TheSamba.com :: View topic

Mon Jan 11, 2021 10:52 am

dabaron wrote: fxr wrote:
I'm not sure where you get 11 days from...

will you be running your heater in August?
Up in the mountains - certainly!
Quote:
to each their own.
Agreed. If the 280's weren't a similar price to the 150's (that currently seem unobtainable) I wouldn't have bothered, but like climbing Everest - 'It's because it's there'. ;)

Mon Jan 11, 2021 11:44 am

Why stop at 280?
https://www.aliexpress.com/item/4001316676700.html...5392%23804

Now we just need a few pioneering souls to buy these at the higher price so the price starts dropping to where us regular folk can afford them.

Mon Jan 11, 2021 2:25 pm

Hey everyone - I've been lurking these LiFePo4 / lithium threads, quietly planning my own battery project and have a couple of questions for the knowledgeable :D

I thought I knew what I wanted to do, but seeing this thread has my mind almost changed - you can't beat the price for that much storage. How approachable is this setup is for a battery noob like me? I've followed all these lithium threads and have an idea of the components I need, but I've never 'built' a battery before. This is the main reason I was just going to go with a Renogy 174ah under the rear bench - it's pretty plug and play at least in terms of the battery + BMS.

But ordering these cells instead would give me a setup that's like 1/4 of the price which means being able to do more van projects this spring. I just don't know what I'm getting myself in for lol. I know no one can tell me if I can or can't do it, but generally looking for opinions on whether this would be a dumb idea for a first timer. I'm pretty capable and try to DIY most of my own projects, but I've never done anything like this and don't want to blow myself up, or more importantly, my westy haha.

Mon Jan 11, 2021 2:36 pm

VanMan2009 wrote: Hey everyone - I've been lurking these LiFePo4 / lithium threads, quietly planning my own battery project and have a couple of questions for the knowledgeable :D

I thought I knew what I wanted to do, but seeing this thread has my mind almost changed - you can't beat the price for that much storage. How approachable is this setup is for a battery noob like me? I've followed all these lithium threads and have an idea of the components I need, but I've never 'built' a battery before. This is the main reason I was just going to go with a Renogy 174ah under the rear bench - it's pretty plug and play at least in terms of the battery + BMS.

But ordering these cells instead would give me a setup that's like 1/4 of the price which means being able to do more van projects this spring. I just don't know what I'm getting myself in for lol. I know no one can tell me if I can or can't do it, but generally looking for opinions on whether this would be a dumb idea for a first timer. I'm pretty capable and try to DIY most of my own projects, but I've never done anything like this and don't want to blow myself up, or more importantly, my westy haha.

Well I've never built a battery before either. But I am pretty handy and there is enough good info on the internet and here that I think I can do it. If you know which way to wire up 12V accessories I bet you could do it too.

Mon Jan 11, 2021 2:41 pm

I'm helping a friends with his 280ah setup. I believe he has a bad cell.

I top balanced these cells myself from 40% to 100%. Under load we're seeing a delta of .5v voltages on one cell. We're hoping to discharge the cell down to 20% then try to top balance again.

Mon Jan 11, 2021 2:42 pm

I'm another that's never built a battery before - but I'm quite happy with electrics and electronics, so it's only the mechanical considerations that need extra brain energy from me.

As long as extreme care is taken not to short out any cells or combination of them, then it should be plain sailing. Nothing ventured, nothing gained etc...

Mon Jan 11, 2021 5:21 pm

shagginwagon83 wrote: I'm helping a friends with his 280ah setup. I believe he has a bad cell.

I top balanced these cells myself from 40% to 100%. Under load we're seeing a delta of .5v voltages on one cell. We're hoping to discharge the cell down to 20% then try to top balance again.

Hell, that ain't good. As a point of reference, since top balance I get about 0.006 max delta at a 25A load on my 280AH EVEs. That's at about 90% SOC, including after sitting for a few weeks. I imagine it'd be slightly bigger towards the edges of the curve.

Tue Jan 12, 2021 9:52 am

fxr wrote: Nothing ventured, nothing gained etc...

Indeed. I went ahead and ordered the cells last night - got a notification this morning they've already shipped! Hopefully I'm on the shorter end of the 20-38 days delivery window they say, but I have plenty to research / learn in the meantime!

What's everyone using to top balance the cells?

