diy solar

diy solar

Do Electric bikes use the same batteries used in solar?

Most here in the DIY forum use LiFePO4 and/or lead acid batteries.

Most of the scooter/e-bike batteries use Lithium MNC cells. Those are prone to thermal runaway unlike LiFePO4, especially if there is a fault with the charging, or a short occurs.
 
I'm surprised it's even legal to sell these things. I'd hate to live in a apartment when people are buying them and storing them inside. As for solar...I'm sure at this point on the solar shed to house the batteries and inverters.
 
realpinochet said:
As for solar...I'm sure at this point on the solar shed to house the batteries and inverters.
Click to expand...

Yup, even with LiFePO4 there's a lot of energy tied up in a decent size pack. We definitely don't want that energy escaping inside our living space.

Our packs live in a steel and cement board "shed" (more toilet cubicle sized) in the car port with the inverters (panels on the roof of the car port).
 
For a spot of perspective, a 10kWh pack contains energy equivalent to a litre of petrol/gasoline.

Even in our concrete and steel home any fuel lives in the outbuildings with the chook food.
 
crossy said:
Yup, even with LiFePO4 there's a lot of energy tied up in a decent size pack. We definitely don't want that energy escaping inside our living space.

Our packs live in a steel and cement board "shed" (more toilet cubicle sized) in the car port with the inverters (panels on the roof of the car port).
Click to expand...
Seems like when these things catch on fire they also pop and shoot out parts of the battery on fire like a volcano. So, yeah encase them! I didn't realize how unstable lithium batteries were until I started this solar journey recently. Again, I'm surprised they are legal seeing how unstable they can be. I bet shipping these things take a lot of insurance. I'd hate to be on a plane with these things in the cargo area.
 
crossy said:
For a spot of perspective, a 10kWh pack contains energy equivalent to a litre of petrol/gasoline.

Even in our concrete and steel home any fuel lives in the outbuildings with the chook food.
Click to expand...
Personally, I don't even like putting the car in the garage. It's gas but still...
 
realpinochet said:
Seems like when these things catch on fire they also pop and shoot out parts of the battery on fire like a volcano. So, yeah encase them! I didn't realize how unstable lithium batteries were until I started this solar journey recently.
Click to expand...
There is a world of difference between the lithium chemistries.

LiFePO4 just doesn't do that. If abused it will bulge and have a bit of a hissy fit, but it's not going to blow up or result in a thermal runaway. It's just not possible with LiFePO4 chemistry. You can pierce them and not a lot will happen. Do that with other lithium chemistries and yeah, all sorts of fireworks are possible.

Any battery storage can result in a fire, all that requires is energising something else in a manner it shouldn't, like a short circuit. Anything that can dump a lot of current in a short space of time has the potential to light up stuff.
 
realpinochet said:
I'm surprised it's even legal to sell these things. I'd hate to live in a apartment when people are buying them and storing them inside. As for solar...I'm sure at this point on the solar shed to house the batteries and inverters.
Click to expand...

What is the most major cause of household fires?

The number one cause of house fires is unattended cooking. Make sure that you stay in the room while you are cooking with a heat source.

The 2019 national estimates for residential building cooking fires and losses show that there were: 178,100 fires. 150 deaths.

In 2020, there were around 173,000 highway vehicle fires reported in the United States. This is a decrease from the previous year, where there were 189,500 highway vehicle fires reported across the country.

Meanwhile e-bikes offer the freedom of mobility without paying off the DMV or insurance mafias so we better crack down on them things cause a dozen spark up every year.
 
Last edited:
32 volt boater said:
What is the most major cause of household fires?

The number one cause of house fires is unattended cooking. Make sure that you stay in the room while you are cooking with a heat source.

The 2019 national estimates for residential building cooking fires and losses show that there were: 178,100 fires. 150 deaths.

In 2020, there were around 173,000 highway vehicle fires reported in the United States. This is a decrease from the previous year, where there were 189,500 highway vehicle fires reported across the country.

Meanwhile e-bikes offer the freedom of mobility without paying off the DMV or insurance mafias so we better crack down on them things cause a dozen spark up every year.
Click to expand...
You seem to have a E bike and took this hard. I'm not asking the Gov to crack down, I despise the federal government and their tyranny. But, that does not mean we can't put batteries into them that don't explode either. I could care less if most fires are from cooking..that does not convince me to put a battery in my house that can explode without warning. Logic would indicate that you do whatever reasonable you can to prevent any fire regardless of source. Right?
 
wattmatters said:
There is a world of difference between the lithium chemistries.

