Charging message: Battery too cold

[FrankH]

Today I tried to charge my Enertia Plus for the first time and I got this message on the display:

As you can see it's not freezing but rather warm for the time of year (8C = 46F).

What to do now? Leave it connected or wait till the temperature rises? That would mean moving my bike inside because it's not going to get warmer outside any time soon... Or should I drive around a bit to heat up the batteries?

[FrankH]

To answer my own question: driving twice around the little square we live at, warmed my batteries up enough so now it's loading.

[BrammoBrian]

Today I tried to charge my Enertia Plus for the first time and I got this message on the display:

As you can see it's not freezing but rather warm for the time of year (8C = 46F).

What to do now? Leave it connected or wait till the temperature rises? That would mean moving my bike inside because it's not going to get warmer outside any time soon... Or should I drive around a bit to heat up the batteries?

Frank,

You can leave the bike plugged in and the cell heaters will bring the battery up to proper temperature to allow charging at the full rate.  Driving the bike and discharging the cells as you've done is another good way to heat the pack more quickly.  Since the resistance of the cell is higher in the cold, they actually heat faster in cold weather.  Until that minimum internal temperature (around 10C) is acheived, then the charge rate will be reduced to prevent damage to the cells due to plating.  There is alot of thermal mass in the battery, so they can take a long time to heat or cool down. The ideal circumstance, although I realize it is not possible for everyone, is to charge the bike in a garage that is somewhat insulated from the cold.  It is also ideal to start charging directly after a ride, so that the pack is still in a "warm" condition. 

[protomech]

Cell heaters = very cool.

What kind of temperature gain can the cell heaters handle? For example, I believe the 2012 Zero BMS disables charging below 20F/-7C. Can the cell heaters heat the Enertia cells to a reasonable charging temperature at 20F ambient? 10F? 0F?

Is there any way to configure the bike to pre-heat from the wall at a particular time to reduce the range degradation in cold temperatures?

I wonder if there's ever a net range advantage to pre-heating the cells with energy drawn from the battery vs just riding away and allowing the cells to heat naturally.

[BrammoBrian]

Cell heaters = very cool.

What kind of temperature gain can the cell heaters handle? For example, I believe the 2012 Zero BMS disables charging below 20F/-7C. Can the cell heaters heat the Enertia cells to a reasonable charging temperature at 20F ambient? 10F? 0F?

Is there any way to configure the bike to pre-heat from the wall at a particular time to reduce the range degradation in cold temperatures?

I wonder if there's ever a net range advantage to pre-heating the cells with energy drawn from the battery vs just riding away and allowing the cells to heat naturally.

Yes, the heaters are a very clever and unique technology.  As long as the bike is plugged in, the heaters will bring the battery pack up to the minimum temperature required for full rate charging.  The conditions under which the pack has started charging (temperature at start of charge and ambient temperature) will determine how long it takes to reach this minimum temperature.  While heating, the BMS will allow charging at a reduced rate as well.

Anytime the bike is on (Enertia Plus or Empulse), the heaters will activate as needed to bring the pack up to temperature.  So, you can "pre-heat" the bike if it's sat overnight off the charger simply by turning it on.  The ideal condition is with the bike plugged in overnight as it means the pack will be both fully charged AND up to temperature as you set out on your ride in the morning.  

[kingcharles]

Cell heaters is a super feature for me. This allows me to ride all year. I was already worried that switching from NiMh to Li would reduce riding to the >0C temperature season.

This proves that the Brammo engineers really did think this trough!
Great stuff!

[protomech]

Wes posted a picture of one of the BPM15/90 modules (7 of which go into the Empulse) opened up.
http://hellforleathermagazine.com/2013/01/fiscal-cliff-bill-extend-electric-motorcycle-tax-credit/



If you look at the module like a cake, there are 4 cells per "slice" making 15V 10Ah, then 9 slices (6 visible in the photo) to make a full module @ 15V 90Ah.

One more question for BrammoBrian - are the cells also liquid-cooled? I don't recall if it is just the motor or cells too - looking at Wes's photo looks like a no. Is there some provision to use forced air to cool the cells? I imagine they would see some temperature rise at 5C discharge rates..

[oml]

I think Ive read something about a electric heating/cooling dual stuff in some magazine over here (Telepolis) which looked about the same, but I dont remember how prototypie/futuristic it was.
It also could be some oldscool heat-transport-by-metal-stuff - it looks like aluminium to me

[EmpulseRider]

I assume those are the heating elements pictured in that open battery (on the white sheet)? I also assume that the batteries are force-air-cooled. I remember someone from Brammo mentioning that these batteries can cool and heat themselves, and I thought they had mentioned that they are air cooled, though I cant locate that specific post.

[Gavin]

Today I tried to charge my Enertia Plus for the first time and I got this message on the display:

As you can see it's not freezing but rather warm for the time of year (8C = 46F).

What to do now? Leave it connected or wait till the temperature rises? That would mean moving my bike inside because it's not going to get warmer outside any time soon... Or should I drive around a bit to heat up the batteries?

Just got back from a COLD transport...message is the same, but the batteries are not 8 degrees Celsius, but negative 8....brrrrrr....it will probably take all night just to warm the batteries enough to even "start" charging...

Truck transport in winter...and mid summer?...have to be the toughest time on these batteries?

Gavin

Ps...did a short ride in Death Valley and I will have to say I was surprised...never thought my biggest concern would be freezing, but it was right at 0 degrees Celsius and I had fall gloves and it was a bit painful

[protomech]

I thought you had returned the Enertia Plus dev bike?

[Gavin]

Yes...about 2 months ago...a sad 2 months...testing was done and Brammo let me have her back. I do have to keep daily logs and send the data files back to Brammo...work work work... **


Next step is mildly complicated, but in a good way

Gavin


**