How difficult would it be to convert this water heater from 12V to 6V?

[shew01]

How difficult would it be to convert this water heater, which does *not* come with a switch, from 12V to 6V? (By the way, my Victoria has a 6V alternator with positive ground. The slim design *might* fit in the floor, behind the stick shift with the water pipes pointing up.)

https://www.amazon.com/dp/B08CZTNDP8...v_ov_lig_dp_it

Would it just be a matter of replacing the fans? (I've searched, and I didn't find any fans that I thought would be suitable, but electricals are not my strong suit.)

Would a Model A 6V battery and alternator have enough juice to power two 6v fans?

Here is a unit that appears to come with a switch.

https://www.amazon.com/dp/B07K2CSQQ3...v_ov_lig_dp_it

Would that switch likely work with 12V and 6V?

[shew01]

This switch might work, but I'm still wondering about the fans.

https://smile.amazon.com/Motor-Gover...omotive&sr=1-2

[AL in NY]

I would look for a 6vDC to 12VDC convertor......Look in Amazon

[Synchro909]

I suspect the only thing/s electric in that heater are the fans. There appear to be two of them so pull it apart and connect them in series.

[shew01]

Originally Posted by Synchro909

I suspect the only thing/s electric in that heater are the fans. There appear to be two of them so pull it apart and connect them in series.

I have bought it yet. I’m still trying to think this through. Amazon doesn’t have the current draw on its web site as far as I can tell.

What is the “normal” wire size for the Model A? 12 AWG? That would be sufficient for up to 20 amps, correct? (The heavier duty convert is only 10 amps.)

DIGITEN DC 6V 5-11V to 12V 10A Step up Converter Regulator Waterproof Boost Power Module https://smile.amazon.com/dp/B019GY2F...ing=UTF8&psc=1


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[nkaminar]

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Changing the fans from parallel to series would appropriate for changing from 6 volts to 12 volts but would not work for changing from 12 volts to 6 volts. If they are in series to begin with (unlikely) you can change them to parallel. Otherwise, changing out the fans is the best approach. Or just run it on 6 volts for reduced air flow.

[Badpuppy]

The LED dimmer switch probably won't handle the fan current. Easiest to run it on 6V with a simple toggle switch. The second item you referenced includes a higher powered dimmer, which you certainly don't need.

A more important consideration is that the fan circuit may well be in common with the housing. Negative battery on the housing will short through the coolant directly to the engine's positive ground. If this is the case it can be remedied by either reversing the fan connections - reversing the air flow - or insulating the fan mounts from the housing.

[BRENT in 10-uh-C]

Likely all that it will do by powering with 6 volts is it will cut the speed in half. Try it on the bench with 6v and see if the motor gets excessively warm while running.

[shew01]

Originally Posted by Badpuppy

The LED dimmer switch probably won't handle the fan current. Easiest to run it on 6V with a simple toggle switch. The second item you referenced includes a higher powered dimmer, which you certainly don't need.

A more important consideration is that the fan circuit may well be in common with the housing. Negative battery on the housing will short through the coolant directly to the engine's positive ground. If this is the case it can be remedied by either reversing the fan connections - reversing the air flow - or insulating the fan mounts from the housing.

Here is a picture of the fans. They look like computer fans. To me, they don’t appear to grounded to the case.




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[shew01]

Originally Posted by BRENT in 10-uh-C

Likely all that it will do by powering with 6 volts is it will cut the speed in half. Try it on the bench with 6v and see if the motor gets excessively warm while running.

That’s probably the best path to try.


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[Synchro909]

Originally Posted by shew01

That’s probably the best path to try.


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My earlier post about connecting the fans in series was wrong - sorry 'bout that!
Running it on 6 volts would drop the power of the fans to one quarter of what it was. I would not recommend it. Power is proportional to the square of the voltage so halving the volts reduces the power to 1/4.

