Best way to charge my leisure battery.

[A900ss]

Hi,

 

I’ve been away for a week around the Black Forest and

Alsace and what an amazing week. First real holiday in my van and loved it.

 

I’m now back and the van probably won’t be used for a couple of weeks. Leisure battery is at about 60% so what is the best way to charge it? Should I plug it into my home mains electricity or is it ok to just let the solar panel recharge the battery over the next couple of days. Battery is sealed lead acid 180Ah.

 

Thanks in advance.

[colin]

It seems strange that your battery is at 60% on returning home, but that would depend on how far you drove since last taking it down.

That aside, if we where parked outside we would leave the solar to do the job, but that depends on how big your solar panel is, especially at this time of year.

[A900ss]

Thanks.

 

Battery is down to 60% ish as I came home a couple of days ago but I have left the fridge on whilst parked on the drive.

:-D

[stevec176]

I have a 100w solar panel and 2 100w Leisure batteries and both are kept charged by the solar panel, even during winter, unless you park your van in the shade.

[StuartO]

If your motorhome is to be idle for a while it would make sense to adopt your storage routine, and in order to preserve as much service life for your batteries as possible, get them fully charged again and then maintain a safe storage voltage rather than subject them to intermittent charging, as would happen if you leave your solar panels on. If your MH has a built in mains charger by all means leave EHU connected but disconnect the solar panels - usually just a matter of taking out a fuse. Worth checking the voltage across the leisure batteries once they are fully charged. Anything in the range 13.2 to 13.8 will minimise any risk of electrolyte loss but no higher, which is why you want the solar panels off line.

[Tracker]

A900ss - 2021-09-27 5:11 PM

 

Thanks.

 

Battery is down to 60% ish as I came home a couple of days ago but I have left the fridge on whilst parked on the drive.

:-D

 

The fridge only normally works on 12v when the engine is running due to it's high current drain which would flatten any leisure battery very quickly.

 

If you need the fridge on better to plug in mains from the house and run it on 230V, or for short term simplicity just use gas.

 

I found the best way was to avoid all that unreliable electronic gubbins and disconnect the batteries. They should hold a decent charge for weeks and this can be easily checked and topped up as required - it did prove more reliable for us done manually with reminders on the calendar and it certainly seemed to help the batteries!

[Derek Uzzell]

Tracker - 2021-09-27 7:19 PM

 

...The fridge only normally works on 12v when the engine is running due to it's high current drain which would flatten any leisure battery very quickly...

 

That’s indeed the case when a fridge is the 3-way type, but a 12V compressor fridge needs to be operable from a 12V supply (eg. a motorhome’s leisure battery) when the vehicle's engine is not running.

 

(There’s nothing in other posts from A900ss to identify the type of fridge his campervan has.)

 

This May 2021 forum thread may be worth reading and I note that the 110Ah leisure battery mentioned then now appears to have been upgraded to 180Ah

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Leisure-battery-conditioning/58235/

[tonyishuk]

Don’t forget your vehicle battery, which generally will discharge at a faster rate than the habitation battery when both “” at rest”” .

 

The vehicle battery usually runs the alarm system, door locking system , waiting for an open the door signal and keeping the ecu from going dormant. Maybe other bits such as trackers, if you have one.

 

I use a Ctek charger that has a connector with a red, yellow, green indicator built in. If I pop my head in the door and see a red led, I know it’s time to give the battery a charge.

 

( Other chargers and LEDs are available!)

 

Rgds

[747]

I too have a battery charging problem but it is not my van. :'(

 

My Grandson left his recently acquired BMW 3.5 litre car at ours while he works in Ireland. I put my digital voltmeter into the cigar lighter and am only seeing 12.0 volts. There is no sign of a battery under the bonnet so I may have to connect a charger to the positive pole used when starting from the battery of another vehicle. The last thing I want is it to go flat as the problems will be above my pay grade. :D

[Derek Uzzell]

Pity you didn’t provide the age and model-number of your grandson’s BMW car, but you might try looking in the boot.

 

https://advancedbatterysupplies.co.uk/blog/bmw-car-battery-help/2013/12/bmw-5-series-car-battery-location/

 

https://advancedbatterysupplies.co.uk/blog/bmw-car-battery-help/2013/12/bmw-3-series-car-battery-location/

 

https://advancedbatterysupplies.co.uk/blog/bmw-car-battery-help/2013/12/bmw-1-series-car-battery-location/

 

 

[747]

 

Cor blimey, it's in the boot. 8-)

 

Thanks Derek.

 

BTW it is a M135i :D

[A900ss]

Derek Uzzell - 2021-09-28 9:19 AM

 

Tracker - 2021-09-27 7:19 PM

 

...The fridge only normally works on 12v when the engine is running due to it's high current drain which would flatten any leisure battery very quickly...

 

That’s indeed the case when a fridge is the 3-way type, but a 12V compressor fridge needs to be operable from a 12V supply (eg. a motorhome’s leisure battery) when the vehicle's engine is not running.

 

(There’s nothing in other posts from A900ss to identify the type of fridge his campervan has.)

 

This May 2021 forum thread may be worth reading and I note that the 110Ah leisure battery mentioned then now appears to have been upgraded to 180Ah

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Leisure-battery-conditioning/58235/

 

Correct. I have a 12V Compressor fridge.

 

Thanks.

[Derek Uzzell]

747

 

It’s not that uncommon for a car’s starter-battery to be in the boot (trunk). This USA thread discussed the matter and BMW was mentioned.

