Makita Battery Dock

[Jonathan]

After I order all the parts to make my super light ebike. I'm now sitting impatiently twiddling my thumbs waiting for parts to arrived. So to make better use of my time, I decided to put together my battery solution.

I've been a fan of Lithium Ions for quite sometime now. However in this project I opted against the use of single cell to create my own battery pack through soldering/welding. I've done my fair share of that through RC.

Battery Packs from power tools have many advantages over the single cells.
1. SAFETY!
- they are design for rugged use where a sleepy construction worker might drop his tools from 2 story up.
2. Convenience of use and maintainability.
- Minimal amount of work to create a battery pack.
- When one goes bad, you can swap it out with another pack w/o having to endure ripping apart the pack, breaking the tabs, remove bad cells and re-solder the lead.
3. Cost. It's much cheaper to purchase packs than cells. Power tools manufacturer buys these in the millions unlike our EV/RC communities which buys only couple 100Ks.

I selected to use Makita (Sony Konion) batteries over the Dewalt, due to the cost/watt advantage. Even if you take into account the 200 cycles less the Makita batteries are still more cost effective. Besides their charger is superior than Dewalt IMHO and I don't have to deal with Dewalt's BMS.

We originally had these battery adapters for another application. The original use of these Makita battery adapter were to provide portable power for contractor use.

But here I've adapted to my ebike for a safe, light and cheap battery solution for my bike.

Standalone Makita Battery Adapter

Makita Battery installed on the adapter

Batteries docked.

[youtube]2xH29VG1OpQ[/youtube]
Here's a video of the batteries installation and removal.

The total cost of my 2S2P 36V / 6Ah pack is $268 8 :wink:
4x Makita 18V / 3Ah ... $220
4x adapter ... $48

 

[tomv]

Wow!!!

This is the best tool pack solution sofar from cost or ease of building perspective.

A few questions:
- Do you need any special logic to discharge batteries? Or is it just B-/ B+ terminals? Dewalt is mighty hard to discharge, need special circuit or bypass BMS
- What's the internal fuse rating for those? Dewalt is 15A if I remember correctly.
- Where do you have your cycle life numbers from? I'd love to see datasheets for those packs
- Did you do any testing with this pack? Discharge graph for it would be mighty interesting.
- How do you make those connectors? Ar they for sale anywhere?

Have fun riding, should be great!

 

[EMF]

Really, really nice! 8) I like your logic. Maybe I could make another battery pack for my ebike with these Konions. You have inspired me to investigate. How much are the battery adapters and what is the part number? Well done!!

 

[Ypedal]

Hmm.. about those connector blocks..?

I picked this up today, 17 packs.. 40 $ ! ( Defective.. but i can fix that )

 

[Doctorbass]

Hey guys.. that's great to see that your interest grow about the famous makita!!!

Remember that this is often the first 1s2p group of cell that is deffective.. the bad spotweld on that first group is a major problem and that make the connection heating and dammaging the cells.

generally no balancing is needed for those cells

I got more than 100lbs of those from now

nominal 1.6Ah
10C
Around 40miliohm in used state.

see also my post about 2kW of these cells for info



here the last box i got. Ypedal.. that's great that you have been able to have the same luck than me :wink:

 

[Jonathan]

tomv:
Do you need any special logic to discharge batteries?
- None just B-/ B+ terminals? No balancing required. All the smarts is in their charger. Cell balancing and thermal management during charging which can significantly improve battery life.

What's the internal fuse rating for those?
- I don't remember there is any last time I took them apart.

Where do you have your cycle life numbers from? I'd love to see datasheets for those packs
- Doc posted the datasheet in the post above. It's 800 cycle to 70% @ 1C. The heavier the drain the less cycles. Roughly 10% cost per C.

Did you do any testing with this pack?
- Not with the pack but I did them as individual cells with my CBA.

How do you make those connectors? Ar they for sale anywhere?
- it was molded. For sale if you guys are interested they'll be $12/each


Ypedal & Docbass:
Where did you get so many cells care to help out a guys trying to build a poor man version of the Tesla Roadster.

 

[Doctorbass]

tomv:
Do you need any special logic to discharge batteries?
- None just B-/ B+ terminals? No balancing required. All the smarts is in their charger. Cell balancing and thermal management during charging which can significantly improve battery life.

What's the internal fuse rating for those?
- I don't remember there is any last time I took them apart.

Where do you have your cycle life numbers from? I'd love to see datasheets for those packs
- Doc posted the datasheet in the post above. It's 800 cycle to 70% @ 1C. The heavier the drain the less cycles. Roughly 10% cost per C.

Did you do any testing with this pack?
- Not with the pack but I did them as individual cells with my CBA.

How do you make those connectors? Ar they for sale anywhere?
- it was molded. For sale if you guys are interested they'll be $12/each


Ypedal & Docbass:
Where did you get so many cells care to help out a guys trying to build a poor man version of the Tesla Roadster.