[nkaminar]

5 Volt fans computer fans are available on eBay. They could probably be run on 6 or 7 volts without any damage.

[shew01]

Originally Posted by Synchro909

My earlier post about connecting the fans in series was wrong - sorry 'bout that!
Running it on 6 volts would drop the power of the fans to one quarter of what it was. I would not recommend it. Power is proportional to the square of the voltage so halving the volts reduces the power to 1/4.

Again, electricals are not my wrong suit. Other than reduced air throughput, why would you not recommend running the 12V fans on 6V? (By the way, thanks for the post. I was thinking it would reduce the power to 1/2.)


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[shew01]

Originally Posted by nkaminar

5 Volt fans computer fans are available on eBay. They could probably be run on 6 or 7 volts without any damage.

Thanks. I’ve been looking on Amazon too. I suppose it’s a roll of the dice on replacement fans. Computer fans are not really made to handle car radiator-style heat. Then, again, the fans that ship with the heater could have a short life as well.


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[Jack Shaft]

When comfort and covienience merges,a 12 volt system is the answer.Component cost is lower and the selection is better.

[Synchro909]

Originally Posted by shew01

Again, electricals are not my wrong suit. Other than reduced air throughput, why would you not recommend running the 12V fans on 6V? (By the way, thanks for the post. I was thinking it would reduce the power to 1/2.)


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When the motor is running at 1/4 speed, it won't move much air and can be easy to stall. That can lead to a burnout.

[shew01]

Originally Posted by Synchro909

When the motor is running at 1/4 speed, it won't move much air and can be easy to stall. That can lead to a burnout.

Thanks.


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[shew01]

Originally Posted by Jack Shaft

When comfort and covienience merges,a 12 volt system is the answer.Component cost is lower and the selection is better.

Up to this point, I haven’t seen much of a compelling reason to convert to 12V. (My car normally starts on first crank on 6V.) But, I can see how 12V would be tempting. You are correct. Virtually everything I’ve found is for 12V.


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[Bruce of MN]

This rheostat or another that is billed for auto fans would be better than an LED controller. https://www.amazon.com/Controller-Un...571361&sr=8-10

[jack wingard]

Originally Posted by Bruce of MN

This rheostat or another that is billed for auto fans would be better than an LED controller. https://www.amazon.com/Controller-Un...571361&sr=8-10

Not sure what is trying to be accomplished with the use of a speed controller. A controller only slows motor max. rpm's by decreasing the DC voltage. It can never increase rpm's since it can't increase DC voltage. So a 12v motor run on 6v the rpm's will already be 1/2 speed. Why would anyone want to slow it more?

[Bob Bidonde]

This is another argument for converting to 12V. All the modern goodies are 12V negative ground.

[Badpuppy]

Originally Posted by Synchro909

Running it on 6 volts would drop the power of the fans to one quarter of what it was. I would not recommend it. Power is proportional to the square of the voltage so halving the volts reduces the power to 1/4.

Power is proportional to the square of current. Fans will run about 1/2 speed.

Originally Posted by nkaminar

5 Volt fans computer fans are available on eBay. They could probably be run on 6 or 7 volts without any damage.

5V fans can be had, just be sure they're physically the same size. The heavy dimmer switch will keep the speed down at 7V, and they will last longer.

[Bruce of MN]

I was addressing the request in post #1 for a switch.

[shew01]

Originally Posted by Bruce of MN

This rheostat or another that is billed for auto fans would be better than an LED controller. https://www.amazon.com/Controller-Un...571361&sr=8-10

Thanks for the link.


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[Badpuppy]

This one rated to 6V -

https://www.amazon.com/RioRandTM-Upg..._t3_B07T35JDTR

The fans in post #9 have plastic housings, which are probably insulative, but check with an ohmmeter to make sure.

Fans don't draw much current; their labels will specify.

[Jack Shaft]

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Originally Posted by shew01

Up to this point, I haven’t seen much of a compelling reason to convert to 12V. (My car normally starts on first crank on 6V.) But, I can see how 12V would be tempting. You are correct. Virtually everything I’ve found is for 12V.


