quick (ha ha) battery question

Bobbie54 · 12-26-2023, 12:41 PM

Assuming my two 6V original batteries were fully charged and in good condition, how much do you think they would discharge under almost no load with no solar and no charging, over a month (cold weather, but no colder than 31)? (Almost because propane detector still draws something.)

HABBERDABBER · 12-26-2023, 01:06 PM

No simple rule of thumb to use for calculation. It depends.....on ambient temperature, age of batteries, previous use and depth of discharges and other factors.
Bottom line is cooler temperatures SLOW the rate of discharge. Chemical reactions happen slower with lower temperatures.

You likely won't self-discharge to anything close to 50% if your batteries are in good condition. Disconnect them with the battery switch to reduce discharge from the smoke and propane detectors.

https://www.comsol.com/model/dischar...d-battery-9720

Bobbie54 · 12-26-2023, 01:11 PM

So if they went down to about 40% odds are they are not in great condition? My plan is to charge them up and then test with a load- if they run down too fast I'll go get them replaced. (I did not turn off the battery switch when I put it away last month.)

HABBERDABBER · 12-26-2023, 03:44 PM

A FLA battery 3-4 years old is a bit "long in the tooth". I'd expect 5+ years on a well maintained battery. If they've seen deep discharge multiple times, that reduces their lifespan.
Nothing is forever, and nothing lasts. That goes for batteries of all types.
A test can show reasonable results, but it's only a one shot test. Open Circuit Voltage is a shot in the dark guess on the robustness of a FLA, IMO. It's how long they can maintain a load that matters.

Bobbie54 · 12-26-2023, 06:29 PM

Quote:

Originally Posted by HABBERDABBER

A FLA battery 3-4 years old is a bit "long in the tooth". I'd expect 5+ years on a well maintained battery. If they've seen deep discharge multiple times, that reduces their lifespan.
Nothing is forever, and nothing lasts. That goes for batteries of all types.
A test can show reasonable results, but it's only a one shot test. Open Circuit Voltage is a shot in the dark guess on the robustness of a FLA, IMO. It's how long they can maintain a load that matters.

It's never been run completely down as far as I know. But I haven't always checked the charge before charging it back up. So now I have the heater running and a light on and will see how far it drops after a few hours. (Set at 62 but if I were sleeping in it I'd turn it off overnight so I figure that's a fair test for whether or not I want to use it if I don't replace the batteries first.)

Bobbie54 · 12-27-2023, 12:28 PM

Quote:

Originally Posted by Bobbie54

It's never been run completely down as far as I know. But I haven't always checked the charge before charging it back up. So now I have the heater running and a light on and will see how far it drops after a few hours. (Set at 62 but if I were sleeping in it I'd turn it off overnight so I figure that's a fair test for whether or not I want to use it if I don't replace the batteries first.)

It did okay under a load for awhile but overnight (I turned off heat and just put fan on low plus 4 of the overhead lights) and it was down to 40% (or lower) in the morning. (I slept past daylight by about 30 minutes so it had a little time to start recharging before I checked.) So I could probably get by with it as is for a bit (next trip I have hookups) but replacing the batteries is on the list.

HABBERDABBER · 12-27-2023, 03:21 PM

Kind of a similar scenario that I had. 7 year old batteries looked OK from voltage readings, but they were weak. I bought 2 Trojan 6V FLA this past Spring. Cost was about $500 USD, but they have a good rep. Be wary of the Costco Interstate 6V batteries as they are 1/2 the cost and a questionable lifespan. Interstate makes a heavy duty 6V that is the same cost as the Trojans.

I'm not sure...do you have one 12V, or 2 six volt batteries in a E17?

Bobbie54 · 12-27-2023, 03:31 PM

Quote:

Originally Posted by HABBERDABBER

Kind of a similar scenario that I had. 7 year old batteries looked OK from voltage readings, but they were weak. I bought 2 Trojan 6V FLA this past Spring. Cost was about $500 USD, but they have a good rep. Be wary of the Costco Interstate 6V batteries as they are 1/2 the cost and a questionable lifespan. Interstate makes a heavy duty 6V that is the same cost as the Trojans.

I'm not sure...do you have one 12V, or 2 six volt batteries in a E17?

I have two six volt. I want sealed batteries this time though. And will probably try Les Schwab so they can do it- they have a trailer bay and are nearby. Not that checking them has been a problem so I might change my mind. (It was a problem in the 15 only because I didn't realize they were not sealed until it was too late.)

