Timers and Battery Health

[rfield54]

I'm going to hook up timers to my Airstreams at the connection between the 30 amp extension cord (from power) and the 30 amp A/S cable. I'm guessing that 1/2 hour a day (timer minimum) will be enough, and not too much charge. Any opinions or first hand experiences? One of my concerns is that I'm gone for up to 5 months in the winter and 4 months in the summer, and am not able to check the water level. I think I'd rather slightly undercharge than the opposite. Thanks - Roy

[Tin Hut]

I use a timer and set it for 2 hours per day. Seemed to work well for me.

[garry]

Just a thought.
Disconect the batt from the univolt and charge with a 120VAC trickle charger ??

Garry

[Mark Wiltrakis]

Tin Hut -

Do you have some kinda "heavy duty" timer to handle the load, or will a basic Home Depot special do the job?

Thanks!

Mark

[Sav'h Steve]

Roy,

If your purpose is to prevent boiling off the batteries, then you want the timer just on that circuit, not on the whole system IMHO.

I have done this AFTER boiling off two new batteries (expensive lesson).

I bought a HD timer and an appliance cord. I cut the HD cord in half and installed a new male and female end. You need two short cords: one from the 110v outlet that the univolt was plugged into to the timer, and one to the univolt.

That allowed me to place the timer under the sofa arm, an easy place to get to. Then I can reset to always on when I want, or just a short time for topping off the batts. Don't forget to check the water levels though!!

This works great for me.

Steve waiting for the 4th hurricane.....
rain bands are coming now as I type

[rfield54]

Originally Posted by Mark Wiltrakis

Do you have some kinda "heavy duty" timer to handle the load, or will a basic Home Depot special do the job? Mark

I don't figure the load to be heavy at all...it's just a basic grounded 24 hour mechanical timer. To accomodate the charger, I'll adapt both ends of the 30 amp cables to 15 amp, which shouldn't be a problem because the trailers won't be drawing much (remember, I'll be gone for months at a time). Thanks for the input. - Rfield54

[nwclassic]

We have a timer (one for outdoor lights) set for four hours/day. We arrived at that setting after trying one, then two hours. Our system is a little different... four golfcart batteries. Our meter (Link 10) indicated that over a one-two week period, we were ending up with less than fully charged batteries due to phantom electrical loads (such as LP gas detector, radio clock, etc). In other words, a one amp/hour draw for 23 hours is not offset by one hour of charging at 6 amps/hour. Batteries removed and put on a 'smart' charger seems like it would better suit your needs. Good luck.

[Sav'h Steve]

Originally Posted by rfield54

I don't figure the load to be heavy at all...it's just a basic grounded 24 hour mechanical timer. To accomodate the charger, I'll adapt both ends of the 30 amp cables to 15 amp, which shouldn't be a problem because the trailers won't be drawing much (remember, I'll be gone for months at a time). Thanks for the input. - Rfield54

Roy,
Since the Univolt CAN put out 55 amps when your batts are low, that is 660 watts of power. Usually the draw is much less. I know that a 500 watt work light will warm up the cord and plug on light duty cords. Prefer to not run the risk.

Steve

[Tin Hut]

I just use an HD timer and extension cord. I figure 2 hours per day wasn't enough to boil, just enough to keep topped off.

Originally Posted by Mark Wiltrakis

Tin Hut -

Do you have some kinda "heavy duty" timer to handle the load, or will a basic Home Depot special do the job?

Thanks!

Mark

[rfield54]

Originally Posted by Tin Hut

I use a timer and set it for 2 hours per day. Seemed to work well for me.

Thanks, Tin Hut. I think that before my trip to the trailers in Utah in two weeks I'll try the minimum on my Bambi, which is parked here at the house, and then test the battery. I can then adjust accordingly. I'll post the results. I emailed Jim Parrot at Airstream with this scenario, and he replied: "I have never heard of this being done however I see no reason that it would
not work"...Interesting.

[wahoonc]

Considering wiring a timer in ahead of the 30 amp branch circuit at the house, the other thought is along the lines that Sav'h Steve, but mounting the timer unit in the closet near the univolt. Anybody have a boiling batteries issue with the intellipower unit?

Aaron

[rfield54]

Originally Posted by Sav'h Steve

That allowed me to place the timer under the sofa arm, an easy place to get to. Then I can reset to always on when I want, or just a short time for topping off the batts. Don't forget to check the water levels though!!

It now seems to me that the best location for a timer would be hardwired to the 120 volt electrical panel. No sense having it in the couch as you'd only need access to it when you'll be away for weeks or months at a time.

[rfield54]

Well, after a week of having the timer on the Bambi, I gave it a test. The timer is placed on the 30amp power cord with a 25' 16/3 extension cord running to (20 amp) power, and is set to turn on for 30 minutes a day. Before today's charge, the battery tested at 12.36 volts. After the charge, it tested at 12.74 volts. I'll test periodically in the future to reconfirm these numbers, but at this point I'm going to conclude that 30 minutes a day is about right.