Genesis Duel Battery, Duel Odyssey Batteries and a NOCO Genius onboard charger.

[JCDriller]

I posted this question a couple of days ago and then deleted it because I felt I may have jumped the gun before reading old threads to find the answer. I've read as much as I can find on this topic and I still am no further on deciding what to do so I feel comfortable asking it again.

I am about to install a Genesis Duel Battery bank with 2 Odyssey Group 34 batteries in my Jeep JKU. It's got the factory 160a alternator so charging them while driving shouldn't be an issue. However, I'm concerned about my weekend warrior jeep sitting in the garage during the week so I'd like to add a NOCOf Genius onboard charger for shore power, keeping my fridge going M-F.

I'm in contact with Shane at Genesis Off-Road and he's been great, just looking for other inputs and perspectives.

My questions are as follows:

1. Which NOCO is best, 1 bank or 2? When the Genesis Smart Isolator senses 13.2v it connects the batteries, so I could apply a 1 bank charger to the starting battery and when it's charged the circuit is closed allowing the house battery to charge. My concern is the resistance applied by the smart isolator or increased battery capacity when they are joined throwing off the NOCO and causing it to malfunction or not charge correctly. This makes me think that 2 banks would be better, but what happens if both banks are charging and the isolator closes? See question 3.

2. Which amperage is best 4a or 10a? I realize that when the Jeep is in my garage 4a will be enough to counter parasitic drain and my fridge, but what about if I'm glamping and have my stereo (amp), fridge, work lights, etc. going. This is where 10a sounds like a better choice. Which amperage would the Odyssey batteries charger better with and again see question 3.

3. If using the 2 bank 10a NOCO charger when the Genesis Smart Isolator is sensing 13.2v and closed will this be like applying 20a to the batteries since they are connected and each receiving 10a?

Thank you for your inputs, I appreciate your collective knowledge and look forward to learning more about this topic.

 

[AndrewP]

With a voltage sensing relay, one charger will do fine. The idea is you put your truck away with both batteries basically charged from driving, and let the smart charger take them through an absorb cycle and then float them.

Assuming you just have normal loads, like idling electronics in your stereo and clock, your parasitic drain will be very low. Find out how much current it takes to hold your relay closed, and add 0.4 amps and you'll know how much charging current you'll need to float your batteries. It isn't much. A 2 amp charger will be plenty. If you really want to know exactly the current required, you'll need to measure it with a power meter or similar.

I don't follow #2. If you are glamping, are you saying you'll still have access to shore power? If so, why do you need a dual battery system?

If you haven't bought your Genesis dual battery system, there are many better and much less expensive products that do the same thing. If the pictures are correct, the heart of the Genesis is an inexpensive continuous duty solenoid and they want $479 for it. Read some more on Voltage sensing relays or Automatic Charging Relays before you spend almost $500.

Anyway, have fun. Electrical projects are typically pretty easy, just be meticulous, fuse the power at the battery, make good solid connections and pay attention to voltage drop in the charge circuit. You'll do great.

 

[JCDriller]

Andrew, thank you for the feedback. If I can get away with 1 bank I'd like to as the Genius Mini and gen1 is much smaller than their larger duel bank setups. Still going to be tight finding a place for it under the hood. I'm thinking that the single bank 10a Gen1 attached to the starter battery would be perfect. Enough amperage to offset the fridge and still small/compact. With the solenoid closed it should still charge both batteries in a reasonable time.

I'm pretty set on the Genesis unit, I really like the drop in aspect. Every time I take on an electrical project I'm miserable in the end. I can weld and wood work all day, but wiring just brings me down.

Finally, I've never glamped with shore power, but it would be nice to know I can take advantage of it if the opportunity arises. We've got a child on the way so I assume we'll be spending more time at established camp sites than we do now.

 

[DiploStrat]

This Ain't Hard

Andrew is right, Blue Sea will sell you a much nicer, more versatile system for 1/2 the price.

That said, when it comes to shore chargers, bigger is almost always better as long as it is smart enough to drop to float.

With an intelligent relay, it doesn't matter which battery you attach to, once that battery rises above the connect voltage, both will charge. But the total amperage available will only be what your charger can produce. With two batteries, I would favor 10A over 4A. I have heard nothing but good things about CTEK products and they are recommended by Chevrolet and Audi, among others.

