Running Class A RV Leveling Jacks With A 24v Solar Battery Bank

Olecram93

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May 31, 2021
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Everything in life is a trade off.

This can be mostly solved by using a healthy 120 vac to 12 volt charger and letting it run a few minutes prior t o starting.

A relay can be added to power the charger when needed.

A charger is current limited so a much more reliable approach than connecting the DC - DC converter.
That's true. I should probably not sweat it too much right?

Another option would be to keep that emergency switch and one of the house 12v OEM house batteries but move it to the front of the RV (opposite side of the starter battery under the hood) to balance the weight a bit. Keep that battery powering just the generator start and the hydraulic pump, and it will serve as an emergency battery for starting as well.

I'm considering this because they are brand new interstate deep cycle lead acid batteries that they replaced at the dealership prior to purchase that would be a shame to put into storage.
 

Gyrogearloose

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Jul 26, 2021
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Yes it is, and You are right I missed that.

Do you know of anyway to be able to keep emergency start feature?

Right now I can press a switch in the dash if the chasis battery is dead and start the engine with the house batteries and i would like to keep that feature if possible.
With that 24vdc system in place I do t think you want to be pressing that e-start switch, sounds like smoke waiting to happen😉.

DC - DC or a charger like @HarryN said. The 24-12 DC-DC might be nice for battery maintenance and charging the 12vdc, just size it right so you don't slap to much current to the battery when charging.
Some Victron dc-dc
 

Olecram93

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May 31, 2021
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With that 24vdc system in place I do t think you want to be pressing that e-start switch, sounds like smoke waiting to happen😉.

DC - DC or a charger like @HarryN said. The 24-12 DC-DC might be nice for battery maintenance and charging the 12vdc, just size it right so you don't slap to much current to the battery when charging.
Some Victron dc-dc
No no, that would never be the case. The whole reason I posted here was to see what would be the best way to power the jack pump with 12v while replacing the battery bank with 24v.

The 12v-24v Victron DC to DC charger is already purchased and ready for install. I got the 15amp version.

Where in my system would be the best place to install it?
 

smoothJoey

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I was thinking as close to the 12v battery as possible. With the higher voltage (24v) on the output side of the charger, the cabling wouldn't have to be as heavy as on the input (12v) side.
Unless the charger has sense leads it doesn't know the house battery voltage and can't compensate.
The unit by its nature compensates for the voltage drop on the supply side.
 

Zwy

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No no, that would never be the case. The whole reason I posted here was to see what would be the best way to power the jack pump with 12v while replacing the battery bank with 24v.

There are several ways this could be done. On my truck camper, I left the AC to 12V DC converter in place and have a switch to turn off power to it. The only thing still hooked to the 12V output of the converter is the jacks for loading and unloading. I run the converter off my GW, either plugged in or off the inverter. This would be my first choice and in your case, I'd have a 12V battery in the circuit, FLS, SLA or AGM to handle the surge. In my case the converter was free and already installed and I didn't need a battery for surge, the converter handles the 45a for the few ms on intial surge, then 26a after that, all four jacks running.

One way it can be done is with relays, 24V is wired to the jacks or hydraulic pump and a relay is triggered off the original wiring providing the ground or power feed of 24V to the motor. The control is left at 12v powered thru a buck converter. 4 jacks take 4 relays, 3 jacks take 3 relays. I use this method on heavy duty trucks when the original wiring gets too much resistance and the voltage drop is excessive. Power is ran from a known good source to the relay and the original wiring is used to control the relay.


The 12v-24v Victron DC to DC charger is already purchased and ready for install. I got the 15amp version.

Where in my system would be the best place to install it?
 

chrisski

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In my case the converter was free and already installed and I didn't need a battery for surge, the converter handles the 45a for the few ms on intial surge, then 26a after that, all four jacks running.
I am surprised a truck camper has a converter to handle 45 amps. I’ve only seen my RV’s converter push 15 amps tops while charging, so you’re lucky to get a OEM installed converter to handle that.
The control is left at 12v powered thru a buck converter.
Do you have a buck converter you would recommend for this? I’ve had my first experience with one and it was rather lackluster. I think what we are looking for is not just to run the trailer jack and that high amperage, but also one that will run the 12 volt system that has a low idle power consumption. My searches have always brought me back to 24 volt to 12 volt battery chargers or 24 volt to 12 volt converters.

Others have used buck converts with 24 volt conversions, but those I’ve seen post this are travel trailers not worrying about high amperage loads.

I’m at the point where I’ll be ordering my Victron Orion 70 amp 24 volt to 12 volt converter and if there’s a better way to do that before then, I’d like to know. I’m sure there is. I just on’t know it.
 

Zwy

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I am surprised a truck camper has a converter to handle 45 amps. I’ve only seen my RV’s converter push 15 amps tops while charging, so you’re lucky to get a OEM installed converter to handle that.

Only 45a initial surge. I've had an IOTA in the shop for years I use for a power supply and it was rated at 75a continuous. I knew before it would work as the battery was dead before when I went to load the camper.

Do you have a buck converter you would recommend for this? I’ve had my first experience with one and it was rather lackluster. I think what we are looking for is not just to run the trailer jack and that high amperage, but also one that will run the 12 volt system that has a low idle power consumption. My searches have always brought me back to 24 volt to 12 volt battery chargers or 24 volt to 12 volt converters.

Others have used buck converts with 24 volt conversions, but those I’ve seen post this are travel trailers not worrying about high amperage loads.

I’m at the point where I’ll be ordering my Victron Orion 70 amp 24 volt to 12 volt converter and if there’s a better way to do that before then, I’d like to know. I’m sure there is. I just on’t know it.
I'm not sure you will get by with a buck converter to power the jacks but if you want to run just the control and trigger relays, then just about any buck converter over a few hundred watts would be more than sufficient. I have a 720w buck converter but I planned on only loading it to 50%, 350w.

If this is a motor home, I'd go power off the starter battery myself and run the engine. If a towed camper, well, I'd probably break out relays/solonoids depending on load and use a small buck for the control panel power source. If each jack has a motor, you can't just wire in series for the 24V as you would need to level by running just one jack.
 

chrisski

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. If each jack has a motor, you can't just wire in series for the 24V as you would need to level by running just one jack.
Thanks.

Each jack has its own motor and any one or two can be powered on at any given time.

Not a motor home either, so for now, I’ll try the Victron Orion 24 volt to 12 volt converter and hope 70 amps is enough. If not, that converter will be for sale by the end of the year.
 

smoothJoey

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I’ve only seen my RV’s converter push 15 amps tops while charging, so you’re lucky to get a OEM installed converter to handle that.
Could be because your converter has a low amp rating or because it is connected to the battery bank via relatively long and thin wires.
The latter is fairly typical RV modus operandi.
 

chrisski

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Could be because your converter has a low amp rating or because it is connected to the battery bank via relatively long and thin wires.
The latter is fairly typical RV modus operandi.
I’m going to find out about this wiring when I do my 24 volt upgrade and install a higher amperage converter 24 volts and 35 amps.

I dread seeing how the OEM converter is wired. Probably much thinner than I would want and I would not be surprised if it was frame grounded to the DC also. I do not know the true rating of the converter, and I think the wire is 6 AWG To go a one way distance of 10 feet. As long as its not frame grounded and the true rating of the converter is 15 amps, than the wiring is fine.

I do think because the converter charger a single 92 ah Deep Cycle FLA battery, 15 amps probably was too much for that battery. Going to a 458 ah battery bank, the converter suddenly became undersized,
 
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