Community Forums

georgetown350 · 02-10-2008, 06:45 AM

Most posts suggest that the chassis battery is not charged by shore power. Some suggest the opposite.
I have our motorhome plugged into shore power for the winter ( Canada cold brr )
and yesterday I started the engine for the first time in about a month of very cold weather and the engine turned over just as fast as if it were summer. The battery seemed like it had a full charge. Is it possible that both batteries are connectetd when hooked to shore power???

Thanks

Steve

georgetown350 · 02-10-2008, 06:45 AM

Most posts suggest that the chassis battery is not charged by shore power. Some suggest the opposite.
I have our motorhome plugged into shore power for the winter ( Canada cold brr )
and yesterday I started the engine for the first time in about a month of very cold weather and the engine turned over just as fast as if it were summer. The battery seemed like it had a full charge. Is it possible that both batteries are connectetd when hooked to shore power???

Thanks

Steve

Tom N · 02-10-2008, 07:21 AM

It's possible you have a solar panel on the roof that charges the chassis battery.

-Tom

Cruzer · 02-10-2008, 08:49 AM

Your coach has two separate battery systems - the house batteries and the chassis batteries. Whenever you are driving a Charge Solenoid closes to tie these two systems together so that your engine's alternator can charge them both up. As soon as you shut off the ignition, the Charge Solenoid opens up and you are back to two separate systems again. When you are plugged into shore power (or running the generator) your inverter/charger (or converter) will "normally" only recharge your house battery system because that's the only system that the charger is connected to.

However, there are exceptions. There are a number of third party devices that can be used to provide charging power for your chassis batteries as well. My 2004 Allegro Bus did not have these so I added one but my 2007 Allegro Bus comes with one of these as standard so it's possible you might have one of these devices on your coach. The two most popular are the BatteryMinder and the Trik-L-Start. The Trik-L-Start is an electronic module that steals battery power from the house batteries to feed to the chassis batteries. It uses a voltage sensing circuit to do this only when your charger is running. The BatteryMinder is an AC powered charger that also enables a pulse mode to keep your batteries desulfated. That's the one that I use but both do an equally good job of keeping the chassis batteries up. There are other brands available but these two are the most popular.

My personal experience with the OEM solar panels is that they help somewhat but they aren't enough to do the job on their own - even in sunny locations with no snow on the roof.

M&EM · 02-10-2008, 09:56 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Stevegeorgetown:
Most posts suggest that the chassis battery is not charged by shore power. Some suggest the opposite.
I have our motorhome plugged into shore power for the winter ( Canada cold brr )
and yesterday I started the engine for the first time in about a month of very cold weather and the engine turned over just as fast as if it were summer. The battery seemed like it had a full charge. Is it possible that both batteries are connectetd when hooked to shore power???

Thanks

Steve </div></BLOCKQUOTE>

Steve, Since you didn't mention solar power, I would conclude that your 2 battery systems tie together by way of a solenoid that is part of a dc control board common on many modern rvs.

This board senses both sides of the solenoid. When either side reaches a set voltage(I can't remember that value) say its 13.5 volts, The solenoid connects the two systems together. The solenoid drops out if both sides are below some lower threshold say 12.7 volts.

This way either of the 2 systems that has charging available to it will share its charger with the other system once it has reached a float voltage.

Hope this makes sense.

Marty

Latitude · 02-10-2008, 10:21 AM

Steve Your coach could have a 'BIRD', Which is a 'Bi directional Isolator Relay Device'

I was asking same ???

When you are on shore power or running the gen The BIRD allows your chassis batteries to be charged after the Coach batteries are fully charged

When you are driving The BIRD also allows the coach batteries to get a charge after the chassis batteries are fully charged.

Rick

georgetown350 · 02-10-2008, 03:54 PM

Dont have a solar panel but you guys are making me believe that there is something charging the chassis battery. The battery just seems so strong for how long in the cold it has been sitting.
Maybe people are using after market chargers unnecessarily to charge chassis batteries when in fact they are being charged by the converter? Perhaps the manufacturers have figured out that we need a fully charged battery to start our rigs.

Thanks for the replies.

Steve

wilanddij · 02-12-2008, 12:15 PM

Steve,
You might want to contact Forest River and get hold of an owner's manual for your coach (if you don't have one). The manual that came with my Southwind has a good description of the 12V charging system, and both house and chassis batteries get charged when driving, on shore power, or on generator. Forest River contact info is here Forest River.

Gary RVRoamer · 02-12-2008, 04:33 PM

Many coaches will charge the chassis battery from shore power and many others will not. For example, most all Fleetwood coaches do, while most Winnebagos do not. It is more common nowadays that it will do so than it used to be - the electronics to manage the process are now relatively cheap and readily available.

Sounds like yours does, but check with the manufacturer to be sure.

chasfm11 · 02-13-2008, 08:24 AM

Rick, I appreciate your information on the BIRD. I found it described in detail on the Intellitec Website. I was surprised, however, that a search of RVUpgrades and several other online RV suppliers didn't turn it up. I suppose that I could contact Intellitec directly and either buy it from them or have them refer me to a supplier that does carry it. Is is possible that the on-line suppliers have it but don't list it in the electronic catalogs.

I was just trying to look at the cost of it. It seems like a great product. I'm pretty sure that I have no link to charge the chassis batteries while on shore power.

Cruzer · 02-13-2008, 12:48 PM

I tired to put a BIRD on my '04 Bus but gave up. It now sits in it's box on my basement workbench gathering dust.

The problem was that the BIRD operates the OEM charge solenoid. Whenever it did that it fed power back to my dash via the wire from the ignition witch and aux start switch to the charge solenoid's coil. RVupgrades does handle the Trik-L-Start, which does not actuate the charge solenoid. It operates on the same principal as the BIRD but is easier to connect and more foolproof.

georgetown350 · 02-14-2008, 11:44 AM

I have a manual but its thin and only contains the basics.

I will call Forest River thanks

Steve

historyljc · 02-23-2008, 11:16 AM

Tiffin makes it clear that on their units the only time all batteries are being charged is when the unit's motor is running. The generator and shore power charge only the house batteries. To be safe, I had a Trik-L-Start put on the chassis batteries. The peace of mind is certainly worth the few dollars it cost.

Periscope Man · 02-28-2008, 09:20 AM

Steve, It's very easy to check, with the coach connected to shore power measure the chassis battery with a digital volt meter, record the reading. Unplug the coach and again check to chassis battery with a digital volt meter and record the voltage. If the reading are basically the same, you are not charging the chassis battery, if the reading with the coach connected to shore power is higher, than your chassis battery is being charged.