Roadtrek isolator to aux battery issue

teknosorus@gmail.com · 04-12-2021, 10:10 PM

I have a 2002 Roadtrek 190 Popular and I am not getting full voltage from my isolator to the aux batteries (house batteries). The voltage leaving the isolator is 14.7 V which according to Sure Power rep is about right for my model, but the power at the first aux battery connection ( with battery disconnected) is only 12.2 V. So it seems like I am loosing voltage somewhere along the way. Has anyone followed the entire line from the isolator to the aux batteries. Mine leaves the isolator connects to a circuit breaker ( voltage still at 14.7 either side of the circuit breaker) heads up towards the motor the goes up onto the frame by the drivers front wheel then seems to head to the rear of the van but on the drivers side. I am going to try and follow it but thought if some has already done so it might save me some time. If you have does the line (wire) connect to anything else before reaching the aux batteries, like main cabin fuse panel?

I am planning on buying new 4 gauge wire and running a more direct route to the aux batteries but want to be sure I am not bypassing a critical connection.

When running the generator I get a reading of 12.7 volts on my aux batteries when they are normally sitting around 12.2 volts.

Any help would be greatly appreciated

JohnnyFry · 04-12-2021, 10:33 PM

My guess (based on experience with my 2008C210P) is that the second circuit breaker in the charging line from the isolator is faulty and giving high resistance. There are 2 self resetting circuit breakers in the line between the isolator output and the batteries in the rear. The first one is mounted directly on the isolator and is to protect from a short circuit in the line to the back. The second breaker is to protect from the house battery from feeding the short from the other side. If you are exceedingly lucky, the breaker could be mounted nearby the battery switching relay: unfortunately, (as was my case) it is mounted in a metal box just behind the pull out battery box and just forward of the rear wheel. The box is small and the cover is mounted with 2 Robertson screws. These breakers, unfortunately, are prone to failure because they act as charge current limiters in the case of a deeply discharged battery. They are not really designed for this service as the contact arcs every time the breaker opens and, in time the contacts become burned and make a poor connection. They are typically 50 amp rating and are available for under $5 from AutoZone, NAPA, etc. I was able to reach the box by driving the rear wheel up on a small ramp, but it is obviously much easier if you have access to a lift. While it is not a good idea to bypass this breaker from a safety standpoint, I would replace the rear breaker with a larger breaker (say, 60 amp) so that the front breaker would open first. This would minimize wear and tear on the rear breaker during high charging while still providing adequate fire protection.

teknosorus@gmail.com · 04-13-2021, 12:06 AM

thanks, I'll hunt for that second breaker tomorrow. Would much rather change a $5 breaker than rewire right from the isolator.

teknosorus@gmail.com · 04-13-2021, 11:14 PM

Found out that the isolator is defective, but have a bigger problem. I discovered that my house batteries are somehow connect to my engine battery. Even with all wires off the isolator I still get 12.2V at the first house battery. Noticed that the engine battery has 3 wires connected to the + post. Not sure if this is common or one of these the connection to the house batteries. The search continues......

Rockwood27 · 04-13-2021, 11:37 PM

On my 12C190P, the generator starts off of chassis battery. Go to the rear of your RT and crawl under it. Look up between the generator and LPG tank at the underside of the floor. There are several large diameter positive wires connected on studs and maybe circuit breakers. Check these to see if they're corrosion free and voltage readings to ground.

JohnnyFry · 04-14-2021, 12:06 AM

Typically there is only a single cable connected to the starting battery and the only connection between the house and starting batteries is through the isolator. It appears that someone has done some rewiring.

teknosorus@gmail.com · 04-14-2021, 12:44 PM

Thanks for that information. I was thinking that I may just remove the two additional wires on the starter battery and see which one was feeding my house batteries. I have ordered a new isolator, so hopefully I will have solved the mystery by the time the isolator shows up. Stay tuned.......

markopolo · 04-14-2021, 01:57 PM

2002 so it's a Chevy? If so, some info:

A 2002 Chevy RT would have come with a Hehr isolator. That's a diode type isolator. It is a 4 post isolator and would have 5 wires connected, one being the voltage sense wire. Sure Power makes diode type Isolators and also makes Separators. At some point RT started using Sure Power separators but that came well after '02.

JohnnyFry · 04-14-2021, 04:34 PM

My 2008C210P came with an Isolator. I think that Booster said that his 2007 came with a separator: if that is the case, it appears that 2007-2008 could have had either one from the factory.

teknosorus@gmail.com · 04-15-2021, 12:41 AM

Thanks. The Sure Power unit that is defective was a 2013, so not the original. According to the Sure Power tech support, you can tell the year by the first two numbers in the serial number.

wny-pat · 04-15-2021, 01:23 AM

Quote:

Originally Posted by JohnnyFry

My 2008C210P came with an Isolator. I think that Booster said that his 2007 came with a separator: if that is the case, it appears that 2007-2008 could have had either one from the factory.

My 2008C210 came with a Isolator. But that has been replaced with a Blue Sea Automatic Charging Relay!

bwatters60 · 04-18-2021, 06:11 PM

On my '08 210 RT Popular, the cable leaves the isolator, and like yours exits the engine compartment and enters the frame headed towards the rear of the vehicle. On the passenger side and forward of the rear tire, the cable exits the frame and enters a junction box with leads from the batteries, inverter/charger, and the Onan (for starting the genny). This junction box (remove the cover) is your next test point. See pics attached.

Thevon · 04-18-2021, 06:37 PM

If possible, could you identify the components that the wires are attached to in your pictures? Thank you

teknosorus@gmail.com · 04-18-2021, 08:01 PM

Thanks for the information and taking the time to send pictures as well. I'll hunt for the box and check my connections there.

JohnnyFry · 04-19-2021, 05:49 AM

The line running through the circuit breaker is from the isolator in front, the fat one in the middle goes to the battery,
the next one over (smaller gauge) goes to the battery switching relay, the last one goes to the Onan starter

teknosorus@gmail.com · 05-10-2021, 07:18 PM

Thanks for all the help. After installing the new Sure Power Isolator I discovered that a 50 amp circuit breaker was defective as well. Once the new circuit breaker was installed all my issues were solved and my house batteries are now being charged when the engine is running.
Now if our country can just open up to travel I can hit the road...... Stay safe all

Floorman · 08-31-2022, 08:14 PM

Also have the '02 ChevyRT190P. I guess my Herh Powerline 33-22 isolator is toast as cables are not connected to the A or the B2 terminals and there are 2-3 cables connected by a bolt, I believe, by passing the isolator. I think I'm getting alternator charge on both the truck and the house battery and convinced that the 2 battery's are not isolated from each other. I have purchase the Surepower (130023A) replacement including the 144-CD connector kit that adapts the alternator plug and all the breakers. While the Herh Powerline has similar terminals on the isolator the Surepower schematic shows only one 50 amp circuit breaker going to the aux (house battery). The Powerline schematic in the RT Owners Manual shows two 50 amp circuit breakers with aux on the isolator side and labeled bat on the battery side in the schematic. Also the Surepower calls out for a 6amp circuit breaker (hard to find) from the E terminal of the isolator and the Powerline has as spec for a 10 amp breaker to the same E terminal going to an ignition switched fusebox location. This thread is great just to give additional information of the coming replacement. I will be curious to disconnect the bypass "bolt connection" and determine the appropriate connection of the cables to the new isolator and get the new breaker or breakers wired into the proper locations. I will update this thread when/if I get it completed

KurtFranz · 08-31-2022, 09:03 PM

Sounds like the same kind of situation I found on my 02 Versatile. The isolater was there but being bypassed for some reason. Initially I thought it was bypassed because it was faulty, however, it was perfectly fine. In my case, the adapter wire to the alternator was bypassed and the alternator wire was connected to the engine battery cable down by the isolater. There was also a small black wire that was connected to the engine battery cable as well. These were all taped together. The house battery cable was still connected to the isolater - but obviously getting no power - so it was never charging while driving - only when plugged in to shore power. I found all of this out when my house battery was dead while on the road. I thought it was charging while being driven and it wasn't.

The PO of the van was obviously unaware of this as well because he replaced the alternator because the volt gauge was reading low. Nothing changed with the new alternator and he gave up trying to figure it out. I assume it was reading low because all it was doing was keeping the engine battery charged - at 12.8 volts or so.

So, I just went and hooked everything up the way that it was supposed to be and everything worked fine. The house battery charged while driving and the volt gauge read about 14.

Maybe your isolater is OK?

Just a few thoughts on the matter.

Floorman · 08-31-2022, 11:01 PM

wow. Thank you for the post. My PO had also replaced the alternator back in 2019 with nearly the same amount of miles as when I got it in August. I bought it from a seller who was flipping it so never got to speak with the PO. I will be sorting this out over the next few days. I will do as you suggested and hook the old Powerline isolator back up, test the breakers for continuity and of course the charging voltage. I will update my post . Thanks again Kurtfranz

booster · 08-31-2022, 11:30 PM

Quote:

Originally Posted by Floorman

wow. Thank you for the post. My PO had also replaced the alternator back in 2019 with nearly the same amount of miles as when I got it in August. I bought it from a seller who was flipping it so never got to speak with the PO. I will be sorting this out over the next few days. I will do as you suggested and hook the old Powerline isolator back up, test the breakers for continuity and of course the charging voltage. I will update my post . Thanks again Kurtfranz

If the breakers are working as in not failed open like they usually do, you should be able to just check the coach battery line to ground and if you have coach battery voltage the breakers have to be closed.

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