Totally off topic: Anyone interested in a group purchase of LifePo4 cells?

[Mad Mike]

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I’ve done exactly this (for both camping as well as whole-home backup during outages, but…

- Often when we’re towing with the Volt the battery is near or fully depleted, so using the car for power would mean that the engine would be starting and stopping reasonably frequently. I have my doubts that this is efficient from a fuel consumption standpoint versus the generator, and in some campground situations nobody camped nearby is going to want to hear and engine starting and shutting down every 5-10 minutes either, regardless of how quiet the Volt engine is…..it’s still going to be something that would certainly drive *me* crazy if I was in a tent nearby, so I’m sure it would bother others. Hence also why I can’t use the generator either.

- The only way to recharge the Volt is with a shore power connection, which of course if we had, I’d just run the AC from that instead.

I should do some testing (perhaps this weekend) out of curiosity and see how long the Volts battery, fully charged, will run a 300-400w AC load before it switches to engine. But I can’t imagine it would be more than 8-10 hours, so this would be a 1 night solution, beyond which we’re back to no AC power again without noise.

In a perfect world, your homemade bank will have 9.5 to 13.5kwh of storage. I believe a Chevy Volt is about 18KWH, so at full charge ~ 50-100% more than your DIY setup.

If you leave home fully charged then use the Volt's HOLD function to maintain the battery while driving to the campsite. You could have up to 18KWh available, and most certainly you could manage more than the DIY 13.4kwh. And cost next to nothing.

Recharging is a moot point, you'd have to recharge either system at some point -- and that's going to be shore power or a gennie. There is an argument for fuel savings, but I'm guessing that's a long shot when you consider the initial cost of the DIY gizmo - nevermind it's potential to throw you curveballs.

 

[mimico_polak]

In a perfect world, your homemade bank will have 9.5 to 13.5kwh of storage. I believe a Chevy Volt is about 18KWH, so at full charge ~ 50-100% more than your DIY setup.

If you leave home fully charged then use the Volt's HOLD function to maintain the battery while driving to the campsite. You could have up to 18KWh available, and most certainly you could manage more than the DIY 13.4kwh. And cost next to nothing.

Recharging is a moot point, you'd have to recharge either system at some point -- and that's going to be shore power or a gennie. There is an argument for fuel savings, but I'm guessing that's a long shot when you consider the initial cost of the DIY gizmo - nevermind it's potential to throw you curveballs.

I'm still looking into...and saving...for a proper inverter that I could connect to my Volt and then use the car as a power bank during power outages.

Once I have the pony panel installed in the basement I'm going to install a plug in connection for the furnace. This would allow me to just fire up the Volt, switch the plug from the house electrical system to the extension cord on the Volt...and keep the house warm at the very least.

 

[GreyGhost]

I'm still looking into...and saving...for a proper inverter that I could connect to my Volt and then use the car as a power bank during power outages.

Once I have the pony panel installed in the basement I'm going to install a plug in connection for the furnace. This would allow me to just fire up the Volt, switch the plug from the house electrical system to the extension cord on the Volt...and keep the house warm at the very least.

I think code in Canada requires a hard wired furnace. Stupid imo as swapping a plug between grid and backup systems is a really safe solution for everyone. I have seen some places wired with red outlets beside normal outlets for furnace, fridge etc and they basically had two separate electric systems in their house. I don't know if I would go to that effort but if seems like a good solution in some cases.

 

[mimico_polak]

I think code in Canada requires a hard wired furnace. Stupid imo as swapping a plug between grid and backup systems is a really safe solution for everyone. I have seen some places wired with red outlets beside normal outlets for furnace, fridge etc and they basically had to separate electric systems in their house. I don't know if I would go to that effort but if seems like a good solution in some cases.

That was my plan. Separate circuit off the pony panel strictly for use by the furnace. Nothing else would be connected to that line.

 

[Scuba Steve]

you could wire in a DPDT switch by the furnace with a plug coming off it. Plug it in and throw the switch furnace is good to go from outside source. Safe as you are going to get probably not to code.

