Battery Help

[Rocketman]

As of right now, this is not an issue, but at some point it will be. My generator is supposed to charge the auxillary battery that I have connected to it with "a small charge intended to replace the power used while starting the generator". Yeah, that's the best description I could find on it.

At some point, I want to install shorepower and a distribution panel that will also convert some of the ac generator voltage to a dc charge for that same auxillary battery.

To top that all off, I want to run a wire from the main starting battery (the one under the hood) to the auxillary battery with an isolator to protect from discharging the starting battery.

So, in that setup, I would have 2 sources of charge coming to the auxillary battery anytime the generator is running. If the generator and the main engine are running at the same time, there would be 3 sources of charge.

I'm sure the battery is going to blow. My question is: How high? 3 feet?, 10 feet?, 20 feet?

Seriously, will it work? What do I need to do to make it a safe and proper install?

 

[jjoerger]

Ask Turtle. When it comes to this kind of stuff he is the man.

Sent from my PG06100 using EO Forums

 

[Turtle]

Xantrex PROsine 2.0

 

[Monty]

That's the dc to ac unit, I think he was asking about the reverse. ac to dc, with a switch to disconnect the starting battery from the loop when the unit is stopped.

But I've been wrong before.

My Sprinter had a 500 watt "converter". Anytime the shore power, or generator was active, it charged the batteries.

 

[Rocketman]

Xantrex PROsine 2.0

Wow...$1,300? Guess I'll just stick with what the generator supplies.

 

[Rocketman]

That's the dc to ac unit, I think he was asking about the reverse. ac to dc, with a switch to disconnect the starting battery from the loop when the unit is stopped.

But I've been wrong before.

My Sprinter had a 500 watt "converter". Anytime the shore power, or generator was active, it charged the batteries.

Looks like it would control the multiple source charging. The thing is...I don't need ANY inverter capability. If I want AC power, I'll start the generator.

All I want to do is make the three sources of charge work safely.

 

[Turtle]

You specified safe and proper. There ya go. You certainly don't necessarily need that brand or model, but you want something with automatic switching between power sources, unless you want to use manual switches like the kind from Blue Sea Systems for boats, but that will get really old after about three days in a van.

You'll if course need a battery isolator between the starting battery and the rest of the system. Sure Power or Hellroaring are the best ones.

But for everything in the van, you'll need a battery charger to charge the aux battery from generator or shore power, and a way to switch between power sources. The switching cab be manual or automatic.

 

[Rocketman]

You specified safe and proper. There ya go. You certainly don't necessarily need that brand or model, but you want something with automatic switching between power sources, unless you want to use manual switches like the kind from Blue Sea Systems for boats, but that will get really old after about three days in a van.

You'll if course need a battery isolator between the starting battery and the rest of the system. Sure Power or Hellroaring are the best ones.

But for everything in the van, you'll need a battery charger to charge the aux battery from generator or shore power, and a way to switch between power sources. The switching cab be manual or automatic.

But...there still seems to be a misunderstanding. No doubt it is due to my ignorance of charging systems. I don't think I need another charger of any kind. Each of those 3 sources are already designed to charge the battery. The only problem that I'm concerned with is connecting all 3 at the same time.

Source 1: The generator produces "some amount of" 12v charge for the battery.
Source 2: The distribution panel has a built in converter and battery charger to charge the battery.
Source 3: The isolated wire from the starting battery. Which is charged by the alternator.

I do understand there may need to be a way to control these 3 sources of charge, but why would I need a battery charger when I would basicly have 3 already working?

 

[Turtle]

Source 1: Connecting the 12-volt output of a generator directly to the aux battery is not exactly the ideal way to charge the battery, unless the 12-volt output is designed to be battery charger, rather than simply 12-volts that will charge a battery. That's a dumb charger, and you want a smart charger, unless you want to sit there with a voltmeter and monitor the charge all the time. Output from the generator should go to the distribution panel and have that charge the battery. I know a lot of generator marketing is "it's got 12-volt output to charge batteries!" but unless it's a monitored charge like with a smart charger, you could overcharge the battery.

Source 2: If the distribution panel has a built-in battery charger, and it is indeed a battery charger designed to charge batteries, then there's your battery charger.

Source 3: There's no current flowing through that wire unless the engine is running and the isolator relay is closed. If the engine is running, the alternator is sending current to the aux battery.

Best way is to connect all three sources to an automatic switch, which will select one of the charging sources to charge the battery through the distribution panel's battery charger. That way you don't have multiple charging sources trying to fry the battery all at once with too much charging current.

 

[Rocketman]

Source 1: Connecting the 12-volt output of a generator directly to the aux battery is not exactly the ideal way to charge the battery, unless the 12-volt output is designed to be battery charger, rather than simply 12-volts that will charge a battery. That's a dumb charger, and you want a smart charger, unless you want to sit there with a voltmeter and monitor the charge all the time. Output from the generator should go to the distribution panel and have that charge the battery. I know a lot of generator marketing is "it's got 12-volt output to charge batteries!" but unless it's a monitored charge like with a smart charger, you could overcharge the battery.

I agree. I would have to dig all that back up to get an exact quote, but even then, it was vague, very vague. I did understand it to be a small/trickle charge, but that's pretty vague.

There is also a problem in the fact that this charge is basicly a backfeed through the starting cable. So, in effect, I'm not sure what I can do with it. I have read..somewhere...that this charge can be disabled inside the generator box somewhere. I would probably take it to an Onan shop to do that if needed.

