Solar charge controller for lithium batterys

@nurderfch1846 The quick answers are 1-Yes, 2-Maybe, 3-Not sure, 4-Maybe

For more details check out the following two links LINK1 LINK2

To give you an idea, here is a LINK  to a commercial product for the 14500 batteries.

Here is a DIY charger circuit LINK

The reason I said 2-Maybe is the charge current is small and there are complications with the protection features if there is more than 1 cell. Typically you need a balance circuit as well for multiple cells. This is the kind I have.

The 3-Maybe is the same basic answer as 2. Moreover, you seem to be saying you want to use the batteries while simultaneously charging them. Without special circuitry that is not only not possible, it is dangerous. You do NOT want a Lithium Fire. Get a concrete slab, charge in a fire bag and do it outdoors if it is DIY.

The reason for 4-Maybe is it is fine for 1 cell charging only, otherwise as already stated probably not.

I use the following to charge my 18650's indoors (also my 14500's and others) https://amz.run/6e5w

@zander Thanks for your quick reply! Thanks for letting me know, that I can´t charge and draw power simultaneously. I maybe would have tried that. I actually have a solar charger where I think that you can do that, that´s why I thought it would be possible. It´s this one: https://www.waveshare.com/product/modules/solar-power-manager-c.htm I have a problem with it: On the USB-C output, it only delivers about 1-1,3V although it says, it should have 5V/3A regulated output. Any idea why that isn´t the case?

@zander So I found this video ( https://www. youtube.com/watch?v=f2yMs-JAyQM) and it says that you can charge and draw power at the same time. Is it possible or not?

Hi @nurderfch1846,

On the USB-C output, it only delivers about 1-1,3V although it says, it should have 5V/3A regulated output.

USB specification, especially USB C, specfies some clever tricks to limit the current and voltage until the load, and  also I think the cable, has indicated it can cope with it.

(USB C voltage can exceed 5V, but only after the load has indicated to the charger that it can cope with it, similarly the cable must indicate it is 'uprated' to 3A capacity.)

Many chargers, especially those with USB plugs prior to C, did not support those protocols, and simply delivered 5V at up to the current written on the charger.... eg 5V 2.2A

Sorry, I haven't worked through all the details, but is it plausible you are measuring the voltage whilst trying to draw an appreciable current?

I am not 100% sure, but I think you should get 5V with no load, but maybe only up to 500 mA (or maybe less than 500mA? .. the spec runs to many 100s of pages, and I am not familiar with it), when using either a load or a cable that doesn't meet the full USB C specification.

Sorry, this reply is very vague ... I am just trying to suggest the type of questions you may wish to research further.

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As for the TP4056, Ron @zander has already provided some good information.

Whenever you buy one of the small, cheap boards based on a single chip, often sold with minimal information ... in this case the TP4056, a good starting point to try is Googling for the chip's data sheet. Very commonly, the board will closely match an application circuit in the data sheet, and indicate the capabilities, options, etc.

Of course, buying these boards is somewhat of a lottery, as there is no direct link or responsibility, and occasionally the board designer 'creatively' changes the design, usually to cut the cost. So don't regard the chip data sheet as anything more than a general indication of what the device was meant to do. It is very unlikely to be 'better' than the data sheet suggests, but it could be very much worse.

Similarly, there are often YouTube's and blogs which may discuss a common item .. some are very good .. others are abysmal!

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Best wishes, Dave

@nurderfch1846 That is a commercial solar charger, I have one. If you look at the board you can see there is way more parts than just the tp4056. I am at the hospital now and can’t reply further until Tuesday

@nurderfch1846 As I said it is if you have the circuit to do that like the wave share board

@nurderfch1846 I can’t see the video, the link is messed up but you can if you have all the parts, the TP4056 is only one part

Hi @nurderfch1846,

So I found this video ( https://www. /a> youtube.com/watch?v=f2yMs-JAyQM) and it says that you can charge and draw power at the same time. Is it possible or not?

I would say, supperficially, this appears to be one of the 'better' videos, and importantly, it points out there are at least two possible cards .. one with just the TP4056, the other with the DW01 as well --- and obviously that makes a difference. However, I am only an observer, rapidly trying to assess the information I can find. This means I take no responsibility for any errors on my part.

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The TP4056 data sheet https://dlnmh9ip6v2uc.cloudfront.net/datasheets/Prototyping/TP4056.pdf

assuming that it matches the chip on your board, given the number of clones, does not  actually show where to connect a load.

