Blue Sea 7610 dual battery relay question

[TheHippieVanMan]

I picked up and installed the Blue Sea 7610 dual batter relay together with a new deep cycle aux battery and a new main battery.

I'm pretty sure I followed the install instructions correctly. With 4 gauge wire I wired my main/starting battery to terminal A with a 100amp fuse in between, and terminal B is wired to my deep cycle battery with a 100amp fuse in between. The Blue Sea unit is grounded to the negative terminal on my main battery. I also have a 20watt solar panel connected via solar charge controller to my main battery (not that I think that makes much of a difference).

Anyway, the only stuff hooked up to my aux battery is basically my stereo, some cabin LED lights and two cigarette lighter outlets for charging phones and what not). After 3 long days of driving (8 hours of driving a day or so), the aux battery seems to be down to 10.2 volts (and I haven't been using the system when the car is off).

It got to the point where there wasn't enough power to even turn on my deck. I took the wire from the aux battery off of the terminal B, turned the bus on and then used a volt meter to check what was coming off of terminal B while the car was running. It was only .03 volts.. When I tested terminal A it was around 12.8v..

I'm wondering if I made a mistake somewhere? Or perhaps my alternator isn't putting out enough power to charge both? I fully charged the deep cycle with a trickle charger before installing it and the new starter battery came fully charged.

Do I need a new and/or larger alternator? Any help would be much appreciated. Thanks in advance.
_________________
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[mojogoat]

Put a volt meter on the starting battery when not running, (should be about 12.8 volts), then while running, should jump up to about 13.8 or more volts then on the aux battery, they both should be the same voltage while running, if not the box doesn't work or not wired correctly.

[Vince Waldon]

....and then I'd suggest running the same voltage readings on your aux battery.... it sounds to me like it's not seeing any charging voltage (the 13.8ish part).
_________________
Vince Waldon Edmonton Alberta CANADA
1970 baywindow

[aeromech]

Hi there,
The Blue Sea ACR you installed is very simple. Sounds like you have it wired correctly. Two large cables with in-line 100 amp fuses between the two lugs on the ACR and each positive post of your batteries, simple. The ACR won't close the contacts and charge both batteries unless it sees 14 volts from your alternator. Once you start the engine there should be a short delay before it closes. Then you should see an LED light illumintae on the ACR. You must have a ground wire connected to the ACR. There are three spade connectors on the lower front. One is for the ground and can be short and run to the frame of the bus. It doesn't need to go all the way to the battery. Make sure that this ground connection is good.

Start up the engine. Look for the LED. If it's illuminated go to each battery and check the voltage. You should see about 14.2 volts at each battery. If the aux battery is still showing battery voltage (not 14.2) then suspect the inline fuse to that battery positive terminal.

Also, the ACR uses a small amount of current just sitting there parked. If you leave the bus for a few days you may find low battery voltage when you try to start. You can use your solar panel to keep the voltage topped off or you can install a small relay to break the ground wire to the ACR when the key is off thereby preventing the battery drain. I can tell you how to do this if you want.
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[germansupplyscott]

charge the aux battery and then test the to make sure the ACR is combining the batteries. if the house battery gets below 10V the ACR may not combine them. also, there is no need for a fuse in the positive wires but i guess it can't hurt. you do need a fuse in the ACR's ground wire. i believe the reasons for needing the ground to be fused are explained in the instructions.

you probably have a drain on the house battery from the stereo, try having just the power plugs connected to the house battery and see if that eliminates the problem, then figure out what is causing the drain.
_________________
SL

[aeromech]

[germansupplyscott]

[aeromech]

I have one at the house so maybe I'll do some experimenting. Here's my point. These things are made for boats. Here's the scenario. You're out on your boat fishing for the day and your live bait well pump is running off your aux battery. What you're telling me is that after about 4 hours of fishing I hear the bait pump slow down and so I start my engine. Because the voltage in the aux battery is below 10 volts I can't charge the aux battery and all my live bait is going to die. I can't see that happening but like I said, I have one at the house and will check it out.
_________________
Lead Mechanic: San Diego Air and Space Museum
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Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[aeromech]

From Blue Sea

What is an ACR, and how does it work?
•What is an ACR? An ACR parallels (combines) batteries during charging, and isolates them when charging has stopped and after battery voltage has fallen. An ACR is intended to keep a load from discharging both of the batteries.

•How does an ACR work? An ACR senses when the voltage of either of the batteries rises to a level indicating that a charge source is active (13.0V for 2 minutes). The ACR′s contacts then connect and the ACR applies the charge to both batteries. If the voltage on both of the batteries subsequently drops to 12.75V for 30 seconds, the ACR will disconnect, isolating the batteries.

