Thoughts on using a 24 volt to 12 volt step down converter for camper 12 volt system?

[Micim987]

We recently got our $500 fixer upper pop up camper and our two Enjoybot 100ah 12v batteries. The camper does have a blown power converter that is older than dirt. What we were possibly considering was replacing the whole power converter setup with a Sungoldpower 24 volt 2000w inverter and then using a 24 to 12 volt buck converter to drop the voltage for the 12 volt accessories. The loads include a water pump, propane furnace, ammonia fridge, and lights that are eventually going to be replaced with LED's. We're not sure how much power everything is using as we haven't ordered a shunt but going to other info online we would say about about 350ish watts without the fridge in 12 volt mode.

Would using something like this be safe or are they not meant for sustained loads? The main reason we would prefer to use 24 volt over 12 volt for the solar and inverter is because of the reduced cost of wiring and being able to use a smaller (and less expensive) MPPT. I do understand that we wouldn't be able to use a DC to DC charger which is fine because we will have solar and the truck we are towing with only has a 4 pin connector (the camper has a 6pin square but no brakes). Other than that what could be the potential downsides to setting up a system like this? We wan't to maintain safety above all else and it seems like going with 24 volts would be safer considering the lower amperage of the inverter and MPPT especially since it seems like the EPEVER MPPT charge controllers tend to blow up above 40 amps output according the the reviews.

 

[MichaelK]

I think you can find the same unit on Ebay for less.

24V to 12V 20A DC DC Converter 20AMP 240 Watt Voltage Step Down Module | eBay

This converter can not be connected to solar panels or wind turbine directly. DC-DC Converter. Over temperature shutdown, Short circuit protection, Output reverse polarity protection. GOLF ADAPTER. 100% full stable output Current.

www.ebay.com

I think those are OK for sustained use, though I'd suggest installing them such that they'll never be exposed to more than half load. That is, use a 20A converter to support a 10A load. And, make very sure they are in a good ventilation spot.

 

[Bob B]

.... and buy a spare

 

[rmaddy]

Would using something like this be safe or are they not meant for sustained loads?

I have the exact 24V-12V 40A buck converter you linked to at Amazon. It's been connected and used 24/7 for the last 6 months without issue. Though I've never had it near a 40A load.

One thing to consider with a 24V setup is to use as many 24V loads as possible. You can get a 24V water pump. You can get 24V LED lights (or wire pairs of 12V LED lights in series as I did). The more you can use 24V loads, the less strain you need to put on the buck converter.

I think you can find the same unit on Ebay for less.

The OP linked to a 40A buck converter. Your listing is for a 20A buck converter. That explains the big price difference. When you choose the 20A version on the Amazon listing then the price difference is only a $1 or $2 from the Ebay listing.

 

[Micim987]

I have the exact 24V-12V 40A buck converter you linked to at Amazon. It's been connected and used 24/7 for the last 6 months without issue. Though I've never had it near a 40A load.

One thing to consider with a 24V setup is to use as many 24V loads as possible. You can get a 24V water pump. You can get 24V LED lights (or wire pairs of 12V LED lights in series as I did). The more you can use 24V loads, the less strain you need to put on the buck converter.


The OP linked to a 40A buck converter. Your listing is for a 20A buck converter. That explains the big price difference. When you choose the 20A version on the Amazon listing then the price difference is only a $1 or $2 from the Ebay listing.

Would I need to replace the light sockets or are they able to handle 24 volts just fine. It already needs some wiring work but I don't want to burn anything out and thankfully all the lights in the top work just fine. Also how would I handle distributing both 12 and 24 volt power? Should I just add a second distribution box like this one and run the 24 volt stuff through it? Then run the existing 12 volt stuff through the main distribution panel? Oh and also I need to look into it further but I believe some accessories use parts of the frame as negative? Would I need to run separate wires for 12 or 24 volt accessories?

 

[rmaddy]

If you are asking about standard 120VAC light sockets then they have no use for DC LED lights.

For both 24V DC loads and 12V DC loads you do need two DC fuse boxes similar to what you linked. The one for 24V would be wired from the batteries (bus bars) and the one for 12V would be the same but have the buck converter in between.

I don't know about using the frame as a negative, especially with two different voltages. In my trailer I do not use the frame at all as a negative attachment point. Hopefully someone else can address that specific question. It might actually make a good separate question.

 

[12VoltInstalls]

possibly considering was replacing the whole power converter setup with a Sungoldpower 24 volt 2000w inverter and then using a 24 to 12 volt buck converter to drop the voltage for the 12 volt accessories

I’m probably the flyer here but what do you need 24V for?

I’d keep it 12V and just enjoy the camper
2000W is fine at 12V though maybe the ceiling.

 

[12VoltInstalls]

In my trailer I do not use the frame at all as a negative attachment point.

My opinion: at least ground the frame. I wouldn’t use it as a source- just as something to make at zero potential.

 

[rmaddy]

My opinion: at least ground the frame. I wouldn’t use it as a source- just as something to make at zero potential.

I do have a ground wire from my negative bus bar to the trailer's frame as a ground.

 

[Micim987]

I’m probably the flyer here but what do you need 24V for?

I’d keep it 12V and just enjoy the camper
2000W is fine at 12V though maybe the ceiling.

My biggest reasoning for using 24 volts rather than 12 volts is that the compartment for the electrical is in the rear and the batteries are stored on the hitch so it would be roughly about 20 to 30 feet of wire and 2/0 wire here is about $4.75 a foot while 2 AWG wire is $2.65 a foot or nearly $100 saved also being able to use a 30 amp MPPT instead of a 60 amp one since the cheap non Victron MPPT's seem to catch fire above 40 amps because they use spring terminals at least according the the reviews. I also personally feel that having 100 amps going through a single wire would be safer than 200 amps at max draw even though the inverter will probably never hit that 2000 watts sustained. I know that the wiring still has to be sized properly and the buck converter is another point of failure but I feel like it would be worth it in the long run and would be safer.

