I'm running a 12v bilge pump on a 24v system

[ramblinrod]

I don't know whether to laugh or cry.

This is a fine example of what today's "instant google experts" can achieve.

Mass confusion and public misinformation.

First, this is an electrical system question. If one accepts false info and makes an error, it can bite them, HARD, like property damage, personal injury or death.

Second, this is a safety device question. If one makes an error with their bilge pump, it can bite them, HARD, like property damage, personal injury or death.

Folks, unfortunately it comes down to this:

1. Some who have answered, know they don't know. Don't accept their advice.

2. Some who have answered, think they know. Don't accept their advice.

3. Some who have answered, are sure they know. Don't accept their advice.

4. If you absolutely do know the answer to a question like this, refer the person to someone local who is a "real" expert, because if they try to post the correct answer, they will be bombarded with ridiculous claims from all the people in the other categories above, that could care less if their advice hurts anyone else, and who have absolutely no skin in the game.

It's sad, but this is the way it often turns out.

If the OP still seeks a correct opinion on this question, a "real" expert will carry commercial liability insurance, just in case, despite all of their education, training, and experience, and investment into their skill and craft, they make a mistake and accidentally kill someone.

Even still, this person doesn't have as much skin in the game as you do.

Once you find them, you now have someone to go to when you need "real" expert advice on matters that a mistake could bite you, HARD! (And it will take far less time than sifting through all of this nonsense, that if you don't already know the answer, couldn't possible discern what is correct or incorrect.)

Then again, if you are willing to "hack" a safety system on your boat, that you, your loved ones, and everyone around you in the boating community are counting on functioning properly and safely, this is the thread for you.

Willing to play electrical system Russian Roulette? Just pick a response and try it.

[ramblinrod]

Originally Posted by coopec43

Fuss
You might be interested in this


https://www.metmotors.com/a-12v-dc-m...sus-24v-motor/

Dude, electrical device specs (especially bilge pumps) are based on supply voltage.

Change the voltage, the specs are no longer applicable.

Note that a bilge pump rated output is at 13.2 Vdc pump terminal voltage, open discharge.

If a 12 Vdc nominal electrical system charging system is on, the voltage could be as high as 14.6 Vdc (less any voltage drop to the pump motor) and it will draw more current, run faster and pump more.

If the batteries are down to 12.2 Vdc it will draw less current, run slower and pump less.

No worries as 12 Vdc (nominal) bilge pump is designed to run under these conditions.

Will it operate at 12 Vdc nominal. Maybe. If it has proper over-current protection (for 12 Vdc operation) it may trip it PDQ. If it doesn't it will run faster and dissipate more energy that it was designed for. It may burn up or wear out sooner. How soon? How long is a piece of string?

[ramblinrod]

Originally Posted by ramblinrod

Dude, electrical device specs (especially bilge pumps) are based on supply voltage.

Change the voltage, the specs are no longer applicable.

Note that a bilge pump rated output is at 13.2 Vdc pump terminal voltage, open discharge.

If a 12 Vdc nominal electrical system charging system is on, the voltage could be as high as 14.6 Vdc (less any voltage drop to the pump motor) and it will draw more current, run faster and pump more.

If the batteries are down to 12.2 Vdc it will draw less current, run slower and pump less.

No worries as 12 Vdc (nominal) bilge pump is designed to run under these conditions.

Will it operate at 12 Vdc nominal. Maybe. If it has proper over-current protection (for 12 Vdc operation) it may trip it PDQ. If it doesn't it will run faster and dissipate more energy that it was designed for. It may burn up or wear out sooner. How soon? How long is a piece of string?

Crap! See, even a real expert can make a mistake when in a rush to get out the door, first sentence, last paragraph should have read...."Will it operate at 24 Vdc nominal?

[Q Xopa]

Originally Posted by ramblinrod

I don't know whether to laugh or cry.

This is a fine example of what today's "instant google experts" can achieve.

Mass confusion and public misinformation.

First, this is an electrical system question. If one accepts false info and makes an error, it can bite them, HARD, like property damage, personal injury or death.

