Questions about continuous duty solenoid

[ccbreder]

Not sure I need a $160 marine device. Here is a Cole Hersee rated at 200 amps, continuous. https://www.amazon.com/Cole-Hersee-...3_1?ie=UTF8&psc=1&refRID=STHAZR80A9V37N69GE4X

 

[SternWake]

Not sure I need a $160 marine device. Here is a Cole Hersee rated at 200 amps, continuous.  https://www.amazon.com/Cole-Hersee-...3_1?ie=UTF8&psc=1&refRID=STHAZR80A9V37N69GE4X

The blue Seas Solenoid link was just an example of overkill.

The Cole hersee you linked is perfect.

One can find CD solenoids for as little as 9$, but they will not be reliable and when they fail, they might take the starter battery with it, in addition to allowing the dreaded starter 'click'

Newbs/ anyone interested in CdS's should bookmark that cole hersee link.
"Superior silver tungsten carbide contacts"

Make sure the ring terminals fight tightly over the 5/16" studs.

wrong:

correct:

Photo Source:
http://www.pbase.com/mainecruising/battery_cables

One can hook one side of the CDS to alternator(+) stud, instead of engine battery (+), for better recharge performance.

This bypasses the inadequate vehicle alternator charge circuit, and will allow the alternator to fed more amps into a well depleted battery, and 'might' also allow the vehicle's voltage regulator to allow higher voltages for longer. Also speeding recharging.

The vehicle's voltage regulator plays a huge part in how effective alternator recharging is.  Most are timid, designed only to top off a slightly depleted starting battery and then dropping to a safer 'float' voltage.  Fine for a vehicle without a house bank, but far from ideal when the alternator is asked to recharge depleted house batteries.

I bypassed/modified my Vehicle's voltage regulator so I choose the voltage and thus command the alternator to obey my will.  Did you just hear a maniacal laugh in the distance?

That was me, adjusting voltage by twisting a potentiometer next to my voltmeters on my dashboard.

 

[Vagabound]

ok I think Vagabound is talking about the when they tapped into the fuse box to trip the solenoid.  if that is correct then that fuse jumper he showed would work fine.
...

Yes, that is what I was talking about.  Thanks.

Vagabound

 

[dr_nelson]

OK, it's that time again. After work and already late...

So, I tried to visualize how I would hook up my house battery to the vehicle's alternator.
This is what I understand so far. All wires at least 2awg. And alternator ground close to alternator.
[img=626x332]

Now, two questions:

0)
Bbefore I got to know CRVL, I already ordered a 150A continuous solenoid. My understanding is that if I go the route of hooking up the alternator, I don't even need the solenoid anymore. Is that correct?
(I saw Bob's video about installing the solenoid - awesome!)

1)
My 2001 Ford e350 Super Duty seems to have either a 95A or 130A alternator (found this via searching for parts and these were the two options for my model). I understand I need fuses between the alternator and the house battery.
Do I need only one fuse close to the house battery Plus terminal?
Or do I need two fuses, one at house battery Plus terminal and one at alternator Plus terminal?


Thank you!


PS: Maybe this matters... I will have 400W of solar with a 230 AH house battery bank and will be driving to work 25 minutes (each way).

 

[Trebor English]

The solenoid switch disconnects the house battery and loads from the starter battery.  Whether you connect at the starter battery or at the alternator you do need to disconnect.  

Every wire needs protection at every point power is applied.  At the house battery you need a fuse.  If you connect to the starter battery you need a fuse there.  The vehicle wiring has a fusible link between the battery and the alternator.  If you connect at the alternator that fusible link will protect your wire from the starter battery.  

It is reasonable to depend on that fusible link  However, you may not know the current rating of it.  You need a fat wire to use it.

 

[Volvocamper]

New to the forum and have a few questions concerning setting up a solenoid in a 2002 Volvo V70,

If I were to connect the solenoid up to an empty fuse jack that was on a timer( 12v when cars is on and12v for a couple of minutes when the car is off) would I run into any problems?

How do I know that my solenoid is working?

Is it a problem if I'm getting 12v in/out of the solenoid when the car is off.

