Leisure Battery Charging

[KennyDuncan]

Is it ok to charge the leisure battery with a smart charger e.g. CTEK, without removing and disconnecting from the motorhome? I assume I would need to ensure the main habitation switch was off, and any other charging source e.g solar panel was also off.

Any help grateful received.

 

[pappajohn]

Yes, that's what your onboard charger would be doing.
No need to Disconnect any other charging source, they will all work together as one.

 

[TheBig1]

why? the onboard charger is far more powerful on the majority of vans

 

[KennyDuncan]

My mh has a fairly primitive charger (Sargent) which basically pushes out 13.8v constant i.e not smart, just a power supply. Thought that connecting up something else might be kinder on the battery when mh not in use. Obviously the smart charger may push out a higher voltage, so was just a little worried that this may impact on other connected equipment. No expert and just a newbie so happy to be corrected.

Cheers

 

[GPW]

My mh has a fairly primitive charger (Sargent) which basically pushes out 13.8v constant i.e not smart, just a power supply. Thought that connecting up something else might be kinder on the battery when mh not in use. Obviously the smart charger may push out a higher voltage, so was just a little worried that this may impact on other connected equipment. No expert and just a newbie so happy to be corrected.

Cheers

13.8 V is safe but will not charge the battery fully and can lead to cell imbalance after a while. Lead acid (wet) needs 14.4V now and again and AGM/GEL needs 14.7.

Look at Victron stuff or other decently made chargers (or inverter chargers) that do the proper stages and set it up for your battery type. That will give you a full charge and give the battery a decent amount of lifetime.

All 12V automobile stuff should be fine at 14.7V, but if you buy a charger with a pulsed 'repair' feature it's probably best to disconnect it for that. You can buy decent cheap isolators for batteries that fit on the terminal so I'd get one and use it as required!

Note that once fully charged the Sargent will probably be fine at the 13.8V 'float' voltage but some chargers do dip down to 13.2V for 'storage' IIRC.

^{_{Subscribers  do not see these advertisements}}

 

[pappajohn]

Or you could connect your CTEK charger and get 3 or maybe 4 years out of your battery then buy another one.
Battery 'nursery' (yes that's what it's become, like looking after a bloody baby) is becoming an obsession.
If you check the fluid level from time to time and don't discharge it too far it will last long enough.

£1200 for a lithium battery.... That's 40 to 50 years worth of lead acid batteries, will that lithium battery last 40 or 50 years... I doubt it.

 

[PhilandMena]

The Sargent system since around 2011 have intelligent battery chargers fitted and are very good for lead acid batteries. No need to firt another unless your battery bank is bigger than 220 AH. The CTEK is the dogs bollocks.

 

[KennyDuncan]

The Sargent system since around 2011 have intelligent battery chargers fitted and are very good for lead acid batteries. No need to firt another unless your battery bank is bigger than 220 AH. The CTEK is the dogs bollocks.

Unfortunately I don't think the EC155 is intelligent! The things you learn after buying your first MH .

Thanks for the responses. A bit more enlightened now.

 

[autorouter]

The choice between smart and dumb chargers is not as simple as usually stated. Some 'smart' chargers sense the battery current and increase the voltage as the battery current falls. That's fine if all they are doing is charging a battery.

The complication in a MH is that the charger can't tell if its output is going to the battery or the habitation loads. When the battery is fully charged, the charger output current reduces to a trickle charge, as it should. However, as the current from the habitation loads increases, the voltage reduces, because the charger thinks the battery is discharged because there is a high current. So the voltage gets lower and lower, so that after a day or so the battery really is rather discharged.

Then you disconnect the EHU, drive a short way to an aire with no EHU, and wonder why the battery is nowhere near charged.

There's various ways to overcome this problem. One is to have a proper multiphase charger that goes through the full cycle when the voltage drops by a significant amount (eg CTEK). Another way is to have a fixed 'power supply' charger that sends 13.8 volts to the battery and habitation no matter what (eg Sargent EC155).

The best way is a both a smart charger and a separate fixed habitation supply. Relays switch the habitation circuits from the battery to the fixed supply. At the same time, the smart charger is switched to the battery. This way is also more expensive, and not usually done on MHs

 

[autorouter]

Sorry, I didn't answer the question. The answer is yes, you can connect a CTEK charger. All chargers, solar controllers etc have diodes (electronic one-way valves) that prevent any back-flow of charging current, so at any time the one with the highest voltage wins.

^{_{Subscribers  do not see these advertisements}}

 

[GPW]

As Autoroute says the electrical environment of the motorhome is varied so the best idea is to buy a charger that is designed specifically for motorhome or marine usage.

So when looking at Ctek avod their car storage chargers and go for a model desiged for motorhomes - they do a good solar system - something 250 IIRC.

Also check Victron as they do an 'inverter-charger' which is the smartest way to integrate charging and inverter use because it turns your van into an intelligent UPS (Uninterruptible Power Supply) and can even do boost and fade (800VA and over) so convert dodgy campsite hookups into clean usable power.

On the other hand if the old 13.8V Sargent does the job it's easier to leave it there and just occasionally give the battery a boost charge to 14.7V (AGM) - which probably almost happens each time you drive a long distance anyway as most alternators run up to 14.4V (for their wet starter battery).