 

https://mechanics.stackexchange.com/questions/41651/why-do-some-cars-have-battery-under-the-trunk

 

Some years ago, when the gel leisure-battery of my Hobby motorhome failed in France, I bought a Banner AGM battery as a replacement as this was the only true ‘no maintenenance’ battery I could lay my hands on at the time. When I got back to the UK there seemed to be some doubt about the battery’s specification and, finally, I contacted the wholesaler who had provided the battery to the garage that sold it on to me. The wholesaler told me that he rarely sold this battery as it was used on VW Phaeton cars and there weren’t too many of these in France. When I checked further I found that the Phaeton model actually had two of these large batteries, both in the car’s boot. It’s mentioned on this link

 

http://karakullake.blogspot.com/2011/12/2-batteries-in-phaeton.html

[Derek Uzzell]

A900ss - 2021-09-29 7:11 AM

 

Correct. I have a 12V Compressor fridge.

 

Thanks.

 

So is your current leisure-battery’s capacity 180Ah or 110Ah?

[747]

Back on topic. :D

 

If the van of the OP will not be used for a matter of weeks, surely the fridge should be emptied and switched off. That way, solar power should keep the batteries topped up. I know my 2 leisure and engine battery are kept topped up by my 100 watt panel. They sometimes need a boost in midwinter but it is still only September.

 

Have I missed something? :-(

[A900ss]

Derek Uzzell - 2021-09-29 7:24 AM

 

A900ss - 2021-09-29 7:11 AM

 

Correct. I have a 12V Compressor fridge.

 

Thanks.

 

So is your current leisure-battery’s capacity 180Ah or 110Ah?

 

185ah (1 x 110 and 1 x 75)

[A900ss]

747 - 2021-09-29 7:58 AM

 

Back on topic. :D

 

If the van of the OP will not be used for a matter of weeks, surely the fridge should be emptied and switched off. That way, solar power should keep the batteries topped up. I know my 2 leisure and engine battery are kept topped up by my 100 watt panel. They sometimes need a boost in midwinter but it is still only September.

 

Have I missed something? :-(

 

The fridge has been switched off.

 

The original question was what is the best way to charge the battery back up to 100%. Plug into Electricity or just let solar do its thing.

 

I’m leaving it to the solar.

 

Thanks.

[rajohno]

I dont have solar, so when parked up at home short term before a trip i will turn on the in built charger 24 hours before to boost up the batteries.

For Longer term park up however (lockdown a prime example) because the in built charger is quite a high power device (20 Amp) for my capacity batteries, I use a small portable Optimate intelligent charger. It takes a while to get the batteries top line, but slow is better and can be left connected indefinitely if needed.

[spirou]

rajohno - 2021-10-02 1

because the in built charger is quite a high power device (20 Amp) for my capacity batteries, I use a small portable Optimate intelligent charger. It takes a while to get the batteries top line, but slow is better and can be left connected indefinitely if needed.

 

Maximum power means nothing under these conditions. When a battery is nearing full it will only accept a limited current anyway. For storage you need to consider the floating/storage voltage. Some will keep the battery at 13.8V, some down at 13.2, some switch between 13.8 and off until it drops below 13 etc. There are different scenarios being used but lower voltage will be better for long periods of inactivity. This all applies to lead batteries, lithium is a somewhat different story.

[Derek Uzzell]

A900ss’s campervan has a Sargent EC160 unit with a 150W 13.8V fixed voltage battery charger. The EC160 was commented on here

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Battery-drain-with-Sargent-Ec160/51938/

 

Sargent seemingly don’t provide guidance on the maximum battery capacity the charger is designed to handle, so there’s no way of easily knowing if 185Ah would be OK as far as Sargent is concerned.

 

Received wisdom is that, when multiple leisure batteries are to be installed, those batteries should ideally be identical. (same type, make, model, capacity and age). This April 2021 forum thread (and the links in it) may be worth wading through

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Adding-a-extra-leisure-battery/57935/

 

[A900ss]

Derek Uzzell - 2021-10-03 9:11 AM

 

A900ss’s campervan has a Sargent EC160 unit with a 150W 13.8V fixed voltage battery charger. The EC160 was commented on here

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Battery-drain-with-Sargent-Ec160/51938/

 

Sargent seemingly don’t provide guidance on the maximum battery capacity the charger is designed to handle, so there’s no way of easily knowing if 185Ah would be OK as far as Sargent is concerned.

 

Received wisdom is that, when multiple leisure batteries are to be installed, those batteries should ideally be identical. (same type, make, model, capacity and age). This April 2021 forum thread (and the links in it) may be worth wading through

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Adding-a-extra-leisure-battery/57935/

 

I don’t use the Sargent to charge the batteries. I use my CTEK mxs 5. It might not be the fastest at 5 amps but it is smarter than the Sargent.

 

I know my leisure batteries are of different sizes but other reports I’ve read state that age/chemistry is the most important thing when pairing and mine are similar ages and same chemistry.

 

I think the topic has gone a little off from the original question. My batteries needed topping up from a low-key SOC and I wanted to know if Solar alone was an appropriate method or should I use a charger to speed things up? I wasn’t really asking about ongoing maintenance (this is not meant to sound rude in any way, apologies if it does).

 

Once full, they are maintained sufficiently by solar. As it is, I’ve let solar top them up and they are now in float mode according to the Victron MPPT controller.

 

Many thanks for everyone’s input. It has been really helpful.