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Experience:  29 years as a Licensed Electrical Contractor in Illinois, 5 year college Electrical Instructor, Former Electrical Inspector, Diploma in Digital Electronics, Former Illinois Licensed Home Inspector
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I have a similar dilemma. I have a 24 Volt DC winch. That consumes

I have a similar dilemma. I have a 24 Volt DC winch. That consumes 250 amps at its peak performance. I need to use this in the field without a car (due to limited space).
I have proposed two solutions to go about this, but each one has a problem, so please correct me where I am wrong

- Solution 1: Get an A/C generator capable of outputting 6W (250ax24v=6000). Then use an AC/DC inverter.
Problem: I can never find an AC/DC inverter capable of supplying this amount of current.

- Solution 2: Get 4x12volt 125Amp car batteries. (as I cannot find 24volts in my area). Connect 2 in parallel and 2 in series in order to make 24 volts and be capable of supplying 250amp.
Problem: Do I need a charger to be connected to the batteries? When it says 125amps on the batteries, what does that really mean? how much time can it power the winch assuming it runs constantly.

Hello.....my name is XXXXX XXXXX I will be happy to assist you with your electrical question. My goal is to exceed your expectations on Just Answer!

1) The use of a portable Alternating Current gasoline generator will have its own separate receptacles for plugging in an AC battery charger if you are looking for a solution to charge the batteries. An Inverter inverts a DC output and converts it to AC, thus no need for an Inverter since any portable gasoline generator will have built-in receptacles. To power a DC load such as the 24VDC motor on the winch, a rectifier converts Alternating Current to Direct Current. An Inverter does just the opposite, as it converts Direct Current to Alternating Current. I am aware of some portable AC generators that can provide a 12 VDC output as well as the traditional AC outputs, but I am not aware of any that provide a 24 VDC output.

2) Automobile batteries are rated in CCA (Cold Cranking Amps). CCA's are required to provide a high amount of current for a short period of time in order to start an automobile engine. For example a starter on an automobile requires a high amount current to turn an engine over. Most automobiles use 12 VDC batteries that are rated a minimum of 500 CCA's and usually well into the 700 or 800 CCA levels. A 125 CCA battery is too small and will discharge quickly.

3) You can easily connect (2) two 12 VDC batteries in series with each other to provide the 24 VDC output. 24 VDC batteries are not commonly sold in automotive stores. Connect the positive from battery "A" to the negative of Battery "B". You will then end up with a negative on Battery "A" and a positive on Battery "B" to connect to the winch 24 VDC winch.

Yes, you are correct if additional amps are required, then the (2) two 12 VDC batteries that were wired in series (string) can be connected in parallel with (2) two other 12 VDC batteries wired in series. If all 4 batteries are the same amps, then you will double the amp output due to connecting 2 series strings in parallel. Connecting batteries in this fashion is called a battery bank.

4) Yes, you will either need a separate AC portable charger to charge 12 VDC and a separate switch to isolate the (2) two 12 VDC batteries from one another or you can leave the 2 batteries in series and purchase a 24 VDC battery charger. I would also suggest installing 12 VDC voltmeters or a 24 VDC voltmeter for monitoring purposes. Run time will be determined as to how much charge the batteries have. Once a 12 VDC battery goes below 12 VDC, it needs to be re-charged. A fully charged 12 VDC battery is approximately 13.5 to almost 14 VDC. Since these batteries provide high current outputs, there is no way to determine the actual run time due to them being rated in CCA's.

The only batteries that can be calculated in an approximated run time are true deep cycle batteries and these are rated in amp-hours and not CCA's. A typical deep cycle battery application provides shorter amounts of current over a longer time period and are meant to be re-charged. However, a Deep Cycle battery can also provide a high amount of current but a much shorter run time. Deep Cycle batteries are pretty much opposite than a automobile battery. However, they are very costly. For example a 12 VDC Deep Cycle battery that is commonly used in solar panel installations and rated @ 198 amp-hours costs around \$500 per battery. The higher the amp-hour rating in a Deep Cycle battery, the higher the cost.

5) Since the 24 VDC Winch is an electric motor, it is possible that the 250 amp load is the Full Load Current (FLA) or the in-rush current when the winch is initially turned ON. That is a huge current draw. More than likely, once the winch is running, the current draw will be smaller than 250 amps. It is possible that the winch has a nameplate rating that will provide the FLA and running current spec's. If no nameplate, I would ask the winch manufacturer if they can provide these to you.

Hope this helps.........If you have any additional questions, let me know and I'll be glad to answer them for you.

Otherwise, don't forget to rate me before you log Off.

The next time you have an electrical question, you can also request for me at:http://www.justanswer.com/home-improvement/expert-your-electrician
..........Thanks..............Kevin!

Customer: replied 3 years ago.

Kevin, that was super useful! thanks a lot. I have some questions on your answer,

The current of 250amps is the operational current when the winch is at full load of 12000lbs. I am assuming that I will run the winch at max load.

