Battery Trials and Tribulations

rfuss928 · November 5

The Victron LiFePO4 chargers mentioned cost more than a WFCO 8735 converter and are lower charger output. The converter manages the entire electrical system of the trailer as well as battery charging. IMO - A much better value and a completely integrated system in the trailer. I would change the converter.

pthomas745 · November 5

Hundreds of dollars of work for 15 amps does not seem cost effective for a 100 amp hour battery. My 60 dollar solar controller handles my lithium batteries just fine.

SLJ · November 5

rfuss928 said:

The Victron LiFePO4 chargers mentioned cost more than a WFCO 8735 converter and are lower charger output. The converter manages the entire electrical system of the trailer as well as battery charging. IMO - A much better value and a completely integrated system in the trailer. I would change the converter.

No thanks.
WFCO 8735 $172.55
Victron 20A Smart Charger $170.85, 30A $182.75

WFCOs have had problems auto detecting Lithium batteries to the point where many have needed to be pulled out and sent back to the factory or modified by the user. Don't think for one minute they will charge a lithium battery at 30 amps.
The Victron smart chargers will also network with the Victron solar controllers and connect to your smart phone and can be shut down automatically by a Victron battery monitor if the temp drops below a users low temp set point. As a backup if your WFCO craps out and won't supply DC, the Victron will also supply the camper with DC and still charge the batteries just by plugging it in to shore power.
Why I chose just adding a smart charger over replacing the WFCO with a problematic one.

Marceline · November 5

Mellow_Yellow said:

@Sharon_is_SAM. I am pretty frugal especially during winter “dry” camping. I don’t have a way of measuring daily usage.

I think that in view of all of your "Trials and Tribulations" you really should install a Victron SmartShunt. It is super easy to install and it will give you an accurate picture of your battery's state of charge (as long as you set it up properly). What you're doing right now is kind of like going on a long road trip without a functioning gas gauge.

rfuss928 · November 5

SLJ said:
Don't think for one minute they will charge a lithium battery at 30 amps.

My WFCO regularly charges at 35 amps as soon as connected to shore power. If the batteries are fully charged, it will quickly taper to float voltage otherwise maintains that 35 amp level until batteries approach full charge.
It takes one to two hours to remove and reinstall the 8735. The most difficult aspect is manipulating the AC breakers' stiff wiring. Pretty straight forward one for one exchange of about a dozen wires.

Cherokee · November 6

Mellow_Yellow said:

@Sharon_is_SAM. I am pretty frugal especially during winter “dry” camping. I don’t have a way of measuring daily usage.

If you do go with to 6v batteries, NuCamp's "guess/maybe" lights will be as accurate as they were before. An inexpensive VOM could measure the drop in voltage which determines the state of charge - just open the lid and touch the leads to the battery poles - That's frugal. One of the main advantages of Lithium batteries is that they produce the same voltage as they are depleted - so a VOM or NuCamp's lights will be of no use. However, one can deplete their charge almost completely; while AGM's drop below usable voltage as they are depleted and shouldn't be depleted below around 50%. The price of AGM's are rising while the price of Lithium is dropping.

Cherokee · November 6

Sharon_is_SAM said:

@Mellow_Yellow - we tow with a 2015 Sienna as well. We will be replacing our AGM battery with lithium come spring. We need more reliable battery life while boondocking as well.

To me, it sounds like you can use an easy fix. Instead of changing converters, just install a 200 A battery in the tub and buy a lithium compatible battery charger to use at home to recharge after camping. Follow the battery manufacturer recommendation regarding charging current. Charging time depends on degree of battery depletion and the current of the charger. The lower the current, the slower the charge. You first need to measure the room in your tub to see what fits.

This is a GREAT solution with the switch that someone else suggested! I'd be tempted if I didn't have a fine solar panel and abundant California sunshine

Mellow_Yellow · December 7

Update: I now have 2 x 6V AGM batteries connected in series in a new battery box.
https://www.amazon.ca/gp/aw/d/B07V4482W1?psc=1&ref=ppx_pop_mob_b_asin_title

This box fits snugly between the battery box and the trailer’s crank pillar. The only mod needed was a small notch to provide clearance for the brake line. NOTE: this is a 2014 BAL trailer chassis with surge brakes.

I have gone from 89 amp hours to 450 amp hours. Woo hoo! I’m doing some driveway testing running the Alde on propane now. With my low-passive drain setup, I should have about 4 days of power. I’m using this battery monitor, which is 6V and AGM compatible: https://www.amazon.ca/gp/aw/d/B0CXP8RRNR?psc=1&ref=ppx_pop_mob_b_asin_title

Marceline · December 8

Mellow_Yellow said:

Update: I now have 2 x 6V AGM batteries connected in series in a new battery box.
https://www.amazon.ca/gp/aw/d/B07V4482W1?psc=1&ref=ppx_pop_mob_b_asin_title
This box fits snugly between the battery box and the trailer’s crank pillar. The only mod needed was a small notch to provide clearance for the brake line. NOTE: this is a 2014 BAL trailer chassis with surge brakes.
I have gone from 89 amp hours to 450 amp hours. Woo hoo! I’m doing some driveway testing running the Alde on propane now. With my low-passive drain setup, I should have about 4 days of power. I’m using this battery monitor, which is 6V and AGM compatible: https://www.amazon.ca/gp/aw/d/B0CXP8RRNR?psc=1&ref=ppx_pop_mob_b_asin_title

Just be aware that this is a pretty hefty amount of additional weight on the tongue.

