Battery Drain!!!

[samsimmons99]

Hi, I have just installed a 200ah AGM battery.
I’ve wired and installed 6 LED lights that require 2 watts each.
When I turn the lights on I get a voltage drop of 0.2v. I noticed that the voltage continues to drop however.
After 15 minutes of the lights being on, I switch everything off and wait 30 minutes to read the battery voltage again. The voltage had dropped by 0.1v! Surely this is far too quick and the battery should be able to run the lights for hours / days.
Can anyone help?

 

[Stealaway]

That's very accurate voltmeter.
I would test the battery with a bigger load. Are you sure that's all that's pulling off the battery?

 

[samsimmons99]

It’s definitely loosing that much
In fact, when I connect the voltmeter to the battery while the lights are on I can see it dropping by 0.01v every minute

 

[Pausim]

Is the battery getting charged properly? AGM batteries need proper charging, they are quite fussy about it. This is the Alpha Batteries guide.

A Detailed Guide to AGM Batteries - Alpha Batteries

With AGM products becoming more widespread in their use, knowing when you can or should use one and how to look after it properly is all the more important - our guide is here to help.

www.alpha-batteries.co.uk

 

[samsimmons99]

It is connected to a ctek d250se which is all wired up as it says to do so

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[Revolvor]

It is connected to a ctek d250se which is all wired up as it says to do so

If you have wired the CTEK D250SE as a B2B then then maybe the engine battery is being trickle charged from the leisure battery.

 

[samsimmons99]

It doesn’t charge the starter battery from the leisure battery, the solar panel will trickle charge the starter battery when the leisure battery is full but the lights come on to say it is doing that. As far as I can tell, it has nothing other than the lights draining it

 

[Guigsy]

My van will pull 0.3A from the leisure battery when everything is switched off. It'll flatten itself completely in about 10 days.

 

[Richard n Ann]

It’s definitely loosing that much
In fact, when I connect the voltmeter to the battery while the lights are on I can see it dropping by 0.01v every minute

That's completely normal. Look at our voltage dropping all night with about a half amp load before the solar starts charging at 9.30am.

TV went off at 1.30am.

 

[Pausim]

It is connected to a ctek d250se which is all wired up as it says to do so

Charging a 200Ah battery at 20A is not going to be quick, perhaps it needs longer charging. I note that the CTEK has 2 AGM settings, one at 14.4V and one at 14.7V. Have you checked that the setting matches the requirements of your battery? If it wants 14.7V but is only getting 14.4V it could reduce the capacity and life of the battery.

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[EML]

That's completely normal. Look at our voltage dropping all night with about a half amp load before the solar starts charging at 9.30am.

View attachment 544519

TV went off at 1.30am.

You're seeing about 0.1V over 7 hours, which is 0.0002 V/minute, at 0.5A draw. The OP is seeing 0.01V/minute, at 1A...

 

[EML]

Hi, I have just installed a 200ah AGM battery.
I’ve wired and installed 6 LED lights that require 2 watts each.
When I turn the lights on I get a voltage drop of 0.2v. I noticed that the voltage continues to drop however.
After 15 minutes of the lights being on, I switch everything off and wait 30 minutes to read the battery voltage again. The voltage had dropped by 0.1v! Surely this is far too quick and the battery should be able to run the lights for hours / days.
Can anyone help?

The numbers don't really add up.

If you really are drawing 1A for your LEDs (2W/12V * 6), and you're seeing the battery voltage drop by 0.2V, then the AGM has an internal resistance of 200mOhm, which is way higher than it should be (it should be maybe 1.5 to 5 mOhms). Sounds like the battery is broken, or very, very old, or your readings are wrong, or whatever.

I'd take the battery out and do some tests on it with a resistor load and a meter. Or maybe it's just not charged? I don't know how that affects the internal resistance, but I'd be surprised if it did this. Or maybe you can get your local friendly garage to put a battery tester on it.

 

[Richard n Ann]

You're seeing about 0.1V over 7 hours, which is 0.0002 V/minute, at 0.5A draw. The OP is seeing 0.01V/minute, at 1A...

The op doesn't give the actual voltage so could it just be dropping surface charge? Ours stays well above 12.7v for an hour or 2

 

[Pausim]

The numbers don't really add up.

If you really are drawing 1A for your LEDs (2W/12V * 6), and you're seeing the battery voltage drop by 0.2V, then the AGM has an internal resistance of 200mOhm, which is way higher than it should be (it should be maybe 1.5 to 5 mOhms). Sounds like the battery is broken, or very, very old, or your readings are wrong, or whatever.

I'd take the battery out and do some tests on it with a resistor load and a meter. Or maybe it's just not charged? I don't know how that affects the internal resistance, but I'd be surprised if it did this. Or maybe you can get your local friendly garage to put a battery tester on it.

That will be a simple drop test to see whether it is capable of sustaining a very heavy load for starting an engine. It could be far too heavy a load for a proper leisure battery which should be designed for long slow discharge.

 

[autorouter]

Hi, I have just installed a 200ah AGM battery.
I’ve wired and installed 6 LED lights that require 2 watts each.
When I turn the lights on I get a voltage drop of 0.2v. I noticed that the voltage continues to drop however.
After 15 minutes of the lights being on, I switch everything off and wait 30 minutes to read the battery voltage again. The voltage had dropped by 0.1v! Surely this is far too quick and the battery should be able to run the lights for hours / days.
Can anyone help?

As Richard n Ann says, it would help if we knew the actual voltage values. You are right that in theory lights drawing 1 amp from a 200Ah battery bank should last 100 hours, when the battery will be down to its 50% level. In practice for that level of amps, it should be even longer than that. But the voltage may drop quite a lot in the first few minutes or hours after the charger has finished charging. That's why we need to know the actual voltage values.

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[Lenny HB]

Or maybe you can get your local friendly garage to put a battery tester on it.

Completely pointless they will do a CCA test which is meaningless for a leisure battery.