 

[AndrewP]

I understand the drop in aspect, however, you could get all the function of that(and more, and proven), in a better and more compact case, with a life time warranty for $200:

http://www.amazon.com/Blue-Sea-Syst...1444782382&sr=8-1-spell&keywords=ble+sea+7622

Add $100 worth of marine grade wire and lugs and you have a far better pro type system that will do just what you want and you save $200(enough for a decent battery). That Genesis smart relay looks kind of cobbled together. The heart of it is an 85 amp solenoid. You will need to get the upgraded version to work safely with your alternator. The Blue Sea above can handle 500 amps and fully combine your batteries if needed for $200.

Heck, even a Blue Sea 7610 at 120 amps continuous/200 amps for 5 minutes would work fine and cost $69.

The upgraded Genesis relay is $519 and if you want the monitoring system it's $790. Not including batteries. Seems like a lot for not very much-what you get is basically that someone else has cut wires to length for you.

Whatever you end up doing, good luck. You will learn more, and end up with a better system not using the Genesis smart relay in my opinion. But if you want to get up and running in a quick Saturday afternoon, maybe the Genesis will meet your needs.

 

[Ducmonsta]

I would call Odyssey and see what they recommend for the batteries. I was looking at Noco but learned that they are not on the approved charger list for Odyssey. I'm not going to get into details of how the Noco charger is insufficient but if you speak to them, they'll tell you the technical answer. They actually tried to get Noco to change their charge rate so they could approve them but Noco had a different opinion of when the float stage of charging would start.

 

[Ducky's Dad]

My experience with Odyssey Grp 34s is that they are not nearly as sensitive to charging voltage and amperage as are their Grp 31s. The 31s are a real pain in the *** to charge and maintain, but the 34s behave, for the most part, just like Optimas. I have had a bunch of all of them.

 

[JCDriller]

NOCO replied to a thread I posted on Wrangler Forum Thread here. I've also spoken with Sean at Genesis Off-road about this idea. A duel battery system and an onboard charger/shore power seem to go together like peanut butter an jelly but surprisingly in the Jeep world I can't find any instances where someone has actually done this.

They recommend a 4a duel bank, but I'm still concerned about the low amperage not being adequate. I've also read a few things about the NOCO's shutting off after 24 hrs of charging and that they don't do well charging severely drained batteries. I hope my house battery doesn't get severely drained, but it would be nice to know the NOCO would charge it if it happens. Aparently the NOCO doesn't detect the drained battery well.

 

[DiploStrat]

Sorry, but ...

You need some serious help with your set up as I am afraid that you are not really understanding all of the technobabble. None of us can give you enough assistance by simple web posts.

-- The Genius dual (it's dual, as in two, not duel as in pistols at dawn) battery system is a very expensive intelligent relay, also known as a voltage sensing relay. With a well designed unit of this type, the resistance across the relay and the voltage drain of the relay are so low as to be negligible. As noted, there are many other products which do more for much less money.

-- With a system of this type, the idea is that the two battery banks are combined whenever there is a charge available to either battery and separated whenever the voltage of either battery drops below full charge i.e., when they are discharging. The intelligent relay system should be sized to handle the maximum output of any one of your charge sources, in your case, that would probably be your Jeep's alternator.

-- This means that you can attach your shore power charger to either battery; it makes no difference. Your charger should be sized to charge both batteries combined.

-- I cannot imagine any reason to mount a shore charger on a vehicle, especially not on a Jeep where space, and weight are at a premium. One exception might be that you are planning to spend a lot of time in RV parks. But in this case I would be looking at inverter/chargers unless I had absolutely no need for 110v.

-- I would not use a dual bank charger, or two chargers, with an intelligent relay; there is no reason to pay the extra price. A dual bank battery charger is useful when you have two or more permanently isolated batteries.

I hope some of this is useful, but you really need to spend some quality time with a qualified auto electrician. Sorry to be a curmudgeon.

 

[Ducky's Dad]

Since we are being curmudgeonly, I'll chip in. I don't even like voltage sensing relays. I don't like automatic switching. My two house batteries are set up on a Blue Sea rotary switch with "Off, 1, 2, Both" settings. When I have the shore charger connected (Ctek 7200 for the Optimas), I can charge one or the other, or both, depending on how the switch is set. Same switch serves the same function for draining the two batteries and for charging from the alternator. Simple, pretty much idiot proof, and relatively cheap. You get to set it to do what you want, and it's virtually unbreakable.

 

[JCDriller]

Diplo, no need to apologize and thank you and ducky for the advice. This is all very new to me and I'm learning as I go which after all is why I'm posting here and tapping into a wealth of knowledge. This is as close as I'm going to get to an auto electrician, don't know any of those... I've done a lot of work to my Jeep, mostly from knowledge I've taught myself through self study and posting/reading on forums so don't under estimate ones ability to learn by asking questions online.

