Bosch Solar Charging

webcurl

Active Member
I continue to hit brick walls trying to do this, not impossible, just in-efficient.
My current setup, less than 75% efficient contains:
A few cheap folding blanket solar panels (Allpowers) in parallel (approx 15VDC) totaling 160W max (160W minus 30% = 112W).
Victron Smartsolar MPPT 75/15 charge controller.
Self made LifePo4 battery pack with BMS - 12.8VDC 2.4Ah containing 4 x 26650 cells.
Redarc 350RS Pure Sine inverter - up to 350W, 12V , 200-240VAC.
Bosch Compact charger (2A).
Delphi Weatherpack connectors.
eg. Solar Panel --> Charge controller --> and/or LifePo4 battery --> Inverter --> Bosch charger --> Bike :(
So this is essentially DC to Storage/Control to AC and then back down to 36VDC! Hence why conservatively less than 80% efficient!
- This will take 2 good sunny days in Ozzie sun to charge both batteries (2 x Powertube 500) from flat to full :(
AND all this weighs approx 6.2kg! I could shave off a few kilos with P3 Solar folding panels (https://p3solar.com/portfolio/p3-75w-12v-portable-solar-charger/) but they are extremely expensive, could also try a Modified Sine inverter (even less efficient) and save another kg.
Has anyone tried a modified sine inverter with any of the Bosch chargers?
And please don't suggest i carry a small generator :)

I would love to purchase 1 or 2 Bosch Travel chargers (12VDC input, 2A) but they don't make them anymore and nobody has any to sell :(

With the standard Bosch charger (4A) i've found that if it doesn't get the 190+ watts it needs it shut's down. This would require a much larger capacity storage battery for when the sun is behind clouds to stop it from starting/stopping too often/quickly, and also 250W+ of solar panels.

I've found that the Compact charger (2A) whilst liking approx 95W of power will continue to operate below that level.

I've found that someone said that if you simply supply 5VDC to the signal line on a Bosch connector you can fool the battery into accepting charge (36VDC).
This would be so much nicer! I'd still keep the charge controller and small battery (for cloud conditions) but eliminate an DC-AC conversion stage. Plus power input to the bike batteries could be more dynamic depending on the solar.
Also found this on ebay: https://www.ebay.com/itm/172786244901?ul_noapp=true
But not much information is given and am not sure how it works, maybe just a 36VDC -> 5VDC converter is embedded into the plug?

Here's hoping anyone else out there has had any luck with solar charging.
 
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Cisforcookie

New Member
Hi webcurl,
I started working on finding a solution for the same problem, but are unfortunately not very knowledgeable about battery systems. I actually managed to get hold on one of the last travel chargers sold (in Switzerland), but this unfortunately has the feature of battery protection, meaning that if it doesn't get the ~90W it needs, it won't charge at all. As I planned to have a rather small mobile 40W panel for moderate recharging, this obviously doesn't work. So I also thought about placing a 12 v battery in between for balancing, such as this one (https://www.amazon.de/SHIDO-LTZ10S-LION-S-Batterie/dp/B00KMSBKVS/ref=sr_1_9?ie=UTF8&qid=1550825898&sr=8-9&keywords=shido). I guess you have connected your converter to the charge controller, so that the charge controller controls the on/off depending on the LiFePO voltage, right?
As I'm planning to have the set on my cargo bike, I would rather buy a charge controller for boats (water protected), but the ones I found don't have load connection, so I'm wondering if the system will work smoothly when I connect the BOSCH travel charger directly to the battery. Do you have any hints on that?
Also very curious to hear if you have any news on your setup.
 

JohnDoe1983

Member
One question if I may please.
I have a Toyota RAV 4 with a 10 amp cigaret lighter outlet.
I want to use my 4 amp 110 volt Bosch charger with the aid of inverter so I will be able to charge my battery while travelling.

Do you think a 500 watt inverter should do the trick ? If not, what should I use ?
Thanks
 

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webcurl

Active Member
One question if I may please.
I have a Toyota RAV 4 with a 10 amp cigaret lighter outlet.
I want to use my 4 amp 110 volt Bosch charger with the aid of inverter so I will be able to charge my battery while travelling.

Do you think a 500 watt inverter should do the trick ? If not, what should I use ?
Thanks
You will only be able to use the 2A charger as 36VDC x 2A = 72W.
36VDC x 4A = 144W (it actually consumes about 195W because of losses)

So your lighter socket at 12VDC x 10A = 120W, theoretical maximum, or 13.8VDC x 10A = 138W.