 

[losthighwaydrifter]

All the talk of using Alternator is great on older say 2002 and back generally speaking, but a lot of newer cars use part time charging where the PCM looks at the cars bat and sees if it needs charged and turns alt. on and off adding resistance ie: another system can cause major and expensive problems!!!modern cars are VERY sensitive to current/resistance and system loads. most can bus systems use 1 or 2 wires for multiple functions by changing the ohms(resistance) in that wire. if you ever try to do keyless entry or remote start on Chrysler you would see this.

 

[Weight]

You need to back further than 2002 to have a separate regulator for the alternator. Never a good idea to put a heavy draw on the alternator.

 

[Volvocamper]

So if understand what you are saying correctly, a dual battery system won't work on a Volvo V70 due to the restraints that the automatic sensor blace on the battery charge?

 

[Weight]

You can't tell except by testing. My advice is worth what you paid.

 

[Volvocamper]

How would I go about testing?

 

[Trebor English]

How would I go about testing?

The way to test it ist to install it and see how it works.  

First, install the wire from the alternator to the house battery.  The resistance of 10 feet of AWG 6 is a reasonable limit.  Skinnier or longer will interfere with charging more.  How close can you put your house battery to the alternator?  Ring terminals installed wrong can easily have more resistance than the wire.

Find a circuit to control the solenoid that is on with the engine on or with the accessory key position.  For the test, keep it simple.  You are unlikely to find "empty fuse jack that was on a timer( 12v when cars is on and12v for a couple of minutes when the car is off)."  

Have a big fuse at the house battery end of the cable and at the alternator end of the cable.  Consider 75 amp fuses for AWG 6 wire.  Have a plastic box for the house battery to protect from something conductive falling on it.  

You need to keep reasonable expectations.  There will be no heating devices, no cooking, no water heating, no coffee, tea or soup.  You will have a short battery life.  Two daily drives of 25 minutes will be good to run a small fan, charge a phone, and power some LED lights.  

If your battery is flooded you can use a hydrometer to see how it is working.  If you have AGM or gel all you have is resting voltage, a very poor, unreliable, indicator of state of charge.  $150 for good battery monitoring electronics probably isn't worth it for a similar price battery.  What battery did you intend to use?  

The engine computer, PCM, can turn off the alternator field current when appropriate.  While cranking to start and when wide open throttle are reasonable.  Since the goal is to recharge the vehicle battery there will be charging.  An attached lightly discharged house battery will get some.  A big bank deeply discharged won't be refilled but the alternator will be heated.  

Disclaimer:  what I did was replace my minivan tiny starter battery with the biggest deep cycle battery that would fit in the original location.  There's no solenoid, just one battery.  Yes, I could leave the headlights on and run down the battery until it is too weak to start the engine.

 

[Volvocamper]

So using two batteries will put too much load on the car. I have already installed everything using two batteries. The two batteries are placed in the trunk of the car. While the alternator is near the engine.

I have connected the solenoid to a fuse jack that gets 12v when the car is on and 12v a few minutes after the car is off. Which powers the solenoid.

The first battery is a starter battery and the second is an auxiliary deep cycle 100 ah battery.

I have tested it and I am getting power.

I think My problem is that Everytime I shut off my car the solenoid stays on for a little bit which drains my starter battery.

 

[Trebor English]

Having a big battery, 100 amp hours, is big.  If it is deeply discharged don't expect a 25 minute drive to fill it up.  

The long wire all the way to the trunk will help protect the alternator.  That's not a bad thing.  If your electricity use is light this set up will work.  

If the 25 minute drive substantially charged the deep cycle battery the voltage will be close to the starter battery voltage.  After the alternator goes off there will be a very low current.  A few minutes of having the two connected won't matter.  The solenoid coil (12 to 17 ohms, depending on model) takes roughly .5 to 1 amp.  That also is low enough to not matter for a short time.  

You can measure this battery to battery current.  Start the engine.  Solenoid turns on.  Connect an amp meter from one battery to the other.  Since solenoid is on there will be zero amps.  Drive 25 minutes, turn off engine.  When the solenoid turns off quickly look at amp meter.  That's the battery to battery current.  Disconnect the amp meter.  Mimutes times amps divided by 60 is amp hours.