LiFePO4 just doesn't do that. If abused it will bulge and have a bit of a hissy fit, but it's not going to blow up or result in a thermal runaway. It's just not possible with LiFePO4 chemistry. You can pierce them and not a lot will happen. Do that with other lithium chemistries and yeah, all sorts of fireworks are possible.

Any battery storage can result in a fire, all that requires is energising something else in a manner it shouldn't, like a short circuit. Anything that can dump a lot of current in a short space of time has the potential to light up stuff.
Click to expand...
True..then you read the "up in smoke" section and realize it's more dangerous than you thought. While you say "any battery storage" and I get what you're saying but I've never had a pack of energizer batteries just blow up or find my remote melted into the sofa. But, yes I get what you're saying.
 
I probably shouldn't, but just to add some balance :)

I operate a 12,000 cell (lithium-ion) powerwall and I'm not in the least concerned about fire/explosions! That's because
1) Each cell is fused.
2) Ambient temps of 50F - 80F
3) It's operated in the low stress / middle voltage range of 3.5v -> 4.0v.
4) It's operated in the low stress charge/discharge range of 0.1C
5) It's monitored closely with a couple of layers of safeguards.

The only 'actual fire' I've seen over many threads, youtubes, posting is from 1) overcharge (a serious issue if allowed) or 2) extreme physical stress - as in puncture, car wreck etc. Neither of these apply to my powerwall.
 
If you use an RV, you'll be sleeping with batteries under your bed...maybe not. But there's no garage there either...there maybe one, but it's still under your bed (or beside it).

 
OffGridInTheCity said:
I probably shouldn't, but just to add some balance :)

I operate a 12,000 cell (lithium-ion) powerwall and I'm not in the least concerned about fire/explosions! That's because
1) Each cell is fused.
2) Ambient temps of 50F - 80F
3) It's operated in the low stress / middle voltage range of 3.5v -> 4.0v.
4) It's operated in the low stress charge/discharge range of 0.1C
5) It's monitored closely with a couple of layers of safeguards.

The only 'actual fire' I've seen over many threads, youtubes, posting is from 1) overcharge (a serious issue if allowed) or 2) extreme physical stress - as in puncture, car wreck etc. Neither of these apply to my powerwall.
Click to expand...
You mean like when your charge controller fails and over volts/charges the batteries and the cheap china bms fails to cut the battery off? I've seen that happen in the mentioned forum. I guess what I was saying is I understand why some build a solar shed!
 
realpinochet said:
You mean like when your charge controller fails and over volts/charges the batteries and the cheap china bms fails to cut the battery off? I've seen that happen in the mentioned forum. I guess what I was saying is I understand why some build a solar shed!
Click to expand...

Neither cheap nor Chinese, though like all electronics, built with Chinese components.

If you had any idea how much that BMS cost... Mine was $1000... @OffGridInTheCity was more... :p

@OffGridInTheCity's BMS WOULD protect the battery in that failure case.
 
realpinochet said:
You mean like when your charge controller fails and over volts/charges the batteries and the cheap china bms fails to cut the battery off? I've seen that happen in the mentioned forum. I guess what I was saying is I understand why some build a solar shed!
Click to expand...
A cheap china BMS monitoring your LifePo4 battery could start a fire on it's circuit board - if you don't have confidence in you're BMS then I'd advise not using it for any chemistry.

I use Batrium and have 3+ years of history and automated monitoring software - so even a modest departure from the 3 years of healthy/routine operations such as pack starting to sag will be brougt to my attention with plenty of time to take corrective action - long before it reaches Critical Fault / Shunt-Trip shut-off or any serious stress on the cells.
 
OffGridInTheCity said:
I probably shouldn't, but just to add some balance :)

I operate a 12,000 cell (lithium-ion) powerwall and I'm not in the least concerned about fire/explosions! That's because
1) Each cell is fused.
2) Ambient temps of 50F - 80F
3) It's operated in the low stress / middle voltage range of 3.5v -> 4.0v.
4) It's operated in the low stress charge/discharge range of 0.1C
5) It's monitored closely with a couple of layers of safeguards.

The only 'actual fire' I've seen over many threads, youtubes, posting is from 1) overcharge (a serious issue if allowed) or 2) extreme physical stress - as in puncture, car wreck etc. Neither of these apply to my powerwall.
Click to expand...