•Why do I need an ACR? An ACR allows two battery banks to be connected so that they can share the output of a single charge source, allowing the user to charge more battery banks than the number of charging outputs. For example, an ACR can be used with a single-output charger, resulting in a simpler system at lower cost than a dual-output charger.

•How many ACRs do I need? To combine two battery banks, one ACR is needed; to combine three battery banks, two ACRs are required.


What are some features of ACRs?
• What does “Dual Sensing” mean? A dual-sensing ACR will sense an active charge source on one or both batteries and not solely on a designated battery. The ACR will operate if the measured voltage on either of the terminals is of a level to initiate a connection or disconnection.

•How does an ACR differ from a battery isolator? Battery isolators use one-way electrical check valves called diodes that allow current to flow to, but not from, the battery. ACRs use a relay combined with a circuit that senses when a charging source is being applied to either battery. ACRs are more efficient than battery isolators because they create little heat and consume minimal charging energy.

•Will an ACR manage the charge of my individual battery banks? An ACR does not direct the charge to the battery that “needs it the most” or has the lowest terminal voltage. If there is a charge present on either battery, indicated by a high enough voltage, the ACR will combine the batteries. To read more about this subject click here to download the ADD-A-BATTERY Sales Sheet (1000kb - PDF file).

•What Charge Sources will an ACR work with? An ACR will work with all charge sources, including an alternator, AC charger, or solar panel. However, low current charge sources might not produce the voltage rise required to force the ACR to combine.


What else do I need to know about my ACR?
•What are the minimum number of connections I need to make my ACR work?Three: One wire to each battery, and one for a ground (GND) connection. For safety reasons, remember to disconnect the negative battery connections before beginning any ACR installation. See this article for more information on selecting the right fuses for Blue Sea Systems ACRs: See Selecting the Appropriate Fuse Rating When Installing the 120A SI ACR

•What does “Undervoltage Lockout” mean?As a safety feature, some ACRs prevent combining into a severely discharged battery. A dual-sensing ACR will monitor the voltage on both batteries and will not connect if either battery is below the undervoltage lockout level. Use caution when combining into a battery with extremely low voltage, because this might represent a faulty battery or a problem elsewhere in the system.

•Why doesn't my ACR automatically combine every time my engine is running?For an ACR to automatically combine the batteries, voltage and time thresholds must be reached. Although these numbers vary somewhat from one ACR product to another, if ACR terminal voltage is greater than 13.0V for 2 minutes, the ACR should combine.

•Why didn't the ACR disconnect when my engine was turned off?The ACR will not disconnect until the low voltage threshold is reached to isolate the circuit. It may take several minutes for the voltage of the batteries to drop to this level. Since the ACR incorporates a delay, additional time (up to 2 minutes) is required before the ACR disconnects.

•Where can I get more troubleshooting information?For specific troubleshooting help with SI-Series PN 7610 and ML-Series PNs 7620, 7621, 7622, and 7623 ACRs, click on the following links: SI-Series ACR Diagnostic Flowchart or ML-Series ACR Diagnostic Flowchart.

Even though it doesn't say what the threshold for undervoltage is I stand corrected Scott. I guess the ACR is trying to protect what it considers a "good" battery from combining with a "bad" battery which could make both fail.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[jakokombi]

Informed debate... Accurate information... Gentlemanly discussion... Contrition??

Just what the hell are you guys doing? This IS The Samba ya know!
_________________
70 Sunroof Kombi
85 Motherfukinvanagon
73 Thing
72 Baja

[aeromech]

[guanella74]

[germansupplyscott]

threshold is 9.5V, not 10 as i stated.

http://www.bluesea.com/products/7610

it also has another page that states the undervoltage lockout was changed from 10.8V to 9.5V in 3.2012 so it would depend on the REV of the unit, don't doubt there are both revisions in the marketplace.

i believe the 7610 can be wired in such a way that you can override the under-voltage protection with a switch.
_________________
SL

[aeromech]

If you have the companion Blue Sea switch I usually install I guess you could combine the batteries and that would allow the Aux to be charged.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[Randy in Maine]

Is this the preferred way to do the camping battery thing?

My buddy (the boatbuilder) just took one of these off a party boat and wants to give it to me. Is there another one that is a better fit for what we do?

[aeromech]

Randy,
Are you referring to the Blue Sea "add a battery" kit? That includes the ACR as well as the battery switch. I've installed several into buses and just finished installing one on my boat last night. They work great and are marine grade parts. The switch is very nice to have on the bus. The ACR makes charging and separating the batteries automatic. The only down side I've found is that the ACR has a constant draw of miliamps which can drain down the batteries if the bus is parked for several days. The work around for that is to install a simple relay which removes the ACR's ground when the key is off.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[aeromech]

Some examples

_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[germansupplyscott]

[aeromech]

FYI - the ground wire is supposed to be fused.

Hmmm, I must have missed that. Thanks.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[airkooledchris]