36v, 10ah NiMH vs DEWALT 36 VOLT LITHIUM ION BATTERIE? what batteries have more power and...

Hi Windshield,

Your type question has been discussed many times at various forums. Please do a search on this comparison.

Also you need to please re-phrase your question to a comparison that makes some sense. Noone would ever make the claim that one 2.3 AH 36V Dewalt Battery pack would outperform a 10AH 36V NiMH battery.

However, 4 parallel Dewalt battery packs might do it 4x2.3 = 9.2 AH, and probably weigh less, even with extra weight of the 4 plastic cases and 4 bms modules = 4x2.5lbs = 10 lbs.

Brian

` :)
Windshield,
No problem, that's what we are here for to answer questions. I sure someone with more knowledge than me about Batteries, will have a answer for you real soon.
This is the way we all learn, and what we are all about at V is for Voltage Forums.
Our EV Battery Collaborative Hand Books are currently being updated since there seems to be quite a bit of interest in other type of Batteries.
If your answer is not there, let us know, we'll find it for you.

Stleride
Moderator Team Captain

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`
NiMH Battery Modules: 12V 10Ah (120Wh 10xD long) for 12V DC Device
Detailed Description
Packing
* 12 V 10 Ah (10000mAh) NiMH Battery Pack made by 10 pcs high quality NiMH D size cells. , assemblied side by side in one row ( 10x1)
* Wrapped by heavy duty heat shrink tube
Volatge 12V ( working ) 14.5V ( peak)
Capacity 10Ah or 120 wh
Charging Rate Standard 1.8 A Max. 5 A ( for each 12V 10Ah module)
Discharging Rate
* Standard rate: 10Amp ( Recommended and warrantied)
* Highest rate for continuous running: 20Amp
* Max. Rate for short time: 50Amp ( Not recommend as working rate )
Prewired
Two terminals are in the battery pack. Charging and discharging plug are seperated for protecting battery overcharging and power off during discharging
* Discharging plug is male standard tamiya connector
* Charging plug is mini tomiya connector which connected a 65o thermostat. to battery pack to protect battery from overcharging.
* a connector daptor from mini tamiya to stnadard tamiya to connect a battery charger is include
Dimension 13.25"L x 1.5"W x 2.5"H
Net Weight 3.6 lbs

D-Size 1.2 V 10000 mAh NiMH Rechargeable Battery Spec Sheet

Peace Out,
Gman

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Windshield,

I've done a few calculations to compare a 10AH NiMH 36V battery to a pack system from 36V Lithium Iron Phosphate Dewalt Battery Packs:

First, see the following site for a good 10 AH 36V NiMH battery on sale for $265.95 including 3 chargers:

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2061

This 10AH NiMH from BatterySpace.com weighs 12 lbs at a working voltage of 36V and is good for 400 Cycles, and can provide 30A continuous current.

4 stock Dewalt packs in parallel produce 9.2 AH and weigh 4x2.4lbs = 9.6 lbs at a working voltage of about 32.5V and are good for >2000 Cycles, Packs can each provide High Current => 4 packs can provide > 4x20A = >80A continuous current.

To ensure a > 10AH pack you can use 5 stock Dewalt packs, to provide 11.5 AH at a working voltage of 32.5 v. It would weigh 5x2.4 lbs = 12 lbs. This includes the additional weight of all the Dewalt plastic and Dewalt control modules of about 2.5 lbs.

Because of the voltage difference, perhaps the best comparison is in Watt-Hours of Energy.

32.5Vx20A= 650 Watts. This can be produced for 11.5AH/20A = 34.5 mins.

Total Energy Available from 5 Dewalt Packs = 650x34.5mins/60mins/hour = 374 Watt-Hours

NiMH: 36Vx20A= 720Watts. This can be produced for 10AH/20A = 30 mins.
Total Energy Available from a 10AH NiMH 36V Battery Ssytem = 720/2 = 360 Watt-Hours

Thus you have about the same amount of energy available in 5 stock Dewalt Packs as a single 10AH 36V NiMH battery, and they weigh the same because of the additional plastic and control modules in the Dewalt packs.

Increasing the Dewalt batteries to a working 36 Volt 9.2AH pack would require a custom pack from discrete A123 batteries that could be removed from Dewalt packs, but would weigh only 4x12x73x2.2/1000= 7.7 lbs, by leaving out the plastic and control modules.

To ensure a >10AH and a working battery voltage of 36V, you can add additional capacity to reach 11.5 Ah, This would require 5x12x73gms/batteryx2.2/1000= 9.6 lbs of A123 batteries in a custom pack, without the Dewalt plastic and Dewalt control modules.

Bottom Line - 5 stock Dewalt 36V Packs would provide about the same energy as a 10AH 36V NiMH battery, and could provide >2.5x the continuous current, would weigh about the same, but would last at least 5x as many cycles as the NiMH battery. Current sale price for NiMH battery is $266. Current eBay price for 5 Dewalt Packs is about $500; adding in 5 Dewalt chargers is about $150, for a total of $650. Therefore you would get at least 5x the lifetime for about 2.4x the cost.

You could drop 2.5 lbs of weight by building a custom pack from the A123 batteries you extract from the Dewalt Packs.

Best Regards,
Brian

` ;)
Thank You.

Stleride
Moderator Team Captain

Moderators are community volunteers who help keep V is for Voltage Forums running smoothly, and provide forum support.

Not mentioned are the fast charge times and the flatness of discharge curves for the Dewalts.

Good points Russ.

The flat discharge curves of the Dewalts plus their greater current sourcing ability will then provide sustained hill-climbing ability and almost constant speed, throughout a ride.

I personally don't have any e-biking experience with NiMH batteries, but I do have a 14.4 V Makita Drill that has NiMH batteries, and they seem to start dropping noticeably in power about 2/3 into their discharge.

Most frustrating of all is the high cost of the replacement NiMH batteries that are almost shot after only a few years of real use. The replacement batteries are more than half the price of a new drill.

I have read on another web site that Lithium Ion batteries have a very finite lifetime regardless of their use - 2-3 years. Does anyone have any more information on this. This might be a deal breaker for many users.

You have to be careful which Lithium technology is being talked about.

The Dewalt Lithium battery, made by A123 Systems, is called a Lithium Iron Phosphate battery and is not the same as the higher voltage Lithium Ion batteries, and is touted to have a long shelf life of at least 5 years.

Brian

Expect more range, if you were to parallel FOUR or more DEWALT 36 volt packs! Each pack is only 2.2 to 2.5 AH, so using only one will give LESS range, but speed/acceleration might be as good or better!