Genesis Offroad Dual Battery System install by Tank Customs and Charger Testing


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May 8, 2018
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Katy Texas
2018 Wrangler JLU Sahara
Gas Pipeliner
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For those that are bored and need something to read and for those just looking for some info if your curious on a dual battery system also if you want any Offroad work and are in the Houston area see @TTEChris at Tank Customs, these guys do EXCELLENT WORK FOR ALL YOUR OFFROAD NEEEDS, the did this install along with pretty much all my mods and I have been super pleased.

Genesis Dual Battery System Install by Tank Customs and Battery Charger Testing 10/20/20

Vehicle 2018 Wrangler JLUS
200 amp stock alternator
Genesis System
Full River Batteries
NOCO Genius 10 here
Odyssey OBC-20A here

12.9 +/-.2 while on both chargers during float.

** Resting voltage 8-10hrs after driving**

Day #1 = 12.8/12.7

Day #2 = 12.8/12.8

Day #3 =12.7/12.7

Day #4 = 12.6/12.6

Day #5 =12.6/12.7

Day #6 = 12.6/12.7 (0.7 isolator closed)

Day #7 = 12.59/12.64 (150 isolator open) *** Turned on acc’s to test disconnect ***

** The resistance on the isolator is pretty easy to determine if open or closed and the closed runs from 0-2 ohms and open runs over 100 ohms **

** Resting voltage 24 hrs after driving**

Day #8 = 12.6/12.6 (isolator closed)

Day #9 = 12.6/12.7 ( isolator open

Day #10 = 12.6/12.7 ( isolator open

Day #11 = 12.6/12.6 ( isolator closed

Day #12 =12.6/12.6 isolator open )

13.7-14.0 volts on EVIC display after it been sitting for 8-10 hrs and after 30 mins of driving the voltage floats up and down during speeding up and slowing down as designed and the longer I drive the lower it goes.

12.8-13.4 volts has been my rolling voltage after driving a little while so smart charging with stock alternator seems to be working as designed, after parking from driving 45+ mins of driving voltage read at batteries are both reading 13.1-13.3 range and slowly drops from their due to parasitic draws from various components and according to Full River the batteries are fully charged at 12.9 and they have been close to that during my overnight checks, I figure the small reduction of .1-.3 have been due to the small parasitic draws that the JL has plus a unknown amount from the smart isolator relay/solenoid and possibly my winch solenoid that is connected to the aux power bus and ground bars.

I also ran a few tests to get an idea how the smart isolator works, I first took voltage readings on both batteries and both were almost identical at 12.7 range and put a temp probe on the Cole Hersee solenoid and temps varied in the 130-140 deg range and that’s supposed to be normal and indicate batteries are connected, I even did a continuity test across the solenoid and reading was low on resistance so it was closed and batteries were connected.

I then unplugged the connector from the blue smart isolator and this according to Shane from Genesis Off-road will disconnect the batteries if they are connected and then plug it back in and after plugging it in to push the boost button and you are supposed to get that click to connect them back together and that occurred as it’s supposed to.

My next test consisted of having it all connected as designed and push the boost to ensure they are connected and then I turned on my headlights and left the lights on with a volt meter connected and according to Shane the variance for the isolator to disconnect can be +/- .1 from 12.7 so it can disconnect anywhere between 12.6-12.8 and mine disconnected in the range of 12.55-12.6 as near as I can tell, voltage on the main crank was at 12.55 and the aux stayed at 12.75

My last and final test was to crank the engine as the main crank battery was like 12.58 and aux was 12.72 so I’m pretty sure they were not connected as the solenoid was barely hot and continuity was high telling me it was disconnected and open.

Once I cranked the engine I put the meter on the main battery and it read like 13.5 and climbing but aux read 12.68 but after about a minute or so I heard a click and my meter at the time was connected to the aux since it was the lower voltage and it was now reading the same as the main crank at 14.05 and the solenoid started to get warm along with continuity dropping to a low number and when I pushed the boost button I got nothing so knew they were connected

So all seems to work as designed and I’m happy that I will have a backup battery just incase I do something silly like leave lights on and the relay and solenoid are supposed to rated for like 1 million cycles but electronics do fail but after looking on line and chatting with Shane these items have been used in the industry for a long time are are readily available so should not be an issue getting replaced if needed.

