Inverters, bike charging and other power questions.

goneoff said:

Many thanks for the clarity. I clearly understand the requirement for measurement in order to size an inverter correctly, however having said that in your opinion are you saying that a 1200w inverter would charge up both my bike batteries simultaneously or my 800w microwave occasionally?
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You really don't want to charge both bikes at the same time it will hammer your batteries and shorten their life. Also even with 350 watts of solar it will take a couple of days the recharge your batteries.
I top ours up one at a time after a ride rather than charging from flat.
 
Neilfg said:
I have 2 ebikes and was surprised at how low the draw was in reality compared to the calculated input figures. My 1000w PSW Inverter works well and is perfect for topping up both ebikes when needed (also a bread maker😁 monitor really helped here) , I have about 160ah batteries total.

I have no experience of a microwave in a van but if it says 800w a 1000w inverter should be fine ( monitor will confirm). I only suggested 1200w as although bigger than required it is sometimes more efficient. I found previously that an inverter working close to it limits was noisy and not as efficient. When I was looking it was an option as a good range available and not that much bigger. As it was I found a 1000w that fitted in neatly and at the right price.
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I have a similar set up to you but more battery bank. I have 2 x 400 watt batteries for e bikes to charge. Cant see us ever using the whole 400 watts, so my question would be, if I charged them up seperately (which is what i calculated on) how long in real terms do you reckon it would take to fully charge one of them from half full. I m not overly interested in the figures of 25 x 400 divided by hours as I dont understand it. A ball park of "3-4 hours best guess" is good enough for me.

Thanks in advance.

Edit, and then I see Lenny HB does something similar to what i plan on doing
 
These small transformerless switch-mode power supplies and chargers have components called capacitors which act like reservoirs to smooth out the input pulses of the AC supply. When first connected, these capacitors need filling up, a process that takes only a few milliseconds but can momentarily cause a very high current. So what does a manufacturer do? State the long-term average current, then get calls from disgruntled uses who are blowing 1.5A fuses on switch-on? Or state the maximum current it ever sees, and let the user draw his own conclusions?

Looking at the output power and guessing the likely efficiency is a better way of working out the steady-state input power. Actually measuring it is better, of course.

A 300W inverter will probably cope with a momentary surge of up to 600W, so when sizing inverters it's the steady-state power that is important rather than the startup surge.
 
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suavecarve said:
I have a similar set up to you but more battery bank. I have 2 x 400 watt batteries for e bikes to charge. Cant see us ever using the whole 400 watts, so my question would be, if I charged them up seperately (which is what i calculated on) how long in real terms do you reckon it would take to fully charge one of them from half full. I m not overly interested in the figures of 25 x 400 divided by hours as I dont understand it. A ball park of "3-4 hours best guess" is good enough for me.

Thanks in advance.

Edit, and then I see Lenny HB does something similar to what i plan on doing
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No idea never time it, but I usually only charge one at a time as well. We always charge when driving when on tour and pop them on charge during the day (sun up) if down one or more bars.
 
If it were me---- not being an electrician------- I would not hesitate to fit a 1500w pure sine wave inverter and keep an eye on battery condition------- when you have surplus power you can use it for other things.
Just how I would do it😊😊

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royw said:
I can put a battery in a remote control the right way 50% of the time.
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What are your consultancy fees?

I have a 100% failure rate and my grandsons hate me because their play station has not worked since "granny Jen fixed it" :LOL:

As for the e-bike charger, I find it cheaper to carry a spare bike than risk blowing up my van trying to charge my bikes off the leisure batteries o_O
 
royw said:
Their data plate may be wrong or being on the cautious side but regardless the value you take is the input requirements on the chargers.
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If I can just leap in here, not knowing anything too much ;), but could it be that the high data plate wattage is allowing for a higher initial current. I'm just thinking of an old car battery charger I had that would start at 8 amps and then gradually go down to about 2-3; and my mobile phone which may start at .5a/1a and then settle down to about .25a charge.
 
