Solution for 12v gadgets in a 24v Defender?

I have a 24v former military Defender 110, 300tdi from 1996. Been browsing the forum to find out that a conversion from 24v to 12v means replacing a lot of electrical parts.
https://www.landyzone.co.uk/land-rover/24v-to-12v.96408/

Since everything is working as is, could there be an easier solution to be able to connect 12v gadgets like a fridge, sound system, usb-charger, etc?

Thanks

Btw, I did try one of these simple 24v to 12v converters to be able to charge my phone - which did not go well. Both the converter unit and my phone got extremely hot.

Tap a supply from one battery (assuming you have twin 12V batteries) - is it just fairly low wattage stuff, you would not want to draw two much from a single battery in a twin battery setup but a little won't cause an issue.

If you take power form one battery make sure its the one nearest earth otherwise if you have a short you may stick 24v through your 12v kit.
Tbh power from one battery long term is bad news for the battery concerned.

lynall said:

If you take power form one battery make sure its the one nearest earth otherwise if you have a short you may stick 24v through your 12v kit.
Tbh power from one battery long term is bad news for the battery concerned.

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If he is only pinching 10-20W for a phone charger it will not make a difference.

True but the op mentions a fridge and a sound system, sound system not to bad but a fridge has got to pull some power?

Split the 24v into two 12v loops. Providing the 24-12v loop is isolated from ground it will work fine.

lynall said:

True but the op mentions a fridge and a sound system, sound system not to bad but a fridge has got to pull some power?

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I read gadgets and assumed it was a charger or nav! White appliances in his Landy I did not think of!

So yeah, I would not want to load up a single battery in a series install with that much load.

The Mad Hat Man said:

Split the 24v into two 12v loops. Providing the 24-12v loop is isolated from ground it will work fine.

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Not heard of that before I like the sound of it, can you explain more?

If its two batteries, then you can have a separate circuit running on one. You would have to check the charge voltage from the alternator across the battery though, i assume the alternator produces 24v which is split across both. Also worth considering that one battery could discharge a lot quicker than the other, and unless you have some fancy dual charging system you could over charge one of the batteries. Which would kill it pretty quickly.

The issue with a separate system is that they'll remain on even with the ignition off, unless you ran a relay from the ignition to switch it off when you remove the key.

What about a system of running all the cars electrics with the batteries in series (24v) as it is now, and the running the auxiliary equipment with the batteries in parallel (12v)?

No idea if that would work but it would give you the correct voltage.

philsefo said:

If its two batteries, then you can have a separate circuit running on one. You would have to check the charge voltage from the alternator across the battery though, i assume the alternator produces 24v which is split across both. .

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That's what I was thinking if he wanted a small 12V circuit, the system will be (is is with nearly all 24V systems trucks included) 2 x 12V batteries in series, as far as the system is concerned the battery is 24V - much like a 12V battery is actually 6 x 2.2V cells so really all it is is 12 x 2.2v it's just that they are not all in the same case.

Now the issue with this is that the batteries should always be bought in pairs, same make, model, batch if possible because you want all the cells to be matched. If you start pulling current from one of the batteries then the potential voltage across that battery will now differ from the other, this will have the result that it will want more power (voltage & current) from the alternator and it will also drag down the charge state of the other battery.

Remember hearing you should never mix batteries in toys and remotes and things, it's the same thing here. By depleting one differently to the other you have effectively just mixed batteries.

A better option here may be a dedicated battery with it's own alternator or 24-12V charge circuit.

discomania said:

That's what I was thinking if he wanted a small 12V circuit, the system will be (is is with nearly all 24V systems trucks included) 2 x 12V batteries in series, as far as the system is concerned the battery is 24V - much like a 12V battery is actually 6 x 2.2V cells so really all it is is 12 x 2.2v it's just that they are not all in the same case.

Now the issue with this is that the batteries should always be bought in pairs, same make, model, batch if possible because you want all the cells to be matched. If you start pulling current from one of the batteries then the potential voltage across that battery will now differ from the other, this will have the result that it will want more power (voltage & current) from the alternator and it will also drag down the charge state of the other battery.

Remember hearing you should never mix batteries in toys and remotes and things, it's the same thing here. By depleting one differently to the other you have effectively just mixed batteries.

A better option here may be a dedicated battery with it's own alternator or 24-12V charge circuit.

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Yeah if one battery is fully discharged then the other will force a current through it, but the wrong way, destroying the battery!
I actually wrote a dissertation on this but yeah i've forgotten most of it, including the correct terminology.

One of these will be easy to fit: http://dcpoweronboard.com/standard-series/

zeaphod said:

One of these will be easy to fit: http://dcpoweronboard.com/standard-series/

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Or failing that, you could either buy another Landy or convert yours to 12V and save some money!

Oldseadog said:

Or failing that, you could either buy another Landy or convert yours to 12V and save some money!

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Er yes, I should have said this kind of thing - maybe the OP is wealthy LOL

zeaphod said:

One of these will be easy to fit: http://dcpoweronboard.com/standard-series/

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Was heading to the bottom of the thread to suggest the same when I saw your post.

There are cheaper ones than those made by Motorola and they work well...can handle up to 20 amps..cant remember the model #

sirredarre said:

Btw, I did try one of these simple 24v to 12v converters to be able to charge my phone - which did not go well. Both the converter unit and my phone got extremely hot.

View attachment 112980

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DC to DC converters been around for a long time and I have built one as part of my electronic tech program in the mid 80ies. There are different brands and qualities, current ratings etc.

Because you had issues with the one you listed does not mean that the idea bad, just get a good quality one with the proper load rating you need. Make sure it is properly filtered...you could also add a 1F Capacitor to assist with filtering and load demands on the 12V output side.

Thanks again for the input and support! Hope to post some progress as soon as I get to this...