batteries but one has never worked properly and has been disconnected for the last week

We only use the leisure battery for charging the fridge and charging two tablets when needed. We have been turning the fridge to the setting 6 during the day as the battery has been showing 13.5 volts plus and the solar panels about half a volt higher than this on charge. The regulator either shows two solid green lights meaning all is well, or one starts flashing meaning the battery is fully charged.

We then reduce the fridge to 3 when the sun goes down and then turn the fridge off completely at about 10.30 when we go to bed.

This has worked well until this evening and we turned the fridge to 3 about 7 pm. We then went for a walk and returned a few minutes ago at 9.45 to find everything shut down and a red warning light on. A volt meter reading shows the battery at 10.4 volts!

Something has drained all of the voltage out of this battery in less than 3.5 hours without anything being switched on apart from the fridge. Would that be the cause.

I also am not able to run my engine to recharge the battery as I am on a busy quay and it is now 10.30 at night. I guess the battery being so lowly charged over night will wreck it, is this correct.

Any help or advice team? It has stumped me.

Thanks as always in advance.

 

[earlybird]

To drain say 70 ah+ in <3.5 hours means you are looking at a load of >20 amps. Is this feasible without something getting warm? Perhaps the fridge itself developed a fault.?
Another possibility is that the battery has failed, despite its youth due to eg, an internal short.
If the battery is OK, I doubt an overnight wait will wreck it, although one such heavy discharge won't improve it. I suggest you get it checked/charged in the morning.

 

[halcyon]

Any help or advice team? It has stumped me.

Thanks as always in advance.

Give battery a good charge, could well be okay.

13.5 is not a good charge voltage, your system for running the fridge may be the problem, you may only have 40% capacity in the battery at that voltage, then draining them more after 7 is reducing further the capacity. Limited recharge could then be producing sulphation and surface charge. reducing charge further and starting a cycle that is reducing capacity further.

You need to get charge up to 14.2 -14.4, even if this needs a lower fridge setting, also check current flow to fridge and battery.

The other battery may be okay, if they were in parallel the charge voltage would have been lower, leading to flat batteries that you saw.

Brian

 

[vyv_cox]

Have you checked the acid level in the battery? That is a massive solar panel input to one battery, we have 125 watts into a bank of three 110Ah batteries. With open lead acid batteries I need to top up with deionised water monthly, taking a surprising amount. We are self sufficient for power, without running the engine, until mid september, when there are no longer enough hours of sunshine. We never turn our fridge down or off for nearly six months, it runs constantly. If you have a Sterling alternator controller you also need to top up batteries regularly, as the instructions tell you.

 

[MJ24]

Without telling you "I told you so" get the engine starter battery working.

Its a very basic safety system.

You say the battery was not working properly, what does that mean?

Sounds more like a wiring problem, or as has been said the solar panels are not properly connected. Assume you have a regulator between the panels and batteries.

You are lucky the failure happened on berth or wherever you keep the boat, rather than at anchor with the wind rising.

Sorry, its basic stuff.

Mj

 

[steveghoward]

OK, first lesson of the morning. Don't press the delete key instead of edit when you are altering a message it has taken 45 minutes to type. Thewords stupid and numpty spring to mind.

Let's try again.

My current situation (sorry) is as follows. I have 2x180 solar panels and, 11 weeks ago bought 2 new vetus 145 amp hr batteries. The panels feed thru a regulator .I always thought that there was some thing amiss as the batteries never seemed to be holding a full charge.

 

[steveghoward]

Continued. . I spent a day monitoring both the regulator and battery and this went from 12.60 charge and 12.44 batt at 10 in the morning to peak at no charging and 13.90 on the batteries at 5pm. It then slowly fell to 12.08 batt at midnight with no charge cos it was dark (of course) .

I thought this was low so had the batteries analysed. The batteries have a CCA (?) rating of 1055. One showed 970 on the dial and the other 573, meaning the battery was effectively dead after 11 weeks.. This battery has been disconnected and I am in discussion with Vetus regarding this. The other battery has been running the fridge since then and appears to be coping until last night when it appeared to drain in three and a half hours putting a red warning light on the regulator.

