Can I use this new PC software version with the DPS3005 (communication version) that I have ?
It took a full year, but I finally got around to replacing those 2 binding posts, Purple and White, with Red and Black ones.
Found a good, inexpensive source for them. Binding Posts
Very nice and very useful. I can think of many times that something like this would of been very handy indeed.
dchomak, great looking power supply.
I saw you had a Ryobi 40v for your blower.
I have a similar battery, have you figured out how to power on BMS to switch battery on. There are 4 connectors + - T1 and T2. All of which seems to be off on a fully charged battery. They are connected to a capacitor because when you measure the voltage on a DVM, it drops pretty quickly from 40v.
So i’m thinking BMS must require someway of knowing it’s connected to a tool to switch the 2 Fets on to output voltage and current.
I’m assuming the 18v batteries you are using have a similar design, need something to switch them on?
T1 is a Test terminal that is used by the charger to determine if the pack is okay—if the FETs are off then the pack will fail this test and the charger blinks the defective led pattern. The FETs connect the terminal labelled (-) to the bottom of cell 1.
T2 is a Test terminal with the same external indicator circuit as T1 for the state of the FETs, but it also has an internal indicator path to the PIC controller.
If anyone knows how to download and disassemble the firmware from a PIC16F1786, then we could look at the source code and get some ideas of what it is doing.
The BMS chip on that board is an O2 micro, OZ8940ATN, which controls the FETs and also has a permanent failure mode to disable and drain a pack. Just check ebay, so many failed 40V packs for sale…
Yup I noticed a lot of complaints online about the Ryobi 40v battery, some reporting that Ryobi will even replace it for free.
Strange that its a permanent failure mode. I did try setting the RST pin high, and it didn’t show a failure initially, when switched to failure. I think it’s because my battery voltage was lower than 32v. I only a 32v power supply to charge it for now. Trying to get a boost converter to charge it.
If you press the test button and get one led to come on, then it should be enough to charge on the OEM charger.
i put the power supply + on a wire that i solder to the top of the cell 10 (+) blob, and the - on a solder wire at the cell 1 (-) glob. This bypasses the FETs and lets you charge the cells directly with no protection.
Also you can just charge half the pack at a time, like 19 volts for each half. i use the flat link between cell 5 (+) and cell 6 (-) to attach the leads, so 1-5 charges, then 6-10. It’s slower this way but at least you can use your power supply to get the job done.
i limit the current to 30mA until the cells get above 2.7, then up the limit to .5A. i set the pack aside and measure the voltage to see if it holds or not over the course of a week or two. Usually if it won’t hold then cell 1 is shorted, but i’ve charged many packs from cell 2 to 10 and they seem to hold okay.
It’s such a hassle to de-solder and disassemble these packs, and the cells are not really that great, that is is not worth the effort just to get a few cells. These cells have a mechanical protection device that will open-circuit the (+) electrode if the internal pressure goes up to the limit. The spec calls out no explosion and no fire for failed cells. There is no way to repair it and it doesn’t reset if it cools and the pressure drops.
Thanks Kennybobby, I’ve read similar suggestions online on the approach you are applying. But my question is don’t you risk the chance of over charging because you are not charging the cells equally if you are connection cell 1(-) and cell 10(+). You are merely charging 10 cells in series which can be dangerous and a fire hazard?
Yes indeed it is dangerous and can be a fire hazard. It is risky and you must be prepared because now YOU are the BMS. You have to monitor it closely, no plug and play and leaving it up to chance.
A DMM is your best friend here—keep it close and handy and check the status until you are comfortable that everything is charging okay.
First check to compare the bottom 5 cell voltage to the top 5—if that is close and stays that way, then the 2 halves are charging evenly.
Then you check the voltage of each cell, if they are all close then the charge is being taken evenly. For example i’m reading 19.09V for a top half, so the per cell voltage would be 3.818 if all are even. i measure 3.81, 3.82, 3.82, 3.81, 3.82, and these are all within 10 to 20 mV of each other.
If any cell is slightly out of family with the rest, then you can use your power supply to just charge that one cell up to the rest and see if it holds. If not then it is defective. If a cell is several hundreds of mV out of line then it may be defective.
With a 32 volt power supply you would expect to see 3.2 volts per cell if all are charged up evenly, and that is plenty to prove out whether the pack is okay or not.
i set the voltage to the max (3.9 to 4.0 vpc) that i want to reach , then set the current limit on the power supply, and then just let it go until the current stops flowing—all the while making periodic checks that everything is making even progress. This is the constant current mode of charging, and low and slow works just fine—there is no need to be in a big hurry.
i never charge to 4.2 vpc or discharge below 3.0: there is not enough energy available beyond the limits to be worth the time, effort and worry involved, too much risk and not any benefit.
Sorry to get so off topic, but i have discussed charging these packs with dchomak, and he is also very concerned about the risk and safety aspects as well.
My experience with all of the Ryobi and Ridgid batteries is that properly functioning packs will discharge through a load by just connecting to the + and - terminals. It’s true that the current has to pass thru one of the 2 MOSFETS, but even very small amounts of current will make it thru.
I have seen some packs, that for what ever reason do not read full voltage across the terminals with just a DMM. The current draw from the DMM is tiny and apparently is not enough to switch the FET to full one. Some time a pack like this functions normally when connected to a tool, other times not.
No special signal is required to T1 or T2 to allow the pack to discharge. T1 and T2 are, I believe, used during charging the pack. You can not charge a Ryobi or Ridgid pack thru the same + and - terminals. The other MOSFET in the pack is in an off state, probably usless a signal is sent thru T1 or T2.
I must say kennybobby has more electronic knowledge of these packs than I do. What I have is a lot of experiential knowlege from messing around with them.
I too must warn that playing around with these things is dangerous. It is very important to know what you are doing, pay attention to what you are doing and never leave a pack unattended. In fact I store my packs in a shed away from the house. Packs that I use and trust are stored in an old vintage refrigerator in the basement. The kind with the latching door, just in case something happens the refrigerator will contain it.
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thanks, dchomak your comments regarding the terminals and mosfets appear to make sense of what is happening in the circuit.
I will attempt adding a load today and see if the mosfets switch on.
VERY GOOD, thank you for your support
hope you like it ,.,
Android APP works perfectly with DPS5005.
Perhaps you could make a cheaper DPS model without display, rotary encoder and plastic holder with integrated bluetooth that can be only controlled via APP ?
no, we can’t . the display is the basic …
it must have basic, wire connection is very safe than other connection
So logic (CPU) is on the display PCB, that makes sense…
Nevertheless DPS is a really great product, especially for enthusiasts on a budget :+1:
thank you
Hi RD tech
love your great products.
I own a number of DSP5015 V1.1 (and others) and there is a 3-pin Rx Tx GND footprint on the board.
Any chance to use this via remote control? I am thinking off soldering a cable on to try it out.
Hidden commands somewhere ;-) ?
Or possible to upgrade the firmware to actual one so remote is accessible. I have a programmer-stick.
I will sure buy more in the future, but would be really great to be a able to use the existing devices as well.
Also - did you think about making your devices a bit more open software?
I expect a great many people from maker communities
and even OEM manufacturers of test and measuring equipment would love to
extend the firmware with lot's of features (I have some in mind ;-) ...)
kind regards
MJB
thank you very much for your message and your support
for your version, it is very old, there is not communication program, so you can’t control by that pins, so sorry
and there is not way to update it
so sorry, there is not way to update it
Hi RD tech. I bought your DPS5015 power supply but I cannot find any instructions on the connections required between the main PCB and LCD or the other daughter board that comes in the kit. Where might I get some information please as even the English part of the guide that it comes with do not show that information. Great little supply by the way 