These battery/charger have no balancing circuit. only a BMS that watch temperature and charge current.


Each of these pack have an internal thermal resetable fuse of 7A 250V (see pics above)

I think it is 70degree C (not sure...)

about the TESLA ROADSTER... i have the same idea.. but to get 6831 will take long! :lol:

 

[Mathurin]

generally no balancing is needed for those cells

Ok, now I'm interested.

 

[safe]

These operate as "Smart Batteries" in that they add all kinds of control logic inside the battery and they even communicate to the charger things like usage history.

I'm interested in the idea of actually doing this too because it really delivers the "Smart Battery" concept without having to build everything yourself.

And the price is not bad either...

Maybe this might be good to try for my Project #003 bike which needs to be 36 volts anyway because of the motor.

 

[tomv]

generally no balancing is needed for those cells

What does this mean exactly? Will they happily take overcharge? What happens if I overcharge them. Nimh heats up and vents hydrogen (not good, but survivable). Just how do you overcharge them? Leave them permanently at 4.2V 200ma?

 

[safe]

What does this mean exactly? Will they happily take overcharge? What happens if I overcharge them.

It's hard to say exactly how they've implemented their "Smart Battery" logic. Since it's a different concept to do this (to control everything from the battery rather than the other way around) it's likely that they made shortcuts to reduce costs in the circuit and deliver a proprietary solution. (the proprietary solution always happens in the beginning as companies grab at control of a new market) My guess is that the people at Makita knew about the Smart Battery standard and rejected it's full implications since it doesn't make much sense for them to do it all, but they used some of the ideas to bring their product to market. The battery clearly is described as controlling the charger (external control logic to the charger) and this is one of the defining charactoristics of the Smart Battery.

I do like this idea and it's a real "fast forward" towards getting to an idealized Smart Battery solution... this might be the short cut to getting there.

http://www.amazon.com/Makita-194205-3-Lithium-Ion-Battery-BL1830/dp/B000EDVTQM

Product Description

From the Manufacturer
18V LXT (3.0Ah) Li-Ion Battery (Slide Style)

Product Description
18V, 3.0AH, Lithium-ion Battery, Built In Memory Chip Memorizes The Usage History & Communicates With The Charger, Less Weight Lithium-ion Battery Weighs 40% Less Than Ni-MH Or Nickel Cadmium, Anytime Charge Lithium-ion Batteries Have No Memory Effect & Can Be Charged At Any Time, Charging Technology Controls Current, Voltage & Temperature To Maximize Battery Life.

I can see using six of these in a 2S3P configuration:

18V 3.0Ah - 18V 3.0Ah - 15 Amps Peak
18V 3.0Ah - 18V 3.0Ah - 15 Amps Peak
18V 3.0Ah - 18V 3.0Ah - 15 Amps Peak

...making a 36V 9Ah 45 Amps Peak system for a base price of $360. (not counting docking and charging)

We need to watch for sales on these things...

 

[EMF]

What does this mean exactly? Will they happily take overcharge? What happens if I overcharge them.

It's hard to say exactly how they've implemented their "Smart Battery" logic.

So, why not let someone answer that does know? Plus I also have had a belly full of this "Smart Battery" nonsense theories, guesses. etc., in every darn thread. It's really annoying.

 

[Jonathan]

These cells do not need to be balanced charge after extensive abusive use. The reason is their discharge characteristics are very uniform. All marching to the same drum beat. As for overcharge, NO! never attempt to overcharge Lithium cells, you will get anything from a pop to a BOOM! depending on chemistry. To my knowledge Konion DO NOT burn or explode. I haven't pop one of these yet so wouldn't know. But I've pop quite a few Lithium Cobalt and the fire was not extinguishable by water. You don't really have to worry about the overcharge problem if you use them as a pack because the Makita charger is responsible for all that.

These batteries were heavily favored in the RC industry couple year ago until Sony decided to pull the plug on single cell sales in North America. I believe you can still get them individually in Europe. They can not handle the abuse like A123 of dumping 30C and charging @ 3C but again we're not having a 10 minute sprint ride like those RC Heli guys. For the capacity/$$$, I believe they are the best bang for your bucks.

Here's a 7C & 10C discharge graph lifted from the a Czech site

Babelfish link

FYI: I'll be using these @ 2-3C discharge with a BMC setup.

 

[Jonathan]

Just to be clear the are NOT "Smart Batteries". In order to qualify as such, the batteries need to report it's current state of charge (SoC). These only report historical data of how it's used back to the Makita charger.

 

[Doctorbass]

After talking to the guy of the Makita service center, he said that they NEVER saw any battery catching into fire. From all thousan's of XLT battery he saw at the job, he only saw ONE poping!... no fire.