Some, they sleep with batteries on their basements. :LOL:

diysolarforum.com

What even is this??

My friend bought a house from an 80+ year old retired electrical engineer. House is grid tied but with 15 rooftop panels and this monstrosity in the basement. Any guesses on what we're looking at here? Thanks in advance.
diysolarforum.com diysolarforum.com
 
sunshine_eggo said:
Neither cheap nor Chinese, though like all electronics, built with Chinese components.

If you had any idea how much that BMS cost... Mine was $1000... @OffGridInTheCity was more... :p

@OffGridInTheCity's BMS WOULD protect the battery in that failure case.
Click to expand...
I'm curious what kind of BMS do you think the server batteries use like EG4 etc? And, you can't visualize them like offgrid can to be proactive if whey are bulging or sagging. What kind of proactive safety precautions can you take with these sort of batteries?
 
Last edited:
realpinochet said:
I'm curious what kind of BMS do you think the server batteries use like EG4 etc?
Click to expand...

Something marginally better than a JBD.

realpinochet said:
And, you can visualize them like offgrid can to be proactive if whey are bulging or sagging.
Click to expand...

Not sure what you're saying here. I would expect them to be destroyed by your MPPT failure scenario along with all current commercial battery options including Big Battery, SOK, Battleborn, etc.

You need a secondary protection circuit that operates exclusively on battery voltage and can only be exposed to battery voltage even if the primary circuit is opened. @OffGridInTheCity's Batrium provides this function.

Ah... you edited after I quoted. 2 options:

1) battery voltage based. If battery voltage > limit, disconnect output of MPPT from battery, yet sensing circuit only sees battery voltage.
2) battery voltage based. If battery voltage > limit, disconnect INPUT of MPPT from PV.

Victron BMV relay could provide either option as well as many other battery monitoring options.
 
sunshine_eggo said:
Something marginally better than a JBD.



Not sure what you're saying here. I would expect them to be destroyed by your MPPT failure scenario along with all current commercial battery options including Big Battery, SOK, Battleborn, etc.

You need a secondary protection circuit that operates exclusively on battery voltage and can only be exposed to battery voltage even if the primary circuit is opened. @OffGridInTheCity's Batrium provides this function.

Ah... you edited after I quoted. 2 options:

1) battery voltage based. If battery voltage > limit, disconnect output of MPPT from battery, yet sensing circuit only sees battery voltage.
2) battery voltage based. If battery voltage > limit, disconnect INPUT of MPPT from PV.

Victron BMV relay could provide either option as well as many other battery monitoring options.
Click to expand...
Thanks bro, I've done a lot of research in the inverter piece of this but need to start researching batteries and panels. I want a good value, we all do, on the batteries but also want them to last and be safe.
 
realpinochet said:
Thanks bro, I've done a lot of research in the inverter piece of this but need to start researching batteries and panels. I want a good value, we all do, on the batteries but also want them to last and be safe.
Click to expand...

It's worth stating that the MPPT PV short to battery type of failure is exceedingly rare. I can't say I've ever heard it documented by a Tier-1 brand.

sunshine_eggo said:
Victron BMV relay could provide either option as well as many other battery monitoring options.
Click to expand...

Clarification: I meant that there are other battery monitoring options besides Victron BMV that could be used for protection in this failure mode - like this one... good to 500V:

Affordable Electric Vehicle Batteries & Components from Electric Car Parts Company

Electric Car Parts Company is your one-stop-shop for affordable electric vehicle parts and components including batteries. Shop our selection and order now!
www.electriccarpartscompany.com

I use one of these to monitor a 1000Ah 12V bank I keep in my office.
 
You must log in or register to reply here.

Similar threads

W
72VDC Lion (NOT LiFePO4) 4kW batteries on tap, looking for a solar solution to charge them.
Replies
10
Views
441
HarryN
H
R
What else does your ‘Vehicle Mounted System’ do for you?
Replies
12
Views
690
HarryN
H
R
Ebike buttery with canbus bms
Replies
0
Views
302
Ricardo Cervera
R
k490
Explosion fears lead San Diego to explore regulating lithium-ion batteries, storage facilities
Replies
13
Views
315
aenyc
A
oldspice
is it plausible to re use "defective" E bike batteries? how would you do it?
2
Replies
25
Views
1K
OffGridInTheCity
OffGridInTheCity

diy solar

diy solar
Back
Top