Neato lithium ion battery revisited

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Re: Neato lithium ion battery revisited

Postby jin7 » June 4th, 2013, 11:40 am

" Re: Neato lithium ion upgrade
-4x Samsung 18650 http://www.amazon.de/Samsung-ICR18650-2 ... sung+18650

-4x Balancer http://www.elv.de/lithium-polymer-lipo- ... usatz.html

The temperature sensor from the old battery pack is accepted, as the lead. Then the two batteries (for each subject) in series parallel to each of the battery balancer and ready. follows photo, mine is still shrink-wrapped and wired not nice, I do not want to hurt you. "
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Re: Neato lithium ion battery revisited

Postby jin7 » June 10th, 2013, 5:33 am

any opinions here from our electrical engineers gurus?
Quite frankly im surprised there hasnt been any feedback yet!
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Re: Neato lithium ion battery revisited

Postby vic7767 » June 10th, 2013, 10:45 am

I'm curious as to which model Neato this kit was installed into. I understand the 2S-2P per side but how was this 4 cell LIPO balancer wired ?
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Re: Neato lithium ion battery revisited

Postby PeteX » September 16th, 2013, 12:52 pm

I know its almost 5 months ago since the last post here, but as i am a "victim" of this german teller of fairy tales, i just want to inform you that it doesnt work out.
I built up 2 packs (soldering iron is not new to me) with separate protected Li Ion batteries using all the stuff of the original battery, and guess what:
The device refuses to work saying the battery is empty and after a few minutes of "charging" the device quits with battery error.
I wasted $100 of cash for batterys with are pretty useless now.
I have a V11 from the US.

So in my whole opinion the Neato cannot run (and/or load) with Li Ion until i am proven wrong.
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Re: Neato lithium ion battery revisited

Postby vic7767 » September 16th, 2013, 1:06 pm

I performed and reported the same results using an XV-11 and LI-ion cell phone batteries with PCBs (Power Control Board) over a year ago. This is not a supported option using the domestic USA version of the Neato. However a VR100 EU version uses LI-ion packs and works quite well. (It's all in the firmware)
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Re: Neato lithium ion battery revisited

Postby glnc222 » November 2nd, 2013, 2:13 pm

Were everything known about how the batteries work and what circuits use them, it might be possible to fool the Neato circuits with some analog device into thinking it is operating NiMh with a LiOn installed -- depends on the details, all black magic to me. Might still be necessary to charge the LiOn's externally (easy enough to add a jack, but the automatic repeated run feature would not be available). I at least wonder what happens when an externally charged LiOn pack is installed and run, with Neato presumably not trying to charge it. All those Neato circuits do is put some voltage on the battery and examine the current flows. When the battery does not take the expected current or exhibit expected voltage change, alarms go off. Apparently the procedure for an NiMh battery can damage or fail to charge LiOn, so it has to be prohibited. There could also be a fire hazard problem of improperly putting current into LiOn, or any battery actually, over-charging, over-heating.
There are little computerized data logging instruments which can be attached to the Neato circuits and report the time profile of current and voltage in those circuits to a PC. Takes someone whose job already uses those tools or whose hobby is big enough.
[edit] as long as Neato is off the charger, the charging algorithms should not be engaged. peculiar it could detect a battery difference then.
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Re: Neato lithium ion battery revisited

Postby glnc222 » November 2nd, 2013, 3:09 pm

The way I might proceed is a switchable device which presents a typical uncharged battery condition to the Neato, and switches to a fully charged state -- skipping the complications in between. One of the LiOn charging circuits in a portable tool like a drill, which have come to use LiOn batteries, might be small enough to fit inside the Neato. When this separate charger finishes the battery, the Neato could be switched to see the fully charged state. Easy enough to tap the contacts on the Neato for power from the base. Just a starting point, additional complications will appear in due course. Maybe battery mavens could supply the needed gadget along with LiOn packs.

