Tundra Battery Tender + Hawk IOTA Q4, Shore Power...Too Much?

[Wallowa]

After just installing a 7611 in my '16 Hawk [in an '05 Tundra] I starting re-evaluating not just the necessity but the possible problems caused by always keeping the Tundra AGM on a Battery Tender AND having the Hawk plugged into 110v in Winter in my shop which charges the 2 AGMs in the Hawk through the IOTA Q4.

Too much of a good thing? Can I over charge either the Tundra battery or the Hawk batteries by having chargers on each system regulated by the 7611?

Thanks,

Phil

 

[veryactivelife]

My situation differs as I have LiFePO4 batteries and a dc/dc charger but what I have observed might help. When my truck batteries are on the tender they exhibit a voltage high enough to start the dc/dc charger which in turn is charging the camper batteries. Since lithiums don’t want to be at full charge in storage I turn off the charger off. So I’m wondering if in your setup if the battery on the tender would have a high enough voltage to trigger the isolator and send a charge to the camper.

Dean

 

[Wallowa]

Yup, my concern also...when I get the time I will call Blue Sea...

Phil

 

[Outnabout]

Maybe you could unplug the camper from the truck to separate the charging mechanisms.

Another thought, my truck is charged by my solar through the Blue Sea 7611. Disconnect one of the charging points and see if your Blue Sea is on. If the led is lit then the batteries are connected and they both should be charging. I may be missing something

Looking forward to other ideas.
Thanks

 

[Wallowa]

Not missing anything...those are several questions I also have.

Using the Blue Sea 7611 separator/isolator; these are my assumptions and questions:

#1 When both are connected, does the shore power via the IOTA Q4 and the solar panel through the Zamp ZS 30 Controller simultaneously put amps into the two Hawk batteries until they are "full" and then put amps into the Tundra battery until it is "full"?

#2 The Battery Tender that I keep on the Tundra battery in my shop will it reverse this process and direct current through the 7611 to the Hawk batteries if their SOC drops below the Tundra battery?

#3 Does the Tundra alternator work through the 7611 to charge the Hawk batteries simultaneously with the solar amperage coming in through the Controller to both the Tundra and Hawk depending on the SOC of each?

What I can't guess at is how the float charge from the IOTA and the Battery Tender affect the function of the 7611 and any subsequent amperage flow to the Hawk or Tundra.

I am getting a headache!

Phil

Ps...Presently installing a Victron 712 Smart so isolating Tundra from Hawk is not feasible; batteries are out of the Hawk.

 

[pvstoy]

Some of us have a circuit breaker at either end of the run similar to the attached image. If you had one of these sized for your system, then you can just flip the yellow bar and now there is no voltage going any further. Problem solved.

 

[Wallowa]

Some of us have a circuit breaker at either end of the run similar to the attached image. If you had one of these sized for your system, then you can just flip the yellow bar and now there is no voltage going any further. Problem solved.

circuit breaker.JPG

I get the idea of a circuit breaker....but why? What exactly is/are the problem ? That is what I am trying to understand.

Questions #1-3.

Thanks,

Phil

 

[pvstoy]

After just installing a 7611 in my '16 Hawk [in an '05 Tundra] I starting re-evaluating not just the necessity but the possible problems caused by always keeping the Tundra AGM on a Battery Tender AND having the Hawk plugged into 110v in Winter in my shop which charges the 2 AGMs in the Hawk through the IOTA Q4.

Too much of a good thing? Can I over charge either the Tundra battery or the Hawk batteries by having chargers on each system regulated by the 7611?

Thanks,

Phil

Your original question... If you wanted to keep the two charging methods separate from each other is where the switchable circuit breaker would work to keep each system separate as a stand alone. I have this circuit breaker at the camper battery and one at the truck battery to protect if the wiring between gets a short.

You have AGM in both locations I would just use the Iota that has the AGM charging mode to do them all at the same time. The Blue seas unit should open up allowing to charger the Tundra battery. With 3 batteries it just takes longer to charge to 100 percent than just one battery would.

I have my Hawk in my shop and when I see the camper voltage drop low around 12.5 I plug in the Iota and charge the camper batteries. I have the Blue Seas separator with the manual switch. When the camper batteries are full I'll throw the rocker switch and allow the truck battery to join in for a few days more.

When 100 percent for all then I'll unplug the Iota and let it sit until voltage reading drops enough to do it again.

You can have different charging inputs as one input will if they are smart will sense the voltage thinking that the battery is charged and might back off. Like your battery tinder may not be smart and have enough voltage to open the separator but not much amps. So the Iota will see the higher voltage and instead of being in Bulk or Absorb mode will back off to Float. But if the tinder has a lower voltage than the Iota at Float mode then the Iota will be in control allowing the Battery tinder to add to the charging amps as the Iota will cycle through Bulk and Absorb modes.

So yes you can have different charging inputs at the same time. It also effects how each work if they are a "smart" charger. What wins, it depends on the voltage level each is at. It can aid or prolong charging.

 

[Wallowa]

Wow...great information, thanks and at my pay grade more than I could understand...but the last sentence I get: "It can aid or prolong charging".

So it is a crap shoot... turning off or on either the solar, IOTA or Battery Tender can either aid or prolong charging. Oh well...

Phil

 

[Vic Harder]

AND, whether it aids or not can be seen on your Victron BMV Phil. Observe the amps going in as you turn on/off the charging sources.

 

[Wallowa]

Bingo Vic! Will do once I get my 712 on-line.


