Leisure Battery orientation

[Johntheo]

I'm a new member. I've searched for threads about this and failed to find them. If this is an old, already well answered, topic, then please point me to the thread. Thank you.

I have an Autocruise Jazz to which some previous owner has fitted with a solar panel and 2nd leisure battery. I'm concerned that it doesn't work anything like as well as other people seem to find with their solar set up. Without a hook up the combined batteries drop to <10V in a few hours when only powering the compressor fridge.

Investigating I find that the original leisure battery is a Lucas 100 a.hr AGM and the 2nd battery a Platinum AGM 100 a.hr, but this has been installed lying on its side. I have read on the internet that this is both acceptable and a terrible idea (different authors, obviously). I have no idea how old either battery is or how abused they have been.

As far as I can see the solar panel, controller etc all seem to be working OK (probably...). I'm wondering if the batteries are the problem and, specifically, whether the one on its side is going wrong. I could, with a lot of work, get it upright in the battery cupboard - would this be a good idea - or will it be knackered and not recover anyway? All advice gratefully received.

 

[autorouter]

Although I've never actually used an AGM battery on its side, from all the manufacturer's info it ought to be perfectly fine. Motorcycle batteries are commonly installed on their side, and work perfectly well.

You could try each battery separately, maybe only one is no good, and it might be pulling the other one down. I think a 100Ah battery ought to last 24 hours at least with a typical fridge. Especially as you say you have a solar panel. Maybe others with similar setup can shed more light on this.

 

[CazPaul]

Batteries are knackered you need new ones, get some gel not AGM they will last you far far longer.

 

[Reallyretired]

I agree with the last post. If your batteries have regularly been overdischarged they have had it. AGM batteries aren't particularly good either.

 

[Johntheo]

Thanks for this advice. There is conflicting ‘expert opinion’ on the Internet about AGM batteries working on their side, perhaps more saying it is OK (?). The batteries might easily be knackered through previous usage anyway, and I understand that a knackered battery connected to a good battery = a knackered pair of batteries.
Anyway, I plan to pull the batteries out and test them individually. I was recommended by the tech officer at CCC to put a 21watt bulb across the battery and see how long it burned bright (drawing ~ 2a). Should go at least 24hrs, he said. Also been recommended to check max voltage battery can be charged to (13.4v?).
CCC man said that the standard battery test done in auto places (voltage drop under heavy discharge conditions) was not a helpful indicator of condition of leisure battery.
Does anyone have alternative/better ways of checking condition? I have a decent multimeter, mains trickle charger and similar kit and a reasonable grasp of electrical matters, but only sparse (but growing) understanding of the subtleties of battery technology. Thanks in anticipation.

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[DBK]

I don't think you need to waste time testing, though by all means give it a go but if they have been discharged regularly to below ten volts they will be damaged. I don't let mine go below twelve.

AGM and gel batteries can be mounted on their side, odd though this seems.

 

[Nigel Crompton]

Are the two batteries wired correctly ? Domestic load off +ve of one battery and -ve of the other.

 

[pappajohn]

GEL batteries are exactly that, they have a gel electrolyte rather than liquid so can even be mounted upside down.
AGM have the electrolyte absorbed into a glass fiber matt (effectively a sponge) and as such have no free liquid.... AGM = Absorbed Glass Matt.

AGM are being dropped by car manufacturers for their poor performance and short life as stop start batteries.

 

[Stealaway]

I'm afraid you are hoping not to have spend £150+ new on batteries? It more than likely they are goosed. You definitely need two batteries IMHO - especially with a compressor fridge.
Bite the bullet and pick a couple of 'named' wet batteries from here.

110Ah / Group 31 Leisure Batteries

We sell 110Ah / Group 31 Leisure Batteries at the cheapest prices anywhere. Our 110Ah / Group 31 Leisure battery is an extremely high quality product at a budget price. With a price beat guarantee you can be certain of the best deal in the UK.

www.tayna.co.uk

I'd have two of these--- https://www.tayna.co.uk/leisure-batteries/numax/xv31mf/

Check the charging voltage and never let them drop below 12.3V.

 

[autorouter]

I have a decent multimeter, mains trickle charger and similar kit and a reasonable grasp of electrical matters,

Is this mains trickle charger the only charger you have, or is there another charger for use on mains hookup?

A proper multistage charger has at least three stages.
First stage, it fires out maximum current, measuring the voltage as it slowly rises. When it reaches a pre-set voltage (about 14.4 volts), it switches to the second stage automatically. At this point it is about 80% charged.
Second stage, it maintains a high voltage, usually about 14.4 volts, measuring the current (amps) as it slowly falls. When it reaches a pre-set current, it switches to the third stage automatically. At this point it is 100% charged.
Third stage, it maintains a trickle charge voltage of about 13.8 volts, putting in enough charge to offset any self-discharge and maybe some very small loads like the clock or alarm.
The three stages are sometimes referred to as I, Uo and U. So sometimes IUoU is written on the charger label to indicate that it's a 3-stage charger.

Different battery technologies require slight variations on this for optimal charging, and sometimes the charger can be set for Wet, AGM, Gel or even Lithium batteries.

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[autorouter]

Leisure battery capacity is usually quoted at the '20hour rate'. For example a 100 amp-hour battery should be able to supply 5 amps for 20 hours, at which point it is entirely flat. Not a good idea for your expensive batteries, because they will likely be damaged by doing this.

However, 5 amps for 10 hours should bring it down to 50% full, where the voltage is about 12.05 volts. Make sure the battery is fully charged first, then load it with 5 amps for 10 hours. Then disconnect everything and let it rest for at least an hour. Measure the resting voltage. Ideally it should be 12.05 volts. If it's much less, the battery capacity is degraded from its original value.

A convenient 5 amp load is a single old-style halogen headlamp or foglamp bulb, which is about 55 watts.

 

[Johntheo]

Thank you. I am rapidly coming to the conclusion that I need new batteries. I very much appreciate the helpful advice I have received and feel I now know a lot more about how to look after them and keep them going as long as possible.