HELP: Inverter is draining battery almost instantly! Why?

[spoon]

Also: When you first hooked up your laptop how long did it run before you had a problem? From what I see on the net your battery should get 500 cycles at 70% DOD. You say you trickle charged it. With what charger?

We've lived with the system for a while (over 6 months on an old battery and 2-3 months on the new Numax), it's only in the last 2-3 weeks that there has been this problem.

I charged it with my standard car battery charger in the workshop, on normal speed (I think it's 10a from memory).

After a good mains charge, and when hooked up to the caravan it was flashing green (i.e. 100% charged).

[lkruper]

We've lived with the system for a while (over 6 months on an old battery and 2-3 months on the new Numax), it's only in the last 2-3 weeks that there has been this problem.

I charged it with my standard car battery charger in the workshop, on normal speed (I think it's 10a from memory).

After a good mains charge, and when hooked up to the caravan it was flashing green (i.e. 100% charged).

So, how many hours did you run your loads when you first started using it? Do you estimate about 100w for the loads?

[spoon]

So, how many hours did you run your loads when you first started using it? Do you estimate about 100w for the loads?

No, nothing like that. We use around 9w of lighting in an evening (3x 3w LEDS) for maybe 5- 6 hours tops. Then the laptop was used via charge controller (sparingly). The length of a movie (lets say 3 hours) every 3 nights or so...


We really don't use alot of power... I don't see how we would have used up the cycle life of a almost new battery.

[lkruper]

No, nothing like that. We use around 9w of lighting in an evening (3x 3w LEDS) for maybe 5- 6 hours tops. Then the laptop was used via charge controller (sparingly). The length of a movie (lets say 3 hours) every 3 nights or so...


We really don't use alot of power... I don't see how we would have used up the cycle life of a almost new battery.

When you say laptop via charge controller, do you mean from a load during full sunlight so that the battery is not used at all?

Also, has your battery always been fully recharged 100% each and every night and if not, how long did it go before getting fully charged?

[spoon]

When you say laptop via charge controller, do you mean from a load during full sunlight so that the battery is not used at all?

Also, has your battery always been fully recharged 100% each and every night and if not, how long did it go before getting fully charged?

Sometimes running in sunlight, sometimes running at night ( I meant via inverter btw). Never any problems either way, 110ah battery should comfortably run a laptop for a night, no?

No, sometimes it takes afew days for it to get back to 'flashing green' on the CC, but it usualy always gets there in the end.

[lkruper]

Sometimes running in sunlight, sometimes running at night ( I meant via inverter btw). Never any problems either way, 110ah battery should comfortably run a laptop for a night, no?

No, sometimes it takes afew days for it to get back to 'flashing green' on the CC, but it usualy always gets there in the end.

Lead acid batteries are not designed to sit without having a full charge. If you say it took a few days to get to full charge it is possible that you are losing capacity because of sulfation. This is a permanent loss of capacity of the battery. I have heard that in as little as a week one can lose capacity, but if your battery is frequently not getting charged back to 100% every night that is troubling. When this happens, it may appear that a battery is getting charged based on the lights on your charge controller, but that does not mean your battery is not sulfated.

If you watch TV at 65w for three hours and run 3X3w leds for 6 hours that would use about 20AH of your battery or about 20%. That is good. But to recharge you would need full sun for an hour or two (to make up for inefficiency in charging) to get it replaced and then depending on your controller from 2-4 hours or even more in absorb to get to 100%.

This rate of charge is also greatly dependant upon the season of the year, weather and orientation of the panel to get the maximum output from the panel. I agree with a previous poster that your grid-tie panel may benefit from an MPPT controller, particulary since you are not getting charged back up to 100% frequently.

[lkruper]

Sometimes running in sunlight, sometimes running at night ( I meant via inverter btw). Never any problems either way, 110ah battery should comfortably run a laptop for a night, no?

No, sometimes it takes afew days for it to get back to 'flashing green' on the CC, but it usualy always gets there in the end.

