New battery isolator

Topic: New battery isolator (Read 2250 times) previous topic - next topic

New battery isolator

May 24, 2017, 07:33:04 pm

Read all the posts covering isolators and have a question,if your old isolator uses the 2 post wiring that Foretravel used for the
house batteries do you have to wire the new one the same way or can you just use one post per battery bank seeing how the
new isolators are much improved than the old ones?

Re: New battery isolator

Reply #1 – May 24, 2017, 08:36:42 pm

As long as the new 3 post isolator has approx the same or greater current ratings. For example I replaced the OEM 190 amp 4 post (approx 126 amp house and 63 amp chassis ratings) with a 240 amp 3 post, which would be 120 amps for house and 120 amps for chassis. Actually ran cooler I think due to the 3/8" posts vs 5/16" posts.

Re: New battery isolator

Reply #2 – May 24, 2017, 09:06:18 pm

Went with a combiner. All the new coaches come with them.

Re: New battery isolator

Reply #3 – May 25, 2017, 12:48:26 am

Ok. What is a combiner?

Re: New battery isolator

Reply #4 – May 25, 2017, 08:07:43 am

Combiners (at the higher end) are smart devices that connect (combine) or disconnect battery banks.
Victron Cyrix-i Battery Combiners

At the simple end they are manual switches with you at the controls.

Re: New battery isolator

Reply #5 – May 25, 2017, 08:36:02 am

If you you are going the combiner route be sure to get one rated with enough capacity for your application.

Re: New battery isolator

Reply #6 – May 25, 2017, 11:03:34 am

Is a combiner another type of voltage sensing relay? It seems like they do the same thing, but then I am not an electrical genius.

Re: New battery isolator

Reply #7 – May 25, 2017, 11:31:38 am

Quote from: Roger & Susan in Home2 – May 25, 2017, 08:07:43 am

At the simple end they are manual switches with you at the controls.

A manual switch with me at the controls would be technically classified as a "Battery Combiner of Average Intelligence".

Re: New battery isolator

Reply #8 – May 25, 2017, 01:07:02 pm

Yes, Ted all combiners have voltage sensing circuits that manage when to allow current to flow. Flow is controlled by relays / solenoids / contactors, all names for similar items. Voltage sensing circuits may have adjustable or non-adjustable settings on when to close AND when to open relay.

This contrasts to diode based "switching". Isolators & Trik-L-Start are diode based. Diodes work by allowing current (amps) to flow in one direction and prevent current flow in the opposite direction. Diodes are simple, without any adjustment and do their job quite well.

Diodes have a 'disadvantage' when compared to combiners in that diodes have a small voltage drop, so to get batteries charged at 14 volts, the alternator must be set to around 14.6. Diodes may be more limited in carrying high amperage.

Voltage sensing has an advantage in that voltage-out equals voltage-in. But we found after purchasing and testing two popular combiners to keep our start battery charged that the voltage setting circuits did not always result in a better outcome than our simple Trik-L-Start diode. And a combiner introduced a new problem that showed up when cranking our Cummins engine.

We do not need high amperage relay based devices to keep our start battery up, so we find our Trik-L-Start just works better for our needs.

Re: New battery isolator

Reply #9 – May 25, 2017, 01:07:10 pm

Works great. Both battery banks stay stable on auto or manual at 13.5 on the dash plug in led voltage gauges.

My alternator is set to be max at 13.6 at the batteries.

VPMS shows 13.3 -13.4, dash gauge which is after the ignition switch shows the needle at 13 volts.

Does not seem to be any issues with the 13.5 max on both the house gels or the optima red top agm's.

First time the battery voltages under way or plugged in do not vary all the time,

Maybe my isolator was bad? I doubt it as my guru looked at it.

We threw out the trickle chargers as once the required charge rate from a discharged by accident set of engine batteries was exceeded it popped its internal fuse and quit charging.

He mentioned he had had coach issues with combiners that auto connected during starting as several coaches who needed to use the engine batteries by themselves to start found out that the engine batteries were bad and had been covered up by the start combiner.

To my limited knowledge the combiner seems to work well. Voltages used to vary while driving a lot.

Now exactly the same all the time running.

Plugged in for four days at Zion river Rv park and after a day or two the two banks stabilized at 13.5 and have stayed there.

Not sure if they were undercharged before or just needed a long slow charge from the new magnum sw 2812 but everything seems good now.

If I had known that the 2812 was going to be installed I might have gone with a heavier alternator to be able to run the front a/c going down the road without the gen on.

Yes it slows the coach a bit. Tested that 30 years ago with engine driven a/c alternators.

But the old 555 cummins did not have the power of our m11's

I posted the combiners info.

Only thing we did not do was to run a front to back extra wire to light up the selector switch to show what mode it is in.

So it works and you can hear it click and the battery gauges move but no light up.

The magnum has the BMS installed so it governs it charge rates by temp by itself but the alternator is a single stage so we set it at 13.6 as it cannot hurt anything as far as I know charging for hours at that rate.

