Battery charging with inverter and 12 dv battery

[MarcusT]

Hello. I am new here and just picked up a Cube Stereo Hybrid with a Bosch CX/500.
I love it! It opens up an old world of riding that I gave up on because of age and lack of exercise.

My question is; Since extra batteries are stupidly expensive, I am considering other options for charging the on bike battery.
I know I can hook up a 12dv-220av inverter to my car, but looking for something portable. I have an old lead acid battery jump starter that I would take camping it weighs about 12 kgs and not very rider friendly. It would charge cell phones, air pumps and jump start a number of vehicles for several days.
Now, they have come out with the Li Ion jump starters that weigh much less and are much smaller. https://www.aboxtek.com/products/abo...w-jump-starter
Has anyone tried this method? I am looking at a a 18000 mAh battery, with a 300 watt inverter, (charger is 2 A) I believe it will work, but have no idea how much charge it will give my bike. (1 hour, 2, 3 charging?)
Tried google with very little results
I appreciate any assistance for this

Cheers

 

[freddi]

Don't know how good these are but came across it when I was looking for charging when away from home. Works of the 12v and means you wouldn't need the inverter.

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[MarcusT]

Appreciate it, but it does not have have a Bosch plug and as the bike is new I would not want to risk voiding the warranty.

 

[Andy-Mat]

Hello. I am new here and just picked up a Cube Stereo Hybrid with a Bosch CX/500.
I love it! It opens up an old world of riding that I gave up on because of age and lack of exercise.

My question is; Since extra batteries are stupidly expensive, I am considering other options for charging the on bike battery.
I know I can hook up a 12dv-220av inverter to my car, but looking for something portable. I have an old lead acid battery jump starter that I would take camping it weighs about 12 kgs and not very rider friendly. It would charge cell phones, air pumps and jump start a number of vehicles for several days.
Now, they have come out with the Li Ion jump starters that weigh much less and are much smaller. https://www.aboxtek.com/products/abo...w-jump-starter
Has anyone tried this method? I am looking at a a 18000 mAh battery, with a 300 watt inverter, (charger is 2 A) I believe it will work, but have no idea how much charge it will give my bike. (1 hour, 2, 3 charging?)
Tried google with very little results
I appreciate any assistance for this

Cheers

Never tried it but it should work.
The biggest problem with some inverters is that other electronics might take exception to, is possibly the shape of the sine wave output.
Many cheaply made inverters have an appalling "square wave" shaped output, nowhere near to it being a sine wave, as the mains is.
Depending upon just how the charger is built, that may or may not be a problem, as if the input to the charger is via an internal transformer, then the square wave will usually be "bent" into more of a sine wave shape by the inductance of the transformer.
But to be safe, buy an inverter with a true sine wave output, which are a bit more expensive though....
See here:-

True Sine Wave Inverter for sale | eBay

Find great deals on eBay for True Sine Wave Inverter. Shop with confidence.

www.ebay.co.uk

Also check with an Oscilloscope just how the output looks with and without load.
A fix for an inverter (if you have already bought it) with a poor output shape, could be a small mains 1:1 isolation transformer, between the inverter and the charger, that should dramatically improve the shape of the output...
Buy an inverter with "power in reserve" as running it on its maximum throughout a charge, may shorten its life. A 50% greater output than actually needed, should cover you well and might prove useful for other electrics, if you are say a camper/caravanner, for example!
Regards and tell us how you got on.
Andy
PS. I would get hold of a strong plastic box, mount the inverter (and maybe the charger) inside and have a small 12 volt cooling fan that runs so long as 12 volts is applied! Keep tings cool!! My own Li-ion charger has a cooling fan built in, but many don't!
PPS. May I ask you to place a picture of the Bosch charger plug here as well please?