 

[LoveCareThinkDo]

I'm tacking this question on to the end of this thread because it is a continuation of three issues already brought up in this thread.

First, in regards to overtaxing the alternator: Are there ways to limit the current that the house batteries take, so that the alternator would not be overtaxed. I know I could stick in a giant current-limiting resistor, but that would reduce the current all the time rather than impose a limit on max current.

Second, in regards to alternators in newer cars essentially being turned off by the car's computer: How do those of us with newer vehicles find out if their alternator is controlled by the computer in this manner? Are there search terms to look for? Or can one simply go by brand and year? (I have a 2008 Dodge Grand Caravan.)

Third, in regards to this whole process messing things up in newer cars: Same question as the second.


Final, bonus question: If one were to put an MPPT charge controller between the alternator and the house battery, would that help get the most charge out of what the alternator was putting out, or would that just introduce too much inefficiency? Please answer for both older and newer cars (just for future reference).

Thanks,
CC

 

[Ticklebellly]

A giant current-limiting resistor would have the effect of introducing voltage drop in the copper run between charge voltage source and the battery to be charged. Think of that against the good advice that you should always over spec copper runs to ensure minimum voltage drops between charge power source and the battery to be charged.

You cannot "overtax" an alternator. They can only deliver up to their spec on demand. A high spec DC2DC device between the alternator Positive output and the battery often results in better charging efficiency. Deeply discharged batteries and short driving periods create the largest discussion about efficiency regards direct alt charging and via a DC2DC device.

 

[LoveCareThinkDo]

Think of that against the good advice that you should always over spec copper runs to ensure minimum voltage drops between charge power source and the battery to be charged.

My point exactly.  I used to be an electronics technician decades ago. But that doesn't mean I know all the devices that have come on the market in the past 20 years.  I also have no idea what they would be called. Googling "current limiting" gets way too many hits. The question is, would it be feasible to use one in this circumstance. I'm guessing they are just expensive enough to make it not worth it. I'm thinking there might be active current limiting devices that have no resistance at lower current but limit the current to a maximum. Either by inserting resistance or by pulse-width-modulating the current, similar to what a PWM charge controller does. 

Wait a minute.... OK, I'm somewhat familiar with the way a PWM charge controller works and how an MPPT charge controller works. (Though my math ain't as good as it used to be.) And I know that both PWM and MPPT charge controllers limit the current going to the battery they are charging. So, wrapped up with my bonus question, do you think an MPPT charge controller would BOTH get the most out of what the alternator was putting out AND limit the current draw on the alternator to safe limits?

You cannot "overtax" an alternator. They can only deliver up to their spec on demand. A high spec DC2DC device between the alternator Positive output and the battery often results in better charging efficiency. Deeply discharged batteries and short driving periods create the largest discussion about efficiency regards direct alt charging and via a DC2DC device.

There are several mentions, in this thread, of alternators overheating and being damaged because the house battery was drawing too much current for too long. As far as I am concerned, that is overtaxing the alternator. Sure, you cannot "suck" more current out of a device than it is designed to deliver. But it is possible to use the maximum it can deliver when it isn't truly designed to handle delivering that much current. For instance, a car battery will deliver enough current to melt a wrench. But it isn't designed to actually handle delivering that much current, so it will be damaged. Alternators and any other current "delivering" devices are the same way. Either something limits the current they deliver to below the maximum current all their components can handle, or they can be damaged by delivering the maximum current they can deliver.

 

[Weight]

You can overheat the alternator. Modern vehicles have a temperature probe and reduce the output. Any vehicle from about 1990 has a computer and the alternator regulator is part of that computer.

 

[LoveCareThinkDo]

You can overheat the alternator. Modern vehicles have a temperature probe and reduce the output. Any vehicle from about 1990 has a computer and the alternator regulator is part of that computer.

So, are you saying that, with newer vehicles, we don't have to worry about overheating the alternator precisely because the computer limits its output if it starts to get too hot?