[edit] just such a gadget was developed by member TimTaler available from Germany shown in later posts -- after irrelevant speculation below; see page 3 of this thread. He has a working LiOn pack in Neato and you can assemble one with his circuit components and inexpensive cells.
Last edited by glnc222 on November 29th, 2013, 5:29 am, edited 1 time in total.
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Re: Neato lithium ion battery revisited

Postby glnc222 » November 2nd, 2013, 5:33 pm

Lithium battery chargers don't look very big: http://www.ebay.com/itm/UltraFire-BRC-18650-3-7V-4000mAh-Li-ion-Rechargeable-Battery-2-Pack-Charger-/190954421083?pt=US_Rechargeable_Batteries&hash=item2c75c53b5b
These packs are not quite right for Neato, four giving a bit too low voltage; prior posts show usable packs. Neato seems to run between 14.5 and 17v. Lithium doesn't seem any more expensive than NiMh in these packs, and Black & Decker tool packs. When they say "digital" charger, it's all in a finger tip size chip. The charger needs ventilation for hot parts, high current regulators, and may have a fan in it. So that part might need to be external to the Neato, compared to behind the exhaust grate, for example. A lot of detailed info needed to see if anything like this can be hacked for the job.
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Re: Neato lithium ion battery revisited

Postby jdublock » November 4th, 2013, 6:48 pm

Hi guys, I'm an electronic engineer with a bit of experience in NiMH and lithium ion batteries however I can't really add much other than to say please be very careful. Lithium batteries are very dangerous and incorrectly charging them may result in fire.

NiMH and lithium ion require different charging strategies. I've had a very quick look at the PCB and it appears Neato have implemented their own charging algorithms in firmware as opposed to using a third party 'hardware' charging solution. Use of VR100 firmware may allowed use of lithium ion batteries but I highly suspect there will be additional hardware protection circuitry in the VR100 units. If anyone has access to the internals of a VR100 then we may be able to find out how difficult it may be to port it over.

But again please don't mess around with li-ion batteries in equipment you don't know the details of. Evidence of the outcomes can be found on youtube.
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Re: Neato lithium ion battery revisited

Postby glnc222 » November 7th, 2013, 4:27 pm

See safety advice in last post.

I am not developing a mod for LiOn batteries myself, but in case of any use, here are sample questions involved in such out-of-the-box wacky systems experimenters can pursue:
1. Can an off the shelf LiOn charger work powered from the connecting plates on the Neato dock? (or only off the power brick directly? What voltage do these chargers take -- from their supplied power adapters? There are little switching power supply units which might convert as needed.)
2. Will Neato run off externally charged LiOn batteries (don't connect to Dock with them installed)?
3. When NiMh batteries are close to fully charged, Neato blinking green, how much current flows into NiMh batteries? (it is best to simulate an NiMh installed with as low as possible current, so power is available for an alternative LiOn charger).
4. Can a simple resistance in place of a battery satisfy Neato's requirements for reading a battery in place while charging?
5. What does Neato software do when battery connection is momentarily interrupted by switching a relay?
6. Can the internals of an off-the-shelf LiOn charger fit inside the Neato?
7. How fast do common LiOn chargers work?
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Re: Neato lithium ion battery revisited

Postby glnc222 » November 10th, 2013, 2:34 am

connecting an additional external charger
Should anyone be crazy enough to want this, an additional external charger connection to the Neato might be possible. Two strips similar to the Neato charger plates, but on the vacuum bottom, on the rear cover plate, all across, about a quarter inch apart. Two springy contacts at floor level in line with the dock center, 3/4 inches apart.
When backing in to recharge, the first contact will hit the wrong plate, but the second will not be in contact until the first hits the proper plate. Reverse of the regular charger plates on the dock and contacts on the Neato.
So a battery could be disconnected from Neato's charging circuit and charged by an external charger, say LiOn compatible -- requiring no interference with Neato's charging power supply, with all its solid state switches to the battery. Whether Neato's system could be fooled into accepting this with some bunch of relays and what not is unknown. I kind of suspect the computer is a bit too nosy about the battery to sneak by it, but who knows?
Or even connect the internal Neato charger to a fake Nickel battery outside, and use the internal supply for a proper LiOn charger. Fortunately this is not a beer hall so I don't have to hear the laughter.
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Re: Neato lithium ion battery revisited

