Grid Charger Power Supplies

[retepsnikrep]

This is a quick thread to evaluate some cheap e-bay constant current led power supplies and there use in dumb grid chargers.

I recently bought two each of the below for testing.

eBay - The UK's Online Marketplace

eBay - The UK's Online Marketplace

In theory two in series should provide enough voltage/current for a dumb grid charger for G1 Insight and Civic 144v 120 cell nominal packs.

At the moment only the top ones have arrived.

They are isolated so can be connected in series but only have two mains wires. (No earth)

Hooking them up to my electronic load gave just over 90V no load voltage.

Under load with voltage set at 87.5v (2 x 87.5 = 175V) they held stead at an ouput of ~216ma which is approx 20w. The mains input power was ~22w so they also seemed pretty effcient. They start cutting back when load gets over 300ma. The maximum load they would sustain was about 285ma at 85V.

I have removed the case from one and will wire them up to a pack on the bench and see how they work in practise. The mosfet pwm controller chip is an STR W6252 rated at 60W, so seems to operate well within that power rating.

http://www.datasheets.org.uk/indexdl...SA00291259.pdf

The pcb and soldering seem pretty tidy. I'll post pics and charge test results in next few days.

[retepsnikrep]

No pics yet camera malfunction. However i have wired them up to an old pack and they are charging it as we speak. Combined they are taking 45w from the 240v mains supply.

[MN Driver]

Wow, Looking at the specs, those things are small and light. Looks great on paper. If I hadn't already gone the Meanwell route, I'd definitely be looking at these closely. Very low cost too if they work out, not to mention fewer parts and connections.

[retepsnikrep]

Couple of pics.

They are putting 250ma into the test battery which is currently upto about 170V.

Temp on either pcb is not over 40C according to my handheld infra red sensor.

Pretty cool running as well with the pcb in free air. Two fixed prety much anywhere in the ima compartment with a 400v 1A diode in each lead provides an ultra light cheap charger/balancer as long as you don't mind the extra wait/time.

[MN Driver]

Which units are you showing in the picture, the two ebay ads show them with cases. I'm assuming based on the wire loom that it is the one from the first link with the yellow and white case?

[retepsnikrep]

Correct the others haven't arrived yet.

[fuelsipper]

Hello Peter. So is what you are posting about the LED power supplies for charging our batteries cheaply? Is this something simular to what 99mpg has posted with the free plans?

When you say dumb charger, it needs to be monitored and pulled off when the charge gets to 177 volts?

Are you also saying that you could put these inside the battery case and just plug in when you want to charge it?

How would one monitor the voltage and to know when it is full and to unplug it? Could you use the OBDIIc&c device? I'm waiting for mine patiently.

[retepsnikrep]

Yes it's similiar to the various cheap charger ideas floating about.

The advantages as I see it are.

1) It's very cheap. Two $24 HV CC psus's + Two $1 diodes for the HV section. ($50)
I also recommend a 9v psu for the battery fan but it's not mandatory.

2) It's very simple. The mains inputs are wired in parallel to the mains supply. The dc outputs are wired in series via diodes to the battery pack grid charger connection points.

3) It's less powerful ~(250ma - 300ma) so if you decide to risk it without powering the fan you have more chance of getting away with it long term. Quite a lot of people use the early 350ma design without battery fans. Also the current tapers off as the battery voltage nears the psu maximum which is a good feature. It also won't charge above about 178V whatever the battery wants to do as the power supplies won't go that high, another good feature IMHO.

4) You can check the voltage with a gauge if you want or you can use a rule of thumb and dumb timer on the mains input to turn it off after a set number of hours. If it charges at 250ma then it will take ~24hrs to charge the pack from flat (Put in 6Ah).

If you assume the worst case scenario with a bad unbalanced pack in that one cell is empty and all the others (119) are full then it will take around 24-30hrs to balance it.

It's just another option which is a bit less complicated to make. It's not powerful enough for phev use but it's very useful for infrequent battery balancing maintenance.

I will post the 24hr test result shortly as I have had a pack charging since yesterday.

Edit

The test pack peaked at 172.5V temp around 9C after 24hr
I have now disconnected the fan and am continuing to charge to see what temp rise will be over next 12hrs.
All charge should be converted into heat. PSU's are drawing about 47W.

[RedJellyBean]

This is HUGE. Thank you so much Peter!
I've already bought all the parts to put together a traditional 350/700/1050mA dumb charger and will still go ahead in putting it together but I'm so tempted to buy a couple of these too, just to lend out to people. For $40 a pop to save an IMA battery... this could be such a game changer. Weekend balance charger; gentle to cells, easy on the wallet.

Edit: I just put down $25 to order a couple for myself. Thanks again, I'll keep the community apprised on my experience.

[eq1]

Originally Posted by retepsnikrep

... peaked at 172.5V temp around 9C after 24hr...

"9C"? Is that right? Sounds cold...