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I stay current on the latest in electrical control for mobile equipment. Isolation of circuits and reducing switch load through the use of relays provides a method of controlling a wide variety of functions without running high amperage circuits throughout the car.
Its not that 6v cant do the job, its the availability of components that limits you. heat, AC, music, seat heaters, lighting, GPS, just about any addition you want to do is available in 12v. As you add components you raise your ampacity requirements, the model a generator is good to 30a,most off the shelf 12v alternators are under 100 bucks and provide 60a at the minimum..

[JayJay]

A solution that you might consider: I have a 12 V power brick with both 12V and USB outputs that I carry with me to power my 12V accessories (like charge my phone) rather than mess around with trying to convert accessories. No reason you could not rig an SAE adapter to the 12V input of the fans and connect to the brick. Not elegantly wired in, granted, but you'd only need your heater part of the season and it might be acceptable to just run a pigtail down to the floorboard. You can also jump the battery using the 12V in a pinch.

JayJay

[shew01]

Originally Posted by Badpuppy

This one rated to 6V -

https://www.amazon.com/RioRandTM-Upg..._t3_B07T35JDTR

The fans in post #9 have plastic housings, which are probably insulative, but check with an ohmmeter to make sure.

Fans don't draw much current; their labels will specify.

Thanks for the link.


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[shew01]

Originally Posted by Jack Shaft

I stay current on the latest in electrical control for mobile equipment. Isolation of circuits and reducing switch load through the use of relays provides a method of controlling a wide variety of functions without running high amperage circuits throughout the car.
Its not that 6v cant do the job, its the availability of components that limits you. heat, AC, music, seat heaters, lighting, GPS, just about any addition you want to do is available in 12v. As you add components you raise your ampacity requirements, the model a generator is good to 30a,most off the shelf 12v alternators are under 100 bucks and provide 60a at the minimum..

Thanks for posting that picture. I think you posted it in the past on another thread, and I was thinking about hunting for it.

By any chance, would you have an Amazon link to it?


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[shew01]

Originally Posted by JayJay

A solution that you might consider: I have a 12 V power brick with both 12V and USB outputs that I carry with me to power my 12V accessories (like charge my phone) rather than mess around with trying to convert accessories. No reason you could not rig an SAE adapter to the 12V input of the fans and connect to the brick. Not elegantly wired in, granted, but you'd only need your heater part of the season and it might be acceptable to just run a pigtail down to the floorboard. You can also jump the battery using the 12V in a pinch.

JayJay

That’s an interesting thought.


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[Jack Shaft]

Originally Posted by shew01

Thanks for posting that picture. I think you posted it in the past on another thread, and I was thinking about hunting for it.

By any chance, would you have an Amazon link to it?


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That's a custom design brother, I bought the pieces and figured the rest. The concept is simple, though in some places I ran multiple function off of one relay, for instance ignition, fuel pump and main relay to fire the fuse panel

[shew01]

Many of the parts I have found are advertised as 12V parts. However, for now, I think I'd like to stay with a 6V positive ground system and make smaller changes rather than make all of the bigger changes that would be required to convert to 12V. I'm not necessarily opposed to 12V in the future, but I recently purchased a new 6V horn, my 6V alternator works fine, my battery works fine, and my headlights work fine. For now, it doesn't make sense to replace a bunch of hardware that is working.

Based on the various responses to this thread, I think I have two viable paths to pursue when I purchase this heater (https://smile.amazon.com/dp/B08CZTND...v_ov_lig_dp_it) in the next couple of days or so. Please help me validate these ideas. I'm not very skilled with amps, wire gauges, etc., and I don't want start a wiring fire in my car.

