house batteries go dead while driving

ggoguen · 11-22-2018, 05:23 PM

my house batteries went dead traveling from Maine to Florida. I checked the voltage at coach battery, with engine running, at 14 volts, at house batteries 12 volts. If I go into motorhome, and toggle the use/store switch from use, to store, then back to use, I get 14 volts to house batteries. ?????
Any ides

carlgorski · 11-22-2018, 05:45 PM

Bad switch or dirty

javelin · 11-22-2018, 11:16 PM

Just to clarify, coach and house batteries are usually the same thing (batteries for lights, water pump etc.) and the chassis battery is the one that starts the engine. So I think you are saying that while the engine is running and you are not on shore power; chassis connect switch is on....the chassis battery reads 14VDC on your voltmeter, but the coach batteries read only 12.0 VDC (which is essentially 25% of full charge). My 2013 ACE has separate coach and chassis battery disconnect (controls BCC latching relays) switches by the door not just one “use/store” switch.

On another post I provided a link to the RV Custom Products manufactured BCC (Battery Control Cabinet) which included a schematic and full description of operation and troubleshooting info. I am not sure if your 2013 Daybreak uses this BCC like many other 2013 Thor class A gas coaches do? If not you can ignore the following:

If it does, you may have a failing interconnect relay (the one that connects chassis and coach batteries together (when emergency starts are required or under normal charging conditions when the BCC tells it to close). When engine is running (chassis battery latching relay is on) ; chassis battery is charging from the alternator. When the chassis battery hits 13.2 VDC the BCC closes the interconnect relay which then allows the alternator to also charge the coach batteries. Similarly when parked; on shore power; engine is off and coach battery latching relay is on; the coach batteries are charging from the converter. When the coach batteries reach 13.2 volts, the BCC closes the interconnect relay which allows the converter to now also charge the chassis battery.

If not the interconnect relay, you may just have a poor/loose connection somewhere in the charge path anywhere from the chassis battery connection at or inside the BCC to the coach batteries. If you have this BCC, changing latching relays or the interconnect relay inside will be “fun”. Take care if you work in the BCC. Disconnect all batteries; shore power etc if you are doing any major tweaking in there or you will be cooking more than turkey.

ggoguen · 11-22-2018, 11:50 PM

Sorry, I meant to say chasis battery. I have already replaced the relay/solenoid in the BCC, (not fun).
My question is, that it all seems to work OK if I toggle the use/store switch, from use, to store, then back to use, after starting the engine. Does this make sense?

blw2 · 11-23-2018, 01:08 AM

What rig do you have? Maybe update your user header...it says for brand "still looking"

The Bird relay n mine went bad a couple years back and I ended up with a dead house battery after a long drive when I expected it to be charged. Maybe a similar problem.....I have no idea of course if your system would be similar or not...
mine is controlled by an intellitec controller and a constant duty relay
the relay went bad not the intellitech controller...

If it was the isolator relay that you've already replaced
maybe it's your controller, or maybe it's not hooked up correctly.(?)

manual for my relay is attached, maybe yours is at least similar.

javelin · 11-23-2018, 01:12 AM

Hi.......so inside the BCC the interconnect relay is basically hard wired (bus bars) between the chassis battery and coach battery external BCC terminals. If you replaced the interconnect relay (and it is operating properly with good contacts inside ?) then tighten/check/clean all connections from BCC coach battery post to coach batteries. What voltage do you measure on the external BCC Coach battery post when the engine is running and the chassis battery is 13.2 or higher? Is it the same as at the coach battery terminals? It might take a few seconds for the BCC to operate the interconnect relay after 13.2 volts is reached.

When you operate your use/store you are opening and closing the latching relays (coach and chassis) I think (not familiar with your set up)......as I say my coach has separate switches for each battery group. Did you have shore power connected while the coach was running? That would show up as 13+VDC as the converter would be charging the coach batteries (coach latching relay on).

I am attaching a picture of the open BCC which shows the interconnect relay between the bus bars and the two RV Custom latching relays (one for coach and one for chassis battery connections).

ggoguen · 11-23-2018, 01:36 AM

I updated my info. I have a 2013 Daybreak, by Thor. Thanks for the schematic, I'll take a closer look tomorrow to see if my system is similar.

ggoguen · 11-23-2018, 01:37 AM

I can't seem to open your attachment. I'd like to see what you have.

javelin · 11-23-2018, 01:27 PM

I will try to repost the internal BCC picture as a JPEG instead of Bitmap and add a picture of the exterior BCC box view. On the left are the termination posts for various coach electrical connections. The labels may not be the same but if you have the BCC box you likely have some version of the RV Custom Products. If you do not have this BCC in your 2013 Daybreak perhaps it is the Intellitec BIRD system mentioned by a previous poster? So not much value for you but other forum folks may get some value from seeing this information as it shows the interconnect and latching relays.

ggoguen · 11-23-2018, 01:33 PM

That looks like the unit I have. I think mine is a TH 1020

javelin · 11-23-2018, 02:16 PM

Well at least we are making progress. The cct board inside the BCC should be labelled FW221 for the latest version I think.....matches the schematic linked on another posting recently.