Overall I’m super pleased with going the route I went to with the Genesis System, heck my charging system is even acting better with the smart alternator doing what it’s supped to do as after 15-30 mins of driving the displayed EVIC voltage drops under 14 and after like 30-45 mins it runs in the low 13’s and have even seen high 12’s and when you slow down and brake the voltage ramps up and once stopped drops back down and that tells me the charging system is working as designed.

I currently am using a NOCO Genius 10 charger/maintainer and I reached out to NOCO, Full River and Genesis Off-road in regard to using the NOCO and NOCO advised it would be very good for the Full River 750-25 AGM’s, Genesis advised that it would work as well but recommended the 20 amp Odyssey as that’s what is best for the amp rating of the 750’s, Full River advised that I should charge on the non AGM mode as the AGM mode on the NOCO charges at 14.8 on the bulk and absorption and they like to see 14.5 +/- .1 during this time but I have not metered the voltage to see if it’s at or above the 14.8, I doubt .1/.2 volt increase from 14.7 to 14.8 would have a huge affect on the life expectancy of the batteries but I will check the next time I do a maint charge to verify the output voltage but when I did my first charge in the beginning of all of this I got like 14.1 initially but will do a charge again to verify the output during the first few hours of charging.

For those sitting on the fence on doing a dual battery system at this point I highly recommend the Genesis System, I have asked @Genesis Offroad countless questions and they have been great at getting back with a solid response and the product itself seems pretty solid and well made so hopefully no battery worries for a long time.


So I have used my NOCO 10 several times and it seems a bit inconsistent on going to float, I have chatted with NOCO, Full River and Genesis about this and my 10 amp charger although acceptable it could possibly be a tad undersized at the 10 amp rating to get my 750’s to Full Charge in a reasonable amount of time so my plan is since Full River highly recommends that these batteries get to at least 14.5 +/- .1 is to do a few runs and voltage checks to ensure I am getting to 14.5 at a minimum before going to maint/float mode and after a few times if it just struggles I will likely step up to something like a 20 amp Odyssey but won’t make that choice until I do further voltage testing.


Well have been testing my new NOCO Genius 10 as linked above and at first I was thinking it had some issues so have been chatting with NOCO support over the last several days they have been outstanding and we discussed a lot and the NOCO has some great points but also has some negatives but the negatives may not be serious.

Pro Points:

Size as it’s very compact
Rugged as a tank, this thing is literally built like a tank and just seems well thought out.
$99 price, this thing is a bargain at this price point
2 yr warranty, everything covered but you can’t drop it
Can charge lots of different types of batteries
Force mode ( can force charge a battery if voltage is to low )
Recover mode ( Can possibly recover a bad sulfated battery )


The manual is a bit lacking to explain in detail what the lights do and how long it takes.

Voltage output, this thing is supposed to put out 14.7 volts +/- .1 but they don’t say for how long that it puts out the 14.7 before it kicks back to sometimes 13.5 and then starts going back up again but I never metered more that 14.2 output but I have two Full River 750’s connected as one thru a solenoid that keeps them connected 99% of the time and they are 64 AH each so still 12 volts but 128 on the amps and they are AGM’s with some load on them during charging.

The only con I have issue with is the voltage output, Full River likes to see their
batteries charged at 14.5 +/- .1 and I just don’t think the NOCO 10 quite makes it and this affects how long it takes to go into float so if you have large capacity charging needs and are in a hurry you would be best suited to go larger on the amps and with some battery makers like Full River that need the 14.7.

The NOCO does seem to take awhile and I have only observed it putting out 14.2 briefly and so not sure what if any this would have on battery life by slightly undercharging but I’m not babysitting a volt meter so maybe it is seeing that 14.7 voltage.

