Alternators and Battery chargers

  • Thread starter Graeme McIntosh
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In summary, the conversation discusses the possibility of generating 2400 watts by attaching four mechanical rotating devices in series or parallel, and using this power to recharge a 60kWh lithium battery that requires 27kW for 3 hours continuously. However, it is determined that the 2.8kW output from the alternator is not sufficient to charge the battery in a timely manner. Suggestions are made to either use a smaller battery or a more efficient alternator, and possibly invest in a bigger alternator. The discussion also touches on the need for parallel connections and the availability of higher capacity alternators.
  • #1
Graeme McIntosh
If I had a mechanical rotating device rotating at 700 rpm connected to an alternator producing approximately 700watts; could I generate 2400watts if I were to attach 4 of them in series or parallel? Would that power be sufficient to recharge a 60kWh lithium battery that uses 27kW in 3 hours continuously?
 
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  • #2
Do you mean that you have a load that requires 27kW for 3 hours continuous? (I will assume a yes)
So the load demand that you are talking about is 27X3 = 81kWh
Alternator will supply 700 X 4 = 2800W, doesn't it? (2.8kW)
How many hours at 2.8kW is needed to charge a 60kWh battery bank? (60/2.8=21.4 hours : almost a day) The Batteries will last for 60/27 = 2.22 hour
You then need a source of 27kW for the remaining time and you only have 2.8kW from the alternator.
So, if that's you actual problem, it won't work.
Perhaps you meant something different from what I have understood. Where have I lost you in the above set of musings?
PS Battery and alternator connections needs to be right for the required load voltage. If the load takes 12V then the alternators need to be in parallel (and synchronised!) If they deliver DC then they will need to be regulated / matched fairly well.
 
  • #3
Yup. That's my problem. Clearly it won't work; but how do I generate the additional power with a maximum of 4 mechanical shafts is my next problem. I'm a little stumped...

I could use a smaller battery or use a more efficient alternator. I really can't use anything smaller than a 50kW battery.

They do have to be in parallel.
 
  • #4
A bigger battery would do the job but not once a day. A smaller battery would be no use at all because your alternators have such a limited capacity.
Bigger alternators are available. I think you will have to bite the bullet and spend some money. :frown:
Graeme McIntosh said:
They do have to be in parallel.
Of course, if you want 12V.
I have seen 120A alternators on eBay!
Is your prime mover powerful enough of four of those?
 
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What is the purpose of an alternator?

An alternator is a device that converts mechanical energy into electrical energy. Its main purpose is to charge the battery and power the electrical systems of a vehicle while the engine is running.

How does an alternator work?

An alternator uses a rotor, stator, and diode rectifier to produce electricity. The rotor spins inside the stator, which contains a series of wire coils. As the rotor spins, it creates a magnetic field that induces an alternating current in the stator coils. The diode rectifier then converts the alternating current into direct current, which is used to charge the battery and power the vehicle's electrical systems.

What is the difference between an alternator and a battery charger?

An alternator is a part of a vehicle's charging system and is primarily responsible for charging the battery while the engine is running. A battery charger, on the other hand, is a separate device that is used to charge a battery when it is not connected to a vehicle's charging system. It is commonly used for charging car batteries that have been drained or for maintaining the charge of a battery that is not in use.

How do I know if my alternator is failing?

There are a few signs that may indicate a failing alternator, such as dimming headlights, a dead battery, strange noises coming from the alternator, or the battery warning light on the dashboard. If you suspect your alternator is failing, it's important to have it checked and replaced if necessary, as a failing alternator can cause your vehicle to break down.

Can I replace my alternator and battery charger with one unit?

While there are some combined alternator and battery charger units on the market, it is not recommended to replace your separate alternator and battery charger with one unit. This is because the functions of these two devices are different and require different components and systems to function properly. It is best to stick with the separate alternator and battery charger for your vehicle's charging needs.

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