Leisure batteries and chargers

[Derbyshirehills]

Hi All
We are fairly new to motorhoming having been caravanners with the kids. We have instantly taken to wildcamping but realise the need to maximise our 12v system and so we are considering replacing the original 2011 105Ah leisure battery with 2 x new batteries.
But I have a sneaky suspicion that the number of batteries, and with what combined Ah capacity, is governed by the capability of our battery charger to fully charge them. Am I right? Is there a formula based on the charger's output which is 12 amps. I'm not at all technical so I'm probably using all the wrong words but I'm sure that there will be plenty of knowledgeable members out there who will be able to advise.
Many thanks
Derbyshirehills
PS Any good battery suppliers?

 

[The laird]

Trying to keep it simple if it were me 2 x 110 amp battery's ( same make and date
1 or two solar panels
Change all interior bulbs to l e d type
Watch your consumption and if managed correctly i.e. Not to waste you can stay off grid for days

 

[Obanboy666]

I had a similiar dilemma with my pvc, planned to add an additional 110 amp battery to give me 220 amps in total as I do a lot of wilding and like my tv and other luxuries lol.
Factory fitted Sargent control unit / charger only 12 amp and advised by Sargent it would charge my 220 amp battery bank but it would take a considerable amount of time and as the charger wasn't an intelligent charger I decided to fit a Ctek MSX 10 charger.
I just fitted an additional 240 v socket next to the leisure batteries and mounted the charger on the van wall next to the batteries. The charger came with 8mm eyelet cables for connecting to the batteries.
I use the original charger for the vehicle battery and the Ctek for the leisure batteries. I have a 100 watt solar panel connected to the leisure batteries but always put the van on ehu at home the day before venturing out to ensure the leisure batteries are 100% charged. I now never have to use ehu or my genny when out on my travels so money well spent imho.
Last week I spent 4 days parked up with out moving and batteries never went below 12.5 v and fully recharged by late morning.

 

[Canalsman]

Any good battery suppliers?

Full members benefit from 15% discount from Alpha Batteries. Details can be found here:

https://www.wildcamping.co.uk/forum.../58643-alpha-batteries-15-off-everything.html

Ideally batteries should never be discharged below 50% so if you double your battery capacity as you intend, 110 amp hours is what you'll need to recharge when on hookup. That will take around 9 hours so on that basis your existing charger will be fine.

If you have room on your roof to accommodate one or more solar panels that is an excellent thing to do. I have 220 amp hours of battery capacity and two 100 watt solar panels. The accepted rule of thumb is to have about the same number of watts solar panel output as you have amp hours battery capacity.

Solar panels laid flat on the roof are not very efficient, but they work well enough based on the above. I get around two thirds of the rated output from my panels when the sun is at its highest. Plenty enough to recharge the batteries by the middle of the day in the warmer parts of the year.

 

[FULL TIMER]

The generally accepted rule of thumb re battery chargers / battery capacity, is battery charger output (amps) should be around 10% of the total battery capacity Amp hours.

article here about best practice for joining batteries etc SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank
and some info on batteries and various types etc Charles Sterling discussing the range of batteries for the leisure market. - YouTube

Also worth taking a look at a few of charles' video's re all things battery / charging etc

 

[Fletch6]

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[listerdiesel]

Ignore recommended charging figures, if you're on a cyclic charge/discharge regime then you need to get the biggest ugliest charger you can fit. 20% or more is fine.

If you have solar already, with a decent MPPT controller, then a 25A single-rate charger is fine, and works well as a shore supply on EHU.

Our trailer has dual 26A chargers, the Mercedes has dual 50A chargers.

These mythical beasts are quite readily available, look up '13.5V Power Supply' on ebay. You need to adjust the output to something the batteries can accept indefinitely, we use 13.80V. Our solar controller actually runs above that when there is decent sunlight, the Mercedes AGM batteries cycle between 14.40V and 13.80V on the solar controllers.

Here is an assortment:

600W 13.5V 44.4A 220V input Single Output Switching power supply

500W 13.5V 36A 220V INPUT Single Output Switching power supply | eBay

CNC 13.5V 26.6A 360W DC Regulated Switching Power Supply High Quality ukgb | eBay

200W 13.5V 14.8A Single Output Switching power supply | eBay

Peter