 

[Brian P]

I'm curious -- if you drive an EV, why not look at an inexpensive way to tap its battery system? Seems to me a small backup gennie would provide you with some peace of mind as it could both power your camper and recharge your EV in a pinch?

Some EVs have the capability of delivering output power from the battery. F150 Lightning, and the Ioniq5/EV6/GV60, come to mind. But ... most current EVs don't have provision for doing this, and hacking into the high-power 400V DC circuit with something homegrown doesn't seem like a good idea.

On mine, and most others, the J1772/CCS connector is one way ... charging. Not discharging.

IIRC the F150 Lightning uses separate power sockets for output power (and only output), and the J1772/CCS connector is still one-way (only input).

I am not sure if anyone has put a bidirectional J1772/CCS connector into production yet. I've heard that some (all?) of the VW ID models are hardware-capable, but it hasn't been implemented yet ... could be wrong.

 

[Brian P]

I think code in Canada requires a hard wired furnace. Stupid imo as swapping a plug between grid and backup systems is a really safe solution for everyone. I have seen some places wired with red outlets beside normal outlets for furnace, fridge etc and they basically had two separate electric systems in their house. I don't know if I would go to that effort but if seems like a good solution in some cases.

I believe code requires the furnace to be on a dedicated circuit, but not necessarily hard-wired. The furnace in my house is plugged into a receptacle that has its own breaker at the panel. House is just shy of 20 years old.

 

[GreyGhost]

Some EVs have the capability of delivering output power from the battery. F150 Lightning, and the Ioniq5/EV6/GV60, come to mind. But ... most current EVs don't have provision for doing this, and hacking into the high-power 400V DC circuit with something homegrown doesn't seem like a good idea.

On mine, and most others, the J1772/CCS connector is one way ... charging. Not discharging.

IIRC the F150 Lightning uses separate power sockets for output power (and only output), and the J1772/CCS connector is still one-way (only input).

I am not sure if anyone has put a bidirectional J1772/CCS connector into production yet. I've heard that some (all?) of the VW ID models are hardware-capable, but it hasn't been implemented yet ... could be wrong.

IIRC @PrivatePilot runs an inverter off the 12volt battery in the volt. The volt keeps the 12v battery topped up from the big battery. It's only good for a few thousand watts and has an efficiency penalty over a direct solution but that's more than enough to run a furnace (and maybe a fridge if you stage things properly). Not as good as the proper bidirectional solution but a great intermediate step compared to a generator you drag out and hook up when the power goes out.

 

[PrivatePilot]

I believe code requires the furnace to be on a dedicated circuit, but not necessarily hard-wired. The furnace in my house is plugged into a receptacle that has its own breaker at the panel. House is just shy of 20 years old.

This is my setup as well. When I’ve needed to run from the inverter or generator I simply unplug the furnace and plug it into the extension cord running from the driveway.

 

[PrivatePilot]

Back on the original topic, for anyone who is actually interested in the group buy….I have final numbers.

These are for 305ah (!) Eve (quality brand name) Lifepo4 cells.

Cells are $125 USD each (which is an amazing price for 305ah grade A new) and shipping for 4 cells (what’s needed to build a 12v pack) via sea is $150. They also charge the PayPal fee back to then buyer so there’s some incidentals, but the total for 4 cells would be around $675usd. So a little more than $900.

I believe this also includes the bus bars and basic hardware.

The BMS would be extra but I can refer to the place I bought my JK BMS from on AliExpress, depending on the amp capacity you need (big inverter vs small inverter) it’s around $60-$130 for that. If you don’t need more than 30-40a I think they’re even cheaper. This is direct from JK via their Ali store, highly reputable.

This is an *epic* deal being able to build a 320ah pack for basically $1K.

I put a lot of legwork into finding these prices, and finding them from reputable sellers, not scammers who will end up shipping you cells with half the stated Ah capacity, or used B grade cells with 20% or more of their DoD consumed already.

Anyone interested, let me know asap as I’ll probably be putting in the order in the next 3-4 days.

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