How solar panel impact battery life for ebike?

Batteries, Chargers, and Battery Management Systems.
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Tangalle   100 mW

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How solar panel impact battery life for ebike?

Post by Tangalle » May 23 2019 8:17pm

Hi every one

I have a specific question.
I am gonna to build a 700wc solar panel system on my ebike with trailer.

I want to choose the battery technology who can provide a good life... I want to say 3 years before it's getting too bad.

LFP technology are the best for that as far as I know.

But it's heavy and expensive.

So I would like to understand how the constant solar panel charge use (or not) the battery. How that's works?

Thank you for your hand

john61ct   100 kW

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Re: How solar panel impact battery life for ebike?

Post by john61ct » May 23 2019 8:51pm

Key requirement is putting in more each day tgan you take out.

Amps and volts, batteries don't care where they come from.

No relationship to battery life, LI cells do not need to get to Full like lead. I suppose overcharging is rarely an issue, total contribution by solar will be tiny compared to EV usage.

Time for balancing may require high volts, depends on if you use a BMS to do that and what sort.

Get a controller lets you set the voltage you need, very few go as high as 48V, might need a little lower V batt to buffer then use a voltage boost converter.

Tangalle   100 mW

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Re: How solar panel impact battery life for ebike?

Post by Tangalle » May 24 2019 12:34am

Tgan?


When I read you response, it's looks like I did not explain myself clearly. I am not English speaker.

I plan to live on a bike for years. With the solar panel and battery.

All day long, the battery will discharge and charge.

Discharge from biking obviously
Charge from solar panel

How this specific utilisation of solar panel with a ebike can influence the battery?

Maybe one day bicycling with solar panel is like 5 cycles.
Or 0 I don't know for battery.

It is not like a electric plug. And you plug it one time each day so you can know.
With a solar panel it's like all the time charging.

I know I should not charging or discharging too much the battery to keep it healthy (and not having more than 0.5c to keep as far as possible the life cycle).

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Easy_Rider   1 mW

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Re: How solar panel impact battery life for ebike?

Post by Easy_Rider » May 24 2019 12:34am

I would not say it is impossible, I would just say it is complicated and might be expensive.

You would need between the battery and the solar panel something like this: https://www.amazon.com/GHB-Controller-I ... way&sr=8-3

But those controllers hardly exist for more than 24V.

So Life-Cycle is not really important at this point, because if you don´t have the right controller to Charge CCCV, most probably you will "kill" any battery long before that....

So maybe you should rethink your plan and use 12V LiFePo4 as additional battery. Those ones can be easily integrated on Solar Panel systems...
I love riding a bike, but I love the most riding my eBike

john61ct   100 kW

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Re: How solar panel impact battery life for ebike?

Post by john61ct » May 24 2019 1:56am

Than.

Yes your concern is not lifespan, LFP is the way to go, that's settled.


Tangalle wrote:Maybe one day bicycling with solar panel is like 5 cycles.

I know I should not charging or discharging too much the battery to keep it healthy (and not having more than 0.5c to keep as far as possible the life cycle).
Don't worry, you won't have room for even close to that much solar panels.

If you are saying you are OK with sitting in one place waiting for five days before you can travel again for a few miles,

then yes that is realistic.

But you really should take advantage of mains power when you can get it.



Tangalle   100 mW

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Re: How solar panel impact battery life for ebike?

Post by Tangalle » May 24 2019 11:42am

Ok, that's my English.

I will do something more simple.

Imagine.


I do 100 miles for exemple on one day.

I start at 100%.
After 10 miles, my battery is 90% because no sun.
At 11 miles until 20miles, I have sun. The battery is charging to 95%
Between 20 to 35 miles, no sun again, battery is going to 65%.

At 35 miles, lunch break, with sun. Battery charge until 75%

Between 35 miles to 50 miles, I am stable at 75%

Between 50 to 70 miles, the battery is going to 50%

70 to 90 miles : a bit of sunshine. The battery is going slowly to 30%

90 miles to 100 : end of day, 20%

At 100 miles, I find a electric plug to 100%

My question is the following.

How this day (number at totally random, don't care about that) can impact the battery Heath ?

Because, if for the battery it's 3 4 life cycle for just one day, my battery need to be changed after 6 8 months of bicycling.

But if this kind of day does not impact the battery life cycle, I can keep a lithium ion for many years without too much impact.

Someone know?