This battery in the last week has had solar charging daily, twice charges by the engine for three hours at a time, and 24 hours mains charge from the pontoon at Nidri.

We are only using this battery to power the fridge and charge two tablets.

When I woke this morning, the light was back to green on the reg and, as I type it is showing 13.66 on the battery and 19.01(!) on the charger. Can this be right.

BTW, I have a completely separate engine starting battery circuit which has never proved a problem. The only reason I could not start the engine last night was through consideration to other boat owners around me.

I am going to book the boat in for a complete engine and electrical check but would welcome any constructive comments.

All I want is a stress free life and a cold beer, is this to much to ask.;

Regarfs

 

[MJ24]

http://www.yachtsurvey.com/boat_battery_basics.htm

Worth a read....

I have had a similar experience of fast battery discharges. Turned out to be the stop solenoid shorting out.

But that was quite frightening to see it happen. I suspect there is a fault in the electric switch board (35 years old)

I also use a battery monitor from NASA. Great bit of kit, but it only monitors one battery.

I also had a battery charging system attached to the alternator, can't remember its name now, but it increases the alternator voltage to boost charging. It worked well for many years, but in the end it seemed to impede the alternator charge. So I took it off, and now the alternator charges at 14.5 a/h all by itself.

CCA is Cold Cranking Amps ? which refers to the ability of the battery to turn the engine for 20 seconds. But no expert, just what I read today.

I can only advise to get a qualified boat electrician in. They should be able to sort the problem pretty quickly.

Good luck..

Mj

 

[ianj99]

I think a better regulator is needed. As has been stated to get close to 100% charge the voltage needs to get to around 14.4v before the charger switches to float mode of about 13.5v. Whether a solar regulator actually exists that will function like a smart battery charger or alternator regulator is another matter.

A quick google has not turned up any multistage solar chargers save one on ebay which claims 4 stages but there isn't enough info in the listing.

The rest are basic pwm controllers that simply switch the panel output on and off fairly rapidly - on for 100% of the time for a flat battery, reducing to off for most of the time as the battery gets above 13.5v and that's the problem.
For example, I have a 20watt panel keeping my domestic battery topped up (no drain when I'm not on board) and it never goes above 13.5v, consequently the battery is never more than about 70% charged. When I start the engine the alternator pumps significant amps into it for over an hour (I use a Sterling digital alternator regulator) before it could be considered fully charged.
In your case, those large panels are wasted - you either need a better regulator or batteries 50% larger to allow for the fact they are never being fully charged. (not charging them fully will also shorten their life).

 

[RAI]

When I woke this morning, the light was back to green on the reg and, as I type it is showing 13.66 on the battery and 19.01(!) on the charger. Can this be right.

That 19.01 volts looks like the panels' open circuit voltage. Is it at the output of the panel controller? I would check the controller to battery connections. If the connections are good and the wiring adequately thick, the battery should hold the controller output close to its own voltage. Maybe the charging current is not getting through.
13.6 volts will only slowly charge the battery, it's about right for "float" charging. Run the engine occasionally and get at least 14.4 volts to reduce sulphates building up.

 

[ianj99]

That 19.01 volts looks like the panels' open circuit voltage. Is it at the output of the panel controller? I would check the controller to battery connections. If the connections are good and the wiring adequately thick, the battery should hold the controller output close to its own voltage. Maybe the charging current is not getting through.
13.6 volts will only slowly charge the battery, it's about right for "float" charging. Run the engine occasionally and get at least 14.4 volts to reduce sulphates building up.

Yes, the regulator has switched off, disconnecting the panel from the battery hence the panels' open circuit voltage at 19 and the battery's at 13.66.

You will never solve this unless a multistage smart regulator is fitted. Running the engine isn't the answer unless you want to do it every day: you need to get more amp hours from the panels, which they can supply if only the charger didn't taper the charge right down, ultimately to zero as 13.6 volts is approached.

 

[RobbieW]

... Whether a solar regulator actually exists that will function like a smart battery charger or alternator regulator is another matter.