 

[MarcusT]

Never tried it but it should work.
The biggest problem with some inverters is that other electronics might take exception to, is possibly the shape of the sine wave output.
Many cheaply made inverters have an appalling "square wave" shaped output, nowhere near to it being a sine wave, as the mains is.
Depending upon just how the charger is built, that may or may not be a problem, as if the input to the charger is via an internal transformer, then the square wave will usually be "bent" into more of a sine wave shape by the inductance of the transformer.
But to be safe, buy an inverter with a true sine wave output, which are a bit more expensive though....
See here:-

True Sine Wave Inverter for sale | eBay

Find great deals on eBay for True Sine Wave Inverter. Shop with confidence.

www.ebay.co.uk

Also check with an Oscilloscope just how the output looks with and without load.
A fix for an inverter (if you have already bought it) with a poor output shape, could be a small mains 1:1 isolation transformer, between the inverter and the charger, that should dramatically improve the shape of the output...
Buy an inverter with "power in reserve" as running it on its maximum throughout a charge, may shorten its life. A 50% greater output than actually needed, should cover you well and might prove useful for other electrics, if you are say a camper/caravanner, for example!
Regards and tell us how you got on.
Andy
PS. I would get hold of a strong plastic box, mount the inverter (and maybe the charger) inside and have a small 12 volt cooling fan that runs so long as 12 volts is applied! Keep tings cool!! My own Li-ion charger has a cooling fan built in, but many don't!
PPS. May I ask you to place a picture of the Bosch charger plug here as well please?

The inverter is good quality, it has a fan, overload protection and auto shut off when the battery gets too low. I have used it with the lead-acid jump starter, and it worked well. I am just not sure how the lithium starter compares in keeping power compared to the old one

As far as the technical stuff you mentioned. It may as well be greek. The inverter kicks out 220av and that's all I know.
Thanks

 

[Artstu]

My 300W inverter wasn't enough for me, so had to upgrade to a 500w one, I'm hopeless with the maths but I'd say you'd deplete a 110 ah 12v battery by about half on one charge.

18 amps won't be much use.

Car inverter for bosh charger

Does anyone know what watts the bosh charger draws - I was thinking of getting a cigarette lighter inverter and can't find what wattage I need. Cheaper than the bosh car charger, and it'll come in useful for other gadgets also. Mucho gracias.

www.pedelecs.co.uk

 

[vfr400]

It's not a good idea to use an inverter to charge an ebike battery from a 12v one. The reason is because of the amount of charge you need. Your 500wh battery would require 42 Ah at 12V. That's not the full story though. You're going through two converters, so efficiency will be about 80%, which then pushes the requirement up to 52 Ah. Lead batteries should only be discharged half-way, otherwise you shorten their life. The deeper the discharge, the more it shortens their life. That means that you need 104 Ah of spare capacity in your lead one to charge your bike.

The standard Bosch charger is 4A. that would be 12A at 12V, and by the time you take efficiency into consideration, that's going to be around 15A or 180W. You need to make sure that your 12V source can provide that much power.

 

[Andy-Mat]

The inverter is good quality, it has a fan, overload protection and auto shut off when the battery gets too low. I have used it with the lead-acid jump starter, and it worked well. I am just not sure how the lithium starter compares in keeping power compared to the old one
View attachment 30189
As far as the technical stuff you mentioned. It may as well be greek. The inverter kicks out 220av and that's all I know.
Thanks

Then wait and see how it works.

But if you get problems, then find someone with an O'scope to look at the output wave form of the inverter...
Best of luck.
Andy

 

[Deleted member 25121]

Has anyone tried this method? I am looking at a a 18000 mAh battery, with a 300 watt inverter, (charger is 2 A)

A 12V, 18Ah battery would in theory store 216Wh of energy. If you use an inverter with say 80% efficiency followed by a Bosch charger with say 80% efficiency (I'm guessing wildly at those efficiency numbers) the setup would provide 138Wh of energy for your Bosch ebike battery.

So your 500Wh Bosch battery would be charged by only 25% before the 18Ah battery goes flat.

A 300W inverter should be OK for the standard 4A 36V (144W nominal) Bosch charger but could be too low for the fast 6A 36V (216W nominal) Bosch charger.

By the way, at one time Bosch produced a "travel charger" that plugged into a car 12V socket, it cost over £100 but doesn't seen to be available now.