Battery Maintenance While in Storage - R-pod Owners Forum

Author

Share Topic

Topic Search

Topic Options

Post Reply

Create New Topic

crankster78 View Drop Down

Senior Member

Joined: 08 May 2018
Location: Minn
Online Status: Offline
Posts: 163

Topic: Battery Maintenance While in Storage
Posted: 19 Aug 2018 at 8:46am

Greetings

Being in a cold climate, I pull the battery and put it on a "smart" charger for the winter. It keeps it topped off with out overcharging, I bring it inside. The chargers are not very expensive.

Crankster78

Crankster 78 R-179 2015

crankster78 View Drop Down

Senior Member

Joined: 08 May 2018
Location: Minn
Online Status: Offline
Posts: 163

Posted: 19 Aug 2018 at 8:49am

Greetings

Being in a cold climate, I bring the battery inside and put it on a "smart" charger. it keeps it topped off without overcharging.

Crankster78

Crankster 78 R-179 2015

offgrid

Senior Member

Joined: 23 Jul 2018
Online Status: Offline
Posts: 5290

Posted: 19 Aug 2018 at 11:12am

Just a point of clarification, it is not necessary to keep deep cycle lead acid batteries warm while storing them, as long as they are maintained at a full state of charge. In fact, low temps are good for the battery because internal corrosion is reduced at low temps. Barring abuse like frequent severe deep cycling, internal corrosion is typically the reason a battery ultimately needs to be replaced. That's why batteries need to be replaced so often in hot climates.

The main caveat here is that, as everyone is recommending, the batteries need to be maintained at full charge. If stored discharged in cold conditions they can freeze, because the sulfuric acid concentration in the battery is reduced when the battery is discharged, leaving essentially water. A fully charged battery would need to be at around -50F or lower before the sulphuric acid will freeze.

So, maintain full charge on your batteries when not in use. This can be accomplished just by leaving your rPod plugged in with the charger on. Check electrolyte levels frequently. And don't worry if the batteries are cold.

One other fine point which is important if you want to get long life out of flooded (not AGM) deep cycle batteries.

The WFCO charger in the rPod has 3 stages, bulk, which charges the battery to 14.4V, absorption, which charges at 13.6V, and float, which is set at 13.2V. Normally this charger will start out in absorption mode and will only revert to bulk mode when there is a significant load on the battery causing its voltage to drop below 12.5V. According to WFCO after 44 hours in absorption mode at 13.6V the charger will enter float mode and drop the voltage to 13.2V.

Here is the WFCO operations manual describing this:

http://wfcoelectronics.com/wp-content/uploads/2016/03/WFCO-Theory-of-Operation-v2.pdf

Its not a great idea to leave a flooded lead acid battery floated at 13.2V for long periods because the sulphuric acid electrolyte will start to stratify from lack of mixing. Bulk charge at 14.4 will cause gassing in the battery which mixes the electrolyte. This is called an equalizing charge. The gassing is what consumes water in a battery but this won't be excessive because the charger will revert to absorption mode at 13.6 within 4 hours.

So, what I suggest for flooded (not AGM) deep cycle batteries, is once every month or so, to trick the charger into going into a bulk mode cycle by discharging the battery below 12.5V. Turn off the charger and turn on some DC loads for awhile to discharge your battery a bit, then turn the charger back on. That should do it.

AGM batteries have their electrolyte (a)bsorbed in a (g)lass (m)at so aren't subject to electrolyte stratification. They are also designed to recombine the gasses generated during charging which is why you don't add water to them. OTOH, they are less tolerant of overcharging that flooded batteries are, not to mention more expensive, so if you are comfortable with adding water to your flooded batteries and equalizing them once in awhile then I think they are still a better way to go, at least until lithium ion gets cheap enough that we can all get the lead out of our RV's.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

Redshift

Members Profile

Send Private Message

Find Members Posts

Visit Members Homepage

Add to Buddy List

Newbie

Joined: 26 Dec 2017
Location: Missouri City,
Online Status: Offline
Posts: 11

Posted: 19 Aug 2018 at 11:31am

Thanks for that description. Very helpful. It is good to know that the pod has a multi-stage charger. Unfortunately, because of some surgery I have coming up, I will have to leave the pod unattended for most of the winter. It is garaged in New Mexico and I will be 900 miles away in Texas. I thought about putting the power to the pod on a timer so it will only charge 2 or 3 hours a day but after reading your discussion, I'm not sure that will have any benefit. I may be able to sweet talk a neighbor into coming by every few weeks and checking the fluid level but we are kind of remote. One of the big dangers up here in the mountains is lightning so keeping the pod on power has some risk. Nevertheless, you have given me things to think about.

-Robert

Hood River RP 180 with winter-ready insulation/heaters upgrade and GoPower solar kit

Ben Herman View Drop Down

Senior Member

Joined: 26 Apr 2018
Location: Gr Junction, CO
Online Status: Offline
Posts: 355

Posted: 19 Aug 2018 at 1:02pm

Originally posted by crankster78

Greetings

Being in a cold climate, I bring the battery inside and put it on a "smart" charger. it keeps it topped off without overcharging.

Crankster78

My variation of this is to bring it into my garage/shop. Cold most of the time and I don't have to mess around with the battery cover to check the water levels periodically.

offgrid

Senior Member

Joined: 23 Jul 2018
Online Status: Offline
Posts: 5290

Posted: 19 Aug 2018 at 2:09pm

What you are describing (no maintenance access for several months) is probably a good scenario to select an AGM over a flooded battery. But as it sounds like you already have a flooded battery probably the best you can do is to top it off as late in the season as possible, let the charger take it through a bulk/equalize cycle and then let it sit in float mode over the winter. I doubt there will be much water consumption that way. Then top off and equalize in the spring as soon as possible.