A quick google has not turned up any multistage solar chargers save one on ebay which claims 4 stages but there isn't enough info in the listing.
...

https://www.google.co.uk/?gws_rd=ssl#q=3+stage+solar+battery+controller - I have a Rogue controller which has 3 stages and is highly programmable. The difficulty I've found since installing solar last year, in the Med, is getting enough charge into the batteries to bring the voltage up to the bulk level for it to switch to absorb. I dont think I've seen that happen yet, that said I'd rather have the solar than not as it cuts down how often I need to find an alternate source. The house batteries are nominally 700ah, we use c. 100a/day - the solar puts back about 60-70a/day

 

[ianj99]

https://www.google.co.uk/?gws_rd=ssl#q=3+stage+solar+battery+controller - I have a Rogue controller which has 3 stages and is highly programmable. The difficulty I've found since installing solar last year, in the Med, is getting enough charge into the batteries to bring the voltage up to the bulk level for it to switch to absorb. I dont think I've seen that happen yet, that said I'd rather have the solar than not as it cuts down how often I need to find an alternate source. The house batteries are nominally 700ah, we use c. 100a/day - the solar puts back about 60-70a/day

Found the Victron ones here http://www.shop.solar-wind.co.uk/acatalog/Victron_MPPT_100-30_Charge_Controller_brochure.pdf

These 'proper' pro solar charger regulators are in a different price bracket to the common, basic types, but you get what you pay for. So you probably need to spend as much on one as you do on a 100watt panel or risk wasting your investment.

 

[macd]

A quick google has not turned up any multistage solar chargers save one on ebay which claims 4 stages but there isn't enough info in the listing.

As said, they do exist. I think some of the more expensive PWM controllers have such a facility, and it's fairly commonplace with MPPT controllers. Mine is fully programmable and operates much like a smart battery charger. Well, it does when the sun's out...

 

[ianj99]

As said, they do exist. I think some of the more expensive PWM controllers have such a facility, and it's fairly commonplace with MPPT controllers. Mine is fully programmable and operates much like a smart battery charger. Well, it does when the sun's out...

Are you seeing about 14.4v at the battery indicating absorption mode?

Some links to Victron:

http://www.victronenergy.com/blog/2014/07/21/which-solar-charge-controller-pwm-or-mppt/ the first question down this page is very like the OP's problem.

http://www.victronenergy.com/live/ve.direct:mpptprefs shows how to set the various stage voltages.

 

[changeman]

Possible that one cell of your battery has failed. Distinctly possible as your other new battery is U/S.

 

[skipmac]

That 19.01 volts looks like the panels' open circuit voltage. Is it at the output of the panel controller? I would check the controller to battery connections. If the connections are good and the wiring adequately thick, the battery should hold the controller output close to its own voltage. Maybe the charging current is not getting through.
13.6 volts will only slowly charge the battery, it's about right for "float" charging. Run the engine occasionally and get at least 14.4 volts to reduce sulphates building up.

Agree the difference in voltage at the panel vs the battery is a big, red flag. When charging from the panels (or any other source for that matter) the voltage at the battery terminal should be almost identical to the voltage at the panel. If not then you have some kind of break or discontinuity between the two. This could also mean that the batteries have been consistently undercharged for some time which could explain why the voltage was so low after a few hours running the fridge.

NOTE: battery voltage is a very poor way to determine battery state of charge. A fully charged battery with a heavy load connected can show fairly low voltage and a partially discharged battery might show a reasonably good voltage if no load is connected. Also if you have a battery that is very discharged, connect a charger for just a few minutes, disconnect and immediately check the voltage it might look just fine. The battery must sit for some time to stabilize before you can get and accurate voltage reading.

One thing that will help you a lot is to get a battery monitor or even a basic ammeter to watch the amps in and out. The monitor isn't the ultimate solution but even a basic, inexpensive model will show you much more than you are getting now.

Also, a leisure battery really isn't the best thing to use for house loads. What you need is a true, deep cycle battery. Anything with a rating for CCA is not a deep cycle battery and will not do well over time with deep discharges between recharging cycles. Don't know the best option over there, but over here the cheapest solution is to buy 6 V golf cart batteries and connect in pairs.