Later mods might be the higher output three stage voltage control like the old link 2000r controllers had and a way to run the front air off the inverter side.

As a newby on this any comments about what I have noticed would be helpful

Re: New battery isolator

Reply #10 – May 25, 2017, 01:35:54 pm

Wow, you learn something new every day. When I installed my Blue Sea SI-ACR almost three years ago, I knew I picked a good one, and i knew Automatic Charging Relay was their name for a Voltage Sensing Relay. I didn't know it was also called a Combiner.

It has been wonderful all this time, wonderful in the sense I'm hardly aware it is there. It just works and causes no problems. Note that it automatically isolates the batteries when starting (which I might undo with the boost switch). Note also that it is dual sensing, so it will combine when charging from the engine alternator, from the inverter/charger, or from solar power.

SI-ACR Automatic Charging Relay with Start Isolation
PN 7610
Features
• Automatically combines batteries during charging, isolates batteries when discharging and when starting engines
• Allows temporary isolation of house loads from engine circuit during engine cranking to protect sensitive electronics—start isolation indicated by blinking LED
• Supports high-output alternators up to 120 Amps
• Ignition protected—safe for installation aboard gasoline powered boats
• LED light is ON when batteries are combined
• Under voltage lockout—will not close when the lower battery is below 9.5V @ 12V System
or 19V @ 24V System—lockout indicated by blinking LED
• Waterproof rated IP67----temporary immersion for 30 minutes
• For 12 or 24 volt systems
• Dual Sensing—senses charge source on either battery bank

Re: New battery isolator

Reply #11 – May 25, 2017, 02:03:36 pm

The ml-acr is a 500 amp unit.

Re: New battery isolator

Reply #12 – May 25, 2017, 02:24:33 pm

Quote from: Caflashbob – May 25, 2017, 02:03:36 pm

The ml-acr is a 500 amp unit.

I know. Way back when I bought my SI-ACR, the MI-ACR wasn't out yet. Besides, 120 Amps should suffice. 120A is more than my alternator, more than my inverter/charger and more than my solar controller are rated to produce.

Re: New battery isolator

Reply #13 – May 25, 2017, 02:58:31 pm

Your alternator was originally rated at 160 amps but I doubt it ever gets anywhere that.

Obviously as the 120 amp unit has worked great for three years.

Thanks for the info matching my results.

My guru tried to get me to switch a few years ago but other items took precedence

Did you wire the switch to light up?

Re: New battery isolator

Reply #14 – May 25, 2017, 06:17:00 pm

I stand corrected. Yes, the alternator is rated at 160A.

Fortunately, the the chassis battery gets first crack at the juice (connected directly to the alternator, while the house battery is connected after the combiner and a longish cable). I remember looking at my battery monitor with the engine running, and not seeing anything near 120A.

If it ever gets in trouble with over-Amps, it is an easy fix to upgrade to the MI-ACR.

I only have the basic hookup. No "combine" monitor LED, and no start isolation. I often have the boost switch on while starting.

Re: New battery isolator

Reply #15 – June 26, 2017, 03:25:44 pm

I have a 1988 320 40 ft - I called foretravel about a low voltage reading on the dash meter -was told it was either a:
1. bad battery - checked good
2. Alternator - changed
or
3. Battery Isolator - Ordered a new one and have received a new style ready to install. I was told it is the same size.
Where is old one located in the coach? Looked in engine and battery compartment. It is hidden?

Re: New battery isolator

Reply #16 – June 26, 2017, 04:13:14 pm

floyd2,

Need the correct info on your coach model. The 320 was not built until the mid 1990's. You could have an ORED, U280, U300.

Re: New battery isolator

Reply #17 – June 26, 2017, 05:01:10 pm

Floyd on the driver side behind the rear duals if you have a small bay door open it up and look on the frame rail might be there, on my 92 it is. Good luck

Re: New battery isolator

Reply #18 – July 20, 2017, 01:35:47 am

The blue sea 7610 sounds like a good smart replacement for my simple ored oem isolater that is disconnected. Any thoughts or suggestions would be welcome.

Re: New battery isolator

Reply #19 – July 20, 2017, 02:19:52 pm

I installed the 7610 three years ago. All I great.

Re: New battery isolator

Reply #20 – August 17, 2017, 11:40:32 pm

So Cole hersche (sp) has a supposedly new diode free smart isolator/combiner solenoid for about $100 bucks for 200 amps. Look like a standard solenoid with an external smarts that monitor battery voltage. Bi-directional from alternator or shore power, charges start battery first based on voltage, then switches to house based on voltage, has boost combiner. I am not well educated in this field, and have no clue if it will work with a good multistage house charger.
Sage advice appreciated.

Re: New battery isolator

Reply #21 – August 17, 2017, 11:51:38 pm

This may be what you are referring to:

Cole Hersee 48530 200A Smart Battery Isolator

This will work great. We put one of these in my son's Lincoln Town Car for his subwoofer amp 2nd battery. Been trouble free for 2 years.