General Battery Charging Questions

LK23 · 08-15-2005, 11:46 AM

I need better understanding of the following questions. I have a 2005 Itasca Horizon 40AD.

1. Do the chassis batteries charge by the solar charger?

2. Do the chassis batteries charge when the generator is on?

3. When the main coach switch near the entry door is turned off is the solar charger charging the coach batteries?

LK23 · 08-15-2005, 11:46 AM

I need better understanding of the following questions. I have a 2005 Itasca Horizon 40AD.

1. Do the chassis batteries charge by the solar charger?

2. Do the chassis batteries charge when the generator is on?

3. When the main coach switch near the entry door is turned off is the solar charger charging the coach batteries?

BradandJanee · 08-15-2005, 11:57 AM

Do you have an inverter? That will charge your house batteries when connected to shore power.

tomsm · 08-15-2005, 12:22 PM

LK23,

I THINK all the Winnie DPs are the same in this. The chassis batteries are only charged by the engine alternator. That's why most owners are using a BatteryMinder or some other charger to keep the chassis batteries charged.

Not sure about #3.

John_Canfield · 08-15-2005, 01:29 PM

Rex - let's define house and chassis... I call the engine starting batteries "starting batteries" (makes sense!) and the house batteries (non-engine starting batteries) "house batteries." Okay...

As far as I know, the starting battteries are only charged by the engine's alternator.

The house batteries (I think) are only charged by the inverter (converter) and/or
solar panel. I didn't think the engine alternator charged the house batteries although Jim (itchn2go) was alluding otherwise.

I'd have to look at the wiring diagram to see where the solar panel is connected. My guess is that it is charging the house batteries regardless.

--John

LK23 · 08-15-2005, 03:28 PM

Wouldn't you think that something as important as this would be covered in your Winnebago manual?

Fred B. · 08-15-2005, 03:54 PM

The house & starting batteries are connected together when the engine is running & are both charged by the alternator. That useless solar panel usually will not keep up with the normal drain on batteries.

Thudman · 08-15-2005, 04:44 PM

I agree with Fred B. At least that's how it work's in my lowly gas rig.

Thudman

bflem · 08-15-2005, 05:34 PM

Engine alternater charges all batteries, shore power charges house batteries only, and solar panel is to maintain house batteries with switch in storage mode. There are exceptions, the Freeedom and Advantage charges all batteries when plugged in and possibly some of the newer high end coaches. At GNR electrical seminar a couple years ago the engineer said you could wedge something under the emergency start switch while plugged in and charge all batteries.

Rick Buddrus · 08-15-2005, 05:56 PM

LK23

1. No they do not.

2. No they do not

3. Yes it is.

If you would like both sets of batteries to charge given all situations, pick up a TRIK-L-START from these folks. It works
http://www.lslproducts.com/TLSPage.html

John_Canfield · 08-16-2005, 02:32 AM

Good answers - I always learn something here. I just ordered a Xantrex Echo~Charge to keep the starting batteries up.

--John

BucknJeff · 08-16-2005, 03:48 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Rick Buddrus:
LK23

1. No they do not.

2. No they do not

3. Yes it is.

If you would like both sets of batteries to charge given all situations, pick up a TRIK-L-START from these folks. It works
http://www.lslproducts.com/TLSPage.html </div></BLOCKQUOTE>

Correct.

So, in review:

The solar charger on your unit charges the house batteries. I'd also add that, as was said, the solar charger is mostly useless.

In the "delivered" configuration, the starting batteries are only charged while the engine is running. Only the house batteries are charged while the generator is running UNLESS you are running the generator while the engine is running. In this case, both the inverter and the engine alternator are charging both battery banks, which are tied together by the isolator relay. While not ideal, the charging device that puts out the highest voltage controls the charging of the batteries in this configuration.

There is another method for keeping the starting batteries charged while parked, as well as regulating the above situation. Intellitec makes a module called the B.I.R.D. (Bi-directional Isolator Relay Delay) which uses the existing chassis/starting battery isolator solenoid (the same one that energizes to charge the house batteries while the engine is running). This device charges both battery banks whenever either is being charged. It is also "smart" and adds some better control of that isolator solenoid you already have installed. Its easy to install, and offers much better control. Find some more information at http://www.intellitec.com/pdfs/BATTE...300366.000.pdf . A similiar device is made for gas chassis as well. It's easy to install, and works great.

You might also read this post, as it has some good information about this topic. http://irv2.infopop.cc/eve/forums/a/tpc/f/248609445...051023511#2051023511

Tom N · 08-16-2005, 06:32 AM

You can tell if the coach and/or chassis batteries are being charged by looking at your One Place panel. When either the coach or chassis batteries are being charged you will see a voltage >13 volts. When they are not being charged the voltage will be <13 volts.