So if your board has this circuit, which obviously only you can check, then I can only assume you are connecting your load directly to battery.

IF THAT IS THE CASE, then the TP4056 has NO influence over how and when you draw current from the battery.

Its only able to control the voltage and current flow from the power source (5v in the diagram). It 'assumes' the current being delivered is charging the battery, but as the video clearly explains, it may actually be principally powering the load.

Accepting that this circuit doesn't provide the  battery with any protection against the load drawing too much current, or overdischarging the battery, I can't see how it makes much difference if you are attempting to charge the battery or not.

As the video explains, the TP4056 limits the current according the resistor, and depending upon the factors described, some  or all of the 'charging' current may effectively go directly to the load, but surely the only effect of that is to reduce the actual charging current.

In summary, I may be missing the obvious, and I emphasise everything you do is at your own risk, but I can't see a problem with supplying power to charge and discharge the battery at the same time.

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The second board the video describes includes a DW01 device and a pair of FETs connected back to back.

DW01 data sheet is at https://datasheet.lcsc.com/lcsc/2204271145_Guangdong-Hottech-DW01_C181096.pdf

and includes the application example

It is unfortunate that this sheet does not show it 'in situ', but

https://www.handsontec.com/dataspecs/module/18650-Lithium%20charger.pdf

shows a circuit diagram

It also has another diagram that explains the load should be connected to the OUT pins, and the battery to the B+ and B- pins.

This shows that the DW01 controls a pair of MOSFETs that control the connection between the battery negative terminal and the load negative terminal.

Also the (charging) output from the TP4056 is connected to the load terminals, so the DW01's FETs can also override the TP4056's attempts to charge the battery.

The DW01 data sheet is confusing with respect to the conditions it will direct its FETs to isolate the battery, but the following are apparent:

Battery voltage too high --- overcharging

Battery voltage too low --- overdischarging

There is also mention of over current .... although there is no obvious current measurement shunt. It is plausible that it is measuring the voltage drop across the FETs, but as these are external, it is more difficult to determine the current overload detection level. (A voltage difference level is mentioned.)

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Once again, it is difficult to imagine why charging and discharging at the same time should represent a problem.

But once again, I may be missing an obvious point. Furthermore, these circuits may not be the same as yours, so I take no responsibility for whatever happens .. I have merely tried to explain some of what these circuits are apparently intended to do, in that hope it aids your research

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Please remember lithium-ion batteries can react violently if mistreated ... so far as I can ascertain, the most common reasons of things going badly wrong are based on overheating, overcharging, and overdischarging ... hence I would prioritise making sure none of these cases ever occur. Obviously, this is only a minimum standard of care, and other factors may also be important.

Best wishes, Dave

@davee I just noticed I put the wrong link, thats the right one (just another version): https://www.waveshare.com/product/modules/solar-power-manager-b.htm

Posted by: @davee

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Sorry, I haven't worked through all the details, but is it plausible you are measuring the voltage whilst trying to draw an appreciable current?

I measured it with no load (just a multimeter).

Do you think I would maybe get 5V with the normal USB-port?

Hi @nurderfch1846,

 I am only a USB user, not an expert, but intuitively, I would have expected 5V from both USB sockets under no load conditions.

The new link shows:

The different maximum current ratings suggest the USB C uses different circuitry, so it is highly plausible they may show different characteristics, especially if one is faulty.

I think I would check the voltage from both USB ports, and try sending Waveshare an email with what you find, if it is not 5V in both cases. Ask if that is what they would expect and if not, can they arrange replacement.

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As background, and maybe evidence, I spotted a discussion article on the Analog Devices website

https://www.analog.com/en/technical-articles/usb-battery-charging-guide.html  

I think the summary is that any functional USB socket will give 5V (or at least 4.something V), for current demands up to at least up to 100 mA, without the load doing anything clever. But I've provided the reference for you to confirm for yourself, that is what the author is saying. I assume that the author is well informed, as Analog Devices manufacture smart chips to use in USB devices to 'negotiate' the higher currents and voltages.

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Contacting Waveshare might not achieve anything, but it is worth a try.

Best wishes, Dave

@davee I already contacted them yesterday. They´re office is closed until wednesday, so not expecting something before then.

Posted by: @davee

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The new link shows:

The different maximum current ratings suggest the USB C uses different circuitry, so it is highly plausible they may show different characteristics, especially if one is faulty.

