replacing GEL batteries in my RV

[pjstock]

this is not strictly (or even At All) a "Solar" question but Will Prowse seems to be the Oracle for all things battery related....

I have imported a 19 year old Class B camper van from Europe. It's two auxiliary batteries are Exide 85AH Gel batteries
Owners of small campers like this are - like sailboat owners I think - obsessed with space optimization, No Wasted space .
These two (probably original) batteries fit neatly into a cavity in the RV's water tank. a cavity that measures L 355 x W 370 (so 2 x 185) x H 210 (to the top of the case)
The original Exide GEL batteries are a bit smaller. the manufacturer reports that they are L 349 x W 175 x H 235 (which must include the handles)

when tested these GEL batteries are reading "REPLACE"
and so I am shopping for some LiFePo replacements.

I would like to reuse this water tank cavity with replacement LiFePo batteries

While our electrical needs will be light (there is a 42W fridge running off the 12V system and that's about all - No AC, no Microwave, no television.....) Will P seems to say "buy as much AH as you can afford" . and so I am thinking 2 x 200AH batteries.

1. is there a 200AH LiFePo that will fit this space? L 355 x W 370 (so 2 x 185) x H 210 Most i am seeing in this size are 100AH

2. a (apparently) top of the line 200AH Victron would cost about.... $2200 CAD / $1500 USD while I am seeing a single 100AH Watt Cycles (that WP seems to have recommended as a budget option) for about $250 CAD / $180 USD. so for 200AH $500 CAD / $360 USD
that's a big jump for a LiFePo novice

what is the downside or the risk of starting small, with a cheap LiFePo battery bank, trying it out for a few trips and if we are not happy upgrading to the Cadillac solution, Victron?

Peter

 

[pollenface]

Like this?

They are just generic 100ah Lifepo4s from ebay/amazon. $220aud each, 100a bms. Good for about 1800w AC power (as a pair).

 

[pjstock]

yes. like that.
though there seem to be hundreds of similar low end batteries
and Mr Prowse has positively reviewed just a few: Budget: WattCycle, Midrange: LiTime and..... Higher End: I expect he likes Victrons despite the cost.

 

[time2roll]

The 2x 100 at the low end is what I recommend. Keep the charging less than the maximum 14.60 volts. 14.20 volts is fine.
Assuming the 200 Ah of GEL was working well for you... the 200 of LFP will have more usable capacity and faster charging.

 

[pjstock]

we have not actually ever USED this base system.
we imported it in December last year (2024) and have been waiting for the snow to clear to tinker with its systems

so we have never actually been able to try out the original system

 

[pjstock]

a key though (or so I think) is using the available but limited space efficiently
so what LiFePo batteries will fit this water tank cavity?

 

[JonMez]

this is not strictly (or even At All) a "Solar" question but Will Prowse seems to be the Oracle for all things battery related....

I have imported a 19 year old Class B camper van from Europe. It's two auxiliary batteries are Exide 85AH Gel batteries
Owners of small campers like this are - like sailboat owners I think - obsessed with space optimization, No Wasted space .
These two (probably original) batteries fit neatly into a cavity in the RV's water tank. a cavity that measures L 355 x W 370 (so 2 x 185) x H 210 (to the top of the case)
The original Exide GEL batteries are a bit smaller. the manufacturer reports that they are L 349 x W 175 x H 235 (which must include the handles)

when tested these GEL batteries are reading "REPLACE"
and so I am shopping for some LiFePo replacements.

I would like to reuse this water tank cavity with replacement LiFePo batteries

While our electrical needs will be light (there is a 42W fridge running off the 12V system and that's about all - No AC, no Microwave, no television.....) Will P seems to say "buy as much AH as you can afford" . and so I am thinking 2 x 200AH batteries.

1. is there a 200AH LiFePo that will fit this space? L 355 x W 370 (so 2 x 185) x H 210 Most i am seeing in this size are 100AH

2. a (apparently) top of the line 200AH Victron would cost about.... $2200 CAD / $1500 USD while I am seeing a single 100AH Watt Cycles (that WP seems to have recommended as a budget option) for about $250 CAD / $180 USD. so for 200AH $500 CAD / $360 USD
that's a big jump for a LiFePo novice

what is the downside or the risk of starting small, with a cheap LiFePo battery bank, trying it out for a few trips and if we are not happy upgrading to the Cadillac solution, Victron?

If ancient 85 amp gel batteries were working for you I’m highly confident the bargain brand lithiums will be amazing. Check out the Ecoworthy /DC house batteries on eBay or Amazon with the Bluetooth, never personally used watt cycle, but I’m sure they’re fine.