The battery rating I provided above was 125 Amp-Hour. That's the largest battery I could find. Now, I am thinking again, I believe there is no need to hook-up 2 batteries to make a 250amp-hour supply. One 125amp-hour battery can power the winch (@ max load) for 1/2 hour. Is that correct?

From what I understand from your answer is that my best solution is to use 2x12v DC batteries connected in series and to connect a 24 v DC charger to recharge them. Is there any risks involved in using the charger (like overcharging)? How do I make sure that charger is charging the battery fast enough to avoid draining the battery by the winch?

The use of winch will be used at an approximate rate of 5 continuous minutes per hour. Am I okay with the 125 Amp-Hour batteries?

Thanks once again.

Rami

1) You mentioned that the 125 rating will be in amp hours and not in Cold Cranking Amps. A battery rated in Amp Hours is called a Deep Cycle battery. These types of batteries are commonly used in the Solar industry. Stay away from purchasing Marine batteries, as many manufacturers advertise these as Deep Cycle batteries and they are not. Many Marine batteries are actually a combination of a Deep Cycle as well as a Cold Cranking Amps.

2) A true Deep Cycle battery is rated in amp hours. For example, if a battery is rated at 40 amp hours, you could run a load of 1 amp over a 40 hour time period or 2 amps over a 20 hour time period and so forth.

The formula for run time on Deep Cycle batteries is:

Run Time Hours = Battery Amp-Hour Rating / Load Current. This will result in the quantity of how many amps per hour you can run prior to the battery starting to discharge..

Yes, you are correct. In your application, you have a 250Amp load and wish to use a 125 amp-hour battery. Therefore, apply the formula.........= 125 AH/250A = .5 hour or 30 minutes. Based on using this for 5 minutes per hour, you should be good to go!

3) An automatic battery charger has an internal protection circuit which senses that the battery is nearing full charge. Once full charge is achieved, the charger automatically stops so not to over-charge the batteries.

4) If looking for a faster rate of charge, you will need a charger that provides a higher amperage output. The rule of thumb for charges is: The lower the charging amperage, the slower the re-charge time. The higher the charging amperage, the faster the re-charge time. If looking for a faster re-charge time, the cost of the battery charger price will be reflective and will cost you more.

Hope this helps.........If you have any additional questions, let me know and I'll be glad to answer them for you.

Otherwise, don't forget to rate me before you log Off.

The next time you have an electrical question, you can also request for me at:http://www.justanswer.com/home-improvement/expert-your-electrician
..........Thanks..............Kevin!

Customer: replied 3 years ago.

So finally to power up the winch i will do this:

1-connect 2x24v dc batteries in series.

2-connect the positive terminal of one battery to the positive terminal of the winch and the negative terminal of the other battery to the negative terminal of the winch .

3-connect a 24volt dc charger in parallel with the winch and batteries .

4-plug the charger into the AC generator .

5-oops, I forgot: connect a switch in series with the winch (recommended by the manufacturer )

6-use 0 gauge wire in making the connections (to sustain 250 amps)

7-connect a voltmeter in parallel to monitor voltage .

8-run the winch.

Is all correct ?

9-Also there's no harm in operating the winch while the charger is connected to the batteries and is recharging them.right ?

Thanks

Rami

1-connect 2x24v dc batteries in series.

You need to connect a quantity of (2) two 12 VDC batteries is series to form the 24 VDC and then combine them with another (2) two sets of 12 VDC in series and them combine both strings in parallel if using 12 VDC batteries or connect (1) one 24 VDC battery. If additional amp hours are desired, then connect (2) two 24 VDC batteries in parallel to double the amount of run-time.

2-connect the positive terminal of one battery to the positive terminal of the winch and the negative terminal of the other battery to the negative terminal of the winch .

Yes, that's correct.

3-connect a 24volt dc charger in parallel with the winch and batteries .

Yes, that's correct

4-plug the charger into the AC generator .

Yes, that's correct

5-oops, I forgot: connect a switch in series with the winch (recommended by the manufacturer )

Yes, I would recommend that as a safety disconnect switch. The disconnect switch will need to be a minimum of 250 amps.

6-use 0 gauge wire in making the connections (to sustain 250 amps)

A 250 amp load will require the use of 4/0 stranded copper wire and not 0 gauge.

7-connect a voltmeter in parallel to monitor voltage.

Yes, that is correct

8-run the winch.

Yes, that is correct

Is all correct ? All is correct except number 6. See above.

9-Also there's no harm in operating the winch while the charger is connected to the batteries and is recharging them.right ?

Yes, that is correct. No harm

Category: Electrical
Satisfied Customers: 2780
Experience: 29 years as a Licensed Electrical Contractor in Illinois, 5 year college Electrical Instructor, Former Electrical Inspector, Diploma in Digital Electronics, Former Illinois Licensed Home Inspector
Customer: replied 3 years ago.

thank you very much, that was super helpful.

Hello Rami............Thank you for the excellent service rating...........much appreciated!

If you have any other questions, just let me know.

Take care and have a great day...............Thanks................Kevin!

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