Recharging a run down leisure battery

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steve yates

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Brand new 115ahr leisure battery from halfords, lost the solar panel that kept it trickle charged crossing the Minch. After about 4 days it didn't have enough juice to run the garmin GPs unit, but could run the echo sounder, and if I switched the cabin lights on, they came on, but were quite dim. ( old ones, not leds)

I have heard you are not supposed to discharge them to below 50%, but I'm assuming this is not that uncommon.

What's the best way to get it back? Get to a pontoon somewhere with shore power and use something like this?
http://http://www.halfords.com/workshop-tools/garage-equipment/car-battery-chargers/halfords-fully-automatic-battery-charger?cm_mmc=Google+PLA-_-Garage+Equipment-_-Car+Battery+Chargers-_-329075&_$ja=tsid:60494%7Ccgn:GoogleShopping%7Ckw:329075&istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istItemId=aiwrritl&istBid=tztx&_$ja=tsid:35522%7Ccid:344535484%7Cagid:25437357364%7Ctid:aud-80976661069:pla-224048583844%7Ccrid:89797547524%7Cnw:g%7Crnd:12582493621568936788%7Cdvc:t%7Cadp:1o4&gclid=COjy-s-ox88CFUI6Gwodb4cL1w
 
If I were in your shoes, I would buy the ctek mxs 5.0 charger (I think that is the correct model for the capacity of your battery) even though I work on a shoestring budget. Simply because the battery was new not long ago and therefore worth looking after.

Despite a few minor problems with ctek chargers (they are not really a fit and forget charger as I have found out from posters here), their benefits are great; they really do recondition a battery; it has brought an old car battery of mine from 12.2volts (drain on car somewhere and failing alternator) back to 12.7 volts (and the battery has remained healthy thereafter.

As your battery is new, perhaps you would fork out £53-ish for a ctek (Amazon Prime?).

Could keep the charger for lots of other uses.

Or, simply stick it on a 'normal' charger ensuring voltage does not go above 14Volts (as a rough guide - read manufacturer's guidelines) and try not to let too many amps in straight away (as in not 10 amps) - I'd say 2 amps-ish and leave it for charging like that for 48 hours or more whilst reducing the voltage to about 13 volts and reducing current too; really saturate the thing with lovely electrons.

If you can't do that (or if an 'ordinary' charger) won't charge the battery (because charger thinks battery is too flat, put the battery in parallel with a good battery and charge both together via 'ordinary' charger (this simply tricks charger into thinking it is charging a healthy battery and allows volts and current into the poorly one.

Then again, is it sealed lead acid, AGM, calcium, etc. Ctek usually sorts them all out, but some special leisure batteries are supposed to have a 3 stage charger (such as my Camden Boss battery - but I get around that). Ctek is an 8 stage charger (sort of).

Halfords give a 5 year warranty, perhaps they would recommend the best charger (then again they may simply wish to sell you a Halfords charger).
 
Shit, 48hrs! I thought it would be about 4-6 hrs or so, but then I do know nowt about this stuff.

Thank you for that really helpful post though. My problem is the boat is in plockton, and I want to try and sail it back to Cumbria. ( failing that at least the firth of Clyde) My 3 available weeks are shrinking rapidly as I have done my back in and am falling behind my work as I can't sit at the desk long enough, so I might end up with only two weeks.

I'm wondering now if I shouldn't just buy another cheaper battery, say 60-80 a hrs and swap the drained one out, to be taken home in the car later and recharged.

Or even, if I connected the new solar panel, and sailed for a couple of days without power, just letting the panel charge to the battery... Would that be able to do the job? At least I'm not tied up at a pontoon for the 2 days. In actual fact the nearest is Mallaig and it will take me 2 days to get there probably, depending on timing of tides and daylight.
Would there be any mileage in doing that and then topping up to full in Mallaig from shore power with a charger?
 
I don't take any pleasure in adding to your woes, but it's not just the deep discharge that is damaging your battery but leaving it discharged. You need to get some charge into it as soon as possible. (And try not to let it get so discharged again unless you like spending money on new batteries!)

One 110 ah battery is only good for perhaps 5 amps over 12 hours and then (if you charge at 5 amps) at least 14 or 15 hours of charging to get it recharged. (It's actually not quite that simple as the battery won't accept charge at the same rate for that length of time. )

The bad news is that leaving the battery discharged is not doing it any good whatsoever.
 
A small solar panel trickle charger is going to take a very long time indeed to benefit the battery in northern Scotland. At this time of year my 125 watts of panel in Greece is struggling to keep up with fridge usage, which it does very easily in the middle of the year. We are now past the equinox, not helped by anchoring in bays with mountains all around, so useful daylight hours are a long way less than 12. Mains charging is really the only option in your case.
 