Sharon_is_SAM · December 8

450 AHrs? What is the capacity of a single battery?

elbolillo · December 8

Mellow_Yellow said:

I have gone from 89 amp hours to 450 amp hours. Woo hoo! I’m doing some driveway testing running the Alde on propane now. With my low-passive drain setup, I should have about 4 days of power. I’m using this battery monitor, which is 6V and AGM compatible: https://www.amazon.ca/gp/aw/d/B0CXP8RRNR?psc=1&ref=ppx_pop_mob_b_asin_title

Two 6v 225ah batteries wired in series would be 225ah NOT 450ah.

Sharon_is_SAM · December 8

So, 112 usable ah.

AnOldUR · December 8

Mellow_Yellow said:

I have gone from 89 amp hours to 450 amp hours. Woo hoo!

It's more like "very nice mod" than a "Woo hoo" moment, but an improvement for sure.

But I'd be more concerned with what @Marceline said. That's going on 200lbs placed further forward on the tongue than your old installment. Have you compared your new tongue weight to what it was originally?

Mellow_Yellow · December 13

thanks for all the input here. My questions and responses are:
1. These are 2 x 6V AGM batteries @ 225 ah each, connected in series. Why doesn’t that give me 450 ah, which I can use up to 70% capacity?
2. I removed the old 12v battery, so technically, I’m only adding 80 additional pounds with the second battery. Also, my 2014 T@B has tiny tanks - only 5 Gallons fresh water, so that should give me a bit of leeway?

3. The new battery box is 10 inches further forward on the tongue than the old battery box. Is that a crucial difference?
4. it is a “woo-hoo” moment if you camp off-grid year round in a dense boreal forest as I do. 89 ah only lasted me 1.5 days with every inch of passive/active drain reduced as much as possible. I was even using rechargeable lights instead of the built in lights and had the radio switched off.

Mellow_Yellow · December 13

I answered question #1: the voltage gets added (2x6V = 12 V) but not the amperage. Still, I’d rather have 225ah than 89 ah. Sadly, I was misinformed on this aspect.

elbolillo · December 13

Mellow_Yellow said:

thanks for all the input here. My questions and responses are:
1. These are 2 x 6V AGM batteries @ 225 ah each, connected in series. Why doesn’t that give me 450 ah, which I can use up to 70% capacity?
2. I removed the old 12v battery, so technically, I’m only adding 80 additional pounds with the second battery. Also, my 2014 T@B has tiny tanks - only 5 Gallons fresh water, so that should give me a bit of leeway?
3. The new battery box is 10 inches further forward on the tongue than the old battery box. Is that a crucial difference?
4. it is a “woo-hoo” moment if you camp off-grid year round in a dense boreal forest as I do. 89 ah only lasted me 1.5 days with every inch of passive/active drain reduced as much as possible. I was even using rechargeable lights instead of the built in lights and had the radio switched off.

When you wire batteries in series you increase the voltage. 6x2=12. But the capacity stays the same 225ah. So you only have about 157ah usable capacity max.

Grumpy_G · December 13

Regarding 2+3, putting an additional 80 lbs on the tongue and moving the batteries and their associated weight forward does increase the tongue weight quite a bit. You'll have to weigh it to know exactly what the new tongue weight is. With a full-size truck it won't make a difference but the Sienna is only rated for 385 lbs on the tongue (if my Google-fu is correct).
Unfortunately you gave up on LiFePo which amongst other benefits is much lighter, less than 50 lbs for a 12V 230Ah battery.

AnOldUR · December 13

Mellow_Yellow said:

1. These are 2 x 6V AGM batteries @ 225 ah each, connected in series. Why doesn’t that give me 450 ah, which I can use up to 70% capacity?

Sorry for deleting my previous posts, but here's the math for anyone questioning this ...

watts = volts x amps
225 amps x 6 volts = 1350 watts
1350 watts x 2 (batteries) = 2700 watts
2700 watts / 12 volts = 225 amps

Horigan · December 13

AnOldUR said:

Mellow_Yellow said:

1. These are 2 x 6V AGM batteries @ 225 ah each, connected in series. Why doesn’t that give me 450 ah, which I can use up to 70% capacity?