Also, are you aware that an inverter can take power even with no loads? Do you turn it off when not in use? An inverter can drain a small battery if left on 24X7.

[spoon]

Also, are you aware that an inverter can take power even with no loads? Do you turn it off when not in use? An inverter can drain a small battery if left on 24X7.

Yep, the inverter is only switched on when needed. With regards the other post, the last few weeks here have been quite good sunshine wise... I would have expected a 250w panel to charge 20% of my battery no trouble, no?

Basically I'm trying to pinpoint what in the system is not working, as I'm on a budget (isn't everyone) I can't change the whole set up for better kit just yet. I'm really hoping that it isn't the new battery as I've just forked out £70 for that.

So, advise is to make sure battery is ok forst.. I do this by checking voltage this evening when no load, and then again say in 24 hours to see there has been no drop?

Also, potentially look at getting an MTTP CC.

I would like to change the inverter too, even if it isn't to blame... It has an automatic fan which is on constantly, horrible noise.

Why, in the evening when the inverter took the battery to red, did the CC light go back to green once the inverter had been turned off... There was nothing charging it?

[lkruper]

Yep, the inverter is only switched on when needed. With regards the other post, the last few weeks here have been quite good sunshine wise... I would have expected a 250w panel to charge 20% of my battery no trouble, no?

lkruper:
Only if you get enough hours of sunshine to finish charging the battery to 100%. Also, the angle of the panel, the season of the year and whether or not there is something shading the panel, etc. You say the problem started in the last few weeks? Have you checked your location for insolation values at this time of the year?


I would like to change the inverter too, even if it isn't to blame... It has an automatic fan which is on constantly, horrible noise.

Why, in the evening when the inverter took the battery to red, did the CC light go back to green once the inverter had been turned off... There was nothing charging it?

lkruper:
The CC needs adequate power to run itself. That is why one needs to plug it into a battery first and let it start up before it will work. The light might indicate that the inverter is drawing power. When you say turn the inverter off, do you also mean turn the loads off that are being run through the inverter as well, or just the inverter by itself?

[spoon]

Y

lkruper:
Only if you get enough hours of sunshine to finish charging the battery to 100%. Also, the angle of the panel, the season of the year and whether or not there is something shading the panel, etc. You say the problem started in the last few weeks? Have you checked your location for insolation values at this time of the year?


lkruper:
The CC needs adequate power to run itself. That is why one needs to plug it into a battery first and let it start up before it will work. The light might indicate that the inverter is drawing power. When you say turn the inverter off, do you also mean turn the loads off that are being run through the inverter as well, or just the inverter by itself?

Yep, the panel is quite close by, I check it for obstructions regularly. It is pointing due south @ around a 45 degree angle.

No, what i mean is. How did the CC indicator go from red to green once the inverter had been switched off, with no power being 'added' to the battery if that makes sense. Surely if the inverter had drained the battery down, it would stay at 'red' until the Solar panel had chance to charge the battery the next morning.

Yep, nothing is left in the inverter. It is attached via croc clips to the battery terminals. When not in use, nothing is left plugged into it.

[sensij]

No, what i mean is. How did the CC indicator go from red to green once the inverter had been switched off, with no power being 'added' to the battery if that makes sense. Surely if the inverter had drained the battery down, it would stay at 'red' until the Solar panel had chance to charge the battery the next morning.

This could be the voltage sag that others tried to explain to you earlier. The load of the inverter on the battery is sagging the voltage below the CC's trigger, and when the inverter is switched off, the battery can "rest" and the voltage settles back at a higher level. For just the idle load of the inverter to sag the voltage enough to trigger the CC light suggests one or more of the following is true:

1) The battery is at a low SOC.
2) The battery capacity has been seriously impaired by chronic undercharging.
3) The inverter idle load is much higher than you are thinking.

[lkruper]

Yep, the panel is quite close by, I check it for obstructions regularly. It is pointing due south @ around a 45 degree angle.