It has the same Current for USB-C and normal USB. The left side of the table with 5V/1A is for another version of the device.

I haven´t tried the normal USB, cause I don´t have an adapter yet, but I will try to get one.

Posted by: @davee

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I think the summary is that any functional USB socket will give 5V (or at least 4.something V), for current demands up to at least up to 100 mA, without the load doing anything clever.

I also understood it like that. The problem could maybe still be, that the load has to tell the USB-port how much current it needs, but It should at least give 5V/100mA even if the load is not communicating. But that´s not the case.

@nurderfch1846 Measuring voltage is often not a useful approach for all the reasons @davee mentioned. You are still failing to understand some basics. The TP4056 is NOT a multi-cell board, it also is NOT a charge while using board. I have a solar system and like all solar systems is used while charging. Those solar systems can do that due to the charge controller used. If you can find a charge controller that matches your battery spec, then it is a relatively trivial exercise, solar panels thru a breaker/disconnect to the charge controller input, charge controller output to the batteries via a disconnect/breaker. Your challenge is understanding the solar panel specs and how that relates to the charge controller. Now buy the charge controller.

You need to either restate your objectives clearly or start a new Topic, but this topic has too many chefs stirring the pot. Maybe do a little research first? As a start, I am enclosing the TP4056 datasheet. It clearly state it is for charging one cell. Nothing in the spec sheet allows for use while charge mode, just check the pinout.

Hi @nurderfch1846 and Ron @zander,

As for the USB output, sorry I just clicked on your link, and looked at the photo image and table ... I didn't notice there was more than 1 model.

As I said, my understanding is that the USB port should always provide 5V at a small current (up to 100mA), because the load can only 'negotiate' if it is powered, and (generally) it has no other source of power. 

Even if there is only 1 power output circuit shared between the two ports, checking both might show the C port is miswired.

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Overall, I have the impression you are looking for battery that is able to supply a considerable current for a substantial time. This is more onerous and risky than the simple, low current, LED load discussed in the video. In particular, there is a much greater chance of increasing the cell temperature.

In addition, I am concerned that you are intending to charge using solar cells, which are obviously very variable in the power they can deliver, and may not have any regulation built in.

Both of these point to a situation that demands a 'professional' approach with equipment that is designed to deal with these 'more demanding' conditions. Hence, I completely understand why Ron is stating this should be your approach, and I am in no way contradicting his safety first approach.

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However, this forum is about DIY approaches, and inevitably some of the projects involve risks, including some that would not be accepted in a commercial environment.

Hence, I am doing my best to analyse the various bits of hardware. Whether you decide to accept my 'best efforts' analysis or not is totally your responsibility. I am in no way recommending a specific solution or course of action ... merely trying to explain the data I have available to me. There is no doubt Li-ion cells can become dangerous.

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CAUTION: The TP4056 is only designed for cells with a maximum voltage specification during charging of 4.2 V.

There are a number of different chemistry variants of Li-ion cells, and some have a lower voltage of operation. Be very careful to match your charge controller with the cell(s) you are using.

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To be clear, the TP4056 device is a simple Li-ion battery charge controller. It cannot perform any other task.

The TMS4056 chip itself provides a pin for temperature monitoring on the battery, but the simple modules discussed do not enable this facilty, so there is no protection against the cell overheating. Overheating, causing the cell to go into thermal runaway, is perhaps the worst risk with Li-ion cells, so this is a serious concern.

The TM4056 has a limited voltage input range, and could potentially suffer from overheating when charging at a high rate (e.g. 1A), with a high input voltage. I suspect it is intended for controlling charging from a well regulated  supply ... e.g. 5V stabilised source.

I am concerned that a solar cell power source may exceed these working voltage conditions, but have no useful data to analyse. At the very least, I think you should ensure that output of the solar is voltage controlled to a minimum useful voltage (maybe 5V???) , before sending it to either of the TMS4056 modules discussed in the video you referenced.

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The TMS4056 is designed to charge a single cell. It cannot handle more than 1 cell in series.

The maximum charging rate that the device can handle is specified to be 1A. A lower maximum charging rate than 1A can be specified, by changing a resistor on the commonly available boards using the TMS4056. Clearly, this resistor should be matched to the cell's charging specification.

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It is not uncommon to find applications in which 2 or more 18650 cells are in direct parallel connection with each other. A commonly published view is that this is permissable, providing all of the cells are identical in every respect, including usage history and charge level at the time of paralleling.