In case you were not aware, there was a recall on the BCC for some coaches (not certain if Daybreak was part of that recall - check with Thor or on line?) because if the latching relay for the chassis battery failed it would disconnect the chassis battery at any time the failure occurred.....while driving/ at night/ etc. So they basically hard wired the chassis battery......moved the ignition/alternator cable feed from chassis switched post to the chassis battery post on the BCC. I would focus on getting your coach batteries recharged ASAP first though......shore power charge them up fully (12.6 volts assuming wet cell batteries) before you do any more trouble shooting. You don't want to damage them or freeze them.

ggoguen · 11-23-2018, 02:28 PM

Batteries are fully charged now. I looked into that recall, and from what I can tell, my unit doesn't fall under it. I thought Thor's repair was a bit cheap, at best.
I have built an 8 gauge jumper, that I can use, if I needed to, for charging. Which is about what they did any way.

ggoguen · 11-23-2018, 04:14 PM

I just went and took voltage readings. MH is at a storage lot, so it takes a little time to look at things, and respond to all of you, but I really appreciate the help. so here goes, see if we can make sense of this.

engine not running, generator not running, no shore power, use/store in use
chassis 12.4 House 12.3

engine running, u/s in use
chassis 14.4 house 12.3

engine running, u/s in store
chassis 14.4 house 12.2

engine running, u/s switched to use
chassis 14.3 house 14.2

engine off u/s in use
chassis 12.7 house 12.7

now I restarted engine u/s in use
chassis 14.3 house 12.4

eng still running, u/s switched to store
chassis 14.3 house 12.4

engine still running, u/s switched to use
chassis 14.2 house 14.1

It seems like I can control this by switching the use/store switch from use to store, then back to use, but I know that's not right.

javelin · 11-23-2018, 05:01 PM

It is a pain to troubleshoot when you have to travel back and forth to the storage yard….especially with bad weather etc. By the way full charge is 12.6+ volts on a wet cell batteries FYI.
Interesting u/s switch cycles correct the problem until you shut the engine off again. It should only take less than a minute after you start the engine for the BCC control system to sense 13.2 volts or higher charging on the chassis battery…..so if you waited 5 minutes is there any change on the coach battery charge voltage? Also after your u/s fix cycles, when the coach battery is charging OK does it stay charging OK if you just leave the engine running?
The BCC cct board has an electronic voltage comparator circuit(s) that senses the 13.2 volt level and above to close the interconnect relay and 12.6 volts and below to re-open the interconnect relay. I am curious what happens when you have your problem (engine running, coach batteries not charging but u/s is on) and you operate the interconnect relay manually using the emergency start switch near the driver seat. You should hear the interconnect relay operate with your manual control. Operate it several times manually, then retest you’re your coach battery voltage. It would be best if you could manually operate the interconnect relay and watch if your coach battery charge voltage changes at that time…….hard to do with one person.
Since your alternator should basically be hard wired directly to the chassis battery (from factory or after this BCC recall) you know it charges fine. The interconnect relay is the only thing between the coach and chassis battery cabling other than tight clean connections or bad set of contacts in the relay. I don’t think the latching relays should have any impact on the intermittent problem but note that the u/s must be in use for the BCC control board to work…….so perhaps cycling the u/s was just hitting the voltage comparators on the BCC cct board……effectively cycling the interconnect relay? You might have a Winter think project and Spring resolve job on this one. Just make sure your batteries are fully charged if you leave them in your coach over Winter.

ggoguen · 11-23-2018, 05:19 PM

Thanks again, I'll try to get the wife over to MH, and cycle the emergency start switch, while I'm under the hood. Gonna take a break from it, for now. I'll post any new data I get in the future.

javelin · 11-23-2018, 06:18 PM

Just noted you are in Florida.....what is Winter?

It is good to sometimes review things and come at it again at a later time. One last comment, if the BCC has already closed the interconnect relay and you operate the emergency switch to manually close it.....of course you wont hear it operate. I am still suspecting bad contacts (even on a new relay) or something wrong on the control board that operates the interconnect relay (assuming all other connections are clean and tight). You want to hope it is "not" a cct board replacement. Enjoy your Thanksgiving holiday.

ggoguen · 11-23-2018, 06:28 PM

Thanks again for the help. Enjoy your Holidays too.
I'll post any new info I can gather, later.

BillW1 · 12-03-2018, 06:35 PM

The BIRD is responsible for connecting both batteries so they charge when either one is being charged. There is a time delay before that happens but it's only a couple of minutes.

I had a similar problem. Sometimes it would charge, sometimes it wouldn't. In my case it appeared that the BIRD only worked part of the time. Perhaps a bad connection on the circuit board or a defective component in the circuitry.

I replaced the BIRD (a fairly cheap DIY procedure) and all my problems went away.

ggoguen · 12-03-2018, 07:31 PM

I don't think I have the "Bird" system, I have a BCC, Battery Control Center, I may be wrong.

TurnerFam · 12-03-2018, 08:00 PM

the BIRD is basically a sensing unit, that the brings both battery banks to the Charging system via an automatic relay, or 12v DC Continuous coil(solenoid, as some refer to).

you may also have a dash mounted AUX or BATTERY BOOST switch, which effectively does Exactly the same thing, except that it is to bring both battery banks together, temporarily, for starting the engine, or starting the generator, or moving the slides, etc, if either battery bank is too low at the moment.
It also uses a 12v DC coil, but may be a differing size or brand from the other.

Mine uses a WhiteRodgers 12v DC Continuous coil for the BIRD...
and a Trombetta 12v coil for the 'AUX' or 'BatteryBoost' manual dash-mounted switch

Also, your USE/STORE door-side momentary two-way switch controls the RV CUSTOM PRODUCTS latching relay, which is similar to the other devices but only 'switches' to CONNECT or DISCONNECT the House batteries from everyday usage, otherwise to help keep your batteries in storage longer without many draws, though their will also be a few small ones regardless.

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