Time to replace our 8 year leisure batteries

UFO

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Our power usage is quite light, around 20ah/day in winter and 15ah/day in summer (see attached), but as I could fit 2 x 125ah into the battery space I went with more than we need.

Never use EHU apart from a couple of hours before we leave on a trip.

I asked Alpha for recommendations for replacement, their reply ‘The batteries you have there have lasted well, I am surprised with this as the particular batteries you have there are not over-engineered for deep cycle use’. That’s probably because of the installed capacity and light use, so limited deep cycling.

120AH Leoch Adventurer flooded lead-acid (SFL-120DT) at £99.99 or the 130 AH version at £109.99.
Or
110AH Expedition Plus Lead Carbon Gel Ultra Deep Cycle (EXP12-110C) at £189.99 or the 250AH version at £389.98.
Prices before discount.

I am tempted to replace like-for-like i.e 2 of the 120AH Leoch Adventurer flooded lead-acid.

Any thoughts or recommendations?

---------------------------
Equipment

The original equipment, Adria Twin PVC first registered June 2009.
- Schaudt EBL208S Elektroblock
- Schaudt LT311 Control Panel

In April 2013 I installed
- Alphaline Plus Deep Cycle Series DC31 MF 12v, 125ah, (20HR) Sealed Calcium battery x 2
- 140W solar panel
- Schaudt LR1218 Dual Battery Controller (Pulse Width Modulation - PWM)

Recently installed
TR16 (AiLi) Battery Monitor

Specification from manual
Schaudt EBL 208 S E
Battery charging with mains connection (EHU)
Leisure battery
• Charging curve IUoU
• Final charging voltage 14.3 V
• Charging current 18 A
• Voltage for float charge 13.8 V with automatic switching

Starter battery
• Charging current float charge of starter battery at max. 2 A

Battery charging via the Schaudt LR1218 solar pulse-width modulated regulator
• Maximum charging current 18 A
• Leisure battery and starter battery are charged simultaneously. The leisure battery has priority.

Battery charging while travelling
• Simultaneous charging of the starter battery and the living area battery by the alternator. Batteries connected in parallel via a cut-off relay
 

Attachments

  • Electrical loads.pdf
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the two options:
120AH Leoch Adventurer flooded lead-acid (SFL-120DT) at £99.99
or the 130 AH version at £109.99.
Or
110AH Expedition Plus Lead Carbon Gel Ultra Deep Cycle (EXP12-110C) at £189.99
or the 250AH version at £389.98.

If you use the "NCC" approved measurements, the 120AH Leoch is 92Ah@C20 and the 110AH Lead Carbon is 100Ah@C20, so actually a bigger capacity as far as the NCC are concerned (this is because the Lead Carbon battery is better at handling bigger loads).


Putting that aside, I would say the more expensive Lead Carbon Gel battery is the better value option as it is designed to give many more charge cycles and can be taken significantly lower than the wet cell option and would be what I would recommend for just about anyone who doesn't want to go down the Lithium route.

However ... clearly you look after your batteries and know just what you are taking from them, so if your future usage is pretty well the same as your previous use, is it worth spending nearly £200 more on the superior batteries if you won't take advantage of the benefits? probably not.
 
Please could someone tell me in non technical terms what deep cycle means please. 5 years ago when I bought my now terminally ill batteries the research suggested 2 110 gels would do for me. (No solar). Is it worth me getting a higher spec and are gels still the way to go? But in light of deep cycle stuff my aging or non exisyent brain cells are going the same way as the batteries cells and I'm now totally confused
 
On the subject of batteries and if there is someone out there who can advise, can I add to the question list?...

- What is the best way to increase the longevity of hab batteries? Do we use and charge? Keep them topped up at all times? Discharge to x% and recharge?

- How can you tell if you need new ones? Do the old ones stop taking charge? Do they not hold charge for a decent period of time?

- Is there a typical lifespan for batteries? If so is it something that one should change before any issues arise or will they start to reduce their effectiveness thereby giving you a clue to change them?

Sorry to hijack the thread :)
 
When a cycle count is quoted, that means the number of times the battery can be taken from full charge down to a recommended minimum capacity (typically 50% of full). Once you have "used up" that cycle count, the battery will only have a maximum of say 70% of what it started its life with.
For example:
A 100Ah battery with a 200 cycle count. If you draw 50Ah from it and then recharge, that is a cycle. Do that 200 times and your battery will no longer be a 100Ah battery but a 70Ah battery and you can only get 35Ah out of it.
It is not a sudden "200 cycles and drop from 100Ah to 70Ah" thing though, it is a gradual drop like a line on a graph. Each cycle takes a bit more maximum capacity out the battery.
And the more you take out each time between recharges, the faster the line on that graph drops. The less you take out, the flatter the line is. So if you take just 25Ah out the battery instead of 50Ah, you might get 500 cycles instead of 200. Which is why doubling the battery capacity could more than double the usable life of them.