Second, this is a safety device question. If one makes an error with their bilge pump, it can bite them, HARD, like property damage, personal injury or death.

Folks, unfortunately it comes down to this:

1. Some who have answered, know they don't know. Don't accept their advice.

2. Some who have answered, think they know. Don't accept their advice.

3. Some who have answered, are sure they know. Don't accept their advice.

4. If you absolutely do know the answer to a question like this, refer the person to someone local who is a "real" expert, because if they try to post the correct answer, they will be bombarded with ridiculous claims from all the people in the other categories above, that could care less if their advice hurts anyone else, and who have absolutely no skin in the game.

It's sad, but this is the way it often turns out.

If the OP still seeks a correct opinion on this question, a "real" expert will carry commercial liability insurance, just in case, despite all of their education, training, and experience, and investment into their skill and craft, they make a mistake and accidentally kill someone.

Even still, this person doesn't have as much skin in the game as you do.

Once you find them, you now have someone to go to when you need "real" expert advice on matters that a mistake could bite you, HARD! (And it will take far less time than sifting through all of this nonsense, that if you don't already know the answer, couldn't possible discern what is correct or incorrect.)

Then again, if you are willing to "hack" a safety system on your boat, that you, your loved ones, and everyone around you in the boating community are counting on functioning properly and safely, this is the thread for you.

Willing to play electrical system Russian Roulette? Just pick a response and try it.

Very true words that there is a lot of advice on here isnt correct.

Its also true that there is also some very good advice being offered on here.

Its also true that SOME local technicians are very good.

But its also true not all local technicians give the correct answers or do the best work.

As always the trick is to decide who is which.

In my experience its usually the ones telling us they have all the answers talk a good story. And the ones that do actually know more are more reluctant to offer their opinion.

[Burrito5000]

I found this thread recently when searching about running 12v motors on 24v. There isn’t great data available, and the back and forth on this thread doesn’t help clarify much. I’ve had success in the past running 12v motors on 24v, but I wouldn’t do it on any critical equipment unless it was an emergency situation. It can be done, but each case will have varying success rates.
I recently made two quick videos of the exact same sump pump set up first with 12v and then with 24v. This is an amazon pump rated for 12v, (not 24v).
With no other changes to the system besides the voltage increase, the following occurred:

V1 = 12.5 V
I1 = 11.5 A
Watts = 144
GPM = 6

V2 = 25 V
I2 = 27.5 A
Watts = 688
GPM = 8.8

So, doubling the voltage in this case resulted in the following increases:
Power Consumption + 478%
Current + 239%
GPM + 47 %

This sump pump setup had a standard 5/8” diameter garden hose connected to it for the test. It is a good example of how increasing voltage while keeping load and other variables the same can start to have exponentially detrimental effects with only marginal performance gains. The hose is restrictive in this system, and adding more speed to the pump only amplifies the restrictive properties of the ‘load’. Over four times the power consumption was needed to achieve only around a 50% performance gain between the two voltage setups. And it’s likely that the life of the pump will be significantly reduced if ran at the elevated voltage.

Here are the links to the two videos:
https://youtu.be/ZNLtQ5crFuI

https://youtu.be/DKq61jBFbhY

[cal40john]

Originally Posted by Burrito5000

I found this thread recently when searching about running 12v motors on 24v. There isn’t great data available, and the back and forth on this thread doesn’t help clarify much. I’ve had success in the past running 12v motors on 24v, but I wouldn’t do it on any critical equipment unless it was an emergency situation. It can be done, but each case will have varying success rates.
I recently made two quick videos of the exact same sump pump set up first with 12v and then with 24v. This is an amazon pump rated for 12v, (not 24v).
With no other changes to the system besides the voltage increase, the following occurred:

V1 = 12.5 V
I1 = 11.5 A
Watts = 144
GPM = 6

V2 = 25 V
I2 = 27.5 A
Watts = 688
GPM = 8.8

So, doubling the voltage in this case resulted in the following increases:
Power Consumption + 478%
Current + 239%
GPM + 47 %

This sump pump setup had a standard 5/8” diameter garden hose connected to it for the test. It is a good example of how increasing voltage while keeping load and other variables the same can start to have exponentially detrimental effects with only marginal performance gains. The hose is restrictive in this system, and adding more speed to the pump only amplifies the restrictive properties of the ‘load’. Over four times the power consumption was needed to achieve only around a 50% performance gain between the two voltage setups. And it’s likely that the life of the pump will be significantly reduced if ran at the elevated voltage.

