New Leisure battery

huddlejonny

Installed new leisure battery yesterday for use in a wild camping spot that we recently discovered.

The battery was showing 4 bars from 5 after installation but tonight it has dropped down to 2 bars on the indication panel.

I presumed that a new leisure battery should be showing 5 bars ( 13v ) for at least a day or two.

Is this normal or is there something draining the new battery also?

Batteries are stored in shops @ 75% charge. They need to be charged before commissioning.

The battery indicator sounds like an uncalibrated instrument, not what I would qualify as a battery monitor.
What resting voltage does each light correspond to?
Penny to a pound 2 lights means over-discharged; recharge immediately.

A fully charged healthy battery with hold 13.0V at rest until you discharge it. As soon as you do that, depending on the quality of the battery, size of the battery, state of charge and size of the load then it will display between 12.6V and 12.8V the descent from there is mostly linear if the load is constant.

I can't say if it's normal without knowing the size of the load, battery, time in discharge, verification of the meter fidelity, system idle load, etc...

...it sounds normal.

If it's a coach build there's probably something draining the battery, if it's a conversion there's also probably something draining the battery but you stand more of a chance there isn't. You can measure it by using a digital multi meter set to DC current in series with the battery and main conductor and taking a reading with everything you know about turned off.

My solar controller and battery monitor are the only two permanent loads on my system (0.5W) . Everything else has an off switch.

huddlejonny

Sir Liamalot wrote: »

Batteries are stored in shops @ 75% charge. They need to be charged before commissioning.

The battery indicator sounds like an uncalibrated instrument, not what I would qualify as a battery monitor.
What resting voltage does each light correspond to?
Penny to a pound 2 lights means over-discharged; recharge immediately.

A fully charged healthy battery with hold 13.0V at rest until you discharge it. As soon as you do that, depending on the quality of the battery, size of the battery, state of charge and size of the load then it will display between 12.6V and 12.8V the descent from there is mostly linear if the load is constant.

I can't say if it's normal without knowing the size of the load, battery, time in discharge, verification of the meter fidelity, system idle load, etc...

...it sounds normal.

If it's a coach build there's probably something draining the battery, if it's a conversion there's also probably something draining the battery but you stand more of a chance there isn't. You can measure it by using a digital multi meter set to DC current in series with the battery and main conductor and taking a reading with everything you know about turned off.

My solar controller and battery monitor are the only two permanent loads on my system (0.5W) . Everything else has an off switch.

Many thanks for that Liam. The old battery was Agm019 90ah, I replaced it with a lead acid 115ah. Up until recently we were using electric hookup. It's a coachbuilt Knauss Traveller.

I'm baffled as to what is draining the battery or how would I go about checking each individual appliance.

Also wondering how long should it take to charge up the battery?

Thanks for your help.

huddlejonny

huddlejonny wrote: »

I replaced it with a lead acid 115ah.

Yeah that's light for wild camping, how long it will last depends entirely on what you are running. I expect that will get you though the weekend with sensible loads running. It gives you about 600Wh to play with. I use aboot 400Wh most days and I'm not powering a lossy inverter.

I run 235Ah, an upgraded alternator and loom,150W solar and a very efficient system which gives me electrical autonomy most of the year.
If I was to do a new build I'd fit 445Ah, 300W solar and a compressor fridge.

huddlejonny wrote: »

I'm baffled as to what is draining the battery or how would I go about checking each individual appliance.

There's a few ways to deal with this; my preferred is install a proper battery monitor and shunt. Using this you will see exactly where your power is going.
Simply turn things off/pull fuses until you get a zero reading.




Bogart Engineering Battery Monitor



500A 50mV shunt

Option two:
Install an ebay shunted volt-ammeter (which will probably require home calibration for maximum accuracy)




Option 3:
Use a DMM to locate a parasitic draw

huddlejonny wrote: »

Also wondering how long should it take to charge up the battery?

That's unfortunately a very difficult question to answer too.
I expect with the factory fitment charger the best you can hope for is 90% charged.
If you buy a good one 95% seems to be the benchmark. I can get my battery up to 100% (107% charged) after 5 days on solar with no load and a state of the art PWM charge controller. My battery is two years old and as good as new, last time I checked it had delivered ~70kWh in service.

It takes about 12 hours to charge a battery and 3-4 days on float afterwards to get it the last 7%. Most chargers will call it a day long before the battery is charged.
It all depends on the charger; say your 115Ah battery has depleted 57Ah and you put it on a 10 amp charger...the charger will take 5 hours to get it to 90% (of it's SOC algorithm) the absorption stage will take as long as the electronic engineer who designed it thought was appropriate usually based on the bulk time.
Another problem with these factory fitment chargers is they are claimed 20A chargers which they do for about 20 seconds then they trickle down to ~ 7A bulk in short order. A good battery monitor (ammeter) will flag all these issues.

The only way to check charger fidelity is to take readings from the battery cells with a reasonably precise hydrometer until you find a regime that gives you 1.275 per cell and then stick with that.