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I don't understand why certain sellers like to keep their price a secret. Other places publish their prices and shipping details so buyers can compare.
It's normal in China, and many other countries, for business to be done by negotiation or through a certain price on volume. If someone gets a better deal, they don't want the customer that didn't get the better deal to know about it. I think it all comes together the same way for high volume transactions as well because the little guy buying 50 cells at 60Ah won't get far trying to buy at the same price as 100,000 cells at 200Ah, for example.

India is similar to this as well. I used to work in Minneapolis(work in the suburbs now, where parking is free) and would visit a store that sold electronics nearby from time to time and it wasn't uncommon for a man from India who is working in the US to come up and be excited while he tries to haggle a deal on 5 digital cameras to send home to his family at a big store that has fixed prices. In India, China, and many other countries, they are not direct with purchases and do not have fixed prices because they sell things market-style where deals are made.

Hope that helps make sense of it a little bit.
 

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Discussion Starter · #42 ·
hello to all
i said yesterday that i would tell how our pack is doing.

we are testing our new pack in the cold weather here in kansas, it was 17 deg F this morning. i realize for optimum performance we should have a heated battery box. our truck is still running great with out it. the battery voltage is staying from highest to lowest .04 between all 48 cells. we have 42 miles on this charge,while running the heater, and our high cell is 3.279 and the low cell is 3.234 vdc. the sos meter shows that we still have about 50% left in the pack.

we will continue to run the pack to about 80% DOD and then tell you all the #'s.

like i said yesterday, we have nothing to hide, it is what it is, we wont bump any # to make it look better.


thanks kevin
 

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I don't understand why certain sellers like to keep their price a secret. Other places publish their prices and shipping details so buyers can compare.
Hello, everyone :
As I said here before, Hipower Rep come here, it is not for sales purpose, just for the technical and experience idea exchange, so anyone want to buy and know more about Hipower cells, you can ask me, ( Candy , I am a senior sales from Hipower, my email adress is [email protected] ), also you can contact our local distributor Mr. Carl Calrk, 001-801-2435300, he can get all the shipment together, and the customer can save a lot local charges at the port.
Thank you
Candy
 

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Dear JRP3,

This is Kevin from Hipower, very glad to meet you. I would give some suggestion about your question. Batteries would made some extra AH, for high C-rate discharge.. Our engineers would make about 5% to extend 3C continuous discharge, they think it is enough.

Hipower battery is somehow different than Thundersky or CLAB, We use "Aqueous solution" technology, it is more suitable for electron translation in Aqueous liquid, the charge and discharge ability is better than "oily solution", and it is more safe. The "Aqueous solution" is translated as Chinese mean, I don't know the real English word is. However, this improved technology really have better discharge curve, and it is easier to control cell's quality as electrical property of cells in producing, cell would have more "same" property as IR, charge / discharge characteristic.

For battery packs, Hipower select the most same cells to assemble battery pack. We use CLMT (cycling,logging, matching,testing) quality control method. Use machine to pick up cells which have most same IR, as candidate, then do charge / discharge cycles, find out the most same charge / discharge curves, them pick up those cells, to make up battery pack. Our acceptable quality level is : With standard discharge to 80%DOD, the difference of cell's voltage in pack should less than 0.1V. charge to 80%SOC, the difference of cell's voltage in pack should less in 0.1V also.

If you take Hipower batteries, we could offer technical detail support, like fast charging restrict, temperature upping with different C-rate, best discharging condition consider the cycle life. We think no one know our battery than our-selfs, we need to be honest, tell customer what can do or what can not do. Customer is not a battery professor but sales need to be. So the relation is health.

Some useful information:
For all Li-batteries, the best using condition is not totally charged or totally discharged, it due to Li-battery chemistry. So, in 100%DOD can cycle 1000 times, while in 80%DOD can use 2000 times. charge to 3.65V is better than 3.85V to extend the life cycles.

All li-batteries, there is liquid in cell, if temperature is too cold, the electron in liquid would not be easily transported. The capacity would be "frozen", some of capacity can not be fully discharged. when temperature returns to normal, the rest capacity (energy) can be discharged. So design a battery box with heat insulating marital to stop cold temperature effect the battery in winter is better. You may also design some of heating wires to warm cells. For Hipower batteries, when discharging, the temperature would rise about 5 Celsius degree with 0.5C continuous discharge, 10 Celsius degree with 1C continuous discharge.