Thank you

flat tire   1 MW

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Re: How solar panel impact battery life for ebike?

Post by flat tire » May 24 2019 1:38pm

It is a law of ebiking that you do NOT want to put solar panels on (or behind) your ebike unless you have absolutely no other choice.

Tangalle   100 mW

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Re: How solar panel impact battery life for ebike?

Post by Tangalle » May 24 2019 2:26pm

Why?
Links?


When I see "sun trip" it's looks like it's possible.


pullin-gs   100 W

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Re: How solar panel impact battery life for ebike?

Post by pullin-gs » May 24 2019 3:25pm

You may want to explore also "How ebike mount impact life of solar panel?".
First thoughts would be to go with flexible panels. They are light and give OK power, and can mounted to conform to various shapes. Flexibles are lighter also.
However......
Issues include flex panels are very fragile....life on flat stationary mount is 5 years at best....put on vibrating bike and things could be worse (1 year or less). https://www.youtube.com/watch?v=onMZ_dRSFUs&t=7s

billvon   100 MW

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Re: How solar panel impact battery life for ebike?

Post by billvon » May 24 2019 3:58pm

Tangalle wrote:
May 24 2019 11:42am
Between 35 miles to 50 miles, I am stable at 75%
That's very unlikely. You won't be able to carry 250 watts of panels.
How this day (number at totally random, don't care about that) can impact the battery Heath ?
For LiFePO4, life won't change much.
For Li-ion, life will go down (battery will be at higher voltages more often.)
--bill von

Tangalle   100 mW

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Re: How solar panel impact battery life for ebike?

Post by Tangalle » May 24 2019 5:00pm

I will have around 600Wc on 4m2
My battery will be 48v

Li-on battery : how bad it will be?

Flexible solar panel : yes for sure. And the cheapest one. I will look your video.

Tangalle   100 mW

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Re: How solar panel impact battery life for ebike?

Post by Tangalle » May 24 2019 5:20pm

pullin-gs wrote:
May 24 2019 3:25pm
You may want to explore also "How ebike mount impact life of solar panel?".
First thoughts would be to go with flexible panels. They are light and give OK power, and can mounted to conform to various shapes. Flexibles are lighter also.
However......
Issues include flex panels are very fragile....life on flat stationary mount is 5 years at best....put on vibrating bike and things could be worse (1 year or less). https://www.youtube.com/watch?v=onMZ_dRSFUs&t=7s
I saw the video.
The heating problem will be less because they will be fit on a roof with free air around. Especially when I will drive

I will not use the flexibility. I want them straight.

So it's not looks like a problem for me.

And you say vibrating will be a problem but do you have any link or report from people who use solar panel on bike?

john61ct   100 kW

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Re: How solar panel impact battery life for ebike?

Post by john61ct » May 24 2019 5:23pm


Tangalle wrote:Imagine.
If wishes were fishes.

Again, (and again) there are **no concerns** about longevity as long as you use LFP and care for them properly, will last many many years.

But your ideas about solar are a fantasy.

Look at the actual numbers.

How much space do you have for panels?

How many kWh per day do you need?

Even in perfect weather (cold and clear),

how many Wh do you get per hour, per square meter of panels? Without tilting toward the sun, cut that in half.

And only 4-5 hours per day are at that rate.


Better to carry a generator with you, unless you are only travelling in densely populated areas with lots of access to grid power.






john61ct   100 kW

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Re: How solar panel impact battery life for ebike?

Post by john61ct » May 24 2019 5:25pm

Other LI chemistries, might get 10-15% of LFP's cycle lifetime.

LTO is even better than LFP, but new so rare, completely different voltage range.

john61ct   100 kW

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Re: How solar panel impact battery life for ebike?

Post by john61ct » May 24 2019 5:27pm

Cheap semi-flex panels might last 2-3 years average, even stationary mounted.

Moving around bumping on roads a lot less.

john61ct   100 kW

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Re: How solar panel impact battery life for ebike?

Post by john61ct » May 24 2019 5:32pm

Tangalle wrote:I will have around 600Wc on 4m2. My battery will be 48v
Likely 400W average even in sunny climate near the equator, for 4-6 hours per day.

So 30-40Ah

How many miles does that get you?

Tangalle   100 mW

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Re: How solar panel impact battery life for ebike?

Post by Tangalle » May 24 2019 5:49pm

I will also a electric charger. Flatpack d'eltek 1800w.

