Bosch Solar Charging

[wildtrak]

That's not simply just 2 Y cables is it?

It was. After digging into the source code of the Diagnostic Software, I found that this supports up to 5 parallel batteries.
However, Bosch never implemented it into the motor software. This was with a 2017 version motor software. System turns on, detects 3 batteries but does not like it and turns off.
It displayed the 3 batteries on the Intuvia just for a very short moment before shutting down.
Charging 3 batteries in parallel (not connected to the motor) worked.
The newer motor software detects it before turning the display on and does not turn on at all.

 

[webcurl]

Is Laufen far away from where you're from in Bayern?

 

[wildtrak]

Is Laufen far away from where you're from in Bayern?

180km. One day ebike ride so to say.

 

[wildtrak]

Some more testing today. Unfortunately, the MPT-7210A only does 100W if I put the panels in parallel. 17.5V to 42V.
If I set them up in series and parallel, I get >6A.
Lets see what the other charge controller can do.

Just strange that it was still charging over 5A at 95% Bosch battery level.

 

[webcurl]

Some more testing today. Unfortunately, the MPT-7210A only does 100W if I put the panels in parallel. 17.5V to 42V.
If I set them up in series and parallel, I get >6A.

Both large paralleled in series with both smaller paralleled?
= (2 x large) + (2 x small)

Just strange that it was still charging over 5A at 95% Bosch battery level.

That's a worry!
How are you determining 95% charge? If it's from the bike display it may be a lights reserve buffer thing, or maybe not

 

[wildtrak]

Both large paralleled in series with both smaller paralleled?
= (2 x large) + (2 x small)

No. Both large in series and both small in series. They're all the same voltage.

How are you determining 95% charge?

That's what the connected Kiox said. In the box is a motor PCB and a stripped Shimano battery with a Bosch BMS. I use this to monitor the battery charging process.
That is not related to the light buffer. That would only cut the assistance off at 5% in this case.
When I monitor the charging process from the Bosch charger using a plug-in outlet Watt meter, I can watch the Watts slowly decreasing when the battery gets full.

 

[Merle Nelson]

I like it that people who understand these things are figuring it all out. I just want to be able to charge bike batteries by solar - the end result, not the journey.

 

[wildtrak]

Two panel in series works much better with the MPT-7210A.
4:30pm, two 50W panels. Almost 80W charging. Battery turned off at 100%.

Too bad that folding 100W panel is sold out.

I will do some more testing when I get the other charge controller.

 

[webcurl]

Two panel in series works much better with the MPT-7210A.
4:30pm, two 50W panels. Almost 80W charging. Battery turned off at 100%.

So the Sunpower's are the real deal.
I have my P3solars usually in parallel but then their individual MPP is 31VDC with an Open Circuit voltage of 39VDC.

 

[wildtrak]

Parallel charging of two 500Wh Bosch batteries with a 50W panel.
Works just fine, takes just a bit over 4 days until both batteries are 100% charged. After both are fully charged, they just turn on and off every few seconds which is no problem.
Even with a smaller 30W panel I could create a hidden remote battery swapping station anywhere.

 

[webcurl]

Parallel charging of two 500Wh Bosch batteries with a 50W panel.
Works just fine, takes just a bit over 4 days until both batteries are 100% charged. After both are fully charged, they just turn on and off every few seconds which is no problem.
Even with a smaller 30W panel I could create a hidden remote battery swapping station anywhere.

Looks like the Elejoy boost converter in there.
Glad to see you didn't do a noob thing like use a black case! I still see now and then young dude's wearing a black t-shirt working outside in our Aussie sun
Are you able to see the Cycle Count from the Bosch BMS's? I thought i read on the German Pedelec forum once that cycle count's increase rapidly via the 5V charge trick and also may brick themselves once reached a certain count?
Good work!

 

[wildtrak]

Looks like the Elejoy boost converter in there.

Correct. And a car USB charger (12-24V) connected to the solar panel side (input) to get the 5V signal.
That signal only goes to the first battery. From there you need the CAN bus connection to the second battery and of course the power connection. As soon as one battery turns on, they talk to each other. The one with the higher charge level will be fully charged first.

Are you able to see the Cycle Count from the Bosch BMS's? I thought i read on the German Pedelec forum once that cycle count's increase rapidly via the 5V charge trick and also may brick themselves once reached a certain count?

I am able to see that, but I don't care. I never heard about that cycle count's increase. I don't beleive that. It is just like turning the battery on using the battery power button.

 

[webcurl]

I am able to see that, but I don't care. I never heard about that cycle count's increase. I don't beleive that. It is just like turning the battery on using the battery power button.

I was never sure as the German->English translator i was using was never that great.

Would be interesting to see if your setup works exactly the same with Powertube's instead.

 

[wildtrak]

Would be interesting to see if your setup works exactly the same with Powertube's instead.

It does.
I have a brand new 625Wh horizontal PowerTube but no bike for it. Unfortunately nobody wants to buy it.

 

[TrevorB]

Found this video on home built 12v charger. I thought there was smarts on charger to battery interface, but seems not. Just 5V to drive electronics in battery and 42V to charge them.