I do have a ground wire from my negative bus bar to the trailer's frame as a ground.

I assume I can't tie both negatives together so which one would I tie to the frame the 12 volt or the 24 volt?

If you are asking about standard 120VAC light sockets then they have no use for DC LED lights.

For both 24V DC loads and 12V DC loads you do need two DC fuse boxes similar to what you linked. The one for 24V would be wired from the batteries (bus bars) and the one for 12V would be the same but have the buck converter in between.

I don't know about using the frame as a negative, especially with two different voltages. In my trailer I do not use the frame at all as a negative attachment point. Hopefully someone else can address that specific question. It might actually make a good separate question.

No all the lights in the camper are 12 volts, socket probably isn't the right word. They are similar to automotive light bulbs I think we don't have it on our property right now so I can't check.

 

[rmaddy]

My biggest reasoning for using 24 volts rather than 12 volts is that the compartment for the electrical is in the rear and the batteries are stored on the hitch so it would be roughly about 20 to 30 feet of wire

Be careful with LiFePO₄ batteries outside on the hitch. You do not want to charge the batteries if they get down to freezing.

If you tried to use a 2000W inverter at 12V that is 200A. If the roundtrip distance from the batteries to the inverter is 30 feet then you must use 4/0 wire or you will have significant voltage drop. Even with the inverter on a 24V system, you need 1/0 wire to properly handle the 30 feet.

You really need to find a way to move the batteries inside and closer to the inverter. That will make the batteries much happier and your costs lower.

I assume I can't tie both negatives together so which one would I tie to the frame the 12 volt or the 24 volt?

That's the part I don't know. Posing that as a separate question would be helpful.

No all the lights in the camper are 12 volts, socket probably isn't the right word. They are similar to automotive light bulbs I think we don't have it on our property right now so I can't check.

See if you can find any specs on the sockets. Maybe they can handle 24V (really closer to 29V) or maybe not. But since LED lights are normally pretty low wattage, keeping the lights at 12V should be fine. Focus on higher amp/wattage items that can be changed to 24V.

Keep in mind that it may just be simpler to keep all DC loads at 12V. With a proper 24V->12V DC buck converter that can safely handle the needed amps, it may not be worth trying to have both 24V and 12V DC loads. If there is worry about one of those really cheap buck converters you should consider a Victron Orion. If you need one for a full 40A, for example, most of the time, the Orion can be trusted to safely handle its rated output all day long.

 

[12VoltInstalls]

since the cheap non Victron MPPT's seem to catch fire above 40 amps because they use spring terminals at least according the the reviews.

That’s not the case with all equipment. Maybe cheap brands but there are lesser-priced units that aren’t fire hazards.

They are similar to automotive light bulbs

You can change those to LED and do well

Keep in mind that it may just be simpler to keep all DC loads at 12V

I would put the inverter up front- there’s a way! Then shorter cables for 12V, and send the 120V to distribution with the appropriate and inexpensive romex wire.

You’re trying to overcome an expensive obstacle by spending more money. You can do better spending less money. I’ve worked in a bunch of campers- there’s almost always a way to make stuff fit and use wire to overcome location.

 

[jberger]

You are overthinking this one, it's a $500 camper.
It's already wired for 12V, even with the "blown" converter, so keep it 12V. 12V replacement parts are dirt cheap, so you can fix what you have without needing to rewire everything just for 24v.
Stick the batteries under the dinette seat or bed, next to wherever the converter is located. They were outside the trailer before, because they had to be due to offgassing, you will not have that problem with LiFePO4. They can live inside, and your wiring hookup can be a couple of feet instead of 20ft.
The power centers are usually modular, so you can just pull out the dead module and replacement with a working one. If you get lucky, you can even get a charger that includes the right charging profile for your pack.

 

[12VoltInstalls]

The power centers are usually modular, so you can just pull out the dead module and replacement with a working one. If you get lucky, you can even get a charger that includes the right charging profile for your pack.

A departure to this advice- which is good- is that the AIO I suggested includes 12V charging capabilities if on shorepower or generator. So the power supply replacement cost is a savings applied to the AIO cost.
If the LiFePo batteries do not upset the tongue weight (which for that size camper should be ~15% of gross weight) by moving elsewhere that is a possibility I didn’t think of because of tongue weight and potential space premium.

 

[Rednecktek]

I gotta keep an eye on this one, I'm looking to pimp my brother's Pop-up in the near-ish future. I think his is a mid-late 80's Coleman.

Fortunately the load is low enough I can keep the 12v system at 12v all the way around. Unfortunately due to environmental conditions I think I'm going to have to stick with AGM/FLA for the battery or roll my own battery with a good BMS. He only charges that thing twice a year and it gets COLD out some days.

 

[Fran365]

I have the exact 24V-12V 40A buck converter you linked to at Amazon. It's been connected and used 24/7 for the last 6 months without issue. Though I've never had it near a 40A load.

One thing to consider with a 24V setup is to use as many 24V loads as possible. You can get a 24V water pump. You can get 24V LED lights (or wire pairs of 12V LED lights in series as I did). The more you can use 24V loads, the less strain you need to put on the buck converter.


The OP linked to a 40A buck converter. Your listing is for a 20A buck converter. That explains the big price difference. When you choose the 20A version on the Amazon listing then the price difference is only a $1 or $2 from the Ebay listing.

Thanks Mandy, I was just going to ask,” 24v or 12v water pump”. I’m assembling a 24v system, slowly.