HABBERDABBER · 12-27-2023, 05:11 PM

So if you get AGM's, check & make sure your converter/charger is set for them. Long period, high voltage charging can damage them. A sealed battery can not disperse the gas production readily and that can cause the damage. Usually, a lower bulk charge voltage setting is what is changed.

Bobbie54 · 12-27-2023, 05:17 PM

Quote:

Originally Posted by HABBERDABBER

So if you get AGM's, check & make sure your converter/charger is set for them. Long period, high voltage charging can damage them. A sealed battery can not disperse the gas production readily and that can cause the damage. Usually, a lower bulk charge voltage setting is what is changed.

And that brings up another question- in the winter, in the garage, I was just charging intermittently by plugging in the trailer. What's a better way to do it? In the summer it isn't an issue as I bring it out more and it's charged by solar and I only plug in if I'm cooling down the fridge.

HABBERDABBER · 12-27-2023, 07:34 PM

Charge it maybe once every 2 weeks for 8 hours. That should keep the batteries topped off. Some leave it plugged in 24/7. But do look into AGM/Gel and the charger settings.

Bobbie54 · 12-27-2023, 07:44 PM

The manual says the charging is automatic when you plug in. So what is there to set?

HABBERDABBER · 12-27-2023, 09:18 PM

Hopefully, others with AGM batteries and Escape trailers familiar with the converter/charger can answer. I don't have my trailer (it's in storage) and I've not diddled with your issue.
You're on your own.

Bobbie54 · 12-28-2023, 12:58 PM

I looked at some more stuff on AGMs and may just stick with FLA. I've gotten into the habit of checking them anyway.

alanmalk · 12-28-2023, 01:12 PM

Quote:

Originally Posted by Bobbie54

I looked at some more stuff on AGMs and may just stick with FLA. I've gotten into the habit of checking them anyway.

A personal experience if I may:
I used AGM batteries for 7 years in my E21 with good luck. My routine for winter was to charge them to 100%, disconnect the + wire, and ignore them until spring. They survived the -15F temperatures in the Denver area just fine thanks to the very low self discharge. (There was no way I was going to haul 75 pound batteries out of the trailer and back.)

Bobbie54 · 12-28-2023, 01:22 PM

I park in the garage and even outside never sees much below 20 and mostly not below 30. But good to know. Couldn't you just turn off the 12V switch to isolate the batteries in place? Do you recall what brand you used?

jennykatz · 12-28-2023, 01:44 PM

We have a 2016 E-21 and so far they have been good . We do have the 160 watt Solar collector and we leave the switch on . So far so good the trailer is in Chicago
area .In May we usually get up there and i check the fluid level so far always above the plates and charges up as soon as we fill the fluid in batteries and plug in she's good to go .

Bobbie54 · 12-28-2023, 01:49 PM

Quote:

Originally Posted by jennykatz

We have a 2016 E-21 and so far they have been good . We do have the 160 watt Solar collector and we leave the switch on . So far so good the trailer is in Chicago
area .In May we usually get up there and i check the fluid level so far always above the plates and charges up as soon as we fill the fluid in batteries and plug in she's good to go .

What kind of batteries do you have?

Rossue · 12-28-2023, 02:21 PM

Quote:

Originally Posted by HABBERDABBER

Be wary of the Costco Interstate 6V batteries as they are 1/2 the cost and a questionable lifespan. Interstate makes a heavy duty 6V that is the same cost as the Trojans.

In 2015 I bought two Costco 6V batteries to replace the single 12V Group 29 I mistakenly spec'd on my build sheet in 2014. They lasted 7 years and would have gone further, however we were in Oregon and near a Costco so I replaced them. The two year old Costco 6V are in great shape.

Constrast that to a 3 year old Honda OEM EFB (enhanced flooded battery) that died. Those batteries are $287 at a Honda dealer and are spec'd for 2020+ CRV's due to the auto stop start. After a wasting a lot of time looking at these overpriced batteries I bought an H5 Group 47 Interstate from Costco for $125. I've been using Costco Interstates in my cars for over 20 years with great results and at a great price.

Bayner · 12-28-2023, 06:10 PM

Quote:

Originally Posted by Bobbie54

... Couldn't you just turn off the 12V switch to isolate the batteries in place?

Unfortunately the battery switch does not disconnect all the electrical loads from the battery. The propane detector will still be a draw, perhaps some other small ones as well but over time they will draw the battery down. Also the solar controller is wired around the battery disconnect in a lot of trailers as well. That can either be a net positive or a draw depending on the exposure of the panel.

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