Battery Isolator and DVSR

February 17, 2022, 06:13:35 pm

I have switched my house batteries to Battle Born lithium and installed a Battery Isolation Manager on their advice. They also recommended I disconnect the existing battery isolator. I am confused, though, because the coach also has a digital voltage sensing relay installed. According to the manufacturer's website, "When the DVSR senses a charging voltage (13.4VDC or 26.8VDC) on either of the banks, it automatically activates and joins the two battery banks after a short delay (5 seconds), so they are charged as one battery bank." Based on that, it appears the DVSR and the isolator would both allow the house batteries to charge from the alternator at times. Is that correct? If so, would I also need to disconnect the DVSR? The downside to that would be the start batteries would no longer charge from shore power. Any suggestions would be appreciated.

Re: Battery Isolator and DVSR

Reply #1 – February 17, 2022, 07:00:27 pm

Seems to me you need B2B charger such as a xantrex echo charger or something similar to charge your chassis batteries when on shore power. My question would be. Is it safe to tie together for starting?

Re: Battery Isolator and DVSR

Reply #2 – February 17, 2022, 07:26:32 pm

Your Battleborn batteries are almost always going to be 13.4v or more. The DVSR is set to come on when charging lead batteries which will be charged at 13.8v or more. With LiFePO4 batteries the DVSR is likely to be on all the time.

You do not need the isolator with the BIM.

"LI-BIM 225 Quick Guide:

The LI-BIM 225 senses voltages of the Chassis (Engine) and Coach (Auxillary) batteries. There are three senarios to when the connection will be made, each with their own response:

Senario 1: Engine is "on" with a Chassis battery voltage greater than 13.4V and a Coach battery voltage less than 13.3V
Response: The LI-BIM 225 will connect the batteries for 15 minutes, then disconnect the batteries for a wait time of 20 minutes. After this wait time, a new voltage reading will be taken of each battery. If the voltages remain within the scenario's parameters, the response repeats.

Senario 2: The Chassis battery voltage is below 12.5V and a Coach battery voltage greater than 13.5V
Response: The LI-BIM 225 will connect the batteries for 1 hour, then disconnect the batteries for a wait time of 2 minutes. After this wait time, a new voltage reading will be taken of each battery. If the voltages remain within the scenario's parameters, the response repeats.

Senario 3: The Normally Open Momentary Switch is pressed
Response: The LI-BIM 225 will connect the batteries for as long as the switch is pressed.
A basic connection diagram is shown below. The ignition terminal should be connected to the ignition switch. The signal terminal has two setups:
Option 1: The signal terminal is connected to a Normally Open Momentary Switch, which is connected to a ground.
Option 2: The signal terminal is connected to a fuse (suggested 2 Amps). This fuse is then connected to a Normally Open Momentary Switch followed by a connection to the Coach Positive Voltage Line."

I suggest...

Disconnect all battery grounds. Disconnect all charging sources. Verify with a multimeter.

Remove the isolator.
Remove the DVSR.
Adjust LN output voltage to the charge voltage BB likes, about 13.6v

The Alternator connects to the chassis battery post on the BIM.
Connect the wire from the chassis battery post on the Boost solenoid that was connected to the isolator to the chassis battery post on the BIM as well.

If the BIM chassis battery post isn't big enough add a new post nearby and connect the alternator, chassis side of the boost solenoid, and a cable from the chassis battery post on the BIM to it.

Connect an ignition powered wire to the Ign post on the BIM.

Connect the wire from the coach battery side of the boost solenoid that was connected to the isolator to the Batt Coach post on the BIM.

This is essentially the same wiring as a B2B charger.

If I am reading this right...

When the ignition is on and the chassis battery voltage (while the engine is running) is > 13.4v and the coach batteries are <13.3 the BIM will begin it's on/off cycle to charge the coach batteries. This stops when the coach battery voltage exceeds 13.3v or the ignition is turned off. (scenario 1)

When the ignition is off the BIM will periodically connect the house and chassis batteries if the House battery voltage drops below 12.5v and the coach batteries are > 13.5v (scenario 2). This seems like it replaces the functionality of the DVSR.

Scenario 3, Option 2 is like using a boost switch.

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