I had a problem last week in "Q" where during the drive from Los Angeles to "Q", my coach batteries did not charge from the alternator. I pulled out the trusty cheepy, cra!!y HFT DMM and hooked it up to the house side of the Isolator Relay. What I saw was after the engine warmed up and the chassis battery was charged, the relay would energize for a few seconds and then drop out, then energize a few seconds later and then drop out.It pretty much conformed to the specs of an Intellitec BIC, except it would not stay energized.For what ever reason, I pushed the AUX Batt switch a few times and finally the solenoid stayed energized.I THINK, no nameplate available, that I have an Intellitec BIC #11-00200-00, which has been replaced by part # 00-00131-00. I will go through the logical step by step process of checking the seven wires in the bundle for proper operation both in static and active modes. The wire bundle from the Molex connector is color coded but there isn't any schedule I can find. I assume the connector was wired by a third party to Fleetwood's specs and nothing in any of their schematics shows the BIC and solenoid.Have any of you had problems with the BIC or do any of you have the wiring schedule?

I've taken several apart and cleaned the copper disc. It can involve drilling out rivets. Possibly the solenoid engages but no house battery voltage change is detected so it disengages.I've also used the aux start to get a failing solenoid to engage.

If it drops out, I would clean the contacts on the coil., both inside and outside of the case.Check the connections on the control wires. This the controller that should operate the relay. Intellitec 00-00131-00

relayThis is a charge relay. They are not repairable.There should be a battery control center under the hood driver's side. Mine has two silver electrically held relays. One is ignition and one is for charging and aux start functions. These are standard continuous duty relays that are available at RV stores, and many auto parts stores.

I replaced my worn relay with one from Grainger.com 6C017 is a 100 amp rated forklift relay with alloy contacts rated to turn on and off 100,000 times under load. I also took the time to upgrade the wiring from my alternator to the new relay, to the coach battery with #4 wire. I never did look for or try to repair the factory relay. My 97 Bounder, the factory relay to recharge the battery failed with the RV about 10 years old. Having a 400 watt solar system masked the problem, as the battery always started a trip full, and rarely ended a trip with less than full batteries. However on this trip, we used the inverter and microwave, and drove home at night. With the coach battery still low on power, I was able to figure out that the engine battery to coach battery relay (that is also the aux start relay) was either not working, or the contacts so dirty they did not transfer power very well. Anyway the new relay solved the problem! I energized it with the +12 from the radio, or via a three way on-off-on switch, I am able to leave the relay on or off as desired. Fred.

You need to figure out whether it is the control or the relay that is flaky- measure the coil voltage on the relay- if it is the type that closes the relay at full voltage, then reduces the coil voltage (so non-continuous rated solenoids can be used), it could be just a little corrosion on the ground side could cut the "hold" voltage to below where the solenoid would stay engaged.Also, I have seen times where the coach battery was dead enough that when the solenoid closed, it pulled the alternator down below the set voltage, at which point it drops the solenoid out.

Testing a Battery Isolator Controller | Good Sam Community

12 Replies

MEXICOWANDERER
Explorer
Jan 30, 2016
Yeah I just ordered a half-dozen 200-ampere MOSFET relays. They do need substantial heat sinking with aluminum finned heat sinks. Mine get extensive protection with MOVs and avalanche rectifiers and a system electrolytic cap. A good setup will last decades with ZERO .00 voltage drop increase.
pnichols
Explorer II
Jan 30, 2016
jumpshowhigh wrote:
Why bother with these mechanical relays...go with something solid state and be done with it.

Outstanding suggestion ... however, are there solid state switches that DO NOT introduce a volt drop from input to output ... and are shaped and have the connectors ... such that they can be a direct drop-in replacement for the mechanical type that I installed in our Itasca motorhome:

http://shopping.murcal.com/Catalog/Bear-DC-Contactor-Family/114-1211-020
MEXICOWANDERER
Explorer
Jan 27, 2016
"Let's take something really simple, stupidize it, with confusion and marginal engineering, then sell it for a lot of money!"

Jeez RV'ers are so gullible.

A simple high quality, bi-directional automatic charging relay can last decades.

Blue Seas Systems, and Sure Power offer great relays that are simple to install and they last and last. A 200-amp model will outlive your rig.