As said, get it charged as quickly as possible. Don't p*ss about pondering chargers. Get it out and take it to a garage. If you're back's too bad, get help.

Then buy a charger, such as the ctek mentioned.

Batteries get accidentally flattened all the time. It doesn't do them any good, but usually they come back, especially if they're as new as yours. The longer it sits flattened, the less likely that is.

I realise it's a small boat without much equipment, but if you don't contrive some means of monitoring your battery you're going to have more adventures like this. Buy a cheap meter and get into the habit of measuring the voltage periodically (after the battery has rested with no load and no charging for at least a couple of hours). If the rested voltage gets below about 12.2V, don't discharge it any more if you can possibly help it. Hoping for the best is not the route to battery happiness.

Am I right in thinking it's a 100Ah battery? If so, that gives you 40, at a stretch 50Ah to play with, assuming it was truly fully charged to begin with, which it probably won't be most of the time with just a small solar panel for company.

(Duh...I see it's 115Ah, so make that "45, at a stretch 55".)

Good luck.
 
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steve yates said:
Brand new 115ahr leisure battery from halfords, lost the solar panel that kept it trickle charged crossing the Minch. After about 4 days it didn't have enough juice to run the garmin GPs unit, but could run the echo sounder, and if I switched the cabin lights on, they came on, but were quite dim. ( old ones, not leds)

I have heard you are not supposed to discharge them to below 50%, but I'm assuming this is not that uncommon.

What's the best way to get it back? Get to a pontoon somewhere with shore power and use something like this?
http://http://www.halfords.com/workshop-tools/garage-equipment/car-battery-chargers/halfords-fully-automatic-battery-charger?cm_mmc=Google+PLA-_-Garage+Equipment-_-Car+Battery+Chargers-_-329075&_$ja=tsid:60494%7Ccgn:GoogleShopping%7Ckw:329075&istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istItemId=aiwrritl&istBid=tztx&_$ja=tsid:35522%7Ccid:344535484%7Cagid:25437357364%7Ctid:aud-80976661069:pla-224048583844%7Ccrid:89797547524%7Cnw:g%7Crnd:12582493621568936788%7Cdvc:t%7Cadp:1o4&gclid=COjy-s-ox88CFUI6Gwodb4cL1w
Click to expand...

You need a charger that will recharge a battery from a deeply discharged state ... They won't all do that.

A Ctek MXS 5.0 has been suggested. but the output is only 5amps max Recharging will take a long time

The more powerful MXS 7.0, with 7 amps max output, would be better.

An MXS 10, with 10 amps output, better still
 
I'm using a Ring Smart Charger (16 A) at home with great results. It is a so called intelligent charger which includes 'help' against charging dead batteries.

To avoid the 'help' on batteries that are really down I've had success by tricking it to believe voltage is OK by either forcing it with and old fashioned charger for some minutes or temporarily adding an extra battery in parallel until the charger is at work.

Like many other intelligent chargers it has a number of stages and programs and will run through these. It is therefore crucial to allow the time needed for all stages to complete. Depending on state and battery response to the charge, time will vary.

If you regularly experience deep discharge I'd either fit a battery that is designed for the use or a voltage protector to cut out when the voltage gets under or over predefined levels.
 
Spi D said:
I'm using a Ring Smart Charger (16 A) at home with great results. It is a so called intelligent charger which includes 'help' against charging dead batteries.

To avoid the 'help' on batteries that are really down I've had success by tricking it to believe voltage is OK by either forcing it with and old fashioned charger for some minutes or temporarily adding an extra battery in parallel until the charger is at work.
Click to expand...

I can't remember which model Ctek I've got but it's on permanent connection in my garage. It has an override button which bypasses all the intelligent stuff and simply pumps amps into a dead battery like a "maintenance" charger until you can switch it over to the intelligent cycle without it failing.

Richard
 
steve yates said:
1.Just on the off chance, what does the voltage need to drop to to be considered flat?

2. And would dim cabin lights be an indicator that it had got that far?
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1. Almost dead flat would be around 11.5V, but it would read lower with any drain. You do not want to get anywhere near that. As said 12.2V rested voltage is as low as you should regularly go. These figures vary slightly depending on the battery spec.

2. Oh, yes. Surely you've been in a car where the voltage drops to the point it won't turn the starter motor. The lights still work, but dimly, until even the interior light is just a dim glow.
 
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Rule of thumb, very roughly (and depending upon what battery you have) 12.1 volts you are looking at a flat battery.