It is certainly not an ideal arrangement, because the cells may not age uniformly, and the performance will be defined by the weakest. (Battery Management Systems with cell balancing arrangements are typically employed to minimise these issues in more sophisticated systems.)

I am certainly not recommending it, but acknowledge you may find it commercial systems, including possibly in 'larger batteries' made up of many cells.  

If you connected two or more cells in parallel, then the total maximum charging rate from the simple TMS4056 board would still be 1A. Nominally, the 1A would be shared equally between the cells, but any differences between the cells will result in unequal sharing. This implies, that the chosen rate should not exceed the maximum acceptable rate for 1 cell, to minimise the risk if 1 cell 'hogs' the entire incoming charge. Of course, this implies the charge time will be much longer than if each cell was individually charged at its maximum rate.

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The TP4056 BY ITSELF is only a charge controller ... it has absolutely no influence on current being taken out of the battery by a load, and I personally cannot see a reason for it, or the battery, to care if a load 'stole' some of the current the TP4056 thought was destined to charge the battery.

Of course, if the load is consuming current, that would otherwise be charging the battery, it will extend the time needed to charge the battery.

I think this is also the view of the video you referenced.

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Also, remember that although the TP4056 chip has a temperature sense input pin, the low cost boards do not appear to have any connection point to this pin and hence have no means of determining the cell temperature. This seems to be a dangerous oversight. Charging, discharging and high ambient temperatures can all raise the temperature of the cell, conceivably to a dangerous level.

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It also follows that the TP4056 BY ITSELF cannot offer any protection from over-current demand from the load or over-discharging from load, regardless of whether there is any active charging at the time ... the battery is in the same position as when the load is connected directly to the battery.

The lack of protection systems is very poor, but it is unaffected by charging whilst a load is connected.

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The alternate board shown in the video that @nurderfch1846 referenced had a second chip, DW01, (in addition to the TP4056) which specifically does claim to provide the battery with protection from the load.

Again, I cannot see a reason for this board or the cell to be adversely affected if a load 'stole' some of the current the TP4056 chip thought was charging the battery.

This alternate board is again designed for a single cell of approximately 18650 typical rating.

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Wiring more than 1 cell in parallel, with all of the same disadvantages and reasons that it is NOT recommended, as discussed previously, would increase the total energy capacity (number of Amp-Hours), but NOT increase the current (number of Amps) that can be delivered, since it includes an over current limit.

My understanding is that you were wanting multiple cells to increase the current, so this is probably not helpful.

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In summary

It is not my field, but I know remote control model vehicles with a high current capacity often (maybe always?) employ more sophisticated management systems than these simple TP4056 boards. If your power demands are comparable to these vehicles, I advise you to look in that direction.

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My discussion refers only to what I can see regarding the two boards discussed in the video. There may be any number of other designs claiming to use a TP4056, each with their own characteristics. TP4056 only 'specifies' a particular chip design, and clearly that has been cloned, etc., implying there may be many different 'TP4056's as well. So you will need to carefully examine and test any boards to ensure they perform the functionality you need. Quality control in this marketplace is best regarded as non-existent.

At best, the level of control and protection of these boards is far lower than the more complex systems used for larger systems. For example, there doesn't appear to be any provision for temperature monitoring. They are probably better than no protection, but you must judge if it is sufficient.

Take care of yourself. Remember, that if a cell does overheat, not only is it a fire risk, but also that the fumes are very toxic.

Best wishes, Dave

@davee @nurderfch1846 As usual, Dave has produced a well-thought-out analysis of the situation. Although Dave and I have tried in our own ways to provide some guidance, I feel it is not being well received.

Let me be a little more direct and show you the equipment I have for batteries and chargers for a future vehicle. I do not yet have a solar option simply because I am an off-grid person and know the capabilities of solar this application is not a very good match, so I have nothing to show you, but if I did, it would be in the neighbourhood of 200Watts. I have 6 180W panels. Each is about 3' x 2'. One of those would need about 4 hours to charge the cells I am including a link to.

In a club situation where a bunch of fellows have some leased land for an airstrip and a clubhouse or shelter to mount 6 or 8 of those panels, then they could be used to top up the battery packs.

I am attaching links to a battery HERE, a charger HERE  and the fire bags (one inside the other) HERE

Just in case the links don't work, here are some pictures.

Almost forgot, for the 18650 and similar smaller rechargeable batteries, this is the charger I use HERE