NOCO also advised that it’s temp compensated and that affects the voltage output to protect the battery so it may be doing what it needs to be doing as it’s a multiple stage smart charger which is recommended for AGM batteries.

**11/04/20 Odyssey 20 amp **

Received my Odyssey charger for testing and started a test run to compare it to the NOCO 10.

This charger is pretty large in comparison to the NOCO but it’s what Genesis recommends for their dual battery setup and according to Odyssey they compared the info I sent them on the Full River 750-25’s and said the charging curve matched what Full River wants to see.

After 30 mins of being connected the metered voltage was 13.5-13.7 and slowly climbing so pretty much on par with NOCO but within a few hours it had slowly climbed to over 14.0 volts and after another hour it was in the 14.5 range and Full River likes to see 14.5-14.7 for their bulk and absorption charge then drop to the low 13’s for float.

I don’t have a method to monitor the entire charge process but I do believe that Odyssey holds the charge slightly above the NOCO by .3-.5 volts and it seems to raise and keep the voltage above 14.5 longer than the NOCO but this was only observed on my random metered voltage checks and it could all come down to the charging algorithms from different makers.

**11/05/20 Update Odyssey 20

Checked my voltage with charger connected all night and just like the NOCO it’s in float mode with charger connected it metered at 13.2 +/- .2 volts, Full River likes to see their float charge in the 13.5 range but so far neither of these battery chargers get to 13.5 during float but since this is a dual setup and the batteries are connected 99% of the time this may have a small affect on float maint voltage but this is purely my guess as I have no scientific data to back this up.

I do tend to see so far that the Odyssey keeps the voltage above 14+ more but again thus just could be the difference in chargers.


Have tested the isolator disconnect several more times over the past few days and tested it the way it’s designed rather than disconnecting the smart relay and then reconnecting and pushing the boost button as all of this works, so when my voltage on the main crank got down to the 12.65 range I connected my meter to the main crank and turned on some accessories like radio and headlamps and monitored the metered voltage and when it got down to 12.58 I heard distinctive click and continued to watch the voltage drop and once it got to 12.5 I proceeded to check the voltage on the aux battery and it metered 12.72 volts and isolator resistance was high so I knew it had disconnected so the batteries were disconnected but as power to feed all factory items comes off the main crank battery it would have continued to drop but does not pull power from the aux.

I then started my Jeep and proceeded to check crank voltage and it metered 14.05 and aux stayed at 12.72 and after approx 2 minutes I heard that distinctive click again to indicate the batteries were connected and sure enough the aux voltage was the same as the crank at 14.0-14.05

Had a few errands to run and I started off at 14.0 volts on the EVIC display and batteries metered the same so ran my errands and lots of stopping and starting and voltage ramped up during slowing down and then dropped as driving and after approx 30 mins voltage displayed was in the 13.2 range so needless to say I am so far very pleased with how my new setup and charging system is working, I do have the ESS system disabled with my Smart Stop/Start module so as far as I’m concerned I have one big 128 AH battery that hopefully will provide me many reliable years of service and if for some reason my main crank battery dies I can use the boost feature, this to me is a huge benefit if I’m out in the middle of nowhere plus I can run lots of accessories off the aux without fear of pulling down the main battery with aux items.

My next plan is to go back to the NOCO 10 charger and see what I get as far as voltage readings and make the decision on whether to use it or the Odyssey 20 for my charging needs, not sure I will keep both chargers as thats a bit much to have on hand but just trying to get the best bang for my buck and optimize my batteries with the best technology to keep them healthy.


Had a really lengthy chat with a Tech from Full River battery and after a long chat and several exchanges of info on both chargers they like the NOCO 10 or NOCO G1500 over the Odyssey 20 and advised not to get to wrapped up in what voltage the NOCO is putting out as it’s a temp compensated charger and likely does see 14.5 volts as the ambient temp in monitored by the charger along with several other factors it’s likely doing what it’s designed to do and they use NOCO chargers for testing along with several others and the techs just like the NOCO brand but also said if I chose to use the Odyssey that was fine as well and the Odyssey at 20 amps is almost in there sweet spot of .2% of the 128AH batteries but not to go over .35% and this is related in the time to charge but also not to over charge so still trying to decide on what to keep but at this point I may just keep both and occasionally use the Odyssey to give a really good charge, like Tim the Tool Man said “ More Power” right :)


Last update for testing the Genesis system and two different battery chargers, I have decided to keep both the NOCO 10 and Odyssey 20 and use the NOCO for the quick top off and then use the Odyssey when my JL is parked for several days to give the batteries a full boost but to be honest if one decided on either one for using on a dual system that would be fine.

