Blue Sea Automatic Charging Relay (ACR) install in Fleet FWC

[Rosbif06]

I have a 2016 Fleet FWC which sits on a 2015 Tacoma with the standard install. I have been researching across many sites possible charging issues with the installed Sure Power 1314A battery separator which I am now looking to replace with a Blue Sea SI-ACR or the Blue Sea ML-7622 ACR.

My questions are:

1) Apart from the "manual override" feature of the ML and lower power draw from the relay, is there any advantage of going this more expensive route?
2) Can I in both cases retain the standard 10 AWG (I think) wire from the Tacoma to the camper or do I need to upgrade it for either or both these options?
2a) if so to what gauge?
3) If I go with the SI-ACR do I need to add another wire for the "Start Isolation" connector?
4) Similarly, with the ML-7622 ACR, do I need to connect any of the isolation wires?
5) If the batteries are connected aka with no start isolation, and I crank the engine, won't there be massive current draw from the camper battery?

I understand the SI-ACR is now standard equipment with FWC, so is the retrofit as simple as removing the camper battery connection, the vehicle battery connection, and the ground on the Sure Power separator and connecting them to the either Blue Sea SI-ACR?

Thanks for any insight, experience or recommendations!

 

[FlipperFla]

Blue Sea Systems has a great website with block diagrams of different systems and a great tech line with a very friendly staff for all your questions. 10 ga seems kind off light to me for a run that long, I used 4 and Im charging 2 group 31 AGMs but I overkill projects for a dependablity factor. The BS site has a chart for run length and current for choosing the correct gauge.

 

[Rosbif06]

I've been thinking about the operation of any ACR or battery isolator, and perhaps there is an important gap in my understanding of how they measure the voltages of the vehicle and house batteries, can someone please clarify?

If the engine is running and ACR/isolator is connected and the batteries (house and vehicle) are charging, all is good. When the vehicle is switched off, the voltage at the ACR/isolator will drop and the house and vehicle batteries will be disconnected.

However, if there is a solar charger on the house side, then the voltage as measured at the ACR/isolator will remain high, and the batteries will remain connected until the solar charger also drops its voltage?

My assumption is that when connected, the ACR/isolator cannot differentiate between house and vehicle battery voltages? Is this correct or is there some clever way they can that I don't understand?

Thanks for the education!

 

[Scoutman]

I've been thinking about the operation of any ACR or battery isolator, and perhaps there is an important gap in my understanding of how they measure the voltages of the vehicle and house batteries, can someone please clarify?

If the engine is running and ACR/isolator is connected and the batteries (house and vehicle) are charging, all is good. When the vehicle is switched off, the voltage at the ACR/isolator will drop and the house and vehicle batteries will be disconnected.

However, if there is a solar charger on the house side, then the voltage as measured at the ACR/isolator will remain high, and the batteries will remain connected until the solar charger also drops its voltage?

My assumption is that when connected, the ACR/isolator cannot differentiate between house and vehicle battery voltages? Is this correct or is there some clever way they can that I don't understand?

Thanks for the education!

Yes, you are correct in your assumption. The ACR doesn't care which side of the equation has the higher voltage. If it sees 13.6+ (don't quote me on that I'm going from memory) for more than 30 seconds then it wants to engage or keep the relay engaged. The nice part about having the manual override switch is that if you're planning to camp for days and have solar keep things topped off, you can switch it to disconnect so that the solar puts all of it's efforts to the house batteries.

I think there is one wire that comes off the relay harness that is the 'input signal voltage'. I believe mine is fed from the house battery and not the starting battery.

 

[DiploStrat]

You need to post this in the 12v forum where this stuff is beaten into the ground. (By folks who actually know what they are talking about.)

A quick scan and you will have all of your answers.

 

[Scoutman]

You need to post this in the 12v forum where this stuff is beaten into the ground. (By folks who actually know what they are talking about.)

A quick scan and you will have all of your answers.

Yes, you will get more answers in the 12v forum for sure. @DiploStrat Was something I said incorrect?

 

[DiploStrat]

Yes, you will get more answers in the 12v forum for sure. @DiploStrat Was something I said incorrect?

Not that I can see.

I have a lot of solar so I would never disconnect the ACR when camping - I want all of my batteries full charged all the time! But your suggestion is not bad if, for some reason, your camper batteries were way down and your solar resources limited, i.e., small panels, shade, clouds.

 

[dwh]

I've been thinking about the operation of any ACR or battery isolator, and perhaps there is an important gap in my understanding of how they measure the voltages of the vehicle and house batteries, can someone please clarify?

If the engine is running and ACR/isolator is connected and the batteries (house and vehicle) are charging, all is good. When the vehicle is switched off, the voltage at the ACR/isolator will drop and the house and vehicle batteries will be disconnected.

However, if there is a solar charger on the house side, then the voltage as measured at the ACR/isolator will remain high, and the batteries will remain connected until the solar charger also drops its voltage?

My assumption is that when connected, the ACR/isolator cannot differentiate between house and vehicle battery voltages? Is this correct or is there some clever way they can that I don't understand?

Thanks for the education!

Single-sensing vs. Dual-sensing.

Single-sensing only reads voltage on one side (usually engine side) to determine when to connect. Dual-sensing reads both sides.

Some of the Sure Power units are single-sensing. I think all of the Blue Sea units are dual-sensing.

The only real advantage to the dual sensing is if you happen to have aux charge sources, such as solar or a shore powered charger hooked to the aux battery side. With dual-sensing, the ACR will tie and the engine battery will get topped off as well. (Not that that much matters...if you're running aux loads off an aux battery, the engine battery will be pretty much full all the time. Still, pushing it up a bit to a higher voltage for a while each day will help to keep it healthy.)

Dual-sensing doesn't really matter for disconnecting, since it's just one battery when tied; same voltage both sides.

The manual "force-tie / force untie" is mostly useful for stuff like using a winch, where you might want extra battery power or might not.

 

[DiploStrat]

.... I think all of the Blue Sea units are dual-sensing.

This is my belief as well.

The only real advantage to the dual sensing is if you happen to have aux charge sources, such as solar or a shore powered charger hooked to the aux battery side. With dual-sensing, the ACR will tie and the engine battery will get topped off as well. (Not that that much matters...if you're running aux loads off an aux battery, the engine battery will be pretty much full all the time. Still, pushing it up a bit to a higher voltage for a while each day will help to keep it healthy.)

Dual-sensing doesn't really matter for disconnecting, since it's just one battery when tied; same voltage both sides.

...

I consider this to be a huge plus when you have charge sources attached to each battery bank - typically starter battery to engine and camper battery to solar/shore. If you park for an extended period (months) between trips, then your solar or shore power keeps the starter battery happy as well.

 

[dwh]

Ya...and I forgot to mention that a force-tie switch can provide self jump capability.