If at rest it is 12.5 Volts, it is suffering damage.

Could this be a solution?
I take it you have to drive to pockton, leave car and sail home?

What if you buy a cheapo battery £30 ish wet lead acid (fully charged), stick in boot of car and drive north.

Also buy a solar panel of 20W (£25 on ebay here http://www.ebay.co.uk/itm/NEW-20W-1...e0c2418&pid=100011&rk=1&rkt=1&sd=401155031986)

Make sure you have jump leads in boot of car.

When at Pockton, take £30 battery and stick in boat, row the good leisure battery back to our car.

Stick leisure battery in footwell and hook up in parallel to car starter battery and also hook the 20W (or larger ) solar panel to the batteries (solar panel on parcel shelf facing South). The car battery will help the leisure battery immediatley and over the time it takes you to sail south, the solar panel MAY put enough juice into both batteries to stop the leisure battery deteriorating (as stated, TIME is of the essence). Be prepared when returning to car to jump or push start it (after disconnecting leisure battery)

OR, sit in car park, start car, hook leisure battery (sitting in footwell) up to starter battery with jump leads and let car run for an hour. 14.5V will force electrons into both batteries for an hour. Then stop car and unhook jump leads and attach south facing solar panel to leisure battery only. Aat least leisure battery gets some amps every day whilst you are away for 2 weeks?

Also have a solar panel on boat to keep cheapo £30 battery ticking over. Use as little electricity as possible.

A very scatter brain idea above that could be improved upon with a little more thought perhaps, but I have to rush off somewhere now.

Good luck
 
All this talk of Ctek chargers which put out 5A, or 7A, seems a bit alien to me.

When I got our current narrowboat, the existing charger has a max of 25A, and the engine alternator charges up to around 33A at best - these were nowhere near enough, IMHO, and I quickly got an inverter charger which starts at 80A on bulk charge, and can be set to run at up to 15.5V.

Admittedly I had a 3 x 110Ah bank, (and now have a 450Ah bank), but even if I had only a 110Ah domestic battery, I wouldnt be happy having to wait for a 5A charger to replace the 50Ah used if depleted to 50% SOC - that's 10 hours, even if you assume that the max charge is drawn for the whole of the period.

In fact, given the assumption that when a battery is drawing only 2% of capacity, (at 14.4V), it is considered to be full, 5A into a 110Ah bank, doesnt seem to be particularly effective.

I can see the Ctek 5Ah and 7Ah units being effective for a car or motorcycle battery which is regularly topped up by the alternator, and may be helped by a trickle charge if being left for some time.

I'm not criticising the use of these low Ah chargers, I merely dont understand their use in relation to replenishing relatively high discharges from batteries?
 
Sailingsaves said:
Rule of thumb, very roughly (and depending upon what battery you have) 12.1 volts you are looking at a flat battery.

If at rest it is 12.5 Volts, it is suffering damage.

Could this be a solution?
I take it you have to drive to pockton, leave car and sail home?

What if you buy a cheapo battery £30 ish wet lead acid (fully charged), stick in boot of car and drive north.

Also buy a solar panel of 20W (£25 on ebay here http://www.ebay.co.uk/itm/NEW-20W-1...e0c2418&pid=100011&rk=1&rkt=1&sd=401155031986)

Make sure you have jump leads in boot of car.

When at Pockton, take £30 battery and stick in boat, row the good leisure battery back to our car.

Stick leisure battery in footwell and hook up in parallel to car starter battery and also hook the 20W (or larger ) solar panel to the batteries (solar panel on parcel shelf facing South). The car battery will help the leisure battery immediatley and over the time it takes you to sail south, the solar panel MAY put enough juice into both batteries to stop the leisure battery deteriorating (as stated, TIME is of the essence). Be prepared when returning to car to jump or push start it (after disconnecting leisure battery)

OR, sit in car park, start car, hook leisure battery (sitting in footwell) up to starter battery with jump leads and let car run for an hour. 14.5V will force electrons into both batteries for an hour. Then stop car and unhook jump leads and attach south facing solar panel to leisure battery only. Aat least leisure battery gets some amps every day whilst you are away for 2 weeks?

Also have a solar panel on boat to keep cheapo £30 battery ticking over. Use as little electricity as possible.

A very scatter brain idea above that could be improved upon with a little more thought perhaps, but I have to rush off somewhere now.

Good luck
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I'm liking the sound of this, thank you. I have a new solar panel ready to fix to boat. I could modify the last idea, and once run attached to car battery with jump leads, get the Ctec charger and leave it charging the battery at my friends house, bound to be more effective than a solar panel? Assuming the car gets enough juice into it.