Or, if you feel spendy you can disconnect the battery and place it on a high end battery charger that adresses equalization, electrolyte stratification, and plate sulfation automatically, like this one:

https://www.northerntool.com/shop/tools/product_200661886_200661886?utm_source=CSE&utm_medium=Shopzilla&utm_campaign=Automotive%20%3E%20Batteries&szredirectid=15347050553764078395810070302008005,%2520Chargers%2520%252B%2520Jump%2520Starters%26utm_content%3D52884&szredirectid=15347050553764078395810070302008005

If you're worried about lightning surges you can shut off all the circuit breakers except the charger, and/or run your rPod power through a surge protector power strip.

Good luck with your surgery.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

jato

Senior Member

Joined: 23 Feb 2012
Location: Kewadin, MI
Online Status: Offline
Posts: 3219

Posted: 19 Aug 2018 at 4:19pm

Since purchasing our deep cycle group size 24 batteries in March 2011 we have followed this format: 1) remove both batteries and set on cement floor in our unheated garage around Thanksgiving. 2) check electrolyte levels, add distilled water if needed. end of Nov. or 1st. week of December put on 2 amp trickle charge until fully charged-this normally takes about 24-30 hours/battery. 3) disconnect trickle charger 4) do nothing until mid April and repeat step #2. Batteries are going on 8 years and still work well for us as we normally dry camp.

God's pod
'11 model 177
'17 Ford F-150 4WD 3.5 Ecoboost
Jim and Diane by beautiful Torch Lake
"...and you will know the Truth and the Truth will set you free."

GlueGuy

Senior Member

Joined: 15 May 2017
Location: N. California
Online Status: Offline
Posts: 2628

Posted: 19 Aug 2018 at 5:47pm

I have a different concept of the 3 stages of a smart charger.

The bulk charge is not a set voltage, but is more limited by the maximum current capability of the charger. In fact, most of the bulk charge stage is at a voltage less than the absorb stage. Once a battery gets to the absorb voltage (during the bulk phase), the amount of current is reduced to maintain the absorb voltage.

Roughly 80% of the charging is during the bulk phase, and the remaining 20% is during the absorb stage. Once the absorb stage is done (based on the amount of current the battery is absorbing at the absorb voltage), the charger will drop into float mode.

The exact voltages for each stage (mainly the absorb and float stages) are almost always at different set points for each manufacturer. If your charger cannot be programmed to the different set points, you will get less than optimized results, but that is just the way it is sometimes. You usually have to spend more money to get a programmable charger.

The equalize stage is "special", and is NOT the same as bulk stage. It's more of an overcharge condition, and should only be done periodically, if at all. AGM and gel batteries generally don't need an equalize stage with a few notable exceptions.

For a more complete explanation of the various stages and how they are controlled, read this tutorial. This is how I understand batteries and battery chargers.

bp
2017 R-Pod 179 Hood River
2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost

mcarter

podders Helping podders - pHp

Joined: 07 Apr 2016
Location: Greenbrier, TN
Online Status: Offline
Posts: 3419

Posted: 19 Aug 2018 at 6:22pm

+1 - good info.

Mike Carter
2015 178
" I had the right to remain silent, I just didn't have the ability."

offgrid

Senior Member

Joined: 23 Jul 2018
Online Status: Offline
Posts: 5290

Posted: 20 Aug 2018 at 5:51am

Ah, if I had a nickel for every instance of confusion caused by corporate marketing language I'd be rich now. Here is the salient paragraph from the link:

"Equalization is essentially a controlled over charge. Some charger manufacturers call the peak voltage the charger attains at the end of the BULK mode (absorption voltage) an equalization voltage, but technically it's not. Higher capacity wet (flooded) batteries sometimes benefit from this procedure, particularly the physically tall batteries. The electrolyte in a wet battery can stratify over time, if not cycled occasionally. In equalization, the voltage is brought up above typical peak charging voltage (to 15 to 16 volts in a 12 volt system) well into the gassing stage, and held for a fixed (but limited) period. This stirs up the chemistry in the entire battery, "equalizing" the strength of the electrolyte, and knocking off any loose sulphation that may be on the battery plates."

In the meantime, WFCO claims in their literature that "three charging states is all your customers need". Both statements are true. How can that be?

Because batteries don't read marketing literature Big smile

. For flooded lead acid batteries of the type we are using in our rPods, occasional cycling and charging at 14.4V provides sufficient gassing to mix the electrolyte and remove light sulfate from the plates, as long as the batteries have not been left at a low state of charge for a long period. That is equalization, even though companies that sell 4 or more stage chargers don't call it that.

If OTOH you leave a battery at a low state of charge for a long period causing significant stratification and sulfation to occur, 14.4V isn't high enough to knock all the sulfate off the plates and mix the electrolyte aggressively. Especially for tall batteries as the article says. In this case, a higher (15-16V) aggressive equalization charge voltage is indeed required.

In the OP's case, the battery is not tall and the assumption is that it is being maintained at full float charge. So only moderate equalization should ever be required. This can normally be achieved during use at the end of the bulk charge phase, but if the battery is just sitting, its a good idea to create the equivalent condition occasionally, which is why I suggested creating a condition where the WFCO charger reverts to bulk charge mode.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold