Leisure battery charging

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JTQ

May 7, 2005
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The AA one identified at 1.5 Amp, really is more a "maintainer" than a particularly effective "Charger" for our circa 100 Ah capacity batteries, but given time it will charge as long as it can identify there is a battery connected.
Just often when we need a charger as opposed to a maintainer, time can quite likely not be on our side.

The CTEK 5.0 Amp unit would firmly be my recommendation for our typical car and caravan size battery uses, not cheap, but look out for offers, and it is likely to be a buy once and use completely unattended.
The others "can" like the Aldi & Lidl offering in the past not be used totally unattended in these have not auto reset after a power outage.

Edit: I would not go with a charger of much higher amperage, as then we start moving into possible issues with car CPU systems, best settle to being gentle, it's infinitely cheaper in the long run!
 
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JTQ

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1. As I have a 150w Sargent solar panel do I need to do anything before removing the LB?
2. Which terminal is best to disconnect first?
1) I would not uncouple , shade or do anything with the solar system, just ignore it and its controller ought just as when on an EHU, sort itself out.
2) with cars, where we can avoid making a spark on the battery post, with the explosion risks that brings, make the final connection and initial disconnection of chargers remote from the battery on the chassis, so with the negative (ground).
With a caravan or just the battery that option is not necessarily available, so do it with charger unplugged from mains, where the current will be way lower just the parasitic "load" of the charger. Though as always with it as well ventilated at the battery as possible.
 
Mar 14, 2005
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OC, I have no intention of making criticisms of you or anyone else's suggestions, it's just that for a typical caravan leisure battery that is a very low amperage out put charger, not sure exactly what it is designed for as it is a little bit on the big side for a motorcycle battery, perhaps it would be suitable for some of the lower capacity mobility scooter batteries.

May I suggest that at least a 3 amp output, preferably 5 or even 10 amp for a typical caravan leisure battery.

Over the years I have bought and now own a lot of battery chargers, from 0.8 amps for motorcycle battery, to 25 amp continuous charge\ 200amp max boost.

I have purchased 2 number Lidl and 2 number Aldi battery chargers, I possibly had value for money from them but discovered that they all expired just as the warranty period ended, I returned one under warranty and it was sent back repaired only for it to fail a couple of weeks later, of course the warranty had expired by that time.

I strongly suspect planned obsolence, my best guess being around 50 uses at best; they are OK for very light DIY use and that is what most people will use them for so should last for many years, I would say that I used them for moderate diy use, certainly not heavy diy or day to day use.

I now stick to C-TEK, Optimate, Noco and Victron, much pricier (the Victron being very overpriced for what it is, but it best suited a particular 280amp lifePo4 that I purchased) said battery chargers do last for my usage (usage that is not particularly heavy) and are proving more cost effective over time.
I have 4 Aldi/Lidl battery chargers which continue to maintain old LA car batteries used for intermittent use lighting in out buildings. The eldest must be 15 years. 3 of the four does have to be manually reset after a power outage, but 1 (a lidl) does automatically turn back on to just its trickle charge setting which has been fine for my application.

I also had a Ctek unit which did fail.. So you cant make generalised assumptions about reliability with any certainty.
 
Apr 23, 2024
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Banus, I am going to assume that the solar charge controller is connected to the battery and not the solar panel directly.

Assuming that is the case, I would disconnect the negative lead from the solar panel to the charge controller.
And then disconnect the battery earth terminal first then then the positive terminal, on reconnecting the battery it is positive terminal first followed by the negative battery terminal.
Then reconnect the earth wire to the charge controller.
A lot of solar panel charge controllers don't like the solar panel being connected first , then the battery. I have attended a few were the owner has removed the battery for some reason and when connected back into the caravan the controller either didn't start up or went into fault. Simply disconnecting one wire from the panel into the controller and then reconnecting solved the problem . On negative earth systems ( where the negative terminal is connected to the metal parts or is unswitched /common to all equipment ) then disconnecting it first and reconnecting it last is the safest option, particularly on cars where you may, if disconnecting the positive terminal first accidentally connect the positive terminal of the battery to the chassis of the car with a metal spanner. In caravans its not that important as there is very little metal close to the battery
 
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Nov 16, 2015
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So getting back to battery chargers in caravans, my "old" 2013 Coachman .

The handbook goes into depth as to the charging of the battery. 14.8v then drops to 13.2v then cycles. Up and down. Don't all the new caravans have these type of charger / 12volt @20 amp supply for the caravans
 
Nov 11, 2009
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So getting back to battery chargers in caravans, my "old" 2013 Coachman .

