12 volt power supply and leisure battery install

An msx10 for £130 (probably cheaper if I shop around) seems like a better bet than the Chinese eBay 20a supply unit though.

This leads me to the thought of 2 ctek’s . An msx10 for 12v supply only, and an msx5 for charging and maintenance only.

Ctek overkill ???
Thinking cap still on.

 

It is certainly the case that you cannot ever properly 100% charge a battery until you have removed most of the loads from it.
The steady 7A drain of that fridge will cause most chargers to drop their output voltage to less than the battery needs.
It will only get properly charged if you leave it on hookup or solar when you are not actually using it.
My setup manages to top up the battery between runs of the compressor fridge for imstance when the load on the battery drops off.

Its almost worth considering a straight 10A 12 volt mains power supply for the fridge off hookup, (should be cheaper than a battery charger - look at LED lighting power supplies around £20) and a separate 7 or 10A Ctek for the leisure battery and the rest of the leisure supply.

 

Another possibility.

 

Even though the ctek10 has a 10amp supply feature is it designed to run for days like this or is it just for very short emergency use? Doesn’t say much on the website.
At least the eBay 20 amp unit is designed for this purpose. (It’s also double the amps and has a cooling fan)

 

I have a 20amp charger and a 90ah battery; this supplies a compressor fridge, Propex, CD/radio, DVD/TV, LED lights, water pump etc. It works perfectly on hook-up, why do you want to separate the battery charging from the power supply?

 

Reading up on all these smart chargers and how to look after batteries, I can’t see how the 12volt supply unit can do this properly at the same time as pumping out power to a fridge, radio, lights etc.
That’s the way I’ve been doing it, but with second hand free normal batteries. They don’t last very long. Would like to get a decent leisure battery but want it to be looked after.
I’m wanting to have the option of camping without hookup for more days than I have in the past.

 

The supply mode on the ctek is designed for when you remove the battery from the car, the ctek sits in its place and acts like a a power supply. It doesn't charge at the same time. I've used this mode over Christmas for my compressor fridge in the house for around a week.

If you want to run the fridge off 12 volt without hookup for any length of time you will quick flatten any battery. Does it run off gas as well?

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If you have a battery you don’t need a separate 12v supply; when on hook-up the smart charger charges the battery, the battery supplies the fridge, radio, lights etc. And if you also have a battery-to-battery charger (not a simple or smart split charge relay) an AGM, or LiFePO4 battery is also charged from the engine.

 

Fridge runs off 12v only. I don’t need or want to run it off the battery.

 

So if you stick to a max discharge of 50% you would only be able to run off-grid for 7 hours on a 100ah battery. If you're sticking to hookup you'll be fine but for any length of time without, the fridge will be the limiting factor

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I can live without the fridge. It stays cold for ages with fresh ice in a tray and your never more than ten minutes away from a supermarket

 

I think my best option is my very first option.
20 amp power supply and ctek msx5.
I can pick and choose battery size and type at will. Probably get an AGM and disconnect the alternator split charge relay.

 

Not sure if it's what your after but I run a 150w (12.5a) version of this in our rapido. Not fan cooled but ours has never got hot. Copes well with compressor fridge, lighting, water pump and device charging. The 300w is £40

https://smile.amazon.co.uk/dp/B07S4C6XL9/ref=cm_sw_r_cp_apa_fabc_QNTPQRSRYKA8CT73AVM1

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I run the CTEK into the battery and the fridge off the battery, I did buy a bigger CTEK as the fridge is an absorption type and uses mucho amperages.

 

I like the thought of this. Small and cost effective. I’ll look in to it.

If I use a ctek for charging I don’t need the power supply to have a charger built in to it.

 

https://www.moonraker.eu/sharman-sm-23-fixed-13-8v-23amp-switch-mode-power-supply

On special offer. Built in fan. 12volt cig socket as well may come in handy.

 

Never one to get things done in a hurry, I’ve finally got some parts delivered to make a start.

 

Went with the mxs 7. Nice quality and comes with a handy quick connection plug so I can wire up the leisure battery permanently or use clips outside of the van.

 

Got the power supply from 12v planet. Nordelettronica 21 amp. This looks and feels like a very well made piece of kit.