 

[pjstock]

point is....we have not yet traveled with this camper yet.
it's been a long hard winter.
so I am relying on the battery tests.

but maybe we just take a chance and take a trip with the original setup

(Though we do have to adapt the 230v European system to the 115v NA system)

 

[time2roll]

Since there are no heavy loads the pair of 100 LFP batteries will serve you well. In the cold the furnace blower fan could be a significant draw and yet the pair of batteries should still be good for several days and more. If the RV has incandescent lights.... best to swap the most used lamps for LED.

 

[Rocketman]

When selecting the batteries - one key feature is to have a way to read the cells - usually Bluetooth in these cheaper batteries.

This feature will help diagnose issues down the road - when needed it is super useful. Often right now it’s $10 or so more to get a battery with it.

Also, make sure the BMS prevents charging below 32F or 0 C. Almost all do these days - but you want to make sure it does.

Since you will be installing batteries I would highly recommend a Victron Smartshunt (or BMV712- if you want a display). This will let you know if your batteries are mostly full or almost empty. It calculates the exact percentage of charge you have. (Right now mine are at 93%).

Good Luck

 

[Rocketman]

Also, check your size available against a “group 31” battery size and also against a “group 24” battery size.

Last year we added Lithium batteries to my brother-in-laws RV. He needed group 24 sized batteries and we were able to find them - vatrer is what we used - but there are bunches out there.

Good Luck!

 

[Enketchum]

Nothing wrong with starting small. Plug and play

 

[pjstock]

you've all been a great help

I was going to order a 115v charger from Germany that matches the original Westfalia 230v charger but A) they are fairly expensive (all in about $ 450 USD and not even bluetooth) and B) the supplier will not ship to Canada or the USA so even getting on is complicated.

and then I see that Watt Cycle sells a variety of chargers for.... $100-150
what was quoted as a $9,000 full Victron upgrade (though not DIY - by a professional RV/solar electrician and including 2 solar panels, which I am nut budgeting yet) it seems I can start small and simple and order a Watt Cycle package for about $500 USD (2x 100AH group 24 batteries, a shunt and a charger)

Question though - chargers seem to come in a variety of sizes 20A, 40A, 60A....

So my dumb beginner question what does a higher amperage charger provide, so a 60A over a 20A (I am going to guess faster charging times when on shore power?)

 

[time2roll]

20 amps charging is plenty on utility power as speed is not important. Fast charge is important to reduce generator run time. Then 60+ amps is more important as long as the generator is large enough to drive it.

 

[pjstock]

The 2x 100 at the low end is what I recommend. Keep the charging less than the maximum 14.60 volts. 14.20 volts is fine.
Assuming the 200 Ah of GEL was working well for you... the 200 of LFP will have more usable capacity and faster charging.

we haven't actually field tested this unit yet, out on the road, on a real trip.
we only bought it last fall and only received it in December.
it has sat in the driveway in the snow all winter
so i haven't tried it out at all. all this research is in preparation for a long road trip this summer.
but the 2x85AH GEL batteries, when tested, area reading REPLACE so a few hundred dollars seems like a reasonable investment even before we road test.

 

[Rocketman]

$9k for a full Victron upgrade…. That’s insane!
DIY is the way to go.

And with the size of your unit - you probably can’t fit in everything they priced in.

I love my Victron equipment- everything is Victron - except the batteries. It just works and works well!

Good Luck!

 

[pjstock]

$9k for a full Victron upgrade…. That’s insane!
DIY is the way to go.

And with the size of your unit - you probably can’t fit in everything they priced in.

I love my Victron equipment- everything is Victron - except the batteries. It just works and works well!

Good Luck!I

Victorn gear is expensive. even if you DIY it.
a 300AH Victorn battery, up here, alone is about $2000 USD (before 13% tax)
the same capacity in three 100AH Watt Cycles would total about.... $550 (though I am only getting two).

The Victron Multiplus charger+inverter is another $1000 USD retail
it adds up fast.

and there were so many pieces to that puzzle (solar panels, inverter, etc) that I would have struggled to make it all work on my own I think.