When we say time is of the essence, how long are we talking? Because it's basically been flat since the 21st Sep, and I'll get there next Thursday prob.

The battery cost £85, maybe I should just bite the bullet, and buy another and swap them out. Prob same price or less than another cheap one and a charger or panel, although I will only have one battery, rather than possibly two (if recoverable) and a charger or extra solar panel.
 
Richard10002 said:
All this talk of Ctek chargers which put out 5A, or 7A, seems a bit alien to me.

When I got our current narrowboat, the existing charger has a max of 25A, and the engine alternator charges up to around 33A at best - these were nowhere near enough, IMHO, and I quickly got an inverter charger which starts at 80A on bulk charge, and can be set to run at up to 15.5V.

Admittedly I had a 3 x 110Ah bank, (and now have a 450Ah bank), but even if I had only a 110Ah domestic battery, I wouldnt be happy having to wait for a 5A charger to replace the 50Ah used if depleted to 50% SOC - that's 10 hours, even if you assume that the max charge is drawn for the whole of the period.

In fact, given the assumption that when a battery is drawing only 2% of capacity, (at 14.4V), it is considered to be full, 5A into a 110Ah bank, doesnt seem to be particularly effective.

I can see the Ctek 5Ah and 7Ah units being effective for a car or motorcycle battery which is regularly topped up by the alternator, and may be helped by a trickle charge if being left for some time.

I'm not criticising the use of these low Ah chargers, I merely dont understand their use in relation to replenishing relatively high discharges from batteries?
Click to expand...

Real leisure batteries are very fickle (depending upon type and manufacturer) to how they like to accept their current.

Some like a few amps only to begin with and so forth.

I agree about crankers though. The recommended battery for my 4x4 is still not large enough for the car really and the alternator needs to be run for 45 mins to put back in what was used to start the big diesel. A short trip around the corner 4 times in a day (in winter) and the calcium cranker is ailing. I have a 5w solar panel that is attached to said vehicle permanently and whenever the engine is not running this trickle chargers the battery. Some owners have fitted two crankers to this type of vehicle.
 
steve yates said:
I'm liking the sound of this, thank you. I have a new solar panel ready to fix to boat. I could modify the last idea, and once run attached to car battery with jump leads, get the Ctec charger and leave it charging the battery at my friends house, bound to be more effective than a solar panel? Assuming the car gets enough juice into it.

When we say time is of the essence, how long are we talking? Because it's basically been flat since the 21st Sep, and I'll get there next Thursday prob.

The battery cost £85, maybe I should just bite the bullet, and buy another and swap them out. Prob same price or less than another cheap one and a charger or panel, although I will only have one battery, rather than possibly two (if recoverable) and a charger or extra solar panel.
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That was a cheap price for a 110Amphour leisure. Not a lot you can do about the time aspect. Just get it to your mate's house on a charger when you can.

The camping and caravan club did a great article on the internet (that I can't find now) that stated one gets what one pays for with leisure batteries. They even said that with cheapo ones that you lose 20% of its capacity within the first week of use (because cheapo ones are made with thin plates and so forth).

So you have a lot of options to consider.

Hope all goes well.
 
Sailingsaves said:
Or, simply stick it on a 'normal' charger ensuring voltage does not go above 14Volts (as a rough guide - read manufacturer's guidelines) and try not to let too many amps in straight away (as in not 10 amps) - I'd say 2 amps-ish and leave it for charging like that for 48 hours or more whilst reducing the voltage to about 13 volts and reducing current too; really saturate the thing with lovely electrons.
Click to expand...

I try to avoid going head on with other people's ideas but I'm afraid that is just wrong (and does not remotely resemble what a CTek charger would apply to it).
Assuming this is a flooded battery, including "sealed maintenace free" but not SLA or AGM, ideally you would want to put this on charge at 14.4V with about a 10A current limit for probably about 12 hours then reduce it to 14V or 13.8V depending on settings available for another 24 hours minimum (no maximum).
If it's really really flat - not the case if it will still light bulbs visibly - you could need a lot more voltage to get it started. In tests in the lab in the battery company I worked for we used up to 18V occasionally with varying degrees of success.
The 12 hrs is approximate, would need a bit of judgement, but you want to get to where the current has dropped well down and the battery is fizzing nicely. Don't worry it takes some hours to lose significant water. Certainly it will benefit from at least 8 hours.
This is more vigorous than a normal charge.
13V will achieve nothing, it's not even a maintenance level.
The longer you leave it discharged, the more it will deteriorate.
 
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