Sorry for deleting my previous posts, but here's the math for anyone questioning this ...

watts = volts x amps
225 amps x 6 volts = 1350 watts
1350 watts x 2 (batteries) = 2700 watts
2700 watts / 12 volts = 225 amps

Be careful not to confuse amps (current flow) with amp-hours (battery capacity, ah) which is what the @Mellow_Yellow was referring to. Some of our battery cables couldn't handle 225 amps...

AnOldUR · December 13

Horigan said:
Be careful not to confuse amps (current flow) with amp-hours (battery capacity, ah) which is what the @Mellow_Yellow was referring to. Some of our battery cables couldn't handle 225 amps...

Totally agree, but I'm pretty sure that the relationship between watts, volts and amps works whether it's amps or amp hours? Just using it to explain why the you don't get double the amp hours with two six volt batteries in series.

It's a formula that's stuck in my head when most things have not.

Horigan · December 13

Agreed. Your formulas are correct and are burned in my brain too. The discussion does highlight that amp-hours should be given at a specific voltage. The 6V battery has 235 aH, at 6V. Putting two in series gives you 235 aH, at 12V. Putting two in parallel gives you 470 aH, at 6V.

Maybe a better way is to use watt hours, like our energy bills are measured. That would include the voltage and be a measure of power available over time...

Mellow_Yellow · December 17

Grumpy_G said:
Unfortunately you gave up on LiFePo which amongst other benefits is much lighter, less than 50 lbs for a 12V 230Ah battery.

It was a tale of woe - the lithium was not charging under tow and during a longer trip, I arrived at my 2nd campsite with a de-charged battery just as a major storm hit.

When I first got the T@B there was an error in the installation of the towing harness. I had a 7-pin plug with only 4-pin wiring and I didn’t notice because my T@B has surge brakes, not electronic brakes. I mistakenly thought it was a problem with the lithium battery.

I’m not 100% happy with the new battery setup because I agree a larger group 24 lithium would have been a better choice and the tongue weight is not ideal. I had the work done at a T@B dealer and they did not inform me of any concerns.

I didn’t realize I was only getting 225 ah with the 6V batteries. Maybe this post will save others from learning this same lesson the hard way.
thanks everyone for your input.

AnOldUR · December 17

I wouldn't feel too bad @Mellow_Yellow. This technology is impossible to keep up with. When you do switch to lithium you'll find even better options and prices than you would have if you'd done it at the time of your latest battery purchase.

A while back, when lithium prices were still high, I went with two 12V 125Ah AGM's in parallel. It wasn't long before lithium prices started to drop, so I switch to two 100Ah LiFePO4 batteries. It's now coming up on two year and I'm finding that I'm again behind the curve. The new single high amp hour lithium batteries with Bluetooth are a big improvement over what I thought was cutting edge. Can't wait to see what comes next!

californication · December 17

@AnOldUR are you saying 2x 100Ah which I bought 2 months ago is already obsolete?!

To be fair, I bought 2x100 24group to place them in front, the same location as the single lead-acid one. I didn't consider going up with 27group or even larger. Now, after changing batteries location from a tongue to an inside of the Tab, I think I could get by with a bigger battery, like 27 group 230Ah, without any hassle.

@Mellow_Yellow it's a process, which takes a bit of time.

pthomas745 · December 17

@californication Maybe not "obsolete"...but the way the prices are going down, there may be a little "buyer's remorse". I bought a 50 amp hour "Redodo" battery in Oct '23 for about 150 dollars. (Well reviewed by Will Prowse).

Today, I can purchase a 100 amp hour lithium, a "WattCycle" for about...150 dollars. (Well reviewed by Will Prowse!)

My bare bones LiTime 100 amp hour lithium from September '21 cost 400 dollars. The changes in features and prices in the lithium battery space has been rather amazing to watch.

elbolillo · December 17

As LiFePo4 batteries continue to be adopted it will only be easier to make the switch, even for those that don't rely as heavily on battery power. The addition of built-in bluetooth monitoring is also a nice feature and will allow for installs without shunts and this should also make the batteries even more accessible.

As with any newer technology, there are always those that spread inaccurate information and scare away some from exploring it. There are so many good resources, like Will Prowse, and other RV and Van installers, that have made it even easier to make the "jump" to LiFePo4.

My experience with LiFePo4 batteries with our Tabs have been nothing but positive and have fit our style of camping perfectly. Even with advances in the technology, we have a setup that should serve us for many, many years!

AnOldUR · December 17

elbolillo said:

Even with advances in the technology, we have a setup that should serve us for many, many years!

Well, maybe many years, but many, many?

californication · December 17

Many, many, many... I meant "Money, money, money"

https://www.youtube.com/watch?v=ETxmCCsMoD0

Slackers · December 18

I think chasing technology is like trying to keep up with the latest fashion trends.

AnOldUR · December 18

Yeah, but ... old guy who's been jeans and t-shirts since teens. Don't always take the leap, but new tech will get my attention.

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