[Larry]

You should have a Vanner Monitor near your engine or chassis batteries. It sends a signal to light a light on the dash to alert of an issue. If it fails, despite voltages in range it can send a signal to light a warning light.

Next time you get a warning light, check the voltages on the input side of the monitor. Hi voltage will be over 30, Lo under 24, and Balance will be the 12 volt readings greater than 1/2 volt different than 1/2 of the 24 volt value. In other words if the 24 volt side reads 26 volts, the 12 volt side should read 13 volts, plus or minus 1/2 volt.

I think the model is Vanner Model 70 and complete information is on the Vanner web site.

[Jim/Chris]

Thanks Jon. I will check and report back

[Mike]

Check the model number of the monitor. They are up to 70D. The original 70A in our 99 Liberty burned down sitting on our driveway.

[Jon]

Jon, wouldn’t an easier test be to confirm the the Vanner Equalizer voltages at the Equalizer and if within the 1/2 volt between the 12 and 24/2 terminals then replace the monitor?

[Dick]

The light is LOW BAT, not BAT BAL. Check alternator output first. Could be alternator or a bad battery connection.

[Jerry]

Tom, I check at the monitor because that is the input the monitor sees and if there is a defect in the terminals or wiring that will prove the monitor is seeing a voltage error.

Then if the equalizer is showing the same voltages I know it is the monitor.

[Jon]

Still haven’t had a chance to go out there and check it but as soon as I do I’ll report back to you all with my findings

[Jon]

Well got out there and took some readings

bus off:

11.8 13.2

25.8. 26.5

Bus on:

26.4 13.2

26.8 13.4

readings are from each vanner seem good to me what do you think?

[gary]

Voltages and balance look good. If you took the readings at the base of the monitor it suggests the monitor is bad.

I would continue to drive the coach as is. Unless and until you get a voltage or balance light, do nothing. If you get one, take readings as soon as possible and if the voltages and balance readings are as good as you posted replace the monitor. If you get a light and voltages in fact are high, low or out of balance the next likely culprits could be the voltage regulator or the alternator.

Cross that bridge if and when you come to it.

What I said above assumes wires and connections are good.

[Jon]

Ok Jon copy that. Thank you for the input. If I get a good deal on a vanner should I just replace ?

[Bernie]

I think Jon is suggesting that you replace the Vanner Monitor.

[Roscoeapproved]

Not to throw a wrench here… What looks right about 11.8V?

Still learning here after 9 years of ownership, I have never checked at the vanner terminals. I have checked at the battery posts and the Vanner monitor and I think 11.8 is low.

My monitor was in the top of the rear electrical box, it is so thin I missed it on first look. The 70D is now on rev C. At least that is what I received from inverter services earlier in the summer.

---

Jeff and Lindsay

91 Marathon XL

[Jon]

The 11.8 is an issue. Looks like time for new batteries. As I said in an earlier post, it is a LOW Bat light not a BAT BAL light. Change the batteries.

[Jon]

Batteries seem to be something owners want to squeeze every last drop of life from them.

It is only my opinion, but to me that is risky. Over the years folks trying to nurse a few more hours of use from batteries have replaced all sorts of perfectly good but expensive parts that were deemed defective, but in fact it was one or more bad batteries making problem diagnosis difficult resulting in replacement inverters, equalizers, etc.

Reading all the posts on Prevost forums has made me replace AGM batteries every 5 years regardless of condition. Not cheap, but also never went crazy trying to figure out if my inverters or other devices were going bad.

[Bernie]

Jon I agree 100%. Even in the car world, as they become more complicated the same is true. I have a lot of experience with the maintenance side of late model european cars. Lack of proper voltage causes a lot of issues. Especially in cars that sit for extended periods of time. I have become very good friends with my local interstate dealer in Sarasota. I can take them batteries, they do a series of tests and either tell me that I should be able to bring it back or just to replace it. I do still use them for some of my general use batteries and with my discount find them cost effective.

With that said, I do love the experience that I have had with Lifelines. I ordered one of the small, light weight Lifelines for one of my race cars. I really didn’t know what to expect. It has been amazing with no downside at all. I will be using it in all of my race cars from here on out.

Sorry to get off subject, I just thought a few of you might enjoy this video. It is a pretty famous car in the BMW world and the end of the video on the dyno is pretty cool. It is the car I referred to using the Lifeline battery.

BMP E30 BMW

Bill III