Plan A (run everything at 6V):

1. Hook up the heater fans "on the bench" to see how much air output is created by the 12V fans running on a 6V battery.
2. If the 12V heater does not have satisfactory air output, proceed with Plan B.
3. If the air output is satisfactory, proceed with the following steps.
4. Add wire of my own to make the heater connections. Would 12 gauge wire be what I'll want to use?
5. Add a dedicated fuse or circuit breaker between the battery and the heater. (I have a fuse on the starter, but I'm thinking that this heater should be separated from the starter fuse. Can someone help me find a suitable fuse or circuit breaker that will work with 6V systems? This https://smile.amazon.com/dp/B07QJ2T2...v_ov_lig_dp_it is the closest I have found so far, and it's 20A. I'm thinking 10A would be what I want, but I haven't found anything 6V rated at 10A.)
6. Possibly add a potentiometer (https://smile.amazon.com/dp/B07T35JD...v_ov_lig_dp_it) for fan speed control. This is rated at 10A.

Plan B (add a 6V to 12V step up converter):

1. As in Plan A, I'll have to add some wire of my own. Would 12 gauge wire be what I'll want to use?
2. Add a 6V to 12V step up converter (https://smile.amazon.com/dp/B019GY2F...v_ov_lig_dp_it). This is rated at 10A.
3. Add a dedicated fuse or circuit breaker between the battery and the 6V to 12V step up converter. (This is similar to what is in Plan A. I need help finding the right hardware.)
4. Add a 12V fuse block (https://smile.amazon.com/dp/B07GBV2M...v_ov_lig_dp_it) to the 12V output side of the step up converter.
5. Route the heater fan connection through the fuse block.
6. Possibly route a 12V cigarette lighter outlet through the fuse block for phone charging.
7. Possibly add a potentiometer (https://smile.amazon.com/dp/B07T35JD...v_ov_lig_dp_it) for fan speed control. This is rated at 10A.

Am I at risk of overloading anything with either of these plans? Do I have circuit protection in the correct places?

[shew01]

Originally Posted by Jack Shaft

That's a custom design brother, I bought the pieces and figured the rest. The concept is simple, though in some places I ran multiple function off of one relay, for instance ignition, fuel pump and main relay to fire the fuse panel

Thanks. You are WAY more skilled than I. :-)

[nkaminar]

I may be wrong, it has been many decades since I took electrical theory classes, but if the voltage is cut in half the fan speed will be cut by 1/4. Power is volts times current. I think the current is cut in half because the voltage is half and the voltage is half. So 1/2 times 1/2 is 1/4.

[Synchro909]

[QUOTE=Badpuppy;1977827]Power is proportional to the square of current. Fans will run about 1/2 speed.


See nkaminar's post at #34.
Yes, power is proportional to current squared but consider this.
Resistance is volts divided by current and remains constant. Power is voltage multiplied by current.
Halve the voltage and the current is also halved (constant resistance). Looking at power in terms of current only, it is resistance by current squared. One half multiplied by one half is one quarter. The fan runs at 1/4 power.

[GeneBob]

Power = Amps X Volts (remember P=IE, it is a piece of pie!)
The minor disagreement with Synchro909 is that you are usually trying to maintain a given level of power, like a 5 watt light bulb. So, if you are trying to provide the same level of power at 6 volts instead of 12 volts, you must double the current. This is why the wire gauge in a 6 volt car is bigger than in a 12 volt car. The age old rule is that if you want to switch to 12 volts, your wiring is not a problem but all your light bulbs, etc must be changed.

[Synchro909]

Originally Posted by GeneBob

Power = Amps X Volts (remember P=IE, it is a piece of pie!)
The minor disagreement with Synchro909 is that you are usually trying to maintain a given level of power, like a 5 watt light bulb. So, if you are trying to provide the same level of power at 6 volts instead of 12 volts, you must double the current. The only way to do that is either increase the voltage back to 12 volts or halve the resistance and that would require the motor in the fan to be rewound for 6 volts. This is why the wire gauge in a 6 volt car is bigger than in a 12 volt car. The age old rule is that if you want to switch to 12 volts, your wiring is not a problem but all your light bulbs, etc must be changed.

