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jsuvman's avatar
jsuvman
Explorer
Oct 07, 2017

Intellitec BCC Isolation Relay

I have a possible issue and was looking for some help. Here is the scenario. This is an Intellitec BCC Mini-Gas #53-00524-100. I also have solar panels and a digital controller that tells me the status of the panels and battery voltage. I will try to put as much info as possible in this first post.

NOTE: Solar Panels are connected to Auxiliary Batteries.
ISSUE: Normally when RV is started, the solar charge controller goes to 13.6+ Volts and Green Charge Light goes all the way to the end. Red Charge Light Is On.

Yesterday when I went in and started the RV it did not do that so I checked a few things. Here are the 3 things I checked so far.

Not Plugged In – Not Running – No Sun on Solar Panel.
Reading on Solar Charge Controller – 12.5 Volts – 0.0 Amps – Green Charge Light "2/3 across" – Red Charge Light On.
Battery Voltages - Checked At Batteries
Auxiliary – 12.45 Volts
Chassis – 12.65 Volts
Tested Auxiliary Start Button In BCC – Heard Click of Isolation Relay

Plugged In – RV Not Running – No Sun on Solar Panel
14 Seconds - Heard Click of Isolation Relay
Reading on Solar Charge Controller – 13.5 Volts – 0.0 Amps – Green Light "all the way" – Red Light On.
Battery Voltages - Checked At Batteries
Auxiliary – 13.5 Volts
Chassis – 12.65 Volts - Didn't show increase.

Not Plugged In – RV Running – No Sun on Solar Panel
14 Seconds - Heard Click of Isolation Relay
Reading on Solar Charge Controller – 12.7 Volts – 0.0 Amps – Green Light "2/3 across" – Red Light On. - Always went all the way across when RV was running.
Battery Voltages - Checked At Batteries
Auxiliary – 12.60 Volts - Didn't show increase.
Chassis – 14.33 Volts

It appears that that when plugged in only the Auxiliary Batteries are charging and when not plugged in, but RV is running, only the Chassis batteries are charging even though I can hear the click of the Isolation Relay in all tests, which when engaged should charge both.

Any Ideas? Think it needs a new isolation relay? Anyway to test it?

Thanks in advance for any replies.
  • MEXICOWANDERER wrote:
    Unless, of course, the relay contact points are bad. The point is a diagnostic test. Doesn't anyone ever emery file oxidized or pitted points any more?


    If you are familiar with this type of "Isolator Relay" it is a sealed unit. There are no contacts to file like you would have on a home A/C Contactor type relay.

    Here is a link to one.
    http://ltdrvparts.com/INTELLITEC-100-AMP-BATTERY-ISOLATOR-RELAY-77-90000-100-7790000110.htm

    That was the original question I asked. Is there a way to test these isolator relays without removing the circuit board since they are behind the circuit board. Only test that the manual shows is to listen for the click and check voltages when it is pulled in.
  • Unless, of course, the relay contact points are bad. The point is a diagnostic test. Doesn't anyone ever emery file oxidized or pitted points any more?
  • Yes the convertor is putting out over 13.3 volts. Hence the voltage on the auxiliary batteries jumping from 12.45 to 13.5+ when plugged in on shore power. So is the alternator as you see. They jump from 12.65 to 14.3 when the RV is started.

    I did not check J1-Pin 5 yet as I was told if there was no voltage on that I would not hear the click of the isolation relay? Is that not true?

    I think I also figured out what they mean here.
    "If there is voltage on the coil, check for voltage between the main and auxiliary batteries. If the voltage is more than 0.1 volts replace the relay."

    Essentially, when the isolation relay pulls in all batteries are in parallel. (Chassis and Auxiliary) Thus there should be no more than a 0.1 volts difference across the relay.
  • Yes, That is what page 7 is saying.
    Check J1- pin 5 for voltage?
    Is the converter putting out the 13.3 volts?
  • enblethen wrote:
    ***Link Removed***That sounds correct as many battery control centers do not have the capability to charge chassis battery from shore power.
    I run a jumper between the two positive terminals to charge chassis battery.
    Is this your model?
    Some battery control centers have what is called a BIRD set up to charge batteries. (bi-direction relay)



    Yes that is the manual, which I have, As you see on page 2 if either set goes above 13.3 volts while charging the isolator relay (solenoid) pulls in and both sets should charge. This is what it has always done from shore power, from the alternator, from the generator, from the solar panels, etc.

    They also say this on page 7, which I do not completely understand?

    "If there is voltage on the coil, check for voltage between the main and auxiliary batteries. If the voltage is more than 0.1 volts replace the relay."

    I think they are saying that naturally when the isolator relay is pulled in voltage should be the same on both sides?

    I would also assume that if the isolator is pulled in, as I can hear the loud click as described in the manual, I should have continuity across the other two terminals on it? I just wish there was a way to checking without pulling out the circuit board as all the disconnects and isolator are behind it.
  • Helpful Hint

    Missing Crucial Data

    Load amperage. How much power is being used.

    In conjunction with INCOMING charge amperage it will tell you where you are...

    Sorta like 40 years ago. Open mailbox. Extract two letters.

    1. Bank balance, deposits

    2. (Deleted DW) Master Card activity

    Deposits: $2,850
    Debits $3,050

    Unsustainable. More + or less -
  • ManualThat sounds correct as many battery control centers do not have the capability to charge chassis battery from shore power.
    I run a jumper between the two positive terminals to charge chassis battery.
    Is this your model?
    Some battery control centers have what is called a BIRD set up to charge batteries. (bi-direction relay)