These safety caracteristic are very similar to the A123.

Around 6Wh/cell 15A max discharge for 5$ /cell brand new.. thatMs difficult to beat i agree.

About overcharging.. NOOOOH !!! ALL LI-ION cell type dont like overcharge!

I usually charge them at 5A no problem (normally the makita charge each cell to 1.5A (3A for 5s2p pack 18V) and i cut the charge at 50mA.. maybe it would be better to stop at 100-150mA.

Do what you want with those.. BUT AVOID to push them to 50+ degree C.. they dont like that... they get dammaged very fast.

Today, The makita guy confirmed me that he want an ebike like mine and will supply all the battery and charger
I placed an order from ebike.ca and will built a bike for him with an X5 and a 48A controller... I'll put many of these cells on it!! probably 10s 10p.

 

[Joey]

Hey Doctor Bass,

Can the Makita packs be wired together without any external protection circuitry, e.g. Shottky diodes? I am interested in either 36V/9Ah or 36V/12Ah configuration. Is it better to wire packs in parallel first then connect the parallel packs in series, or is it better to wire packs in series first then parallel the series packs?

-- Joey

 

[Doctorbass]

Hey Doctor Bass,

Can the Makita packs be wired together without any external protection circuitry, e.g. Shottky diodes? I am interested in either 36V/9Ah or 36V/12Ah configuration. Is it better to wire packs in parallel first then connect the parallel packs in series, or is it better to wire packs in series first then parallel the series packs?

-- Joey

No diode are needed. You only need to wire packs in parallel first then connect the parallel packs in series. All paralle pack MUST have the same charge!!otherwise, the lower pack will charge thru the higherpack at a too high current. (these cell must be charged at max 2A current each cell (that mean a 3Ah pack must never be charged over 4A.

If you talk about makita PACK that's of, no external addition of protection circuit.. they alsu have a 7A resetable thermal fuse inside.

But if you talk about using the cells only, they need special attention about thermal protection.

Doc

 

[Mathurin]

just over 300$ for 5 of these, new, on ebay. Cheap!

 

[Jonathan]

@ $60/Pack you can get them from Amazon for free shipping.
If you want ebay route SCENTERPRISES4408 from time to time have them for $50/pack + shipping.

Prices of power tools pack have surely been going up.
I remember when I was able to grab these for < $50 and the Dewalt for <$100, and that was only last year.

Is it inflation :? or the EV community is rapidly growing

A few of you ask about the dock. You can purchase them directly from here.

 

[Joey]

I am seeing two different Makita 18V LXT battery pack models and two different LXT chargers on the web. I think the DC18SC is the charger to get for use with 18V 3Ah packs, but what is the difference between the two battery packs? Which is better? Is 194205-3 the same model as BL1830 but indicates newer date of manufacture?

battery packs: Makita BL1830 18V LXT
Makita 194205-3 18V LXT

chargers: Makita DC18RA
Makita DC18SC

-- Joey

 

[Jonathan]

It's the right one. What' you're looking for is BL1830. Don't get the BL1815. The 18 indicate 18V while 30 indicate 3.0 Ah.

As for the 6digit model number it just indicate what packaging it was sold under.
194205-3 ... means sold individually
194230-4 ... means sold in two packs
194288-3 ... means sold in ten packs

 

[Joepostal]

Just purchased 4 of these on ebay and 4 of the custom clips... going to burn up my 250watt motor for fun
I have a mongoose cx 450 that has been waiting for a cash infusion. Well maybe it is 450 W... anyhow wonder how it will survive the 36v. I am sure I will burn the controller first... Any suggestions?

I suppose I will go the cheap route and put a 1000 watt currie motor on it and use the controller for their 1kw motor...
That is just going to be the intermediate step to have a faster ebike and learn more.

I want to keep the pedals but I think it is going to be hard once I go full out like the cx 450 on evalbum that Denise made.
It is only 2 miles to work so capacity is not the issue. Such a great starting platform. Upgrading to downhill shocks is going to be a bit expensive but once the shocks are replaced and the speed improved the gearing on the pedals is too low and a huge front sprocket won't fit so I might have to modify the battery box to make room for a big sprocket.

I looked at all the bikes I could find and have lots of great ideas thanks to everyone for posting their builds and battery information.

 

[TylerDurden]

It is only 2 miles to work so capacity is not the issue.

If you go 1KW, you could wheelie all the way.

36V should be ok... get out yer drill.

 

[johnbendixhansen]

Jonathan

Could you please contact me regarding the Makita battery adapter:

John Hansen

johnhansen@cmastinc.com

www.camstinc.com

727 251 8998

Thanks

 

[hawkjr9]

Does anyone know how to reset or replace the fuse or circuit breaker? I have 3 of these batteries that I know the cells are good but the charger says the pack is bad and wont charge them.