I see no disagreement at all. As you say, P=IE. Resistance (R) is E/I. R is constant. That is, it is unchanged regardless of what voltage is supplied to it so if the voltage is halved, the current is also halved. That makes the new current and voltage I/2 and E/2. Now, to put those figures back into the power formula, we have P=I/2 X E/2=IE/4. That is, the power is reduced to 1/4 what it was.

[Badpuppy]

I stand corrected for my fuzzy thinking: V/2 ~ P/4.

In my defense, (somewhat) axle friction and wind resistance will be reduced, and the motor will spin rather faster than expected.

[rocket1]

I love LED lights how about a red LED next to the heater control switch make a small polished stainless plate and hang it from the bottom screws on the dash.

[shew01]

The heater arrived over the weekend, but I’m going to wait for warmer temperatures before I start working with it.


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[5851a]

Does an A have enough water pump pressure to circulate water through a heater core. I'm just curious as I've never thought about it.

[shew01]

Originally Posted by 5851a

Does an A have enough water pump pressure to circulate water through a heater core. I'm just curious as I've never thought about it.

I’ve been wondering about that as well.

It looks like the Snyder’s hookup kit has a curved pipe that snags water in an effort to push it though the heater.

https://www.snydersantiqueauto.com/P...earchByKeyword


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[5851a]

Thanks for the answer.

[mass A man]

Plan "C" might be getting an original Autolite manifold heater. They work very well.

[shew01]

Originally Posted by mass A man

Plan "C" might be getting an original Autolite manifold heater. They work very well.

Yeah, I’ve considered that, but I don’t want to cut the firewall. I’m hoping I can put a couple of heater hose holes in the wood floor, but the jury is still out on whether the water will actually circulate to the heater or not. When temperatures get warmer, I plan to check out fan speeding 6V and on the 12V converter. We’ll see where this project goes from there.


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[DHZIEMAN]

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This converter may be overkill but the motors in that heater, if run on 6 volts may be just fine but if you want to do as little mod as possible, Then this item from Amazon will convert 6V dc to 12 and no other mods are needed! https://www.amazon.com/DIGITEN-Conve...omotive&sr=1-3

[shew01]

Originally Posted by DHZIEMAN

This converter may be overkill but the motors in that heater, if run on 6 volts may be just fine but if you want to do as little mod as possible, Then this item from Amazon will convert 6V dc to 12 and no other mods are needed! https://www.amazon.com/DIGITEN-Conve...omotive&sr=1-3

Thanks, I ordered one.


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[nkaminar]

My car came with a coolant powered heater in a box. It had been installed in the car before so the holes in the firewall were already there. I re-installed it but wanted to use the tap in the outlet neck instead of the adapter in the hose. So I make my own scoop by soldering a modified copper elbow into a brass pipe nipple. I have a thermostat, which is in the radiator hose. The heater works great even in the freezing temperatures we have had here recently. The car is insulated. It is a four door and the heat reaches the back seat. The heater is the boxy one available from the vendors. I put a ball valve in the line so that I can turn off the hot coolant to the heater in the summer.


I think there are different water pumps available that pump more coolant than others.

[shew01]

Originally Posted by nkaminar

My car came with a coolant powered heater in a box. It had been installed in the car before so the holes in the firewall were already there. I re-installed it but wanted to use the tap in the outlet neck instead of the adapter in the hose. So I make my own scoop by soldering a modified copper elbow into a brass pipe nipple. I have a thermostat, which is in the radiator hose. The heater works great even in the freezing temperatures we have had here recently. The car is insulated. It is a four door and the heat reaches the back seat. The heater is the boxy one available from the vendors. I put a ball valve in the line so that I can turn off the hot coolant to the heater in the summer.


I think there are different water pumps available that pump more coolant than others.

That’s interesting. Would you mind posting some pictures of how you have it mounted in the car and in the engine bay?


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[DHZIEMAN]

Happy to suggest! Let us know how it works out!