All batteries of any technology last longest if they are not used. And the harder they are used, the less recharge cycles they can manage until they drop to a certain maximum capacity (say 70% of when new).
Lithium batteries have multiple thousands of cycles generally, but drive them hard - say 80 or 90Ah out a 100Ah battery and that cycle count drops a lot.
The cheaper Lead Acid batteries have cycle counts in the low hundreds and cannot cope well with deep discharge - that means drawing a battery below 50% (more than 50Ah from a 100ah battery). If you go below that on a simple Lead Acid, you start to hurt the battery and impact its ability to recharge well. Go a lot below that and you really hurt it.
A Deep Discharge Lead Battery is designed to be ab!e to go below 50% without significant damage. You still shorten its working life by doing so just like with the cheap Lead Acid or even Lithium, but you don't damage it like the cheap/simple Lead batteries.
The best Deep Discharge batteries you can discharge right down to fully discharged (100% DOD) and they will still be able to fully recharge without a problem. I wouldn't recommend you do that as a regular use, but they are capable of it. Deep Cycle batteries also end up with a much better chwrg cycle count at "normal" 50% discharge use than the cheap ones have (so instead of 200 cycles, you might have 1,000 cycles).

What should you get? No simple answer.
For example, UFOs battery question... For their use, they use very little of the battery capacity they have so their batteries have lasted well and th ability to deep discharge or even come close to 50% has not arisen. The less you take out the battery, the longer it will physically last.

5 years is not too bad for a battery, but it sounds like they have been bad for a while? If you say should have changed them last year, a 4 year life is still pretty reasonable. if you are drawing a fair amount of power out the battery (voltage dropping to 12V or below on a frequent basis) than you maybe need a bigger battery bank? Get a Deep Cycle battery maybe which could cost twice the price but last maybe 4 times longer?

Personally I am a fan of the Lead Carbon batteries over the basic Lead Acid. They are very forgiving of excessive discharge so if 'caught short' one night you will be ok for longer than a basic battery - that piece of mind can be priceless (my own Lead Carbon battery bank I know I can draw much more than if I had a simple battery. I don't intend to use that as a matter of course but having that reserve available is a good reassurance).

Lithium is the "daddy" of the Motorhome Leisure Battery options of course if your budget runs to it (plus any extras needed to support it).
 
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Thanks wildebus - very informative.
clap.gif


I just need to remember it now when mine need changing
smile.gif
 
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Just ordered 2 x 120AH Leoch Adventurer flooded lead-acid (SFL-120DT). I figure that as the last pair, which are similar, lasted 8 years these will do. I don't see how we use power changing as it has not over the last 12 years we have been using the van.

Thanks for all the advice, much appreciated, as batteries although on the face of it are simply storage devices in reality the 'science' is more complicated.
 
makes perfect sense :)
 
Your reply is excellent wildbus. I've copied and pasted it into my android 'notepad' app, and it'll stay there until I completely understand it.

I have a solar panel on the roof, which seems to keep both hab batteries topped up on a daily basis. Do you think this constant, but minor, re-charging has any affect on the batteries cycle count?
 
Not really. This is pretty typical and after all, the idea of batteries is to use them. No point in mollying them to such an extent that you double their design life but are frightened to use them :)
I've finally got round to adding the solar to my new (to me) van just a week ago and it is so nice to have the batteries keeping up a decent charge level with free power rather than having to plug in every few days. (y)

As an aside, I mentioned Lead Acid as being a good deep discharge battery ...
The following two bits of info may be of interest ...
Victron sell a battery they call a "AGM Super Cycle battery" and which many distributors market as an "immortal" battery as it can be drained down to 100% DoD - so totally drained. (I was quite tempted by these a few years ago).
Cycle life
≥ 300 cycles @ 100% DoD (discharge to 10,8V with I = 0,2C₂₀, followed by approximately two hours rest in discharged condition, and then a recharge with I = 0,2C₂₀)​
≥ 700 cycles @ 60% DoD (discharge during three hours with I = 0,2C₂₀, immediately followed by recharge at I = 0,2C₂₀)​
≥ 1000 cycles @ 40% DoD (discharge during two hours with I = 0,2C₂₀, immediately followed by recharge at I = 0,2C₂₀)​

Well .... they also sell a Lead Carbon battery which outdoes the "immortal" battery in every way!
Cycle life
≥ 500 cycles @ 100% DoD (discharge to 10,8V with I = 0,2C₂₀, followed by approximately two hours rest in discharged condition, and then a recharge with I = 0,2C₂₀)​
≥ 1000 cycles @ 60% DoD (discharge during three hours with I = 0,2C₂₀, immediately followed by recharge at I = 0,2C₂₀)​
≥ 1400 cycles @ 40% DoD (discharge during two hours with I = 0,2C₂₀, immediately followed by recharge at I = 0,2C₂₀)​
​
That 500 cycles at 100% DoD is actually better than the majority of wet cell batteries when cycled to just 50%. And the other manufacturers Lead Carbon are pretty similar.
 
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