Batteries - R-pod Owners Forum

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Dowdpod

Newbie

Joined: 13 May 2016
Location: North west mich
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Posts: 4

Topic: Batteries
Posted: 17 Apr 2019 at 1:45pm

We have a 2017 171 R-Pod,
We are going to be doing more Boon docking this summer, and are considering switching to a 12v Lithium Ion battery.
Anyone else switching?
How have they performed? Worth the Money?
Help me decide 🤷🏼‍♀️
Dowdpod

offgrid

Senior Member

Joined: 23 Jul 2018
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Posts: 5290

Posted: 17 Apr 2019 at 3:34pm

I haven't switched yet but if you plan to keep your Pod for many years then I think a 100AH minimum Li battery would work well for you and be economical in the long run, as well significanlty lighter. You will want to change the battery charger as well, and get a higher quality one set up fro Li batteries, so bear that cost in mind. Also, both for security (its a high dollar item) and to protect it from freezing temperatures (Li batteries don;t like to be charged when its below about 25-30 def F) you might want to relocate it to a storage location inside your Pod. Li batteries don't outgas so it's Ok to put in in your heated space.

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

Dowdpod

Newbie

Joined: 13 May 2016
Location: North west mich
Online Status: Offline
Posts: 4

Posted: 18 Apr 2019 at 8:03am

Thank you for your suggestions.

GlueGuy

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Joined: 15 May 2017
Location: N. California
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Posts: 2627

Posted: 18 Apr 2019 at 8:44am

One thing that might not be obvious with different battery types is the amount of discharge they will sustain without damage. For example, most lead-acid "deep discharge" batteries will sustain about a 50% discharge before they start to sustain serious damage. AGM batteries can sustain perhaps 60% discharge.

Lithium Ion on the other hand can usually handle up to 90% discharge.

The point being that a basic lead acid battery with 100AH rating can only actually use 50AH before it will need charging. An AGM battery of the same capacity can actually use 60AH. Lion 90AH. So you should factor in usable capacity as opposed just the AH rating on the label.

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

offgrid

Senior Member

Joined: 23 Jul 2018
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Posts: 5290

Posted: 18 Apr 2019 at 10:53am

Yes, Li batteries have roughly 70% more useable capacity than the equivalently rated Pb battery. And they're good for at least 2-3x the number of cycles, so that means they're the equivalent value of around 3-5x what a equal capacity rated Pb battery is worth over their useful life. Since they cost about 2.5-4 times what an equivalent Pb battery costs they come out a bit ahead in terms of life cycle cost so can be a good deal as long as you're planning to keep your trailer long enough to get the cycles out of them. If you plan to sell your trailer in a year or two, probably not so much.

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

podwerkz

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Joined: 11 Mar 2019
Location: Texas
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Posts: 966

Posted: 18 Apr 2019 at 1:17pm

If you run the numbers to gain about 40-50 more usable amp hours (dropping in a $1000 lifepo4 battery and a $300 converter/charger) it makes very little sense (unless you factor-in weight for 2 LFPs vs 2 lead acids, and of course, battery lifetime)

Plus, your charge line from the tow vehicle to the LFP battery is now essentially useless, and the factory battery monitor panel is also useless, it will show full even when the LFP battery is not even close to full. LFP batteries have a different charge and discharge profile.

So, instead of replacing the on-board battery and charge system, I ADDED a LiFePo4 battery, with it's own chargers, solar and wall powered, to the trailer, under the dinette booth, near the factory converter/charger.

But I also kept the standard factory converter/charger and lead acid batteries.

The two systems are independent, charged separately, and power different loads. Now, I have GAINED 100ah (~90ah usable) in addition to the 180 ah (~90 ah usable) that the house batteries provide.

So, 280 ah total for about the same amount of money spent, plus my house batteries can still be charged with the tow vehicle aux charge line during travel.

r･pod 171 gone but not forgotten!

offgrid

Senior Member

Joined: 23 Jul 2018
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Posts: 5290

Posted: 19 Apr 2019 at 8:14am

Originally posted by podwerkz

But I also kept the standard factory converter/charger and lead acid batteries.

The two systems are independent, charged separately, and power different loads. Now, I have GAINED 100ah (~90ah usable) in addition to the 180 ah (~90 ah usable) that the house batteries provide.

So, 280 ah total for about the same amount of money spent, plus my house batteries can still be charged with the tow vehicle aux charge line during travel.

By far the lowest initial cost way to add additional amphours if that is the goal is simply to add a second Pb battery on the tongue. Most folks don't have any need for the complexity of two separate battery systems, and for most folks the added tongue weight isn't a show stopper.

Regardless of what battery type you have, replacing the not so stable and reliable charger that comes with the rPod is something most owners will face eventually anyway, so I don't really consider that a cost of going to Lithium.

I do agree that the benefit from going to Lithium comes via the much extended lifetime, which is why the caveat is that the owner plan to keep the trailer for a long time.

if you want to charge from the tow vhicle charge system, there are battery to battery chargers available for charging Li batteries from vehicle charging systems. They are commonly used on class b's that have been converted to Li house batteries. I haven't looked into this myself, but there is a review and in depth discussion of these on the Battle Borne website.

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