Chassis battery charging

[jimc99999]

I have a 1997 Windsor that seems like it may no longer be keeping the chassis batteries charged.

It has a Heliotrope RV-30 solar controller and dual battery charger, but it seems flaky. It often shows battery voltage between 17-38V, and the chassis and house batteries are connected backward (I.e. chassis voltage is from house batteries). 

I think it has a chassis battery trickle charger but it isn't labeled so who maybe it's not (pictured).

A couple months ago, the chassis batteries were too low to start the coach. We were in Crescent City, CA, it had been cloudy for a couple months and the infrequent sunshine was at a very low angle. The batteries were around 12.8V, so I hooked up a battery charger and got them charged up to 13.6V, and they started the coach. I checked a few days before we were leaving there, batteries were still good but we had plenty of sunshine the last couple weeks. 

We've now been in Medford a few days with lots of sun, no shade. I turned on the ignition to adjust the leveling jacks and noticed battery voltage was on the low side; enough to activate the gauges and run the leveling jacks but too low to start the motor. The Heliotrope had the "charged" light lit, so it wasn't charging. I turned on the ignition for about 30 seconds, and the Heliotrope decided to start charging. After 30 minutes of clearing out the cabinet to get a picture of the back of the Heliotrope, and looking again at the electrical items by the motor, the battery voltage at the dash gauge is now where it should be for a charged battery that will start the coach easily.

I'm thinking of replacing the Heliotrope with the Blue Sky Sun Charger 30, and adding a Trik-L-Start charger. But if I already have an apparently non-functioning trickle charger, I guess that should be removed. Anyone know what exactly is this unit?

Also, what is the purpose of this device? The power wires come up from both sides of the auxiliary boost relay. The right side power goes to the chassis battery cutoff switch, and the left-side power leads to the house battery cutoff switch.

A

[Gary 05 AMB DST]

I would clean all the connections first. It looks very dirty.

Gary 05 AMB DST

[John Haggard]

23 minutes ago, Gary 05 AMB DST said:

I would clean all the connections first. It looks very dirty.

Gary 05 AMB DST

Yes

Clean everything 👌

A spray can of electrical cleaner

Electric motor cleaner.

WD 40 ?

 

[waterskier_1]

Jim, that green box with a green light is the device that is supposed to allow charging of the chassis battery(s) while on shore (generator) power.  The light being lit should show the device is working.  On my 97 Dynasty, it was lit, but NOT working.  When it is lit, you should see the same voltage on either of the end terminals to ground.  That should be above 13.5 volts (depending on the charge stage you are in).  If you have over 13.5 volts on the chassis battery(s), then they are being charged.  You may have another problem causing the chassis battery(s) to discharge at a faster rate than they are being charged.  If you do not have the same voltage on both terminals to ground, then the device has failed.  Replacements are scarce, and very expensive.  It's better to get a Amp-L-Start or Trik-L-Start type device and replace that green unit entirely.

[jimc99999]

2 minutes ago, waterskier_1 said:

Jim, that green box with a green light is the device that is supposed to allow charging of the chassis battery(s) while on shore (generator) power.  The light being lit should show the device is working.  On my 97 Dynasty, it was lit, but NOT working.  When it is lit, you should see the same voltage on either of the end terminals to ground.  That should be above 13.5 volts (depending on the charge stage you are in).  If you have over 13.5 volts on the chassis battery(s), then they are being charged.

Thanks, I'll check that out. My suspicion is that device may have failed or be failing, and the Heliotrope solar charging device is flaky. 

I've figured out that the other device is a battery isolator, which *also* allows charging current to push to both batteries, while isolating draw. Does the isolator only allow charging current to push to both batteries at bulk charge, I.e. over 14V? So float charge voltage doesn't go through the battery isolator? Otherwise it seems like the Trik-L-Start would be redundant.

[waterskier_1]

Jim, the large (often blue) device is an isolator, as you suspected.  But it is used ONLY when the main engine is running.  It takes the alternator output and divides it between the chassis battery and the house batteries.  It is only in play when the engine is running, and only used when charging from the engine alternator.  It is completely out of the circuit when the engine alternator is not running.  

Regarding the Solar.  You don't say, so I'm going to assume you have the single solar panel that Monaco used.  That panel was about 100 Watts, when new.  That solar controller (the Heliotrope) is a PWM (Pulse Width Modulation) type controller.  They are the least efficient controllers.  The 17- 38 volts you are measuring is the INPUT to the controller from the solar panel.  The controller then "massage's" that voltage to a level around 14.2 volts to charge the HOUSE batteries (as wired by Monaco).  As I mentioned, the PWM type controller is inefficient in taking that 17 - 38 volts and using all the related power to charge batteries.  A much more efficient controller uses MPPT (Maximum Power Point Tracking) to "massage" the 17 - 38 volts to squeeze every bit of power over all voltage conditions into your batteries.  All this said, that 100 Watt panel, is barely enough to keep you house batteries from going dead while in storage.  It was never enough to charge the batteries up - only to offset the natural discharge and the few item that always draw from the batteries (like smoke alarm, CO alarm, and other) from discharging the battery.  Unless someone has rewired the controller (doubtful, unless more panels were added, and then still not likely) it only charges the House batteries.  That "green" device was then supposed to charge the chassis batteries if the house batteries were above a certain voltage (around 13.5 volts).  So, theoretically it could keep both batteries from discharging, but in real world, it just wasn't enough.   

[vegaman19760]

Jim....

You did not mention how old the batteries are.  Do you know the age of those Chassis Batteries?

[jimc99999]

On 4/7/2021 at 10:15 AM, waterskier_1 said:

Regarding the Solar.  You don't say, so I'm going to assume you have the single solar panel that Monaco used.  That panel was about 100 Watts, when new.  That solar controller (the Heliotrope) is a PWM (Pulse Width Modulation) type controller.  They are the least efficient controllers.  The 17- 38 volts you are measuring is the INPUT to the controller from the solar panel.  The controller then "massage's" that voltage to a level around 14.2 volts to charge the HOUSE batteries (as wired by Monaco).  As I mentioned, the PWM type controller is inefficient in taking that 17 - 38 volts and using all the related power to charge batteries.

The Heliotrope can show those numbers at night, so it seems like it's attempting to show battery voltage. Recently it has been accurately displaying battery voltage.

 

On 4/7/2021 at 10:15 AM, waterskier_1 said:

Unless someone has rewired the controller (doubtful, unless more panels were added, and then still not likely) it only charges the House batteries.

It does show voltages for each set of batteries, although the chassis batteries are connected to the house side. 

[jimc99999]

On 4/8/2021 at 6:40 AM, vegaman19760 said:

You did not mention how old the batteries are.  Do you know the age of those Chassis Batteries?

They are 2 year old O'Reilly's Super Start Extreme, size 65, 850CCA. I got those because I don't think I can fit 2 group 31s, they are all listed at 12.5" long and my tray is 12x20. 

For some reason I thought they were AGM, but I cleaned them tonight and saw they're standard flooded. I popped the caps off one of them and the water is about 0.25" below the plastic, but still covering the plates. Should I add some distilled water?

I thought everything was working fine again, but we boondocked this weekend and the chassis battery voltage dropped to around 12.3V. I charged them back up with the generator powering a battery charger. After driving the coach 7 hours today, I removed the chassis batteries and am letting them sit disconnected overnight to see if the voltage drops if they are not being charged. If not, I guess I'll have to figure out what's draining them. 

After being charged all day from the alternator, after I removed them from the coach to clean, them both measured 13.03V. With the coach idling this morning, voltage across the batteries was around 13.6V. I forgot to check voltage with the engine running when I arrived this afternoon. They measured 12.95V just after turning the coach off and 13.02V after the coach was plugged into shore power about 30 minutes.

On a side note, there was 14.3V across the chassis battery cables after turning off the battery disconnect and removing the batteries. I've previously checked continuity across the disconnect and it seems to actually disconnect. The engine bay trickle charger (pictured above) should be disconnected by the switch. It was almost dark so the solar panel shouldn't be producing any power, in case the heliotrope is wired directly.

 

Edited June 8, 2021 by jimc99999

[jimc99999]

Adding water didn't help the batteries, they were still a bit weak starting the coach even at normal voltages. I stopped by O'Reillys and they load tested the batteries, one was in the last 25% of its life. The manager decided to warranty both of them and with 2 new batteries it cranks much better.

[vanwill52]

Research Blue Sea ML-ACR.  Replace the Lambert charger, Solid State Isolator, and Battery Boost contactor with ONE rugged, guaranteed-as-long-as-you-own-it device.  You need only look at it to see which state it is in.  About $200.  Draws only milliamps except for the fraction of a second when it is switching from one state to another.  Does not require the increasingly difficult to find and expensive DUVAC-equipped alternator.  You MIGHT need to make one 4/0 battery cable.

While you are doing that, check the condition of your Chassis Disconnect and House Disconnect switches.  Many of the older ones are nearly falling apart.

[jimc99999]

10 hours ago, vanwill52 said:

Research Blue Sea ML-ACR.  Replace the Lambert charger, Solid State Isolator, and Battery Boost contactor with ONE rugged, guaranteed-as-long-as-you-own-it device.  You need only look at it to see which state it is in.  About $200.  Draws only milliamps except for the fraction of a second when it is switching from one state to another.  Does not require the increasingly difficult to find and expensive DUVAC-equipped alternator.  You MIGHT need to make one 4/0 battery cable.

While you are doing that, check the condition of your Chassis Disconnect and House Disconnect switches.  Many of the older ones are nearly falling apart.

My battery disconnect switches look and feel ok. 

That Blue Sea ML-ACR looks interesting. I guess you'd connect alternator charging directly to the chassis batteries, and inverter/charger/solar charging directly to the house batteries, and let the ML-ACR balance the charging? 

[vanwill52]

Correct.