You will possibly burn fuses and/or wires if you take more than the 10A.
 
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webcurl

Active Member
I forgot to mention that the "setup" i specified was un-tested.
Update:
The Allpowers folding solar blankets were disappointing, in the hot Aussie sun at peak with perfect direction from the panels to the sun, the 100W produced only 58W and the 60W produced 40W, connecting them in Parallel was not much of an advantage and one of the diodes was getting too warm. I know it's a no-no to parallel 2 different panels but thought it might be ok as the voltages were supposed to be the same, but no.

I purchased an extremely expensive P3 Solar panel https://p3solar.com/portfolio/p3-125/
This has been able to produce 114W in ideal conditions and 40 watts in overcast conditions. Outside of Australia you may want more panels.
I was a bit disappointed about the weight they quoted - 1.48kg, turned out to be 1.77kg but still much lighter than the Chinese ones, apart from that the panel has been excellent, needs to be pointed towards the sun maybe more than Powerfilm but lighter and folded size smaller than Powerfilm.

My buffer battery pack consists of (approx 450g):
4 x http://www.evlithium.com/A123-Battery/632.html
2 x https://www.aliexpress.com/item/DIY-Battery-Container-Holder-SMD-Box-For-2x-26650-3-7V-Rechargeable-Battery-4Pin/32908972131.html
1 x https://www.ebay.com.au/itm/4S-30A-12-8V-w-Balance-3-2V-LiFePo4-LiFe-18650-Battery-BMS-Protection-PCB-Board/292643000850

The Victron Smartsolar MPPT 75/15 (450g) has been mostly good, yes you can control through Bluetooth battery charge parameters, load switching conditions, etc.

The Redarc 350RS Pure Sine inverter i believe is a re-badged Cotek SE350-212 (http://www.cotek.com.tw/product/Pure-Sine-Wave-Inverter-SE350/) - this has been excellent although bulky and weighing in at 1.23kg :(
I've tried to find a 150W Pure Sine Inverter with similar qualities but have given up, the good qualities are: Extreme temperature operation, auto restart upon low or high input voltage - this is crucial unless you're sitting next to it keeping an eye :)
I've tried several times to ask Bosch if they or their customers have had any experience in using Modified Sine inverters with their e-bike chargers to no avail. So, at this stage do not want to risk damaging mine.

In use:
In ideal Oz sun conditions with ideal positioning (adjust every 3-4 hours) the P3-125 is supplying enough power to keep the Bosch 2A charger going and put a small amount of power into my buffer battery.
In less than ideal conditions the Bosch charger will be on until the buffer battery goes below 12V (on average) (actually cutting out at 11V or less) then the panel charges the buffer battery (with Bosch charger off) until it get's to about 14.2V at which stage the Bosch charger will be turned on again.
So with about 40w solar in overcast conditions, it's switching on and off approx every 1/2 to 1 hour.

The parameters of the Victron are temperamental and don't exactly work as i desire but on the whole if you leave it alone it's ok.

The Bosch 2A charger (580g with mains cable) is either fully on (approx 90W) or off.
I have a 12VDC to dual USB charger adapter to power my USB devices with the buffer battery.
All of this weighs (with cables) approx 4.8kg and takes 8-9l of volume :(
So on a good day 12 hours of decent sun i'd be lucky to get both batteries (2 x 500Wh) from flat to 90%.

I'd still love to bypass the inverter and Bosch charger and directly inject 36VDC but am not prepared to void warranties yet, also it's necessary to carry the Bosch charger when around mains power.
 

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webcurl

Active Member
One question if I may please.
I have a Toyota RAV 4 with a 10 amp cigaret lighter outlet.
I want to use my 4 amp 110 volt Bosch charger with the aid of inverter so I will be able to charge my battery while travelling.

Do you think a 500 watt inverter should do the trick ? If not, what should I use ?
Thanks
Who else is interested in charging their batteries in-car? It would be nice to be able to get Bosch to re-release their 12V Travel charger!
 

JohnDoe1983

Member
You will only be able to use the 2A charger as 36VDC x 2A = 72W.
36VDC x 4A = 144W (it actually consumes about 195W because of losses)

So your lighter socket at 12VDC x 10A = 120W, theoretical maximum, or 13.8VDC x 10A = 138W.

You will possibly burn fuses and/or wires if you take more than the 10A.