No, what i mean is. How did the CC indicator go from red to green once the inverter had been switched off, with no power being 'added' to the battery if that makes sense. Surely if the inverter had drained the battery down, it would stay at 'red' until the Solar panel had chance to charge the battery the next morning.

Yep, nothing is left in the inverter. It is attached via croc clips to the battery terminals. When not in use, nothing is left plugged into it.

I believe another poster mentioned voltage sag. When a load is on a battery is can draw down the voltage, and the CC may be reacting to this. If the voltage dropped too much it might not be high enough to run the CC. This sounds like it could be a sulfated battery. If it is still under warranty, perhaps you could get it replaced. Try to get one with a recent manufacture date and check voltages on any new battery you might get.

[inetdog]

... The inverter is connected via crocodile clips onto the battery terminals.

The problem is this, my system runs fine with the LED lighting etc. When I try and plug my laptop in via the inverter, the indicator on the charge controller goes from green or flashing green to RED very quickly, within a few minutes.

1. Your battery does not seem to be large enough for the load the inverter is putting on it or else your new battery had been sitting on the dealer's shelf for too long without being kept properly charged. Or you have damaged it by chronic undercharging. If your charger takes a couple of days to get the battery back to full charge it is not doing the job you need. It may be more of a battery maintainer designed for float-only use rather than a charger for cycle use.
If it a flooded battery (cell caps you can open) you should check the specific gravity (SG) with a temperature compensated hydrometer to see if it is actually charging properly.
2. The crocodile clips are not going to give a secure enough low resistance connection to your battery and that can cause additional voltage drop under load that can make the situation worse. You can get an idea of whether this is a problem for you by measuring the voltage at the battery terminals (posts) themselves while the inverter is loaded and then measure the voltage at the inverter terminals at as close to the same time as possible. Then go back and measure at the battery posts.
A voltage drop of even a fraction of a volt will be costing you power and performance.

[Sunking]

Your main issu is nothing is sized correct to work with each other.

A 1000 watt 12 volt inverter requires a battery that can supply 100 amps with 2% or less voltage sag. To do that with a FLA battery requires 800 AH weighing around 540 pounds worth, or a 400 AH AGM battery weighing roughly half that. Regardless if you use FLA or AGM they both cost roughly the same. AGM will only last half as long and cost twice as much per AH. So an AGM long term is 400$ higher cost than FLA.

To charge a 12 volt 800 AH battery requires a 1000 wat panel with 80 amp MPPT charger.

Sorry but you are not even remotely close to having what is required. Thus is why it does not work. It failed the day you bought it. It just took you some time to figure out what happened.

[spoon]

Your main issu is nothing is sized correct to work with each other.

A 1000 watt 12 volt inverter requires a battery that can supply 100 amps with 2% or less voltage sag. To do that with a FLA battery requires 800 AH weighing around 540 pounds worth, or a 400 AH AGM battery weighing roughly half that. Regardless if you use FLA or AGM they both cost roughly the same. AGM will only last half as long and cost twice as much per AH. So an AGM long term is 400$ higher cost than FLA.

To charge a 12 volt 800 AH battery requires a 1000 wat panel with 80 amp MPPT charger.

Sorry but you are not even remotely close to having what is required. Thus is why it does not work. It failed the day you bought it. It just took you some time to figure out what happened.

I had a horrible feeling it may come to this

Thanks all for the replies, I understand SAG now. When I went back in the evening and checked the battery voltage it had dropped to 12.36... Worrying as there had been no load on it from when I checked it earlier in the light and it was 12.59.

So, I think that the battery is no good. Luckily I have the spare. I guess the question now is: How can I save my system and what bits do I need?

I'm guessing the cheapest way would be to keep the good battery & the panel and look to get a more suitable CC and inverter. Perhaps a smaller one would be better as I don't use alot (I can always keep the 1000w in case). So maybe something around the 300-400w range would be better for my needs?