The techs at Full River all really like the NOCO even though the Odyssey charge curve comes very close to what they like to see and the voltage output holds the higher on the Odyssey as they say that’s only part of what they look at and NOCO is a solid company that makes great products.

I originally had concerns on the solenoid pulling very high milliamperes and the result of it pulling the batteries down to the 12.7 +/-.1 range before it disconnects ( mine disconnect @ 12.58-12.6 ) but after it disconnects there is no further power used off the dual system but I still had some concerns so I reached out to Genesis and Mike H. responded.

“Odyssey states that their AGM battery is fully charged at 12.84V. The discharge of .14V overnight won't cause any harm to the battery. We have a lot of customers who have fridge/freezers onboard that are always connected without issue, and the small draw of the isolator is far less than a cycling fridge. That being said, we also have quite a few customers who employ a trickle charger like the one below if the vehicle is going to be parked for longer periods of time.”

** link not included for charger as this is a personal choice.**

I don’t run Odyssey batteries but have compared the two that my JL would run and the full charge rate would be the same at 12.84 for Odyssey and Full River but I dug a bit deeper and was concerned about having the batteries fully charged at the 12.8 range and then if it were parked say for a day or more the solenoid would slowly pull the charge down to the 12.7 +/-.1 before disconnecting and I had read that the cyclic discharge on AGM batteries like this will shorten there life span so again I reached out to the Full River folks and this is what they said.

Our batteries are rated for a certain amount of discharges and pulling them down approx 10%-15% charge on a daily basis has no affect on cyclic discharge life cycles as it’s only when you go below 50% on a regular basis is the life cycle affected but in the scheme of things this reduction of longevity is minimal but of course not having a parasitic draw is optimal but all newer vehicles have these parasitic draws so over the life of the battery if one were to say reduce the charge by 10% versus 1% on a daily basis it likely will only be several months of life added by the reduction of draw and regular recharging with a properly sized battery charger makes a huge difference and our batteries like to be in the .2-.35 % range so for you that would be 25-40 amps but that’s with a non regulated charger and we highly recommend a smart charger that is correctly sized.

So from what I have gathered from getting info from Odyssey, NOCO, Full River, Genesis and guys like @JimLee and @Overland_Texas along with Mike H. at Genesis it’s best to run a periodic charging on my new setup on a regular basis to get the most life I can from these batteries and enjoy the peace of mind of having the additional power to back me up if needed, plus even when my batteries are pulled down to the 12.6 range due to the normal parasitic draws associated with the JL plus the what I consider a large draw of the Cole Hersee relay going from 12.9 fully charged to 12.6 daily is only a reduction of 3% from a fully charged state if my math is correct but not sure what is considered fully drained on these batteries but it may not be an issue for battery longevity so the only real concern is the wear and tear on the smart isolator and solenoid but they are supposedly rated for a long duty cycle and hopefully will last many years.

I will also have to say and it may be a placebo affect but my JL just seems to run better with the more consistent higher amp voltage, it feels like it cranks much faster and easier and then of course the charging system seems to do what it’s supposed to do in conjunction with the smart alternator as I don’t have the consistent 14+ volts like the charging system or batteries are not working together and I have done about a weeks worth of checks on voltage and testing of correct operation of the Genesis system documented here plus I have done add it all checks that are the same and just redundant of what I have already posted and I will continue to do checks as I go.

Most likely I will do weekly voltage topoffs with the NOCO and monthly with the Odyssey but initially I will do some type of weekly charge just to keep the batteries healthy.

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