Thanks for the info. In fact, I was thinking about buying something like this to be plug to my car battery and transform the 12 volt into 110 volt to power my charger. It seem that from the picture below, my charger need 2.2 amp at 110 volt.

Would I need 500watt, 1000m watt inverter ? Like Shakespeare said: that is the question.


Cheers.
https://www.amazon.ca/Power-Bright-PW1100-12-Inverter-1100/dp/B000NIG2FG/ref=sr_1_4?s=hi&ie=UTF8&qid=1550932948&sr=1-4&keywords=12v+inverter
 

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webcurl

Active Member
Thanks for the info. In fact, I was thinking about buying something like this to be plug to my car battery and transform the 12 volt into 110 volt to power my charger. It seem that from the picture below, my charger need 2.2 amp at 110 volt.

Would I need 500watt, 1000m watt inverter ? Like Shakespeare said: that is the question.


Cheers.
https://www.amazon.ca/Power-Bright-PW1100-12-Inverter-1100/dp/B000NIG2FG/ref=sr_1_4?s=hi&ie=UTF8&qid=1550932948&sr=1-4&keywords=12v+inverter
350W is plenty if all other conditions and safeties are met.
And like webcurl said: I'm only answering the question, if you blow fuses, your RAV4 catches fire or you cannot start it after charging the Bosch, then just remember: webcurl only answered the specific question! :)
 
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JohnDoe1983

Member
Yes I understand. My math was. 110v x 2.2 amp= 242 watt, I all ready have a 300 watt inverter with 400 watt peak. I will try it.
Thanks for the info
Cheers.
 

webcurl

Active Member
Hi!
In our application, what can be the difference: Modified Sinewave or Pure Sinewave ?
Thanks
In your application within a RAV4 where there's an abundance of power whilst the motor is running or a large Lead Acid to draw from and no concerns about weight:
Pure Sinewave - Safe but more expensive.
Modified Sinewave - Might blow the Bosch charger or reduce it's lifespan and possibly in-turn damage the Bosch battery/system, less bulky but much cheaper.

In my application:
Pure Sinewave - Safe, more expensive but heavy/bulky.
Modified Sinewave - Might damage the Bosch gear as above, probably less efficient, cheaper, might save 1kg in weight and less volume to carry (with my bikes total gross weight limit of 140kg).

But please do ask Bosch as i've had no joy at all from my attempts. It depends on how they designed their respective chargers as to how resilient they would be and in turn the chargers safety design upon failure with a Modified Sinewave inverter.
 

webcurl

Active Member
And my bikes gross weight rating of 140kg - my weight - weight of R&M bike - 5l water - my current setup of 4.7kg of solar charging equipment - 2.5kg of packing bags (panniers, etc) = 11.8kg.
That's 11.8kg for Tent, Sleeping gear, clothing, bike fix gear, cooking gear, food, etc. I'm on the limit, especially on rough terrain (and especially with only 5l of water)! :)
 

JohnDoe1983

Member
Wow!! Thanks for the info. Will not take any chance and buy a good expendise sinewave inverter. Since it will always be carried in my rav4, weight is not a problem. I only want to charge the battery while driving from one place to another one.

Thank you very much Webcurl.
 

webcurl

Active Member
Hi webcurl,
I started working on finding a solution for the same problem, but are unfortunately not very knowledgeable about battery systems. I actually managed to get hold on one of the last travel chargers sold (in Switzerland), but this unfortunately has the feature of battery protection, meaning that if it doesn't get the ~90W it needs, it won't charge at all. As I planned to have a rather small mobile 40W panel for moderate recharging, this obviously doesn't work. So I also thought about placing a 12 v battery in between for balancing, such as this one (https://www.amazon.de/SHIDO-LTZ10S-LION-S-Batterie/dp/B00KMSBKVS/ref=sr_1_9?ie=UTF8&qid=1550825898&sr=8-9&keywords=shido). I guess you have connected your converter to the charge controller, so that the charge controller controls the on/off depending on the LiFePO voltage, right?
As I'm planning to have the set on my cargo bike, I would rather buy a charge controller for boats (water protected), but the ones I found don't have load connection, so I'm wondering if the system will work smoothly when I connect the BOSCH travel charger directly to the battery. Do you have any hints on that?
Also very curious to hear if you have any news on your setup.
I've updated my setup, as for you connecting directly to battery/solar it depends on how the travel charger behaves on input voltage, if it switches off nicely when battery voltage is too low (but not too low to damage battery) and then switches on again when battery voltage is high enough without this happening too quickly? My setup allows for a certain latency on load switching.
If you ever get tired of your Bosch travel charger and want to sell it or if you burn it out i'm an interested buyer! :)
 