LK23 · 08-16-2005, 02:44 PM

Thanks to everyone who replied. I think I have a pretty good understanding now.

Since the chassis battery is only charged when the engine is running, I need to find a way to keep my two chassis batteries charged while in storage. I am not interested in taking a charge from the coach batteries. Has anyone tried the solar chargers? Camping World has the Solar Battery Saver SE in 2, 6 and 18 watts.

John_Canfield · 08-16-2005, 03:30 PM

Rex,

Assume the parasitic demand on the starting batteries is about 250 milliamps (.25 amps) for 24 hours a day, 7 days a week. So by simple math (.25x24) you need to put 6 ampere/hours of current back into the battery every 24 hours for a no-discharge situation of the battery.

An 18 watt solar panel will put out at the VERY most 1.38 amps (18 watts/13 volts) during moments of intense sun when it is about 90 degrees to the panel. Let's say you are getting about 4 hours of very angled sun, 2 hours of better angled sun, and maybe 2 hours of good output. Let's assume 20% efficiency for the 4 hours, 50% efficiency for the next 2 hours, and 75% efficiency for the peak 2 hours. I get ((1.38 x 0.20)x4) + ((1.38 x 0.50)x2) + ((1.38 x 0.75)x2) = 4.554 ampere/hours per day.

Now we can answer the question about the 18 watt solar panel. I can say with some finality that the 18 watt panel may or may not keep up with the starting batteries

I made a lot of assumptions here - about the efficiency of the solar panel, the parasitic drain on the batteries, your latitude, we assumed that every day is completely cloud-free, the daylight is the same year round, etc, etc.

I know from personal experience with a 50 watt panel that was on my boat when we had it at 10 degrees of latitude in the Caribbean, the most current I ever saw was about 50 watts worth during the middle of the day. That high output only lasted an hour or so.

My guess is that you would need more like a 30 or 40 watt panel to keep them topped off year round, rain or shine.

Now - if you want to reduce the variables in the math here, measure the current drain on the batteries. It could be only 100 milliamps in which case the 18 watt panel might work. If it is 400 milliamps, you might need more panel. Also don't forget the batteries will self discharge by themselves due to their internal resistance. If the batteries are in poor shape, it might take more power to keep them up.

Sorry about such a long-winded answer, but I wanted to introduce you to the number of variables involved.

--John

LK23 · 08-16-2005, 04:32 PM

John,

Thanks for the detailed answer. Bottom line, would not a 15 watt solar charger be better than nothing at all. At the present I have nothing charging the chassis batteries while in storage and there is no 110 volt AC source.

Today I started my motor home after having sit for 8 weeks. The chassis battery was so low that it wouldn't start so I had to use the coach assist switch. I was thinking that a solar charger may not have maintained a full charge but it may have prevented depletion of the batteries.

kenbt · 08-17-2005, 07:37 AM

When I was at the factory I was told by the techs that when the disconnect switch is on the solar panel still charges the house batteries. The chassis batteriers and starter batteries are charged by your generator the same as if you are plugged in. You can verify that by first checking the voltage meter on both before starting the generator and then checking them when it is running..you will find them with a higher voltage reading when the generator is running.

The Godfather · 08-17-2005, 09:30 AM

LK, we are on our 2nd Itasca Suncruiser (gas). I just wanted to let you know that I would recommend two 100W solar panels and controller to keep up with your "house batteries." The solar panel that comes from WB is only a 10W and really won't help you at all. I also suggest having a jumper cable set in your unit because I have had my engine battery drain so low that the jump switch would not work, where the jumper cable between the house and engine battery did the trick. Sometimes I feel like energy management is the biggest challenge of "dry" camping.
Dick

DickNJo · 08-17-2005, 10:01 AM

Just a bit of experience. When we first got our used Itasca gasser the engine start battery would be so low after parking for two weeks that I would have to jump from the house batteries to get started. After I installed my main solar system for the house batteries I switched the leads (twin 16? gage) from the toy panel to the start battery. It will now hold for up to three weeks of boony camping. Some day I'll have to replace that 5 yr old battery, but not yet.

Hofsdad · 08-18-2005, 11:03 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by John_Canfield:
Good answers - I always learn something here. I just ordered a Xantrex Echo~Charge to keep the starting batteries up.

--John </div></BLOCKQUOTE>

John,

Your posts are always very insightful so I have to assume you did some research before deciding on the echo-charge. I'd appreciate if you could share why you chose that solution. I've not had any problems yet, but will soon be heading into the season where the rig sits a lot more and I'd like to prevent any issues before they surface.

Thanks,