The handbook goes into depth as to the charging of the battery. 14.8v then drops to 13.2v then cycles. Up and down. Don't all the new caravans have these type of charger / 12volt @20 amp supply for the caravans
My 2013 also had similar, but as it was kept in store I always brought the battery home and pout it on the CTEK. An anti theft measure too.
 
Oct 19, 2023
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So getting back to battery chargers in caravans, my "old" 2013 Coachman .

The handbook goes into depth as to the charging of the battery. 14.8v then drops to 13.2v then cycles. Up and down. Don't all the new caravans have these type of charger / 12volt @20 amp supply for the caravans
My solar controller does something similar (when it's sunny). 14.8v for 2 hours then 13.7v maintenance charge. The caravan charger takes it to 13.7v then maintains that level.
 
Nov 16, 2015
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I decided last week to treat myself to a new charger, so I bought this one
Nexpeak , 10 amp on Amazon
I have tried it on my two batteries and the "repair mode" seems to have done it's job . One battery after being off charge would drop to 12.65v after 12 hours. Now after 6 hours on Repair, after 12 hour rest it now sits at 12.95v
Screenshot_20241214-102418.jpg
 
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JTQ

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Now after 6 hours on Repair, after 12 hour rest it now sits at 12.95v

But recovered with what percentage level of capacity?
The loss of capacity, effectively what batteries are all about storing energy, is what renders most to the salvage bin.

Have you tested to be able to comment on the new chargers ability to reset after an on charge mains power cut? This aspect might be of interest to others deliberating on charger purchases, certainly those living with overhead mains supplies.

Interesting price for what is a powerful domestic charger.
 
Nov 16, 2015
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But recovered with what percentage level of capacity?
The loss of capacity, effectively what batteries are all about storing energy, is what renders most to the salvage bin.

Have you tested to be able to comment on the new chargers ability to reset after an on charge mains power cut? This aspect might be of interest to others deliberating on charger purchases, certainly those living with overhead mains supplies.

Interesting price for what is a powerful domestic charger.
I haven't tried all the aspects of the charger yet, having only bought it last week. It feels slightly light , 1.26lbs (560 grms), the cables are quite short.
Time will tell if my purchase has been worth it.
To be truthful, I don't get many power cuts here and Charging my batteries would be one of the last things on my mind.
 
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I decided last week to treat myself to a new charger, so I bought this one
Nexpeak , 10 amp on Amazon
I have tried it on my two batteries and the "repair mode" seems to have done it's job . One battery after being off charge would drop to 12.65v after 12 hours. Now after 6 hours on Repair, after 12 hour rest it now sits at 12.95v
View attachment 8008
Hutch, would you mind putting your multimeter on it and measure if it actually outputs 10 amps, much appreciated if you can confirm (or otherwise).
Bestest
 
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JTQ

May 7, 2005
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Hutch, would you mind putting your multimeter on it and measure if it actually outputs 10 amps, much appreciated if you can confirm (or otherwise).
Bestest

At the risk of stating the obvious, my apologies if so.
To provoke it to push out its rated current the battery would need to be in a state requiring the charger to sense it has to adopt its "bulk" charging rate, be that the battery's SoF is low enough, you are very lucky to catch it peaking a pulse or it can be dragged down by a load it is providing.

Interesting would be the voltages it achieves during the absorption, float and long term caretaking phases, and in the latter does it actually drop to a zero positive current.
These values could well be specified in the manual it may have been provided with.
 
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Jul 18, 2017
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I have 4 Aldi/Lidl battery chargers which continue to maintain old LA car batteries used for intermittent use lighting in out buildings. The eldest must be 15 years. 3 of the four does have to be manually reset after a power outage, but 1 (a lidl) does automatically turn back on to just its trickle charge setting which has been fine for my application.

I also had a Ctek unit which did fail.. So you cant make generalised assumptions about reliability with any certainty.
We had a LA charger that was at least 50 years old and still going strong however the Jeep and the caravan both have AGM batteries and the spare battery at home is also AGM so had no alternative except to update the charger which can recharge LA, AGM or lithium batteries.
 

JTQ

May 7, 2005
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We had a LA charger that was at least 50 years old and still going strong however the Jeep and the caravan both have AGM batteries and the spare battery at home is also AGM so had no alternative except to update the charger which can recharge LA, AGM or lithium batteries.
That still could be useful if ever you had a battery go really flat that a more modern charger with smart technology could not sense what in needed to do, ignore it or assume it was a 6 volt rather than a 12 volt.
 
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That still could be useful if ever you had a battery go really flat that a more modern charger with smart technology could not sense what in needed to do, ignore it or assume it was a 6 volt rather than a 12 volt.
My son in law has it just in case of an emergency.
 