So again given my situation I'm looking to charge two batteries that are connected in parallel using some kind of relay or switch. At the end of the day 99.9% of the time I'll be using it to keep my batteries charged and my fridge cold between weekends. I doubt we'll spend much time at RV parks, it just seemed like a convenient idea since NOCO had an onboard charger model that could always be with me. I believe their micro 1 bank 4a charger will fit under my wiper cowl on my Jeep and since its waterproof it's really not taking up any space or adding much weight (my jeep is already a pig). I can simply plug it in without popping the hood. Total cost of this set up is <$100 so not expensive.

I agree that the 1 bank 10a sounds ideal if it'll fit, just got thrown off when NOCO posted that a duel bank charger would be better. I'm still trying to wrap my head around what happens if a duel back charger is installed on two batteries in parallel. I know that it becomes basically one battery with more capacity but does the charger continue to apply 10a total or or does this get turned into 20a since each connected battery has a charger hooked to its own set of terminals.

 

[AndrewP]

JC-Any smart charger is going to work. Just buy one and forget about it.

What Diplo is getting at is that you are approaching dual batteries and a VSR (Voltage Sensing Relay = Automatic Charging Relay) wrong. Once your battery comes up to charging voltage the VSR is going to close and charge both batteries to the same voltage. It's as simple as that. So whether you use a Genesis, a Blue Sea, National Luna, or a Samlex does not matter. They all work the same. Pick the best one, with the best warranty-that's Blue Sea. Or pick another, it doesn't matter. The Blue Sea units are very, very efficient-to keep the relay closed, they use only 0.175 amp or less. That's important if you add a low power solar charger.

For shore charging/floatng, very little amperage is needed. You can pick whatever you want, but any NOCO, BatteryMinder etc is going to work fine to condition and charge just 2 batteries. As a for instance, right now, I have a 2 amp BatteryMinder charging/floating 5(five) 100 amp hour batteries through 2 Voltage Sensing Relays. My power meter say it takes 0.46 amps to do that, of which 0.35 amps is used to keep the VSRs closed. So don't stress on your charger. A 10 amp charger will be huge overkill, which is good, generally. Just be sure the float is 13.5 volts or a bit less so you don't cook your batteries.

 

[DiploStrat]

News you can (perhaps) use ....

If you go to my website, you will find a boringly pedantic document on the challenges of sizing and charging a battery bank for an overland camper. Overkill, perhaps, for your Jeep, but, for what it is worth, I find that my biggest draw is the Nova Cool refrigerator.

Of more immediate use might be the slides that I use for my dual battery presentation at OEXPO. They are arranged step by step and evolve from no isolation, through manual switches, key control, and VSR. They lack the bad jokes that I make in person, but they are fairly self explanatory.

All of these contain many useful links for further reading. (And the odd pesky typo.)

I will never argue with the great Ducky on the oddities of Odyssey batteries. There is much to be said for the simplicity of a manual switch. I am just too much of an old idiot to trust myself to remember to open and close the switch at all of the right times, i.e., engine on, engine off, sun shining, on shore power, etc. But lots of folks do just fine with a manual switch. If you go this way, consider some form of large tell tale to drape over the steering wheel to remind you of the state of the switch.

I don't own a shore charger as I have a huge inverter/charger that happily cranks out around 100A. (And yes, I have used it to charge the neighbor's car.) Were I too spend the money for a stand alone shore charger I would pay the extra for one large enough to de-sulfate, etc. But, as noted, the key thing is to be sure that it drops to an appropriate float voltage.

N.B. A lot of us recommend Blue Sea products because they are marine rated. Also, some of their relays use "latching." That is, they only require power when changing state. Their big dumb relay (which I use) incorporates a "coil economizer" to reduce the draw when closed.

Again, I hope that some of these rambles are useful.

 

[Ducky's Dad]

Sorry, Just so you know...
I dont think that attitude is welcome here..
If somebody does not desire an electro project to rival the Space Shuttle,
They are not an Expo Guy.

I feel appropriately chastised and apologize profusely. I must also confess that I don't like ABS, or hill descent control, or stability control, or traction control, or computerized torque distribution, or TPMS, or lane departure warning, or GPS, or auto-dimming headlights, or any number of other things. I don't even like electronic transfer cases. I am a bad person, and will now crawl back into my hole for a while.

 

[DiploStrat]

They are not an Expo Guy.

Ouch! One hopes there is a smiley in there somewhere! :Wow1: