We're storing our coach for 3 months in a climate where the temp. freezes at night. It was suggested I purchase a "power pulse" 12 volt system to keep the batteries charged properly. I called the local RV dealer to ask if they carried this and I was told I did't need one if I had my coach plugged in all the time, which I'm doing. It was also suggested I put a low wattage light bulb in the battery compartment, which I have also done.
Any thoughts as to the need to get a "power pulse" or something similiar.
Using pulse chargers or additives is a very controversial subject. Most battery experts agree that there is no conclusive proof that more expensive pulse charges work any better than constant voltage chargers to remove sulfation. They also agree that there is no evidence that additives or even aspirins provide any long-term benefits.
marine-electronics.net/techarticle/battery_faq/b_faq.htm#10]
Power Pulse Battery Maintainer (http://www.foreforums.com/index.php?topic=9441.msg42265#msg42265)
My house battery manufacturer specifically notes that in charging the batteries, the "conditioning" mode is to be turned OFF as it will damage the batteries. I have also noticed that incorrectly charging some types of RV batteries may damage them in as little as a day according to manufactures notes.
Should not need a light bulb as they can't freeze if anywhere near 1.275 with conventional batteries regardless if charger is plugged in or not. Freezing is another "wives tale" unless bats almost flat and super cold Yukon weather.
Jimmy, looks like a Lockheed Electra in your profile photo.
Power Pulse is a questionable device that brings strong opinions on both sides.
I don't think fully charged batteries will freeze at temps above zero, so maybe a bulb is not needed, and maybe be a bit dangerous.
Thanks to everyone for there thoughts. Pierce and Gaylie, I'm sure what the plane is, it was fighting a forest fire close to our house last summer, you can see the orange from the flames.
Jimmy,
Great old plane. The Dodgers first airliner when they moved west.
Should have included the lead-acid freezing point chart in my last post. Even with a full charge, they will lose about 20% of their cranking amps until they warm up. Here it is (copied and pasted):
Electrolyte Freeze Points
at Various States-of-Charge
for a Wet Lead-Acid Battery Table
Approximate
State-of-Charge
(SoC)
Approximate
Depth-of-Discharge
(DoD)
Approximate Electrolyte Freeze Point
100% or 0% Discharged
-77°F
(-67°C)
75% Charged or 25% Discharged
-35°F
(-37°C)
50% Charged or 50% Discharged
-10°F
(-23°C)
25% Charged or 75% Discharged
5°F
(-15°C)
Flat Battery or 100%
(DISCHARGED)
20°F
(-6.7°C)
Thanks for the information Pierce.
Charged batteries will not freeze at - 40 degress F. We deal with those temperatures for extended peroids of time with no problems .... But anything below 32 deg F reduces their working ability to about 50%....of their warm weather ability.
Safe Travells
Dave
Your newer model coach may be different, but on the older Foretravel models (like ours) keeping the "coach plugged in at all times" does
not keep the
engine start batteries charged. Assuming the same setup on your coach, you will need
some type device that will maintain a proper charge level on your start batteries.
You can search this Forum for recommendations on any of several add-on charger/maintainers that will do the job nicely.
I am not a battery and or charger expert, but it appears that my new Cole hersee smart isolator defaults to charge the start battery first to proper voltage, then switches to bi-directional both battery banks based on average voltage I assume. I have a smart 4 stage convertor/charger to finish the charge.
The battery isolator is
normally only in the game when the big engine is running. The OP is asking about
storing their coach 3 months plugged in to shore power. In
standard configuration, your smart 4 stage convertor/charger would only charge the house battery bank while plugged into shore power, however your
smart isolator (combiner?) may indeed allow it to charge
both battery banks.
A smart battery combiner that allows the inverter/charger to maintain
both battery banks would be one possible solution to the OP's situation.
A "thief" type maintainer device that steals power from the house battery bank to keep the start batteries topped off is another possible solution. These are inexpensive and simple to install - only 3 wires. Trik-L-Start is the one we use. It has been quietly doing the job for 4 years...I never even think about the start batteries, because they are
always fully charged, even when our coach is parked (plugged in) for a long period.
Ultra TRIK-L-START Starting Battery Charger/Maintainer (http://www.lslproducts.net/TLSPage.html) (Max 5 Amp output)
AMP-L-START Starting Battery Charger/Maintainer - Overview Page (http://www.lslproducts.net/ALS_Overview_Page.html) (Trik-L-Start's 15 Amp big brother)
Xantrex also markets a highly regarded "thief" device, with 15 Amp output capability for larger battery banks.
http://www.xantrex.com/power-products/power-accessories/auxiliary-battery-charger.aspx