Nov 16, 2015
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That still could be useful if ever you had a battery go really flat that a more modern charger with smart technology could not sense what in needed to do, ignore it or assume it was a 6 volt rather than a 12 volt.
That is exactly, what I have done, my 20 year old Halfords charger, has a 20 amp fuse, and it charging voltage is a max of 13.5.
IMG_20241215_101856_714.jpg
 
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At the risk of stating the obvious, my apologies if so.
To provoke it to push out its rated current the battery would need to be in a state requiring the charger to sense it has to adopt its "bulk" charging rate, be that the battery's SoF is low enough, you are very lucky to catch it peaking a pulse or it can be dragged down by a load it is providing.

Interesting would be the voltages it achieves during the absorption, float and long term caretaking phases, and in the latter does it actually drop to a zero positive current.
These values could well be specified in the manual it may have been provided with.
I agree totally , the smaller the battery's capacity ,the shorter will be the max output period( On some of the 'smart' chargers the high current pulse can only be seen on an oscilloscope or data logger, the microprocessor does this to test the batteries internal resistance which gives it important information and on some you have to tell it what type and capacity the battery is and you can also buy a temperature monitor which also feeds back information a good quality LI-ion battery has this control system built in ) . To test caravan power supplies/chargers I have built a 15A constant current 'load unit ' and a smaller 5A constant current load so I can fully stress the repaired/upgraded charger/PSU's that come my way. One feature I'm looking for is the ability of the units is to shut down if the maximum rated current is exceeded sometimes caused by a shorted cell(s) in a battery. When charging a battery whether at home or in the caravan/motorhome careful monitoring is advised to avoid 'cooked' batteries and damage to fuses and wiring.
 
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That still could be useful if ever you had a battery go really flat that a more modern charger with smart technology could not sense what in needed to do, ignore it or assume it was a 6 volt rather than a 12 volt.
Friend gave me his Li ion battery after went flat and smart charger wouldn't kick it into life. My dumb 1.2A LA charger had no problems charging it as it outputs 12V regardless of battery state. 12V powered the BMS up so battery could take a charge.
 
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That still could be useful if ever you had a battery go really flat that a more modern charger with smart technology could not sense what in needed to do, ignore it or assume it was a 6 volt rather than a 12 volt.
I've got an alde smart charger I took off a customers small caravan as it couldn't detect a really flat battery and it would only charge it up to 6V(Customer left the caravan on their drive for months without being plugged in) so much for it being a 'smart' charger
 
Mar 14, 2005
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I've got an alde smart charger I took off a customers small caravan as it couldn't detect a really flat battery and it would only charge it up to 6V(Customer left the caravan on their drive for months without being plugged in) so much for it being a 'smart' charger
If a 12V LA battery has discharged to the point where smart charger saw it as only a 6V battery, then it has been allowed to discharge to the point where it is seriously compromised and probably permanently damaged, and there is a greatly increased chance any attempt to recharge it could be dangerous.

Recharging of such batteries should be carefully supervised and not done using automatic chargers designed for unsupervised maintenance, in case a failed cell or cells overheats with the possibility of an explosion.

Sadly the owner of the battery should have been "smarter" and maintained the battery correctly - don't blame the charger which was probably only doing exactly what it was designed to do for safety reasons.
 
Nov 16, 2015
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Hutch, would you mind putting your multimeter on it and measure if it actually outputs 10 amps, much appreciated if you can confirm (or otherwise).
Bestest
Sir Haggis, I put my batteries on charge today, but individual, they only drew 2.8 to 3 amps charge, but considering they were almost at 12.9 volts the current charge is not surprising.
 
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If a 12V LA battery has discharged to the point where smart charger saw it as only a 6V battery, then it has been allowed to discharge to the point where it is seriously compromised and probably permanently damaged, and there is a greatly increased chance any attempt to recharge it could be dangerous.

Recharging of such batteries should be carefully supervised and not done using automatic chargers designed for unsupervised maintenance, in case a failed cell or cells overheats with the possibility of an explosion.

Sadly the owner of the battery should have been "smarter" and maintained the battery correctly - don't blame the charger which was probably only doing exactly what it was designed to do for safety reasons.
Totally agree and yes I am a qualified electronics (retired) and a caravan engineer so yes I educated my client on battery maintenance and the need to keep it charged ,once I fitted a charger which wasn't too smart for its , and the batteries own good , after taking the battery home and nursing it back to health and then sealing the battery compartment and providing an external vent, all at no extra cost to the service I did on the caravan. Whoever installed the electrical system in that Freedom caravan and then sold it on wants horse whipping for putting someones life in danger
 

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