Source 2: If the distribution panel has a built-in battery charger, and it is indeed a battery charger designed to charge batteries, then there's your battery charger.

Agreed. This is what I'm looking at: WFCO 25 Amp Distribution Panel - Brown - Distribution Panels - Electrical
"Automatic three-stage charging provides superior 12V system performance while maintaining the ideal charge and maintenance of your battery. Output: Absorption 13.6V DC (includes charging and load); Bulk 14.4V DC; Float 13.2V DC. "

Source 3: There's no current flowing through that wire unless the engine is running and the isolator relay is closed. If the engine is running, the alternator is sending current to the aux battery.

It is definitely supplying current...but it is a regulated current?

Best way is to connect all three sources to an automatic switch, which will select one of the charging sources to charge the battery through the distribution panel's battery charger. That way you don't have multiple charging sources trying to fry the battery all at once with too much charging current.

I could go with that...as long as it doesn't cost $1,300 Do you have a link to such a critter? I'll see what I can find.

From what I'm finding on the interweb, as long as ALL sources are regulated, the multiple source is not a problem. The only source that I'm not sure about is whatever the generator is sending back to the battery and supposedly that can be disabled.

BTW...thanks for the help Turtle. I know I can be a bit stubborn sometimes. I get it from talking to Highway Star too much

 

[Turtle]

I'll post mote later, but for now, seek out GoPower Automatic Transfer Switch. 30 amp should do it.

 

[Rocketman]

I'll post mote later, but for now, seek out GoPower Automatic Transfer Switch. 30 amp should do it.

will do...thanks! Everything I've found is close but not what I see as correct.

Edit: That seems to be for transfer from shorepower to generator power?

 

[Turtle]

That's to get you familiar with what they do. They make switches that transfer between three or more power sources.

 

[josh786]

With all chargers charging at one time. The only problem I see is that you may have to high of a voltage (IF) you have a deep cycle battery as your house battery. But as long as your charger on your generators AC output is a smart charger and it is not in equalizing mode it will quickly drop into cv mode. Because you will at that time have two batteries and two main charge sources (The power returned from the generator directly back the starting wire is almost zero compared to the 50+amps from the other charging). Also am I missing something as to why you would run both for an extended amount of time? (Longer than 15-20min) So my two cents says short time 15-20 min I would not worry but might check the output on the charger to make sure that it is set to a reasonable charge current.

 

[Rocketman]

With all chargers charging at one time. The only problem I see is that you may have to high of a voltage (IF) you have a deep cycle battery as your house battery. But as long as your charger on your generators AC output is a smart charger and it is not in equalizing mode it will quickly drop into cv mode. Because you will at that time have two batteries and two main charge sources (The power returned from the generator directly back the starting wire is almost zero compared to the 50+amps from the other charging). Also am I missing something as to why you would run both for an extended amount of time? (Longer than 15-20min) So my two cents says short time 15-20 min I would not worry but might check the output on the charger to make sure that it is set to a reasonable charge current.

You are correct. Would likely never be for an extended period. In my thinking, it would occur on a really hot day where I might deliver a load, crank up the generator and rooftop to give the rooftop some time to cool the van while driving from the reciever to a layover spot. Or if I just wanted to move a small distance and not shut down the rooftop and generator for the move.

 

[Rocketman]

That's to get you familiar with what they do. They make switches that transfer between three or more power sources.

Ok...thought we were derailed again..lol. I'll look at it a little closer. I have an idea what it does...but pretty clueless as to how it does it.

 

[josh786]

In that case I would not do anything different. When you put the isolation in use a continuous rated solinoid (sp?) Put a switch on the dash that is connected to the ignition switch. It will leave the batteries connected in the on position (if the ignition is on)but in the off position they will act as two systems. You could even wire a light to this switch that will be on when the ignition is on and the switch is off. So that you remember to turn it back on.

 

[Turtle]

Or you could just use a battery isolator that does all that automatically.
Key on = connected.
Key off = disconnected.
All without having to wire it to the ignition.

 

[Rocketman]

The stuff that I find is mostly built for either solar/wind generation systems. I have found this one: CTEK D250S DUAL Universal 12-Volt Battery Charger - Multiple 12-Volt DC Power Sources CTEK Power Inc Battery Chargers CTEKD250S

I guess what I like most about that link is the diagram about 1/3 of the way down the page. If you replace the solar panel display with the distribution panel charger, that would be pretty close to what I have in mind...that is..if I disable whatever amount of charge the generator is sending back through the starter cable, leaving me with only 2 sources to deal with.

 

[Turtle]

It seems you're trying to complicate the simple. I'm not sure why you are stuck on that distribution panel. It's a converter power center that takes 110-volt AC power and converts it to 12-volt DC current, and it's a battery charger. Adding a second battery charger like the CTEK, while it adds a transfer switch, it's a little redundant.

But OK, it seems you want a 100% 12-volt system in the van, never needing the use of an inverter for 110-volt appliances, and only using 110-volt appliances when they are plugged into shore power or running off a generator. Correct?

If so, get this: Rapid Mobile 3 Way Automatic Transfer Switch

Incidentally, you mentioned "if I disable whatever amount of charge the generator is sending back through the starter cable..." Define "starter cable" please. Do you have your generator connected to the van's starter?