Blue Sea Systems Automatic Charging Relays (ACRs)

$ 56.27

Score By Feature

Based on 509 ratings

Satisfaction

9.58

Packaging

9.22

Customer service

9.53

Delivery

9.69

OveReview Final Score

How Our Score Is Calculated

Product Description

Continuously rated at 120 amps

Input voltage is 12/24V DC and auto-ranges.

Suitable for systems with 12 or 24 volts.

Questions & Answers

Is this a relay or solid state diodes, just so we're clear? Is there going to be a 0? As with power diodes, is there a 7-volt drop across the switch?

It's not a diode splitter because there's no voltage drop. It's a relay, albeit a solid state one, for all intents and purposes.

Is it possible to wire this so that the batteries are manually combined (i.e. override the isolation) with, say, a toggle switch? Is the "kit" required, or do I not require it?

No, unless one of the batteries has a voltage greater than the required for combination, this init will not combine. The combine function can be "locked out." The combination is disabled when 12 volts DC is applied to the lock out terminal. When one of the batteries reaches the required voltage level, the unit will automatically combine them.

Will combining the power of both batteries work if only the accessories are powered by one battery? To put it another way, the second battery is only for the?

These ACRs have been installed on my new Sea Ray boat. It does not appear to be functioning properly to me. I started getting warnings on my dash about "low voltage" and that I needed to "run the engine over 1000 RPM or turn things off to avoid battery drain." So, with a test meter in hand, I went down last night and checked the batteries while the engine was idling at over 1000 RPM. The battery in the engine is charging, but the battery in the house is not. So, does it only charge everything when the house battery voltage falls below a certain threshold, or does it charge everything all the time?

Selected User Reviews For Blue Sea Systems Automatic Charging Relays (ACRs)

It's a neat little battery charge/discharge relay that's a lot better than the old diode isolators

5/5

Recently installed, so far so good, and super-easy to use. Build quality is excellent. Use to connect a house battery to an engine battery (with a solar module connected) so that either can pass power back and forth. The unit is straightforward, with two main power lugs (one for each 12V battery), a spade lug for ground sensing (required), a lug for start bypass (optional) (disconnects the house battery during engine start), and lugs for an optional remote 12V LED status indicator (unit has integrated LED indicator). br>br>Operational location: The unit connects battery sources together if one *or* the other has a higher voltage (it's a relay, so when connected both batteries are wired together). For example, I have an engine battery and alternator, as well as a house battery with solar. I want the alternator to charge the starting and house batteries, but not allow house loads to draw from the starting battery when the engine is off (typical configuration), but I also have a solar PV module that produces surplus power so charging the starting and house batteries So the house battery is connected to one terminal and the start battery to the other; when the engine is running, the start and house batteries are linked; when the engine is off, the start and house batteries are disconnected *unless* the solar output pushes the house battery voltage above 12. When the voltage reaches 8 volts, the relay closes and the two batteries are linked together. When the sun sets, the relay opens, separating the batteries once more.

Rohan GOUGH

| Apr 12, 2021

It all depends on your circumstances and the type of battery you're using

3/5

First and foremost, the unit's construction quality is outstanding. There are no issues in this area. Unfortunately, the Si's usability is limited. Depending on your setup and battery type, ACR is severely limited. br>br>It works great if you only use FLA, AGM, or Gel batteries and plan to use this relay as the only connection between them. It's reliable and does what it's supposed to do. br>br>My two main concerns are:br>br>1- With LiFePo4/Lithium batteries, these relays don't work as they should. The Lithium battery's higher voltage is read as a "charge source" by the relay, which is always turned on. The purpose of having a relay is defeated in this situation. A selectable voltage threshold for connect/disconnect is required for this relay to function properly with modern Lithium batteries and charging systems. br>br>2- A manual disconnect switch is part of my setup. This allows me to detach the auxiliary battery from the charging source entirely. When the switch is turned "off," the Si-100 is turned off. The LED warning light on ACR flashes continuously, indicating that only one battery is plugged in. This feature wastes battery power, and the LED will eventually burn out. A "test" button on the unit is required to display the flashing light. It's inconvenient to have it running all the time. Overall, it's a good relay, but it lacks modern Lithium battery functionality and the ability to adjust to different configurations. 3 out of 5 stars.

Myles George

| Apr 01, 2021

I got a secondhand one (update: I got a new one)

3/5

WTF (IT DID NOT WORK). UPDATE: the ML- Both the ACR and the switch were broken! I was annoyed at first because they arrived in used condition, but I was even more annoyed and angry when I had to troubleshoot them because they were not working properly. I have a meter, and I tested everything, and everything pointed to the ML- I had to return the ACR because it wasn't working properly (the switch wouldn't even turn on). *The ML- The ACR I bought as a replacement from another vendor was installed, along with the switch (which had the SAME wiring as the used one I bought off here), and it worked flawlessly right away! You can take a chance if you think your potentially wasted time is worth the minute cost savings, but I'm not going to do it again. br>br>It wasn't just a waste of money; it was also a waste of time that I can't get back. This has made me very angry. It ruined an otherwise pleasant afternoon, so I purchased from a different vendor to avoid having to deal with the problem again.
. br>By the way, this is my ML- When I took ACR out of the package, I noticed that it appeared to have been used; the wiring pigtails had solder on them and there was some electrical tape residue. The ML-'s backside I'm not happy that it appears I received a used product; I was in a hurry for my purposes and couldn't wait to get another one, so I didn't mess with the return policy, but I'm still unhappy about it. br>br>I'm not happy that it appears I received a used product; I was in a hurry for my purposes and couldn't wait to get another one, so I didn't mess with the return policy, but I'm still unhappy about it YMMV.

Bryant COATES

| Nov 30, 2021

Thank goodness I found out about this unit before I had to replace my broken isolator! This device is absolutely incredible

5/5

It's ridiculously simple to set up and it gets rid of the. 5V- The old isolator that it replaced had a 7V voltage drop, and now not only can my alternator fully charge both the start and house batteries, but the charger connected to my house bank also charges my start battery seamlessly! I'd like to point out that if you're retrofitting this device onto an older RV that also has one of the old style fixed low voltage charging/dirty DC providing converter/chargers, such as the Magnatek/Parallax 6300-, you'll need to use a converter/charger that has a fixed low voltage charging/dirty DC providing converter/charger. Replace it with one of the compatible Progressive Dynamic 4 stage chargers, such as the 7300 and others. It's a simple slide-in upgrade that completely modernizes your DC system!.