Community Forums

fatsurf · 08-05-2022, 11:21 AM

First boondock trip with the new solar (380 watts). I have 2 fat tire ebikes 1 with 12ah bat the other has a 15 ah bat both are 48 volts. Both chargers say 200 watts. I plug them into my 1000 watt inverter for charging. It was eye opening the amount of battery it consumes to charge my bike batteries. I did not think of the power math involved and really drained my bats the first time charging at night. Down to <50% in the morning (2 6v gc T105 batts). Next day we rode the bikes in the morning and I charged them from 2 to 4:30 with the solar doing most of the heavy lifting with 20+ amp solar output. House Batteries charged back up with the remaining sun after 4:30. This morning my house batteries were at 12.4 volts, much better then the 11.8 volts yesterday morning.
Moral of the story it to be aware charging ebikes is power intensive and should be thought out in advance. The up side is I am now riding solar powered ebikes.
//Greg

DavidEM · 08-05-2022, 12:39 PM

I have a single 'Lectric Ebike and don't use it as much as you do. I watch the charge level and it takes a couple of camping trips with moderate trail use to get down to about 30% SOC. Then on the way home I hook the battery and charger up to a small 300 watt inverter which I plug into a dash outlet. That dash outlet is on a 20A fuse, but I am pretty sure a 15A one would work. The battery is fully charged by the time we get back home after a typical 2 hour drive.

I have never tried just charging from the house batteries through the inverter. I suspect it would draw down the batteries by maybe 30 amp hours.

David

twogypsies · 08-05-2022, 06:15 PM

Quote:

Originally Posted by DavidEM

I have a single 'Lectric Ebike and don't use it as much as you do. I watch the charge level and it takes a couple of camping trips with moderate trail use to get down to about 30% SOC. Then on the way home I hook the battery and charger up to a small 300 watt inverter which I plug into a dash outlet. That dash outlet is on a 20A fuse, but I am pretty sure a 15A one would work. The battery is fully charged by the time we get back home after a typical 2 hour drive.

I have never tried just charging from the house batteries through the inverter. I suspect it would draw down the batteries by maybe 30 amp hours.

David

There was a fairly recent post of bike batteries exploding in the RV.

baraff · 08-05-2022, 06:38 PM

Quote:

Originally Posted by twogypsies

There was a fairly recent post of bike batteries exploding in the RV.

That was a scary thread. We have two Lectric Bikes and if I remove the batteries and bring them in for charging I will only charge them when we are in the motorhome and never overnight. I have thought about buying charging bags but the batteries are huge and finding bags that are large enough is challenging.
Usually we leave them in the bikes and charge them directly from the 20amp circuit in the power pedestal, or from our exterior outlet if the pedestal location is not convenient, weather permitting.
The problem is people buy cheap no name replacement batteries or chargers online and expect the same safety and performance. (I'm not saying that is what happened in that exploding battery thread). So many unknowns and variables on charging lithium batteries. I will stick with factory recommendations.

AlanTerry · 08-05-2022, 07:02 PM

Just FYI that your batteries if charged to often before they are really in need DO develop a memory and will give you a shorter lifespan over time. Just like your cellphone battery does.

96 Wideglide · 08-05-2022, 07:23 PM

You don't have much of a house battery bank!

Any room to add another pair?

rffowler55 · 08-05-2022, 07:44 PM

Quote:

Originally Posted by baraff

That was a scary thread. We have two Lectric Bikes and if I remove the batteries and bring them in for charging I will only charge them when we are in the motorhome and never overnight. I have thought about buying charging bags but the batteries are huge and finding bags that are large enough is challenging.
Usually we leave them in the bikes and charge them directly from the 20amp circuit in the power pedestal, or from our exterior outlet if the pedestal location is not convenient, weather permitting.
The problem is people buy cheap no name replacement batteries or chargers online and expect the same safety and performance. (I'm not saying that is what happened in that exploding battery thread). So many unknowns and variables on charging lithium batteries. I will stick with factory recommendations.

We bought the following charging bag after reading the post mentioned above:

FLASLD Lipo Battery Safe Bag Explosionproof - Large Capacity Fireproof Bag for Ebike Battery Charging and Storage (19.3 x 4.3 x 7in)

twogypsies · 08-06-2022, 12:16 AM

Here's the post of the battery fire:

https://www.irv2.com/forums/f59/fire...ry-582719.html

xrated · 08-06-2022, 05:53 AM

Quote:

Originally Posted by AlanTerry

Just FYI that your batteries if charged to often before they are really in need DO develop a memory and will give you a shorter lifespan over time. Just like your cellphone battery does.

Nope, not true. You probably are thinking about the old Ni-Cad batteries from years ago. Modern Lithium-Ion batteries do not have a memory issue. The old Ni-Cad batteries...they recommended that you deep discharge them and to NOT charge them after every use unless it was a deep discharge. Here is a link to a good article explaining the Li-Ion batteries for ebikes and their proper care....

https://www.electrifybike.com/blogs/...-ebike-battery

corjaguar · 08-06-2022, 08:41 AM

I would think twice before I charge lithium batteries indoor......some auto manufactures have issued warnings suggesting you park your car outside at night while charging. The apartment/store front fire in NYC was caused be the occupant of the storefront was charging a couple of ebike in the store at night....I believe it killed a couple of people.

Persistent · 08-06-2022, 12:42 PM

Not all e-bike batteries are the same. They come in many varieties.
Some older ones are not lithium based. Even lithium batteries come in different chemistries and different qualities.

Some chemistries are dangerous to charge. Some are not.

Preventing overcharge is important. Some chargers are high quality and well tuned for a specific chemistry. Some are not.

Mixing chargers intended for one purpose can cause issues when used for a different configuration. All require a battery management module that matches the battery.

Chinese designed, built, and sold do not have liability risks. The sell for less. Just try suing them!

US brands have liability risks. Even though the batteries and probably the chargers are built in China, they are willing specify higher cost designs to reduce liability risk.

I wish you good luck and happy trails ahead!

gatorb8 · 08-06-2022, 01:16 PM

a 15 AH 48v bike battery is equivalent to a 60 AH 12 battery
That will dump a 120AH 12 V battrry to 50%
you have 2 bikes so multiply that by 2
there is a lot of energy in those 48V lithium batts!

fatsurf · 08-06-2022, 01:25 PM

Quote:

Originally Posted by 96 Wideglide

You don't have much of a house battery bank!

Any room to add another pair?

I wish I could add another pair of batteries but the batteries are in the step. with what I have and what I use the 225 amp hours it's adequate for our needs especially with the solar now to charge them works well. If and when I upgrade the batteries I'll probably change out to a pair of LifePo batteries.

fatsurf · 08-06-2022, 01:27 PM

Quote:

Originally Posted by gatorb8

a 15 AH 48v bike battery is equivalent to a 60 AH 12 battery
That will dump a 120AH 12 V battrry to 50%
you have 2 bikes so multiply that by 2
there is a lot of energy in those 48V lithium batts!

That was my point there's a lot of wat hours in a 15 amp hour 48 volt battery.