Just got off the phone with Blue Sea Tech [20+mins] and he boiled it down for me...the ACR is simply a voltmeter linked to a relay..my 2 AGMs in parallel ['bank' in Hawk] and Tundra AGM are two separate "battery banks" in parallel that when the relay is closed the ACR voltmeter reads it as one single battery and when open it treats them as two batteries. When 7611 relay is open and voltage of 13.6v for 30 sec [or 13.0v for 2 mins] is metered it closes the relay to connect the "two batteries'" [2 AGMs in Hawk and 1 AGM in parallel] and the charging system from any source now charges both. 7611 will open the relay if a voltage of 12.75v is metered when the relay is closed or if the 'auxiliary' battery [Hawk] voltage drops to 12.25v when the relay closes. 12.25v is to keep the relay from cycling back and forth from closed to open as the alternator voltage varies on start-up.

Whew! So can you damage either the Hawk "bank" or the Tundra battery by leaving the Tundra on the Battery Tender hooked up while the IOTA and or solar are inputting amps/volts by over charging the batteries; no, as the relay will open if voltage in either exceeds a lockout voltage of 16v...which should not be reached in an AGM is my understanding [?] unless a charger goes haywire...and the two battery systems will be charged simultaneously from any source producing power once the voltage of either drops below the 13.6/13.0 thresholds.

The rate of charge from the alternator, Battery Tender, solar or IOTA is still an unknown and depends in three instances on the rate of the smart chargers input [IOTA and Battery Tender and Zamp ZS 30 amp Controller] and on the alternator output [rpm/time] or on solar output [watts and current amps produced] when measured.

Hence I will take Vic's idea and try to view the approximate battery SOC changes from these 4 sources when I get the 712 installed.

Blue Sea said that they do not have an ACR for LiPo4 batteries; what are the folks with LiPo4 batteries using as an isolator? He did say the the truck and Hawk batteries need to all be the same type of battery [AGM..etc.]; so if in the future I go to Li batteries in the Hawk, I assume that means a new Li battery for the Tundra.


If I confused this information or miss-stated it, please feel free to chime in.

Thanks,
Phil

 

[pvstoy]

Blue Sea said that they do not have an ACR for LiPo4 batteries; what are the folks with LiPo4 batteries using as an isolator? He did say the the truck and Hawk batteries need to all be the same type of battery [AGM..etc.]; so if in the future I go to Li batteries in the Hawk, I assume that means a new Li battery for the Tundra.

When you get to the point that you want to put Lithium batteries in the camper, you would be removing the battery separator and going with a DC to DC charger that is hooked up from the truck alternator. So you can have different batteries types as the two would never see each other.
.

 

[Wallowa]

When you get to the point that you want to put Lithium batteries in the camper, you would be removing the battery separator and going with a DC to DC charger that is hooked up from the truck alternator. So you can have different batteries types as the two would never see each other.
.

OK...more education and appreciated! Now I will start investigating "DC to DC" options and setups...I enjoy learning, so all is good.

Our 75AH FWC Exide AGMs are going into their 5 year; but have been mostly well tended. Just don't know if I ever drew them down too far and shortened their capacity and life span.

Thanks...Phil

 

[Vic Harder]

Phil, I'm using the Victron Dc-Dc charger and 2AWG wiring between truck and camper... 5 years is a goodly amount on the camper batteries. They could last a while longer if you are not regularly depleting them. I don't know what some folks do to their batteries.... folks in my Miata club used to replace theirs every 2-3 years. I drove mine for 20 yrs without replacing it!

 

[Outnabout]

My batteries are still seem strong at 5 years. Exide AGMs from that came stock in the camper. I have a pretty good job of keeping them topped off and rarely, if ever, brought them below 12.6v

 

[Wallowa]

Just check the alternator amp rating on my 2005 Tundra Access Cab....with the "towing package' my alternator is rated at 130 amps...

The 7611 is supposed to be used with an alternator output up to 120 amps..

So, what are the ramifications of my truck having 130 amp alternator? Blown fuse that FWC installed?

Thanks...Phil

 

[Vic Harder]

No ramifications to worry about. If you are drawing 120A over that 7611 it would be to "jump start" your truck from the camper batteries.... implying you had VERY heavy cabling between truck and battery.

You should have breakers at either end of your truck to camper wiring. You are still using the factory installed wiring, right? So a 30A fuse/breaker at both ends would be suitable. That will protect the 7611 as well.

 

[pvstoy]

Not to worry. That rating would be at max rpm of the pulley and what is seen at the back of the alternator. After losses in wire size and length and fittings you'll not see 130 amps at the camper separator.

Just check the alternator amp rating on my 2005 Tundra Access Cab....with the "towing package' my alternator is rated at 130 amps...

The 7611 is supposed to be used with an alternator output up to 120 amps..

So, what are the ramifications of my truck having 130 amp alternator? Blown fuse that FWC installed?

Thanks...Phil

 

[Wallowa]

Not to worry. That rating would be at max rpm of the pulley and what is seen at the back of the alternator. After losses in wire size and length and fittings you'll not see 130 amps at the camper separator.

Thanks all for the input....hopefully I can retain that. Retention of information seems to become problematic with age!

Vic knows, since he held my hand through the installation, but I also just got my Victron 712 Smart up and running...first time I have ever used Bluetooth, pretty slick; now I need to keep phone battery up to snuff this winter on my ski bum tour....but seeing the SOC will mean a lot for my planning...

Next will be the installation of my second solar panel; which all of this will compliment.

Appreciate everyone's help,

Phil