 

[ianj99]

Agree the difference in voltage at the panel vs the battery is a big, red flag. When charging from the panels (or any other source for that matter) the voltage at the battery terminal should be almost identical to the voltage at the panel. If not then you have some kind of break or discontinuity between the two. This could also mean that the batteries have been consistently undercharged for some time which could explain why the voltage was so low after a few hours running the fridge.

As I said earlier, the reason for the different voltage is because the regulator has switched off - this means its disconnected the panel from the battery, Its done this because its set to do so at around 13.6v. This is why the batteries are not being charged to their full capacity and therefore cannot power the fridge for the expected time.
A more sophisticated regulator is needed. The basic (non multistage) ones whether pwm or mppt are intended to provide a real time supply of power or maintain an already charged battery so it looks like this is the type the OP has. There is no other explanation that makes sense - the panels are working, his batteries were new, its simply that there is not the expected charge getting into them. (or the charging current has been tapered off by the regulator so much that there is insufficient daylight hours)

 

[skipmac]

As I said earlier, the reason for the different voltage is because the regulator has switched off - this means its disconnected the panel from the battery, Its done this because its set to do so at around 13.6v. This is why the batteries are not being charged to their full capacity and therefore cannot power the fridge for the expected time.
A more sophisticated regulator is needed. The basic (non multistage) ones whether pwm or mppt are intended to provide a real time supply of power or maintain an already charged battery so it looks like this is the type the OP has. There is no other explanation that makes sense - the panels are working, his batteries were new, its simply that there is not the expected charge getting into them. (or the charging current has been tapered off by the regulator so much that there is insufficient daylight hours)

There has to more than just the regulator switching off. I think it would have to be defective in some way to explain the voltage difference or there has to be some break or high resistance in the cables to the battery or ground.

Here's my logic. If the charge voltage is set to 13.6V, at some point the batteries reach that voltage but are not fully charged, the regulator sees the set voltage from the batteries and switches off. If there is any load on the batteries the voltage at the batteries will almost instantaneously drop below 13.6V, especially if the battery is not fully charged. Even with no load on the batteries it would take only a very short time for the voltage to drop below 13.6V. A fully charged battery after proper resting time, with no load on will only show 12.6V +/- 0.05V more or less.

As soon as the voltage at the battery drops below 13.6V the regulator, if functioning, should again switch on since it is now seeing voltage below the set point.

Don't know anything about the regulator the OP is using but it must be without any logic at all if it has only two states, on and off. Even most (yes maybe not all) dumb regulators at least keep a float voltage to maintain a battery when that regulator decides the battery is charged.

 

[ianj99]

There has to more than just the regulator switching off. I think it would have to be defective in some way to explain the voltage difference or there has to be some break or high resistance in the cables to the battery or ground.

Here's my logic. If the charge voltage is set to 13.6V, at some point the batteries reach that voltage but are not fully charges, the regulator sees the set voltage from the batteries and switches off. If there is any load on the batteries the voltage at the batteries will almost instantaneously drop below 13.6V, especially if the battery is not fully charged. Even with no load on the batteries it would take only a very short time for the voltage to drop below 13.6V. A fully charged battery after proper resting time, with no load on will only show 12.6V +/- 0.05V more or less.

As soon as the voltage at the battery drops below 13.6V the regulator, if functioning, should again switch on since it is now seeing voltage below the set point.

Don't know anything about the regulator the OP is using but it must be without any logic at all if it has only two states, on and off. Even most (yes maybe not all) dumb regulators at least keep a float voltage to maintain a battery when that regulator decides the battery is charged.

The economy regulators are usually simple pwm with no microprocessor - they connect the panel to the battery by a transistor switch. The on time (switch closed) is large when the battery is low, and very short when the battery approaches the float setting and off when float is reached. Hence there is a drop across the switch when its open - open circuit panel volts on one side and battery volts on the other. The resting time will be short - the regulator will periodically close the switch as soon as the battery drops below 13.6 to maintain it off load at 13.6.
True, the battery would not remain at 13.6v for long, but maybe the OP measured it with no load. If he had kept monitoring the panel volts he would have seen it drop to battery volts, especially when a load was applied. His regulator could of course be faulty.