Postby glnc222 » November 11th, 2013, 4:30 pm

economics of LiOn batteries

Another member mentioned to me the Vorwerk vacuum is sold with its LiOn battery as good for the lifetime, or at least several years, a huge contrast to the nearly annual replacement required of the hefty NiMh batteries. These things aren't piddly flashlights, with all the motors. At $80 a year to replace Neato batteries, that's worth $400 over a five year lifetime and goes a long way to explain the higher price of the German model (one might hope an improved vacuum model is available after five years, though it seems to take a competing supplier). Yet LiOn battery packs for computers and power tools etc., don't appear more expensive than NiMh batteries. They do require more expensive quality control for their delicate chemistry and safety issues, so a bit surprising. The bottom line is that for Neato to compete on price, battery cost over time looks like the most significant component of price. iRobot looks like a LiOn battery is offered only on its gutter cleaning robot, understandable as similar to a power tool in hard use. Interesting they don't offer LiOn's on their vacuums. Are these companies in the battery business, and virtually doing the old razor blade business model?
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Re: Neato lithium ion battery revisited

Postby glnc222 » November 13th, 2013, 11:21 pm

switching batteries -- a technical minutia
Neato's computer does not detect fullness of battery charge just from the voltage. When the battery is removed in any state, the program insists on doing a charge cycle, however short, to register the battery state. Apparently it wants to see the current flows to the battery (just in case you might be trying to sneak in one of those prohibited LiOn batteries...). This trips up swapping in a LiOn battery even externally charged, getting caught in the act.

To swap in another fully charged battery a relay is needed to switch in the new battery without interrupting power, like disabling a burglar alarm. A Nickel battery needs to be connected externally while Neato does its extra charging thing, and then switched out instantaneously. It might be useful to attach a large filter capacitor to the power input to maintain power over the millisecond taken for a double pole relay to switch from one battery to the other. Alternatively there could be a make-before-break switching setup, but what happens with two batteries at different voltages momentarily isn't clear. It all gets quite complicated. Only experimenting would find out what is actually involved.
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Re: Neato lithium ion battery revisited

Postby glnc222 » November 16th, 2013, 4:35 pm

causes of battery wear

Higher capacity of Lithium batteries does not increase Neato's run time, which is programmed; it may affect durability, which has substantial costs to users.

The short life of Neato NiMh batteries remains something of a mystery. Some battery tech sites advise Nickel batteries actually last longer than Lithium -- when used optimally. They note both deep discharging and fully charging (less obvious) reduces life. Over-charging, sure, but just fully? Maybe long life Hybrid cars stay in the middle. The higher capacity of Lithium (4500mah in Vorwerk vacuums) may allow a more optimum use in the heavy duty vacuum application (but some higher loads in the Vorwerk with faster front brush and side brush etc.)

It has also been noted Neato over-heats the batteries when charging, going too fast (thermistors tripping at 45 C but allowing drift to 50C too high); slowing down might take too long for convenient use. The constant maintenance charging of Nickel with its higher self-discharge rate, to keep ready for use, can exacerbate this effect. That all supports need for the higher density Lithium batteries. Odd the main feature of Lithium touted for power tools is their low self-discharge rate; no mention of durability. Roomba products share the same short Nickel battery life.

I wonder if the temperature can be fixed by just biasing thermistor lines in the battery pack with a resistor (parallel or series as needed), to read 5 C high and cut out earlier. Takes a long time to measure durability without elaborate equipment. One might extrapolate from short term changes in discharge curves from 24/7 repeated cycling over a few days. Needs a battery specialist or factory work.
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Re: Neato lithium ion battery revisited

Postby glnc222 » November 20th, 2013, 12:18 am

More Possible Circuit Detail
Supposing two extra dock contacts are added to the bottom as suggested previously:
If the ground lines can be shared, one extra plate can connect the positive side of the Neato battery line to an external Nickel battery, which will last a long time being always near full charge.
The second extra line connects the LiOn battery's positive to an external, separate charger.

A DPDT relay inside the Neato, trips on power from the regular dock contacts, switching internal battery connections to the external Nickel, and the LiOn to its external charger. When starting the Neato, withdrawing from the dock releases the relay returning internal power to the LiOn battery. Maybe some gap to fill in with a capacitor. ([edit] there is also the power line for motors (available at the fan) which switches on before rollout starts, which could unlatch the relay so Lithium powers the wheels; activated by Testmode On over USB.)
One problem is preventing the Nickel from fully charging until the LiOn is charged. An external relay controlled by the LiOn charger might place a load on the Nickel to keep it discharged.
Just the Mythbuster tradition: what would it take to get an effect, just to see how impractical it really is? Certainly a bit weird.