Wright

New Member
I am having similar issues with Shimano. I tried to go with a commercial outfit out of California but they could not get Shimano to respond to a request for the S propritory plug. Why should this be so difficult? I had hoped that someone would come up with a commercial solution not that touring with e-bikes is becoming more popular. The market is there and price and weight is not really the deciding factor with a spare Shimano battery costing $800 cdn and a weight of 7 pounds.
 

webcurl

Active Member
I forgot to mention that the "setup" i specified was un-tested.
Update:
The Allpowers folding solar blankets were disappointing, in the hot Aussie sun at peak with perfect direction from the panels to the sun, the 100W produced only 58W and the 60W produced 40W, connecting them in Parallel was not much of an advantage and one of the diodes was getting too warm. I know it's a no-no to parallel 2 different panels but thought it might be ok as the voltages were supposed to be the same, but no.

I purchased an extremely expensive P3 Solar panel https://p3solar.com/portfolio/p3-125/
This has been able to produce 114W in ideal conditions and 40 watts in overcast conditions. Outside of Australia you may want more panels.
I was a bit disappointed about the weight they quoted - 1.48kg, turned out to be 1.77kg but still much lighter than the Chinese ones, apart from that the panel has been excellent, needs to be pointed towards the sun maybe more than Powerfilm but lighter and folded size smaller than Powerfilm.

My buffer battery pack consists of (approx 450g):
4 x http://www.evlithium.com/A123-Battery/632.html
2 x https://www.aliexpress.com/item/DIY-Battery-Container-Holder-SMD-Box-For-2x-26650-3-7V-Rechargeable-Battery-4Pin/32908972131.html
1 x https://www.ebay.com.au/itm/4S-30A-12-8V-w-Balance-3-2V-LiFePo4-LiFe-18650-Battery-BMS-Protection-PCB-Board/292643000850

The Victron Smartsolar MPPT 75/15 (450g) has been mostly good, yes you can control through Bluetooth battery charge parameters, load switching conditions, etc.

The Redarc 350RS Pure Sine inverter i believe is a re-badged Cotek SE350-212 (http://www.cotek.com.tw/product/Pure-Sine-Wave-Inverter-SE350/) - this has been excellent although bulky and weighing in at 1.23kg :(
I've tried to find a 150W Pure Sine Inverter with similar qualities but have given up, the good qualities are: Extreme temperature operation, auto restart upon low or high input voltage - this is crucial unless you're sitting next to it keeping an eye :)
I've tried several times to ask Bosch if they or their customers have had any experience in using Modified Sine inverters with their e-bike chargers to no avail. So, at this stage do not want to risk damaging mine.

In use:
In ideal Oz sun conditions with ideal positioning (adjust every 3-4 hours) the P3-125 is supplying enough power to keep the Bosch 2A charger going and put a small amount of power into my buffer battery.
In less than ideal conditions the Bosch charger will be on until the buffer battery goes below 12V (on average) (actually cutting out at 11V or less) then the panel charges the buffer battery (with Bosch charger off) until it get's to about 14.2V at which stage the Bosch charger will be turned on again.
So with about 40w solar in overcast conditions, it's switching on and off approx every 1/2 to 1 hour.

The parameters of the Victron are temperamental and don't exactly work as i desire but on the whole if you leave it alone it's ok.

The Bosch 2A charger (580g with mains cable) is either fully on (approx 90W) or off.
I have a 12VDC to dual USB charger adapter to power my USB devices with the buffer battery.
All of this weighs (with cables) approx 4.8kg and takes 8-9l of volume :(
So on a good day 12 hours of decent sun i'd be lucky to get both batteries (2 x 500Wh) from flat to 90%.

I'd still love to bypass the inverter and Bosch charger and directly inject 36VDC but am not prepared to void warranties yet, also it's necessary to carry the Bosch charger when around mains power.
Woohoo, bought a smaller, lighter inverter in Oz. An 8zed 150W Pure Sine, weighs 550g and now my setup with one panel weighs in at 4.1kg - that's one P3 125W panel, Victron charge controller, buffer battery, inverter and Bosch 2A charger.
About to mortgage the house and buy a second P3 125W panel to go in parallel for overcast conditions which will then bring the weight to 5.8kg.
But all of this still needs a "rest" day or more to charge 2x500Wh batteries providing there's sun at all.