Tue Jan 12, 2021 10:52 am

VanMan2009 wrote:
Indeed. I went ahead and ordered the cells last night - got a notification this morning they've already shipped! Hopefully I'm on the shorter end of the 20-38 days delivery window they say, but I have plenty to research / learn in the meantime!

What's everyone using to top balance the cells?

Hate to burst your bubble - but I was given a Fedex tracking number the day I ordered the cells (Dec. 1st) and still haven't received it.

The way it works is basically they will generate your US tracking number (coming from CA most likely) ahead of time. Probably so you can't cancel the order. Once the CA warehouse gets the big shipment in they will then redistribute using US tracking number.

Tue Jan 12, 2021 1:12 pm

VanMan2009 wrote:
What's everyone using to top balance the cells? I bought this one in preparation for the cells arriving:
https://www.amazon.com/gp/product/B07M9N73YQ

Seems to work just fine. There's a multi-turn pot inside for calibration of each of voltage and current in case it doesn't agree with other trusted devices. It's found other uses already. :)

Wed Jan 13, 2021 5:56 pm

Fitted a 130A Tribeca alternator (thanks for the link Sodo) in anticipation of more current being needed than the rather anaemic EJ22 one could give. For the time being the sense wire is connected back to the output, but eventually it'll come from the DCC50S.

Wed Jan 13, 2021 8:03 pm

fxr wrote: Fitted a 130A Tribeca alternator (thanks for the link Sodo) in anticipation of more current being needed than the rather anaemic EJ22 one could give. For the time being the sense wire is connected back to the output, but eventually it'll come from the DCC50S.

Do you have any pics/writeup on the installation? Anything to be concerned about?

I have an EJ25 from an Impreza (with the corresponding alternator), is the Tribeca alternator a much better one?

Wed Jan 13, 2021 8:40 pm

Tribeca alternator is 130Amps.
Its a bolt-on mod.

The Tribeca alternator has a one-rib wider belt.
You could put the pulley from your (110A?) alternator on the 130A if you want.

Wed Jan 13, 2021 8:46 pm

Why the need to go from a 110A to 130A alternator?

Wed Jan 13, 2021 10:32 pm

dobryan wrote: Why the need to go from a 110A to 130A alternator?
Because if you don't have a DC to DC charger, the LiFePO4 battery will take as much current as the alternator can give and more. 0.5C is 140 amps for the 280ah pack and 0.5C is easily doable for most of these cells. Even 0.2C is almost 60 amps.

Wed Jan 13, 2021 11:12 pm

gtinseth wrote: dobryan wrote: Why the need to go from a 110A to 130A alternator?
Because if you don't have a DC to DC charger, the LiFePO4 battery will take as much current as the alternator can give and more. 0.5C is 140 amps for the 280ah pack and 0.5C is easily doable for most of these cells. Even 0.2C is almost 60 amps.

True that. But why would you charge a LIFePo4 battery directly off an alternator? The DC/DC charger will give the correct charge profile and the alternator direct charge will not.

Thu Jan 14, 2021 11:05 am

dobryan wrote: Why the need to go from a 110A to 130A alternator?
My alternator was rated at 75A apparently - that had to be replaced! If it had been 110A I wouldn't have bothered.

I was fitting the 130A one onto an EJ22 - this required some filing of both the alternator body and the top of the clamping pillar to fit. It misses the intake structure by 2mm - but it does fit!

Thu Jan 14, 2021 11:16 am

Got it. That makes sense. :D

Thu Jan 14, 2021 2:16 pm

I just checked the specs for my rig. The SVX engine came with a 95 amp alternator. I have decided to use 200Ah CALB cells (because they are locally available and I am impatient) and the REDARC BCDC 1240D dual input dc to dc charge controller. I will use the Overkill Solar BMS for this battery (good reviews and nice Bluetooth State Of Charge infotainment).

Question: Can anyone comment on whether this 95 amp alternator will be adequate?

Obviously, the other draws will have a large influence, especially the rad fan and blower fan draws when my AC is on, but I am adding a sail switch for the rad fan to shut down the AC trigger for the rad fanwhen on the highway. BTW, the factory VW radiator-switched fan control will not be affected by the sail switch and will operate as stock. I have no big-ass audio system and I do have a TF-65 fridge.

Thu Jan 14, 2021 2:22 pm

What are the specs on that DC DC charger? They usually have an upper limit on amps they can charge at.