openinverter forum

Apologies for the sort-of double-posting but people were more interested in my vehicle choice rather than components in the other thread.

From what it seems to me, for a 16 kWh pack (approx), you've got:
Gen 1 Volt modules + Simp BMS
A123 Pouch modules (https://www.thunderstruck-ev.com/used-a ... dules.html)
LG Chem 16s(1p?) modules (https://www.thunderstruck-ev.com/used-l ... dules.html) - EV West has these new it seems at $735/each.

The issue is the BMS - while the A123 and LG Chem ones seem like a nice deal (800 A discharge current out of those LG cells is nice!), but adding in something like the Orion 2 @ 96 Cells is almost as much as the used cells themselves. In contrast, pick up the Volt battery (entire thing) for ~2500 including shipping, ~$300 for Simp BMS, and done? For a short-ish range (but I will eventually do CHAdeMO too), this seems ideal. Looks like things get much more complicated if you start wanting to parallel packs (in all scenarios here).

Is there something I'm missing here?

Thanks,
-Mat

Definitely go the Volt/Simp route out of those options.

Also with the Volt pack you might be able to reuse other components such as current sensor, heater, fuses and contactors

Thanks. Ok, good to get a reality check from others.

jon volk wrote: ↑Thu Mar 12, 2020 12:38 pm Definitely go the Volt/Simp route out of those options.

I saw in one of your videos you have two of the BMSes from two packs - what did you end up doing to parallel the packs? Do you have that documented anywhere?

Now to go get a pack - https://www.ebay.com/itm/2013-2014-Chev ... 3798590671 is the one I was looking at. Car seems to be in decent shape, and the pack looks good.

-Matt

I've been playing around with a couple different methods. Currently just switching back and forth between two CAN inputs every 7 minutes. Working on a custom VCU board and I may just end up doing two standalone BMS circuits that will talk to a main teensy 3.6. Its all still in flux at the moment.

Jon or others, Has anyone had success doing two Volt gen2 packs together?

What do you mean success? In terms of the BMS or just paralleling two Gen2 packs?

jon volk wrote: ↑Sun Mar 29, 2020 4:00 pm What do you mean success? In terms of the BMS or just paralleling two Gen2 packs?

Ideally in figuring out a BMS solution that doesn't involve cutting up the packs to parallel at the cell level (as would be needed for something like the Orion)

I also haven't seen someone actually use the gen2 packs in a car. Based on other data I've seen they closer to the Pacifica's LG Chem packs than the gen1.

P.S.Mangelsdorf wrote: ↑Sun Mar 29, 2020 4:25 pm I also haven't seen someone actually use the gen2 packs in a car. Based on other data I've seen they closer to the Pacifica's LG Chem packs than the gen1.

EVEngineering on YouTube (also kerrymann on diyelectriccars.com) Has used the gen 2 Volt packs before.

slow67 wrote: ↑Sun Mar 29, 2020 5:25 pm
EVEngineering on YouTube (also kerrymann on diyelectriccars.com) Has used the gen 2 Volt packs before.

Has he? I know he broke one down but I'm pretty sure Sylent was still running the gen1. The Gen2 might be for the airplane?

P.S.Mangelsdorf wrote: ↑Mon Mar 30, 2020 12:02 pm

slow67 wrote: ↑Sun Mar 29, 2020 5:25 pm
EVEngineering on YouTube (also kerrymann on diyelectriccars.com) Has used the gen 2 Volt packs before.

Has he? I know he broke one down but I'm pretty sure Sylent was still running the gen1. The Gen2 might be for the airplane?

He put them in his BMW I think.

slow67 wrote: ↑Mon Mar 30, 2020 1:35 pm He put them in his BMW I think.

That's my understanding... he certainly includes Gen 2 in his battery comparison spreadsheet (here) and video;

Kevin Sharpe wrote: ↑Mon Mar 30, 2020 2:03 pm
That's my understanding... he certainly includes Gen 2 in his battery comparison spreadsheet (here) and video;

Yeah, that spreadsheet has been great.

Kerry was a big help in pointing me in the right direction when I was running the University of Hartford electric racing team.

Answering some of my own questions re: BMS for parallel packs, the Thunderstruck BMS claims to be able to handle parallel packs, though its not the cheapest route.

P.S.Mangelsdorf wrote: ↑Mon Mar 30, 2020 4:48 pm Answering some of my own questions re: BMS for parallel packs, the Thunderstruck BMS claims to be able to handle parallel packs, though its not the cheapest route.

Depending on what you want from a BMS you might be able to use the ISA Shunt for monitoring the battery... it's currently in use in BEXUS and has some great features

Kevin Sharpe wrote: ↑Mon Mar 30, 2020 6:38 pm

P.S.Mangelsdorf wrote: ↑Mon Mar 30, 2020 4:48 pm Answering some of my own questions re: BMS for parallel packs, the Thunderstruck BMS claims to be able to handle parallel packs, though its not the cheapest route.

Depending on what you want from a BMS you might be able to use the ISA Shunt for monitoring the battery... it's currently in use in BEXUS and has some great features

I may end up using that, but from my understanding that does not have individual cell monitoring, correct?

I've blown up cells due to over current (in an old lead acid pack that was un-monitored) and I'm going to be pushing this pack hard so I primarily need the BMS to warn me before stuff goes boom. That, and give me SOC so I don't strand myself.

P.S.Mangelsdorf wrote: ↑Mon Mar 30, 2020 7:48 pm I may end up using that, but from my understanding that does not have individual cell monitoring, correct?

Correct, it can monitor three points on the pack.

P.S.Mangelsdorf wrote: ↑Mon Mar 30, 2020 7:48 pm I've blown up cells due to over current (in an old lead acid pack that was un-monitored) and I'm going to be pushing this pack hard so I primarily need the BMS to warn me before stuff goes boom. That, and give me SOC so I don't strand myself.

You'll have to take a view on whether cell level monitoring is required on modern batteries The ISA has multiple functions including Ampere hour and energy counter and it may be worth reviewing progress on Damiens latest builds before making a decision.

Here's the datasheet;

https://www.isabellenhuette.de/fileadmi ... _IVT-S.pdf

Kevin Sharpe wrote: ↑Mon Mar 30, 2020 9:15 pm
You'll have to take a view on whether cell level monitoring is required on modern batteries

I'd prefer it, but I've gone back and forth. I know plenty of people have had success without it, but I'm leaning towards the safety net of having more data than less.

Kevin Sharpe wrote: ↑Mon Mar 30, 2020 9:15 pm
The ISA has multiple functions including Ampere hour and energy counter and it may be worth reviewing progress on Damiens latest builds before making a decision.

I'm following the progress. Both fortunately and unfortunately I'm in a holding pattern during this covid-19 crisis. I'm being overly cautious and "fun" money is being diverted to emergency savings for now. Hopefully we'll get past this soon.