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Tue Jan 05, 2021 6:12 pm

I've started down the rabbit hole of trying to fit four 280Ah LiFePo4 cells under the driver's seat, together with an Overkill BMS.

Today was swivelectomy day.

I removed the AGM 35Ah 'last resort' aux battery that was in the driver's side battery box, and rationalised the wiring in there to allow everything to work as before, with the 29DC 120Ah battery under the rear seat keeping things functional for the time being. That 120Ah didn't quite cut it when stuck in a campsite for a couple of days trying to ride out a storm last year - it was Mrs fxr who suggested we went for something much bigger, but it had to go under the front seat(s) to provide extra storage under the rear seat.

I ground off the welds that held the swivel static panel to the non-swivel slides, so removing the swivel entirely, but it such a way that it could be installed in another van if sold.

I made up a cardboard box that was the same size plus 2mm in each dimension as the 280Ah cells I have on order - delivery promised by April 6th. This proved that it's possible to get all four in there, two in the battery box, two under the seat, with room for the BMS under the seat as well. I'm relieved my pre-op measurements were validated! A Renogy DCC50S will be squirelled away elsewhere.

The Town & Country seat had to be raised up by 6mm from the sliding rails in order to clear the carpet on the door side, easily done with a few washers.

There's room enough in there to allow for insulation and a heating pad, but I haven't got around to organising the heating pad yet.

Early days...

Tue Jan 05, 2021 6:17 pm

Looking good. I am interested in the science that makes beer into electricity. Any links?

Tue Jan 05, 2021 6:21 pm

sphet wrote: Looking good. I am interested in the science that makes beer into electricity. Any links? Apparently the Aussies are into that! https://www.forbes.com/sites/bradjaphe/2020/08/14/...65ab0617b4

For some reason I've got a continual supply of beer cartons, so it seemed logical to use one as a dummy battery. ;)

Tue Jan 05, 2021 6:24 pm

Nice progress! :popcorn:

Tue Jan 05, 2021 6:26 pm

I'm pretty interested in adding amps for a new aux system but the LiFePo4 charging voltage requirements make me have to consider everything from the stock 65 amp alternator and wiring to a new voltage regulator just to get high enough. I think I have more gremlins to sort out first before I can think of LiFePo4. Whats your charging voltage on your system?

Tue Jan 05, 2021 6:36 pm

fxr wrote: That 120Ah didn't quite cut it when stuck in a campsite for a couple of days trying to ride out a storm last year - it was Mrs fxr who suggested we went for something much bigger

120AH of lead barely lasted 2 days?
280AH of LiFePO4 is a whole lot more than "5 days".
But you got the go-ahead.....that'll be our little secret. 👍🏽

Ya know 280 Ah makes Solar just 'hobby'.
At 150Ah I'm about "4 or 5 days".... and towards 10 days with solar.
280Ah is like 9 days right there.

Energy storage is really "where it's at".
It's the next level that we never really considered.

Tue Jan 05, 2021 6:40 pm

I'm getting a 'new to me' alternator. I followed Sodo's link to the ebay $42 130A Tribeca alternator and ordered it. :)

https://www.thesamba.com/vw/forum/viewtopic.php?p=9542985#9542985

The charging voltage will be set by a Renogy DCC50S.

Tue Jan 05, 2021 6:59 pm

Sodo wrote:

Ya know 280 Ah makes Solar just 'hobby'.
At 150Ah I'm about "4 or 5 days".... and towards 10 days with solar.
280Ah is like 9 days right there.

Energy storage is really "where it's at".
It's the next level that we never really considered.
It was some of your observations that made me think the 'infinity battery' was feasible for our vans, so thank you. ;) Yup, 120Ah of lead-acid (60Ah max really usable) is pretty pathetic compared!

Tue Jan 05, 2021 8:41 pm

Quote: Re: 280Ah LiFePo4 under driver's seat

Now we're talking. And to think that just five years ago or so I was thinking of paying $700 for a PeaceVans under-van tray to hold 200 ah of lead acid boat anchors.

sphet wrote: Looking good. I am interested in the science that makes beer into electricity. Any links?

Isn't that backwards? don't we want to turn electricity into beer?

Wed Jan 06, 2021 7:49 am

I might be interested in your old seat swivel or anyone else that does this and wants to part with their seat swivel.

The catch is that I don't really want to pay market value for them so if anyone just wants to make a few bucks and have them out of their face lemme know.
:)

Wed Jan 06, 2021 9:17 am

I'm interested. Especially since 280aH cells are less than $430 shipped. https://www.aliexpress.com/item/1005001563505796.html

Wed Jan 06, 2021 9:28 am

Now this is getting into the price and capacity range that makes sense. I'll be following this closely since I'll be building out the West Coast Westy next fall.