But you put your finger on the other problem (beyond the expense) - the size of the gear.
in a small Class B camper like a James Cook (Westfalia interior on a MB Sprinter base) space has to be optimized carefully., like on a boat That's one of the joys of a Westfalia interior - everything is well thought out.
the professional upgrade quote wasted a lot of space IMO. the combination Victron charger + inverter measured about 20 x 10 x 6 inches. too big to fit in the wall cavity the original was nestled neatly into
and the single 300AH battery was 15inches long - too long to fit in the special cavity in the water tank (that takes the two Group 31 original batteries)
and so all that gear would have had to go onto a pull out tray in the rear storage area of the van. so it didn't make sense space optimization-wise.

the Watt Cycle pieces (2 x group 21 batteries and a small charger) will fit into the original spaces.

though I will have to stick an inverter somewhere when I get to that point.

 

[Enketchum]

Have you decided how you are going to charge these, yet? Solar? Shore power? Generator?

 

[pjstock]

Have you decided how you are going to charge these, yet? Solar? Shore power? Generator?

at this point I am just working on converting the shore power setup from 230V feed to 115V north american.
In most of Canada "wild" camping is difficult (private property etc etc) and so one usually winds up in a camping area of some kind. where there would likely be shore power.

I *think* they should also charge off the alternator, while driving (though I am not yet sure how that connection works. (I assume that if it is currently working and I just swap the already installed wiring to the new LFP batteries, that it should continue to work)

it has the original solar panels but I have to figure out how to test them. (next step) the German supplier of these originals replied to my inquiry about how to test them saying simply that, from my photos, they looked shot and that given they are almost 20 YO they I can assume they should be replaced.

But I would like to confirm that they are no good before I toss them. there must be instructions out here on how to test solar panels.

 

[Enketchum]

at this point I am just working on converting the shore power setup from 230V feed to 115V north american.
In most of Canada "wild" camping is difficult (private property etc etc) and so one usually winds up in a camping area of some kind. where there would likely be shore power.

I *think* they should also charge off the alternator, while driving (though I am not yet sure how that connection works. (I assume that if it is currently working and I just swap the already installed wiring to the new LFP batteries, that it should continue to work)

it has the original solar panels but I have to figure out how to test them. (next step) the German supplier of these originals replied to my inquiry about how to test them saying simply that, from my photos, they looked shot and that given they are almost 20 YO they I can assume they should be replaced.

But I would like to confirm that they are no good before I toss them. there must be instructions out here on how to test solar panels.

20 years of being glued onto the roof would lead us to believe they are trash. I would leave those as peeling them up will probably destroy the roof material.

Solar panels are very cheap right now. You can get flexible panels and glue them down or go for better glass panels and screw them down. Your solar charge controller is probably PWM and will not charge your new batteries very fast. We can help you with all that if you want.

Your alternator will charge the batteries but lifepo4 have a very low internal resistance and will suck up as much power as the alternator can make. This can damage the alternator if you don't control the power. Do you know if your alternator is tied to the battery system?

 

[time2roll]

it has the original solar panels but I have to figure out how to test them. (next step) the German supplier of these originals replied to my inquiry about how to test them saying simply that, from my photos, they looked shot and that given they are almost 20 YO they I can assume they should be replaced.

But I would like to confirm that they are no good before I toss them. there must be instructions out here on how to test solar panels.

Basic test is to disconnect and measure the open circuit voltage. Then measure the short circuit amps. Test in full sun after gently cleaning the panels.
Compare to the specification or post the results here for a quick evaluation.

 

[pjstock]

the current solar controller (photo attached) is a Schaudt (now "Lippert") LRS1214 12v 14A

does that mean anything?

as for the alternator. that is a very helpful Heads Up.
"Do you know if your alternator is tied to the battery system?"
I don't *know* (but will find out before I install the replacement LFP batteries) but I expect it is. (since with the charger and solar disconnected, after even a short drive the voltage of the auxiliary batteries is increased. (though I am going to test that now. and in fact after a 10minute drive the aux battery voltage increased from 12.50v to 13.02v. so I have to assume the alternator is connected.)

attached are photos of the current battery connections. if they tell anyone anything helpful.

 

[Enketchum]

Yeah I have no idea what controller that is but I highly doubt those panels make any power anymore. Flexible panels glued to a roof roast in the sun and kill themselves over the course of a few years

 

[pjstock]

Your alternator will charge the batteries but lifepo4 have a very low internal resistance and will suck up as much power as the alternator can make. This can damage the alternator if you don't control the power. Do you know if your alternator is tied to the battery system?

My WattCycle batteries arrived (2 x 100AH) as well as the 20A charger and the monitoring gizmo

But what do I do about this alternator problem?

 

[Enketchum]

My WattCycle batteries arrived (2 x 100AH) as well as the 20A charger and the monitoring gizmo

But what do I do about this alternator problem?

Measure it. Or get a DC to DC charger