So I don't care how much energy I will have. So days it will be awesome, another day bad.

It was not the topic of this topic to speak about the longevity of solar panel but I will look it carefully.


So lto and lfp are ok. Links to prove it ? I want to understand more than someone tell me (even it's good!!!!)


I don't have plan and circuit : it will be my life. One week I will do nothing and the next day I will go where I wish. Could be 10 or 10.000km away

john61ct   100 kW

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Re: How solar panel impact battery life for ebike?

Post by john61ct » May 24 2019 6:39pm


Tangalle wrote:So lto and lfp are ok. Links to prove it ?
There is no "proof", too many variables.

Googling will find plenty of product data sheets and detailed forum discussions.


Tangalle   100 mW

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Re: How solar panel impact battery life for ebike?

Post by Tangalle » May 24 2019 7:43pm

Ok, so if I understood about my topic question :

- yes it will impact but not so much if you use a battery with long life cycle.

Nmc could a good balance.

billvon   100 MW

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Re: How solar panel impact battery life for ebike?

Post by billvon » May 24 2019 8:44pm

Tangalle wrote:
May 24 2019 5:00pm
I will have around 600Wc on 4m2
My battery will be 48v
Flexible solar panel : yes for sure. And the cheapest one.
OK let's do the math on that.
At 20% efficiency (which is a good, expensive panel) you would need 4 square meters to get 600 watts under perfect conditions. On the road you'd need closer to 6 square meters if you want to get close to 600 watts under normal conditions. That's a panel 3 feet wide by 18 feet long, and will weigh around 50 pounds. (Justin did a 550 watt panel; it was 37 pounds. Best he did was about 370 watts. And he tilted his panels to maximize insolation.)

Now, what do you think will happen when the first gust of wind hits it? Justin's trip used a single touring trike with two people on it and two hubmotors, so he had a lot of weight close to the ground. Sounds like you will be lighter.

3 200W Sunpower flexible panels will be about $1320. Then you have to add frame, mounting foam, fiberglass etc etc.

But you said the _cheapest_ one? Increase all those size and weight numbers significantly.
Li-on battery : how bad it will be?
The two worst things you can do to a lithium ion battery is to keep it at full charge and keep it hot. Constant solar charging does both. You'd want to be _very_ careful with ventilation and charge state.
--bill von

Tangalle   100 mW

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Re: How solar panel impact battery life for ebike?

Post by Tangalle » May 24 2019 8:54pm

Thanks for the advice for the overwarming battery (lithium nmc)

For solar panel :
-flexible solar panel are not so heavy because even without solar panel I will have a roof on the trike to protect against sun. And I will have obviously a roof on my caravan trailer.

-price 1 watt = 1 euro one Amazon
MOHOO Panneau Solaire 50W 18V SUNPOWER

I will have 48ah 48v battery with a charger if I need to charge because no sun.

Wind : I will see. I saw any sun trip guy having trouble with that and they are mostly one on the bike

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Re: How solar panel impact battery life for ebike?

Post by john61ct » May 24 2019 10:57pm


Tangalle wrote:Ok, so if I understood about my topic question :

- yes it will impact but not so much if you use a battery with long life cycle.

Nmc could a good balance.
You have come to a conclusion here that I do not see any relationship to the responses you got.

Maybe it would help if you state exactly what you think will impact longevity?

Why would you then suddenly propose changing to a chemistry that does not support good longevity?

Balance between what and what?

I don't think it is a language problem - you need to be more precise in your thought processes.

docware   100 W

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Re: How solar panel impact battery life for ebike?

Post by docware » May 25 2019 7:52am

How solar panel impact battery life for ebike ?

Negatively, if you will be succesfull in your intention, as dwelling at higher SOC is negative for battery lifetime.

https://www.researchgate.net/publicatio ... g_High_SOC

So you invest your money and effort to make battery lifetime worse. Understandable ?

john61ct   100 kW

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Re: How solar panel impact battery life for ebike?

Post by john61ct » May 25 2019 3:43pm

The guideline really is most critical as

"do not **store** at Full for a high percentage of lifetime".

If maximum range is required, and the bank is constantly cycling between Full and lower SoC

then that effect will be minor.

Certainly not as important as not going to too low a discharge point, when that is avoidable.

In any case, as we all know, it isn't the solar aspect that "threatens" too high an average SoC, but the desire to cover ground, X miles per week, that will threaten "too low".

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