Here are the links to the two videos:
https://youtu.be/ZNLtQ5crFuI

https://youtu.be/DKq61jBFbhY

A test of ohm's and the power laws.
V = IR
P = VI
so substituting also gets you
P = V^2 / R


The resistance of the wires don't change so R is constant.
Since voltage is squared, doubling the voltage results in 4 times the power consumed.

Ohm's law doubling the voltage with R constant doubles the current.

Mechanical output, power into pumping water increased by 50%, but you are putting 4x the power into the system, so the rest of the extra power is turning into heat.

Can the water dissipate the extra heat fast enough? If not you have a melted down pump.

Just like the slot cars I used to melt as a kid not knowing the math.

[S/V Illusion]

Depends on how fast you want to burn out the pump motor winding and buy replacements.

[rslifkin]

Thinking about it, for the sake of maximizing bilge pump flow, it might be viable to use a voltage regulator before the pump to feed it 14v regardless of battery voltage (being that 14v is within what you'd expect to see on a 12v system and it'll pump more water at a higher voltage). Only concern would be reliability with the extra components involved.

[capn_billl]

What they don't make 24v bilge pumps?

DC motors aren't as voltage sensitive as electronics.

I ran a 6 Volt VW starter on 12 Volts for decades, but it was built very stoat.

A small 12 volt Rule pump isn't going to last long at double it's rated voltage.

I would either find a way to run a split voltage to your bilge pumps, (they are intermittent).

OR buy the correct pump.

Bilge pumps are important.

[ForeverDes]

Originally Posted by rslifkin

Thinking about it, for the sake of maximizing bilge pump flow, it might be viable to use a voltage regulator before the pump to feed it 14v regardless of battery voltage (being that 14v is within what you'd expect to see on a 12v system and it'll pump more water at a higher voltage). Only concern would be reliability with the extra components involved.

That's exactly how I have my windlass set up. My house bank is 24v, which runs just outside the chain locker, where's there's a 100 amp step down buck transformer that provides constant 13.8v. Works well, and I sized the wire for 12v, because it was installed before I changed the house bank to 24v. I'm not worried about the inefficiency inherent in using a step down transformer, because the windlass doesn't run for long periods of time.

[Baronkrak]

Originally Posted by cal40john

A test of ohm's and the power laws.
V = IR
P = VI
so substituting also gets you
P = V^2 / R

An electric motor is about Electromagnetic Force.

[RaymondR]

Bound to end in tears.

[coopec43]

Originally Posted by capn_billl

What they don't make 24v bilge pumps?

DC motors aren't as voltage sensitive as electronics.

I ran a 6 Volt VW starter on 12 Volts for decades, but it was built very stoat.

A small 12 volt Rule pump isn't going to last long at double it's rated voltage.

I would either find a way to run a split voltage to your bilge pumps, (they are intermittent).

OR buy the correct pump.

Bilge pumps are important.

I'm running 24V bilge pumps on a 24V system/.

I'm running a 12V starter motor on 24V

I plan to run an Adler Barbour fridge/freezer motor on 24V (It is designed to run on 12V or 24V. Their advice is that it runs better on 24V)

"The versatility provides for allfreezer or combination refrigerator/ freezer systems. Your appreciation of 12/24 volt DC refrigeration ......."

[coopec43]

Originally Posted by ramblinrod

Crap! See, even a real expert can make a mistake when in a rush to get out the door, first sentence, last paragraph should have read...."Will it operate at 24 Vdc nominal?

So you consider yourself a real expert eh? (Don't be so modest!)