Wed Jan 06, 2021 9:35 am

Does anyone have reliability concerns about battery cores from unknown Chinese suppliers? 200+Ah under the seat is very appealing but no warranty or product support feels like a pretty big gamble.

Wed Jan 06, 2021 9:36 am

Here is 272aH cells I think were around $500 shipped (bought in november).

This is going into a custom tin top interior. Friend made the box and I just hooked it up. Note the shunt is not needed. One thing I do like on this install is how its a 'drop in' battery the size of a group 29 battery and the fact it protects the 'weak' cell connections.

Also: peek the cordless Dewalt heatgun in the background. It was gamechanger for this install.

Wed Jan 06, 2021 9:44 am

Vanuber wrote: Does anyone have reliability concerns about battery cores from unknown Chinese suppliers? 200+Ah under the seat is very appealing but no warranty or product support feels like a pretty big gamble.

$3000 for 300ah with 10 year warranty OR
$550 (after BMS) for 280ah with no warranty.

Yeah even if these cells are lower quality and only last 5 years I think its a good gamble.

I bought the 150aH lifepo4 under drivers seat and it has been INCREDIBLE for past 4 months. I have used the system quite a bit - probably over 20 nights of camping and have only cycled the cells 10 times. They're rated for like what, 2000+ cycles?

The price point of this capacity really influences future builds. I feel you're going to see a lot of weekend warriors delete solar panels from their vans given such big capacity per price point.

Wed Jan 06, 2021 9:48 am

shagginwagon83 wrote: Vanuber wrote: Does anyone have reliability concerns about battery cores from unknown Chinese suppliers? 200+Ah under the seat is very appealing but no warranty or product support feels like a pretty big gamble.

$3000 for 300ah with 10 year warranty OR
$550 for 280ah with no warranty.

Yeah even if these cells are lower quality and only last 5 years I think its a good gamble.

I bought the 150aH lifepo4 under drivers seat and it has been INCREDIBLE for past 3 months. The price point of this capacity really influences future builds. I feel you're going to see a lot of weekend warriors delete solar panels from their vans given such big capacity per price point.

Weekend warriors for sure, quarterly campers absolutely. Even if you did this with a portable Solar System to help with a slightly longer camp, that might even be more convenient.

Wed Jan 06, 2021 10:06 am

vwhammer wrote: I might be interested in your old seat swivel or anyone else that does this and wants to part with their seat swivel.

The catch is that I don't really want to pay market value for them so if anyone just wants to make a few bucks and have them out of their face lemme know.
:)
The problem would be the shipping cost. The package would be both big and heavy - so I expect it'll eventually go to someone who can pick it up. Shipping rates for private individuals seem to be an order of magnitude more than commercial enterprises have to pay. :(

Wed Jan 06, 2021 10:53 am

shagginwagon83 wrote: One thing I do like on this install is how its a 'drop in' battery the size of a group 29 battery and the fact it protects the 'weak' cell connections.

slick!

anything special done to the charging system otherwise? how about hot/cold climate concerns?

Wed Jan 06, 2021 10:55 am

shagginwagon83 wrote:
$3000 for 300ah with 10 year warranty OR
$550 (after BMS) for 280ah with no warranty.

Well, when you put it that way:)

Also, digging the box. Would make it nice and easy to take out for winter storage. Too bad that won't fit under the driver's seat.

Wed Jan 06, 2021 12:16 pm

Russpauly wrote:

Weekend warriors for sure, quarterly campers absolutely. Even if you did this with a portable Solar System to help with a slightly longer camp, that might even be more convenient.

because i'm a silly boy i took my real world usage numbers this fall with my 150Ah setup and did some estimations for hot weather.

at an ambient temp of 90F/24hours, i expect to consume 60Ah, with half of that consumption being the pumpin bass for the bulk of evening jammin. the 150Ah LiFePo will last 2.5 days before the bass stops and the beer gets warm.

adding a 100W solar panel at 80% output (80W) for 4 hours each day will add back 26Ah each day. i can pump the bass and have cold beer and klondike bars for 4 solid stationary days.

doubling the solar panel capacity to 200W (160W @80% output) 4 hours/day, i can pump the bass, guzzle IPA's, and have klondike bars for 11 stationary days. i will have run out of beer and klondike bars long before that.

to that end, 150Ah with a 100W panel with a moderate load in 90F for days on end will be plenty of capacity for most "normal" folks who aren't pumping the bass for hours on end while breakdancing around the fire pit.