Community Forums

golden · 11-11-2011, 07:20 AM

I've been trying to find an answer to my question but have concluded I'm not asking it right.

My 3 yo engine starting battery keeps draining very quickly, even when I use the battery cut off switch. It has been properly maintained when not in use and always checked for water level. Still it goes down and has been doing this for over a year. I used a trickle charger on it this summer when I was in one location for three months and it worked fine. Where I store it, there is no shore power so that option isn't available to me.

I'm thinking of buying a plug in to the cigarette lighter 5w battery maintainer/charger (solar panel) that I can put on the dash. My problem is, I have a battery cutoff switch that is always turned off when the MH is not in use. I believe it cuts off power to the cigarette lighter thus would be of no use to me with a plug in panel unless I left the battery on at all times.

Is a solar panel enough to keep the battery maintained if I don't use the battery cutoff or is the trade off not worth it? FWIW, I have a 2004 Itasca Class A, 8.1L gasser. My house batteries don't go down because I exercise them at least once a month as do I the starter battery at 2200 rpms for about 15 minutes.

Any suggestions? Oh yeah, batteries aren't in my area of expertise so please no technical explanations as I won't be able to understand it!

Conquest102 · 11-11-2011, 07:35 AM

first test the plug with switch on/off by plugging something in and turn switch off. that will tell you if you can or not. most of the small dash panel 12"x 5" only put out 700 milliamps at best.that means very little power to the battery the bigger one's are mostly direct to the battery. you could modify a plug to work but you must have a tester to make sure you get positive and negative correct.

I have a little one from harbor freight for my van it makes winter starting a lot easier. if you turn every thing off and can still get power to the cig plug you should be ok.

rex · 11-11-2011, 05:15 PM

Denny my coach is stored outside with no shore power connection. I installed a 15-watt solar cell on the roof and connected it to the House batteries. I then installed a Trik-L-Start to the House and Chassis batteries. This Trik-L-Start will charge the Chassis batteries ONLY when the House batteries are fully charged, and then at about 5-amps. Have never had a problem with the Chassis batteries since I installed these two devices.

Dave78Chief · 11-12-2011, 09:25 AM

The AUX Battery Disconnect switch near the entry steps only disconnects the house batteries. The chassis battery stays connected. In addition to any chassis parasitic drains, there are a some coach items that are always connected to the chassis battery also. Looking at page 2 of http://www.winnebagoind.com/diagram/...ire_146761.pdf, the 3 breakers on the left side (40 amp Chassis Front Panel, 6 Amp Step Control, & 25 amp Step Power) all connect back to the chassis battery thereby adding to your battery drain problem.
Selecting a size of solar battery maintainer system will depend on how much parasitic current draw is present. For sake of example, if parasitic draw is 1 amp, then you will need enough solar charging energy to provide for that 1 amp discharge during the charge cycle PLUS at least 1 more amp to restore the energy used over night when the sun was not shinning. Cloudy days add to the discharge rate. Please understand I am not saying your parasitic draw is 1 amp. I only used that for the sake of example.

The 15W charging device Rex suggested will only provide around 1 amp of charging current (15W/12VDC = 1.25amps). Solar Panel Wattage ratings are max rating and you will most likely only see 25% less than that on average. That type of unit (http://www.thebatteryminder.com/a_ad...c015_side2.pdf) could be connected directly to your chassis battery or setup like Rex did by connection to the house battery with a Trick-L-Charger also added. However, the way Rex did it means you also have to account for house side battery parasitic loads (yes, there is potentially some of those even with the AUX Battery Disconnect in the Disconnect position).
If you do not feel comfortable using a multimeter to measure your parasitic amperage load (

http://www.youtube.com/watch?v=yFCT-YZbU5o

), then get some one to do it for you. Once you know that value, you can select a solar setup that will ensure the chassis battery system can be properly maintained. Part of that means allowance for battery drain during a period of a few cloudy days. The 15W unit may be enough or you may need to go up to 30 Watts.

With a battery if you have a constant 1 amp discharge, then in 24hr you will drain 24 amp-hrs (AH) of energy from the battery. If you only provide 1 amp of charge current to restore that energy, it will take you somewhere around 26hrs of charging time to restore that 24AH due to effieciency issues. If you only have 8 hrs of full sun, then you only restore 7-8AH. As you can see there would be a 16-17AH deficeit each day. This is why you need to know what the actual parasitic draw current is so you can select the proper size solar system. When connected to shore power, the converter/charger, or inverter/charger, has way more than enough current to overcome the discharge issue. The addition of the Trick-L-Charger works great in that scenerio.

Dave

golden · 11-12-2011, 10:07 AM

Dave,

I just sent you a PM.

Denny

Conquest102 · 11-12-2011, 11:47 AM

Dave AWESOME post you explained it PERFECTLY.

IMDSailor · 12-19-2011, 06:44 PM

This thread supplys the answer to my current, pardon the pun, question. @ Dave, is the Trick-L-Charger the same as the Battery Minder or are they different beasts? Do you advocate the use of the BM over the TLC? If so why or why not?
I just bought a 5W Solar charger and now relize that it is probably not be enough. I too do not have access to Shore Power during storage.
I've been reading other threads about going solar, it seems this would be a small first step.

Dave78Chief · 12-19-2011, 08:10 PM

IMDSailor,

The battery minder is a solar charge controller. I used the wrong name when I said Trick-L-Charger. I should have said Trick-L-Start (Ultra TRIK-L-START Starting Battery Charger/Maintainer). The Trick-L-Start acts as a cross connect between the coach and chassis battery systems allowing a charging system connected to the coach battery to also charge the chassis battery. So, you would connect the Battery minder to the coach battery set and the Trick-L-Start between the coach and chassis batteries. Connected like this both battery systems would be maintained. If you go to a campsite with shore power (or use the generator), the Trick-L-Start would still keep the chassis battery system charged. The Trick-L-Start does not care what the coach charging source is, it just uses it to charge the chassis battery also. Sorry for the confusion. Many people have 110VAC shore power availble at their storage site. They Trick-L-Start allows them to use the installed converter/charger or inverter/charger to maintain both batteries.

Dave

IMDSailor · 12-19-2011, 08:32 PM

Thanks Dave, I think I've got it now. Now I just have to source out the parts. In Eastern Canada we're not fortunate enough to have Campers World and such. I think my local Canadian Tire should have what I need. Based on your math and logic I'll take back the 5W panel and go straight to the 15W.
Thanks for all the info.

IMDSailor · 12-20-2011, 01:04 PM

Dave, I now have a 15W panel and a charge controller. I had to order the Trick L Start on line. If I've read the instructions correctly the Charge Controller only attaches to the chassie battery and until I get the TLC the panel won't charge the House Batts. Is that Correct? Or is there another place to hook up the controller so that the panel charges all the Batts, like at the Batt Isolater?

Dave78Chief · 12-20-2011, 01:38 PM

Sometimes a picture just fits the bill

This way you also get the benifit of chassis battery charging when camping with shore power connected (or a generator).

Dave

IMDSailor · 12-20-2011, 02:34 PM

I'm guessing that it doesn't matter that the house Batts are 2 x 6V and the chassis batts are 2 x 12V.
Thanks again for all your help.
Stewart

Dave78Chief · 12-20-2011, 04:08 PM

Should not be any problem. Each system is still 12VDC. Many RV's are like that.

Dave

TDiGuy · 12-20-2011, 04:37 PM

The problem is the draw down... I found that my Engine bat was powering my cd changer and the radio all the time... My battery would run down in about 4 days... I found a rocker switch near the cd changer marked radio. With it off I have gone dry camping for 3 weeks and been fine.
Only drawback is that the clock on the radio resets to 1:00 when you turn it back on. I start my engine once a week now and flip the switch and use the clock as my timer : >)