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Smart Fortwo ED3 451
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Discussion Starter · #1 ·
Hello people.

Given the fact this vehicle needs a reliable replacement 12V battery I "by accident" found a special one @ a good price.
It seems to be the right one given the fact it is a LIFEPO4 one, but who knows?
Lithium battery LiFePO4 BS Battery BSLi-02 12V-140A, 2Ah by BS Battery.
Here's the link to its price, pic and specifications:
I am also showing pix of it from their web site.
Product Camera accessory Rectangle Audio equipment Gadget

Kitchen appliance Font Musical instrument Home appliance Audio equipment


How about it?

Regards.
 

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Smart Fortwo ED3 451
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Discussion Starter · #3 ·
2Ah, 140A is small, maybe a bigger/larger capacity.

Sent from my REVVL V+ 5G using Tapatalk
I understand that, but do we really need a higher amperage battery, given the fact this car has no starter to drain a lot of juice?
Thanks.
 

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2017 453 Passion ED/EQ
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I understand that, but do we really need a higher amperage battery, given the fact this car has no starter to drain a lot of juice?
Thanks.
You may need a higher amp hour capability if you are not allowing enough time to fully recharge between starts. If, for example, you are doing multiple stops shopping at stores within a few miles of each other, then the car won't have sufficient time to recharge the battery back to the energy level lost each time you started it. The amount of time varies, depending on battery temperature as well as how low the voltage drops. It seems to me at the minimum, it needs at least 10 minutes. At the max, for normal depletion, 45 minutes. A large amp hr rating will let you do all your starts and still get you safely home. Even if you haven't given it enough time to bring the energy level back. And once you plug in and recharge from an outlet, your starter battery will be brought back to best voltage overnight with the main battery pack.
Also, how do you know the battery management system will work correctly for a LiFePo4 battery, when it was intended for a lead/acid battery? The amp and voltage charging levels might not be acceptable, and how about load leveling and balancing? That's important for lithium, but not for leadacid.
 

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I've been using a LiFePO4 battery in our 2017 ED for almost a year now and have experienced no problems whatsoever.
It's important to remember that the starter battery is only used for a brief time during start up and then begins to charge
from the H/V pack as required. However a 2 amp hour motorcycle battery just isn't going to cut it in my opinion.
My battery is a 38 amp hour and fits perfectly in the OEM space provided. Even Tesla's use a LiFePO as replacements
which are lower in Amp Hours than the factory provided versions...Also, some manufacturers' now fit LiFePO4 as standard.
 

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That relates to a motorcycle's regulator. My LiFePO battery has it's own internal BMS which negates
any overcharging concerns...
 

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I can tell you in normal days operation even a motorcycle battery is good enough. As mentioned in other threads, if the ignition is of only the Radio and/or parking and indoor light is taking energy from the battery.
In operation, as soon the contactors are closed, the energy comes from the DC/DC converter.

Only bad situation is if the drain current will cause a faster recharge by the system. in this case the bad situation of a potential brown out of 12V can happen, which can kill the HV battery.

would be interesting to know if a LiFePO4 Battery and its BMS open the line in to low levels automatically. This feature would safe the HV battery :)
 

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Would be interesting to know if a LiFePO4 Battery and its BMS open the line in to low levels automatically. This feature would safe the HV battery :)
Interesting, normally, I would expect a BMS of a liFePO4 car battery to disconnect the battery at 2.5 volts per cell, or about 10 volts, although with the abuse-resistance of LiFePO4 cells, the BMS may allow as low as 2 volts per cell, or 8 volts to account for starting in cold weather.

What might the "brown out" voltage be that triggers the Smart BMS failure and bricking?

Also, I hate to once again denigrate MB's quality, but I am fairly convinced that a big part of the problem is that OEM factory battery is poor quality compared to the discount auto-parts store battery (Advance Auto Die-Hard Platinum) I replaced my OEM battery with. I think that, to be safe, the OEM battery should be replaced with 4-year warranty aftermarket battery - flooded type, not AGM.

A question for anyone: has anyone experienced a bricking where the 12V battery was not an OEM battery?
 

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Be careful with those lithium batteries.
I used one in my scooter and it did great till one day I was riding and heard a pop and seen smoke behind me.
Managed to get the battery out before it caught my scooter on fire.
It was just out of warranty when it went up in smoke.
Been a bit weary about getting another one since.
I’ve got pics of the battery if anyone wants to see it.
 

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I've been using a LiFePO4 battery in our 2017 ED for almost a year now and have experienced no problems whatsoever.
It's important to remember that the starter battery is only used for a brief time during start up and then begins to charge
from the H/V pack as required. However a 2 amp hour motorcycle battery just isn't going to cut it in my opinion.
My battery is a 38 amp hour and fits perfectly in the OEM space provided. Even Tesla's use a LiFePO as replacements
which are lower in Amp Hours than the factory provided versions...Also, some manufacturers' now fit LiFePO4 as standard.
I notice you live in Vancouver and will probably not have problems, but the cold weather performance of LiFePO4 cells would be a problem for using this battery in a lot of areas. Generally they do not charge well below 0C, and do not discharge well below -20C. The BMS may halt charging and discharging if the temperature reaches these limits.
 

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this is the battery after it decided to go up in smoke.
Thankfully my scooter is fine aside from some light damage to the battery compartment.
I’ve wanted to get another one but the cost is more then I want to spend on a new battery for for it.(the label burned itself to the battery compartment of the scooter which I haven’t messed with to see if I can remove it.
Tire Wheel Automotive tire Automotive lighting Motor vehicle
 

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this is the battery after it decided to go up in smoke.
Thankfully my scooter is fine aside from some light damage to the battery compartment.
I’ve wanted to get another one but the cost is more then I want to spend on a new battery for for it.(the label burned itself to the battery compartment of the scooter which I haven’t messed with to see if I can remove it.
Was this battery in a gas motor scooter? Any replacement-for-lead-acid lithium battery should have a BMS to prevent the overcharge or overdischarge that causes such a battery failure.

My other EV s a Burgman-sized electric scooter with a 4.5 kwh 72 volt LiFeMnPO4 pack (24 cells), Testing some older cells, I found them to be abuse-proof as far as thermal runaway fires. Discharge them to zero, over charge to 4.5 volts - the only thing that hapens is some swelling and loss of capacity.
 

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Yes
The brand of the battery is mmg lithium and it was designed to be a drop in replacement (meaning the management was built into the battery)
Unfortunately no it did this literally days after the warranty was up.
My buddy thinks it was a defective battery.
I have dealt with lithium batteries before for hobby r/c and never had one go like this one did.
I know the construction of them are a bit different in the chemicals but still I found it odd when I seen many having good results from them.
The scooter’s charging system never went over 13.5 which was in the scope of the recommended voltage from the manufacturer for the battery(14 volts was the max)
But the fire risk is real and really scary when they do go up.
 

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The scooter’s charging system never went over 13.5 which was in the scope of the recommended voltage from the manufacturer for the battery(14 volts was the max)
But the fire risk is real and really scary when they do go up.
I noticed just the other day I had 14.67v on the battery in my smart while it was plugged in charging the mains.

Lebikerboy, does the LiFePO4 battery you have in your smart have a maximum acceptable voltage?
 

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That’s awfully close to being risky for a lithium battery.
You would probably need a stand alone management for the battery to prevent overcharging.
 

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Yea that’s why I pulled the battery before it could take my scooter with it when it went up.
I’m not sure if I’ll get another one or not(price is keeping me from doing it given what I’ve had happen with the last one)
 
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