Onboard ebike charger

[shinyballs]

While looking for a charger to use onboard for my ebike, I came across this Lambda PFE series AC-DC power bricks -

http://www.us.tdk-lambda.com/lp/products/pfe-series.htm
http://www.designworldonline.com/ArticleDetails.aspx?cid=205&id=2929
http://www.newark.com/tdk-lambda/pfe500s-48/switching-power-supply/dp/12P6490

A lot of good features... but the shocking price! What do you nerds think?

Presently I'm using a Cosel 36v 16Amp ps which works great except its too bulky to carry around on a backpack or rack for long trips and doing opportunity charging.

 

[dimitrib90]

This charger will not work for you because they do not have a 36V option.

 

[shinyballs]

This charger will not work for you because they do not have a 36V option.

This Lambda 48v is adjustable from 38v-57v
My batt setup is 22s5p(74v 16Ah,1185Wh) of K2s split into 2 subsets of 37v for charging/balancing. Cosel is set to 40v and use two MKS 3in1 for balancing. The model PFE500S-48 matches my pack voltage/amps.

 

[ZapPat]

Two things I can think of after checking the datasheet:

1 - You will need a big heatsink to go with the AC-DC converter if you want to have any chance of getting your 500W of power. Here's the size of the power supply unit vs their recommended heatsinks. A fan could reduce the heatsink's size significantly too...
PSU: 100 x 13.4 x 160 (mm)
HS: 116.8 x 38.1 x 61 (mm)

2 - It isn't specified if the converter will automatically fallback on it's voltage to maintain it's max current output. It just states "automatic recovery" to it's over-current protection, which dosesn't sound too promissing. In other words, don't get a unit that switches off when the overcurrent limit is achieved, as you want one that will throttle the votage back to maintain the output current at it's max value.

Good luck!

 

[7bobw]

So for us dummies how does this work.

 

[shinyballs]

Greatly appreciate the input Zap! The "automatic recovery" is quite a downside for charging. I also noticed this with my Cosel ps, while charging my fully discharged pack, it shows 22amps in the Wattsup and continously drops down to 18, and in seconds - just shuts off power. I can only use it if pack is at least 60% charged.

There SWS series says in its overcurrent protection :
">105%, Constant current style"
http://www.lambdapower.com/products/sws-series.htm

Would this ps work? Not sure if they mean ps not switching off but maintains max output current value. The model SWS600L-48 would meet my charging requirements.

 

[ZapPat]

That model looks like it should work well for charging (although it looks a bit bigger than the other ones?).

I use a vicor power supply for my charging needs (flatpac series) - small, efficient and reliable. I have two 48V 600W models, but only need one for myself, so might part with one. The voltage is trimmable up 10% and down 50%, and it provides about 16 amps as I recall.
View attachment vicor flatPAC Power supply data.pdf

 

[shinyballs]

That model looks like it should work well for charging (although it looks a bit bigger than the other ones?).

I use a vicor power supply for my charging needs (flatpac series) - small, efficient and reliable.

Not sure about the size of the other models, the SWS600L-48 is smaller though compared to the SWS1000L-48. 2.4 x 4.72 x 7.48" vs 2.4 x 5.91 x 9.45"

That Vicor Flatpac is awesome... when thats mounted (ala Iacoca Ebike charging setup), charging is as simple and convenient as filling up from a gas station. pm sent Zap

Is there a work-around to avoid the "automatic recovery"? My Cosel ps always switches off when its charging an empty pack.

 

[ZapPat]

That model looks like it should work well for charging (although it looks a bit bigger than the other ones?).

I use a vicor power supply for my charging needs (flatpac series) - small, efficient and reliable.

Not sure about the size of the other models, the SWS600L-48 is smaller though compared to the SWS1000L-48. 2.4 x 4.72 x 7.48" vs 2.4 x 5.91 x 9.45"

That Vicor Flatpac is awesome... when thats mounted (ala Iacoca Ebike charging setup), charging is as simple and convenient as filling up from a gas station. pm sent Zap

Is there a work-around to avoid the "automatic recovery"? My Cosel ps always switches off when its charging an empty pack.

There has been some discussion here on ES of current limiting circuits for DC power supplies, check it out with the search.

You may be able to trim the voltage down on your PS when your battery is low, then return it to it's normal voltage after a certain time. Maybe something else simple would be using a big resistor in series with the PS if the battery is very low... Maybe something around 1 ohm, but use ohm's law to get a better idea. If you do this, getting a number of identical resistors can help, since you can set them up in series/parallel setups to get what value you need, plus they share the dissipation equally.