But "Super Gigavolt Hyper Drive Ultra (get this) Intelligent Snapper Zapper Charge Sharing" devices like Ginzu Knives, will always snare the unfortunate.

The gizmo freaks who prey on the gullible will always be out there. On a tour bus that had a massive battery bank and 260 amp alternator I configured a tiny 100-amp Sure Power charge divider to power a massive 500-amp rated relay. It worked like a charm. A bi-directional relay will remain bi-directional even powering a thousand amp simple relay.

"Hey Ernie, whatzat big truck backing up to the loading dock?"

"Must be another batch of product warranties"

"Oh my God! Quick, get on the computer and change our Brand Name and P.O. Box!"
jumpshowhigh
Explorer
Jan 27, 2016
Why bother with these mechanical relays...go with something solid state and be done with it.
enblethen
Nomad
Jan 27, 2016
Make sure what you get is rated for "continuous" duty. Starter relays will not hold up.
D_E_Bishop
Explorer
Jan 27, 2016
Thanks to Bob, Bud, Fred, Chris B and Roy, my gut feeling when this took place down in "Q" was go get a new solenoid, I'm am, however, glad I waited til I got home and researched everything. I did not know exactly how the BIC worked to charge the house battery from the engine alternator, now I do. It's nice to have wise and reasonable folks to bounce things off of and you guys fit that bill.

By the way, I found a solenoid listed in a catalog for OLD VEHICLES down at the local parts house. It was more than some other places but I know this one is for use as a battery isolation system. It has a two year warranty and I told the owner, no big deal the last one lasted 26 years so I way ahead.

Thanks again guys.

David
RoyB
Explorer II
Jan 26, 2016
My BLUE SEA SI-ACR relay here is under control of the Truck Alternator system. This ACR RELAY only connects the AUX battery whenever the truck battery is being charged.

Mine has a trip voltage setting which is set to 14.2VDC.

I see the same thing when I first start up the ACR relay (SOLENOID) engages and connects both batteries together. Then as soon as the truck start battery reaches full charge then it shuts off the ACR RELAY.

The Truck Battery being so close to the truck alternator I suspect it very seldoms stays in BOOST charge very long.

Don't know if your smart solenoid does this same procedure or not.

I think my setup has a manual control to force it into BOOST charge... With the AUX battery so far away from the alternator in my setup it may not ever even recognize it at all... It will always read the truck start battery DC Voltage...

Check on google how the BLUE SEA SI-ACR charge setup works - they have some good info pages on that... Perhaps this will give some clues what to do on your charge setup...

Roy Ken
Chris_Bryant
Explorer II
Jan 26, 2016
You need to figure out whether it is the control or the relay that is flaky- measure the coil voltage on the relay- if it is the type that closes the relay at full voltage, then reduces the coil voltage (so non-continuous rated solenoids can be used), it could be just a little corrosion on the ground side could cut the "hold" voltage to below where the solenoid would stay engaged.
Also, I have seen times where the coach battery was dead enough that when the solenoid closed, it pulled the alternator down below the set voltage, at which point it drops the solenoid out.
Golden_HVAC
Explorer
Jan 26, 2016
I replaced my worn relay with one from Grainger.com 6C017 is a 100 amp rated forklift relay with alloy contacts rated to turn on and off 100,000 times under load.

I also took the time to upgrade the wiring from my alternator to the new relay, to the coach battery with #4 wire. I never did look for or try to repair the factory relay. My 97 Bounder, the factory relay to recharge the battery failed with the RV about 10 years old.

Having a 400 watt solar system masked the problem, as the battery always started a trip full, and rarely ended a trip with less than full batteries. However on this trip, we used the inverter and microwave, and drove home at night. With the coach battery still low on power, I was able to figure out that the engine battery to coach battery relay (that is also the aux start relay) was either not working, or the contacts so dirty they did not transfer power very well.

Anyway the new relay solved the problem! I energized it with the +12 from the radio, or via a three way on-off-on switch, I am able to leave the relay on or off as desired.

Fred.
enblethen
Nomad
Jan 26, 2016
relay
This is a charge relay. They are not repairable.
There should be a battery control center under the hood driver's side.
Mine has two silver electrically held relays. One is ignition and one is for charging and aux start functions. These are standard continuous duty relays that are available at RV stores, and many auto parts stores.