The ultimate Neato subtlety: LiOn's weigh less than Nickel, but Vorwerk's have an extra side brush motor to add some weight. Neato's use Nickel because the weight is needed for traction on the wheels. When using LiOn, some steel plates might be needed to make up the difference. The weight must be calibrated to tension on the suspension springs.
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Re: Neato lithium ion battery revisited

Postby glnc222 » November 23rd, 2013, 7:25 pm

Missed NiMh Opportunity

Neato's software and electronics does not appear able to take advantage of higher capacity NiMh batteries which have come to market recent years. 4500 mah batteries (compared to supplied 3200's), the same size as Vorwerk's LiOn battery I'm told, can fit in the Neato (and certainly slightly smaller 4200's less tightly; 4500's supplied by Robot-Doc.com, for instance). These seem to have slightly lower discharge curves maybe 1/2v lower. When used Neato charges them up fully leaving the excess 2ah over the used 2ah charge all at the bottom. If fully charging Nickel batteries is a factor in lifetime, they might get a much longer life if the 2ah surplus was distributed above and below, leaving a 1ah margin at the top and the bottom. Neato would then have to run at slightly lower voltages.

Whether that is compatible with the motors (certainly not an issue for the digital electronics), and there is merely a matter of software atuned to the battery type, is unknown. The blower originally had a nominal rating of 12v, though varies with different models over time. 12v rated gear motors run without problems at higher voltages, especially when pulse modulated. The specifications for batteries seems peculiar in that Neato Nickel packs are rated 7.2v each for 14.4v in series used, which is just the voltage where Neato demands recharging. Neato runs only on voltages over the battery rating, so are these ratings meaningless? It could just be how it works when the excess 1ah charge is placed at the bottom of the discharge to protect the 3ah standard Neato battery from damaging deep discharge, that they have to fully charge it to get the needed run time.

But it looks like to optimally use larger batteries they would have to at least adjust the software, if not the electronic components.

safety issues with LiOn batteries

iRobot supplies LiOn batteries for its Looj gutter cleaning robot -- which is used outdoors. Computers, phones, and power tools are all attended when used. The fire hazard involved with defective LiOn batteries (compared to fail-safe Nickel), is critical when used unattended inside a building, putting all that property at risk. AirBus will not use LiOn in planes and Boeing has to seal them in fireproof vaults (not to mention electric car issues). Yet Vorwerk distributes LiOn batteries for home use in vacuums. Either they spend a great deal on quality control, European attitudes and product liability laws differ from the U.S., or there is just no U.S. market for the higher priced Neato versions. U.S. litigious legal and product liability environment alone could dictate no LiOn batteries in vacuums sold here.
Bottom line -- don't expect these to be supplied for vacuums in the U.S. Besides, as mentioned above, the same long life ought to be achievable with larger Nickel batteries.
Lot of unanswered questions surround these products.
Last edited by glnc222 on November 24th, 2013, 4:57 pm, edited 1 time in total.
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Re: Neato lithium ion battery revisited

Postby djos » November 23rd, 2013, 8:46 pm

The whole point of the larger battery packs is to get at least 30% unused capacity left over at the end of each run - apparent this is how the car makers are getting 10 year life spans from NiMh battery packs.

Anyway there's really no point to chasing LiOn batteries for Neato's, they've clearly done a great job of engineering the XV series for NiMh only.
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Re: Neato lithium ion battery revisited

Postby jorgeli » November 24th, 2013, 1:17 pm

I think the battery quality on Neato is poor .
I have mine Neato for 3 months now and has always reduced the run time frpm 50 min to 30min.

Thats not many charging cycles :-(

I can compare with my Husqvarna Automower 220 that charging 5 times a day for 2 seasons now, and still going strong.
And it is running on NiMh to.
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Re: Neato lithium ion battery revisited

Postby invenio » November 24th, 2013, 2:20 pm

Frankly, I'm not surprised that Neato is not using the best batteries available. Considering they are coming into the market with retail price points of $220 (w/ free shipping), they probably have to cut corners anywhere they can to make a profit. I'm sure "high performance batteries" was one of the first things they cut from the "wish list." When I bought mine, I kind of presumed that the batteries were going to fail. This is one of the primary reasons I bought the extended 3 year warranty.
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Re: Neato lithium ion battery revisited

Postby jorgeli » November 25th, 2013, 2:11 am

I love my neato, and it cleans verry good,
but it has a effective fan that drains battery faster then other vaccums, and there it needs better quality on battery i think.

And NiMH has been for so many years , so it would not be so much more expensive to higher quality.
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