royw said:
I answered your question, its not for debate, you calculate the supply voltage * current you need to add some latitude for tolerance.
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Lucky said:
If I've followed this correctly, the answer to "Charging Electric Bikes, the Ultimate Question of Life, and Everything" is 42, calculated by an enormous supercomputer named Deep Thought over a period of 7.5 million years. Unfortunately, no one understands what the question is.
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Shame that book reference went over royw's head but *I* thought it was funny!
 
is there anyway to step up from 12v to 36v (for a bosch ebike charger (without going via 230v inverter)?
 
gerry mcg said:
is there anyway to step up from 12v to 36v (for a bosch ebike charger (without going via 230v inverter)?
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I don't think so the electronics in the charger need to communicate with the electronics in the battery. I use a 1000 watt pure sine for ours.
 
Lenny HB said:
Discontinue a few years ago, it was expensive £150 and took 4 to 5 hours to charge a 400 watt battery.
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I still see them listed, at around £100. However, I'd buy the £40 third party one that orridge posted, if it was me.
 
I post a you tube video a while ago on this, the "communication" Lenny mentions is a lower voltage that needs applying to the battery while charging this may be the video

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royw said:
I post a you tube video a while ago on this, the "communication" Lenny mentions is a lower voltage that needs applying to the battery while charging this may be the video
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That was interesting that the battery just needs a 5v signal from the charger to start charging, I was expecting to see some data on that line.
You could get away without making a plug and just connect with flying leads with male push-on connectors on them.
 
Lenny HB said:
That was interesting that the battery just needs a 5v signal from the charger to start charging, I was expecting to see some data on that line.
You could get away without making a plug and just connect with flying leads with male push-on connectors on them.
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Yes agreed, I suspect that low voltage feed may be for its bms system ?
 
Tamste said:
Anybody tried this one just for e-bike battery charging direct from 12V?
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orridge above says he has one..
I am just reading up on this thread to try and gain info.
Be interested if orridge can give an update how that charger is going.

I have 2 cheap Argos 24v E fold up bike. Great outlay at £279 each !!! :whistle2:
Just connected a charger and battery up at home using a plug inline power meter.
Showing me 0.5amps and 65watts ?? So nothing great there.. Rating on the charger is 230v 2amps.

I have an 1100w Inverter but its not pure sine wave.
Whats the options guys, Do I risk a charge using this inverter ??????
Amazon product ASIN B07GRGKXDF

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tonka said:
I have an 1100w Inverter but its not pure sine wave.
Whats the options guys, Do I risk a charge using this inverter ??????
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How expensive is a new charger if it blows it?
Personally I wouldn't take the risk.
 
I'm sure it would work from a small pure sine wave inverter. 300 or 250W certainly. Worth a try on a 150W inverter, if the powerup input surge doesn't trip it, it should be fine.
 
tonka said:
orridge above says he has one..
I am just reading up on this thread to try and gain info.
Be interested if orridge can give an update how that charger is going.

I have 2 cheap Argos 24v E fold up bike. Great outlay at £279 each !!! :whistle2:
Just connected a charger and battery up at home using a plug inline power meter.
Showing me 0.5amps and 65watts ?? So nothing great there.. Rating on the charger is 230v 2amps.

I have an 1100w Inverter but its not pure sine wave.
Whats the options guys, Do I risk a charge using this inverter ??????
Amazon product ASIN B07GRGKXDF
Click to expand...
Seems to work ok have only used a couple of times so will provide a better update after we have used it in Anger over the next few months.
 
gerry mcg said:
is there anyway to step up from 12v to 36v (for a bosch ebike charger (without going via 230v inverter)?
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Not sure if this company is any use to you.

Einfach unterwegs E-Bikes aufladen

Powerbutler ist das mobile E-Bike 12V-Ladegerät für Auto, Wohnmobil, Caravan und Boot
powerbutler.de

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