Battery isolator elimination

Topic: Battery isolator elimination (Read 706 times) previous topic - next topic

Battery isolator elimination

June 30, 2023, 04:22:31 pm

Hi folks,
I'm getting ready to install a new Victron inverter and lithium batteries. I know there are several of you that eliminated the battery isolator and are using DC to DC chargers. I also have a DC to DC charger in my van so I am very familiar with them and what they do.

So, my question is, if I eliminate the isolator, what am I doing with the other wires coming into the isolator? There is a lead from the alternator and another one from the start battery.

I've been reading on other forums (SOB) that people just left the isolator in place and have had no issues. This kinda makes sense as the lead coming out of the isolator is a 2 gauge wire that is at least 25 feet long. At 12 - 14 volts, I can't see how that is going to stress the alternator all that much with the voltage and amperage drop in that distance to the batteries. But, I already have the DC to DC chargers and will probably install them anyway. I just don't know if my start batteries are going to get charged if I eliminate the isolator and what to do with the alternator input wire.

More questions to come on this I'm sure. I will post pictures once it's all done.

Kevin

Re: Battery isolator elimination

Reply #1 – June 30, 2023, 04:33:33 pm

Move the alternator wire in the center of the isolator and move it to the starter battery side. Or do like most of us did and put 2 terminals where the isolator was and attach the alternator wire and the start battery wires to one of the terminals and your b2b and coach batteries on the other.

Re: Battery isolator elimination

Reply #2 – June 30, 2023, 06:56:15 pm

I ditched the isolator 3 years ago. It's pretty easy to do. Just think about how you want to charge each battery bank, and run the cables as required. The post linked below shows my solution, which has worked just fine.

Delco Remy 28SI Alternator Installation

Re: Battery isolator elimination

Reply #3 – June 30, 2023, 07:43:55 pm

Check out this post answers 19-22

What is DUVAC?

Re: Battery isolator elimination

Reply #4 – June 30, 2023, 10:38:24 pm

Thanks for the answers guys. I'm pretty good with electricity, but when it comes to alternators and boost solenoids, that's where I don't have much experience.

So, I know that I will run a cable from the start battery to the DC-DC charger and it will charge the house batteries. Do I simply run the alternator cable directly to the start battery? What keeps the alternator from overcharging the start batteries?

This picture was posted by Tommy D. Is this what it should look like?

Re: Battery isolator elimination

Reply #5 – June 30, 2023, 10:41:42 pm

Also,
Another question before I forget. How does the generator charge the 12 volt batteries? Is it only producing 120v and the inverter is charging off of the 120v?

Thanks
Kevin

Re: Battery isolator elimination

Reply #6 – June 30, 2023, 11:34:11 pm

Kevin, your alternator will put any where between 13.6 to as high a 15+ volts depending on which alternator and how the regulator is set. 14.2 being about right. Start batteries are built differently than deep cycle batteries. Your Dc to Dc charger should be programmable to your house battery type for 3 stage charging, bulk, absorb, and float. As well as protect you alternator.

Re: Battery isolator elimination

Reply #7 – July 01, 2023, 12:33:27 am

Quote from: kjsifer – June 30, 2023, 10:38:24 pm

Thanks for the answers guys. I'm pretty good with electricity, but when it comes to alternators and boost solenoids, that's where I don't have much experience.

So, I know that I will run a cable from the start battery to the DC-DC charger and it will charge the house batteries. Do I simply run the alternator cable directly to the start battery? What keeps the alternator from overcharging the start batteries?

This picture was posted by Tommy D. Is this what it should look like?

The voltage regulator in the alternator is what keeps the start batteries from over charging.,

Re: Battery isolator elimination

Reply #8 – July 02, 2023, 03:10:23 pm

There are 3 solenoids under the bed. What are the two that are together for? I assume the one that is by itself is the boost solenoid?

Thanks
Kevin

Re: Battery isolator elimination

Reply #9 – July 02, 2023, 03:57:44 pm

Should be unique numbers on each of the cables. Compare those numbers with your coach's wiring diagram.

Re: Battery isolator elimination

Reply #10 – July 02, 2023, 05:19:57 pm

If you follow the cable from one of the solenoids it will go to the pass side top of the motor that is the intake grid heaters for cold start. Have someone turn the boost switch on and off while you check which one clicks. IIRC one is the starter solenoid.

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Battery isolator elimination

June 30, 2023, 04:22:31 pm

Re: Battery isolator elimination

Reply #1 – June 30, 2023, 04:33:33 pm

Re: Battery isolator elimination

Reply #2 – June 30, 2023, 06:56:15 pm

Re: Battery isolator elimination

Reply #3 – June 30, 2023, 07:43:55 pm

Re: Battery isolator elimination

Reply #4 – June 30, 2023, 10:38:24 pm

Re: Battery isolator elimination

Reply #5 – June 30, 2023, 10:41:42 pm

Re: Battery isolator elimination

Reply #6 – June 30, 2023, 11:34:11 pm

Re: Battery isolator elimination

Reply #7 – July 01, 2023, 12:33:27 am

Re: Battery isolator elimination

Reply #8 – July 02, 2023, 03:10:23 pm

Re: Battery isolator elimination

Reply #9 – July 02, 2023, 03:57:44 pm

Re: Battery isolator elimination

Reply #10 – July 02, 2023, 05:19:57 pm

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