For fast charging, All Li-battery charging method is CC/CV, and they need balancing time. Hipower battery can take 1C current charing is CC mode, which is 0%~90% SOC, 1C continuous is no effect to cycle life. While for CV mode, which is balancing time, need about 1~2 hours.

I hope it would be helpful.

Kevin,

you mention too cold and back to normal for temperature changes. But you didnt mention what too cold or normal is. Can you clarify with actual ranges of temps? Also would the cycle life of a cycle be reduced if it was say always stored at 80F as opposed to 70F or even 100F etc? And also what about charging below freezing too.

thanks
 

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Discussion Starter · #45 ·
hello all

well i just wanted to up date our mileage and voltage. for the new pack.
we have run our pack down to 20.5% on the sos meter,after 59.5 miles. 20.2 of which were on the hiway, 60-65 mph.it has been cold here so we are also running our heater. we started with our total pack voltage of 163.2 vdc.

after pulling in the drive way tonite and not giving the cells any time to rest or regain any voltage by sitting, the highest cell was 3.144. lowest cell was 2.933. for a total pack voltage of 147.636. for 48 cells.

we put the batteries on the charger tonite,it is the 5th time on the charger,and we will see in the morning how it is, the weather guy says single digits tonite for the temp. so some cold test runs in the morning.

thanks kevin
 

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Kevin,

you mention too cold and back to normal for temperature changes. But you didnt mention what too cold or normal is. Can you clarify with actual ranges of temps? Also would the cycle life of a cycle be reduced if it was say always stored at 80F as opposed to 70F or even 100F etc? And also what about charging below freezing too.

thanks
Hello Dexion,

Hipower LiFePO4 battery can discharge in -20°C to 60°C, it would not effect cycle life.
The best using condition is 15°C to 45°C, have best available capacity.
Low temperature would effect capacity,not effect cycle life. But we should avoid liquid be frozen, it would effect the inner structure little. We estimate liquid be frozen about -35°C. While we suggest working condition above about -20°C.

For high temperature, LiFePO4 battery is very suitable for high temperature condition compared with other Li-battery, other Li-battery would get dangous condition or cycle life loss. For LiFePO4 battery, all professor think working condition lower than 75°C is safe. While we take 60°C, as recommend for using. just take it.

For charge, 0~45°C

For storage, -20~45°C is no problem, would not effect cycle life, you know storage means electron would not move, battery inner, any thing would be no move, -20~45°C is OK for storage.
 

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Thank you. I have taken to just keeping them at 25C (80F) all year round (im in detroit) via heating pads under the batteries. I just wanted make sure I wasnt lowering their life that way.
 

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Hey Dex, how are those Blackhawk Li batts working out for you? .... and do u use the heating wires on 110 VAC only?

Cheers,
 

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They are working fine I cant really see any difference from day 1. I really dont take them down far. Most I go is down to 40% soc but thats rare (perhaps 4 or 5 times.) Notmally its down to 60% soc. But, I cant really complain so far. I have about 15000 miles on the pack. The heaters are 220V (as is the charger.) On 110 there is no heat but I do have a 110 charger if needed (never use it.) I just leave it plugged in all the time and the thermostat turns it on and off as needed my situation (having 220 at work to use) is pretty nice and takes a lot of the problems out of commuting in an electric car in the winter.
They take a while to cool/heat (based on the one thermometer probe I have stuffed in the pack somewhere.) So the 1 hour commute isnt a problem. I just plug in at work, unplug when I leave in the winter. I can unplug it for 4 hours in 30F weather and its still 70F or so at the probe.
 

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HiPowerKevin or Strawberry:

Can you tell me the dimensions, weight, and internal resistance for your 10 Ahr and 14 Ahr cylindrical cells? Thanks. My understanding is the 14 Ahr cells are new, are those being sold now? Any further info or spec sheets would be great. Many thanks for the information.

BTW I bought some 10 Ahr cells from Carl http://www.evequipmentsupply.com and have been testing them -- they seem to be doing well at 10C rates.
 

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HiPowerKevin or Strawberry:

Can you tell me the dimensions, weight, and internal resistance for your 10 Ahr and 14 Ahr cylindrical cells? Thanks. My understanding is the 14 Ahr cells are new, are those being sold now? Any further info or spec sheets would be great. Many thanks for the information.

BTW I bought some 10 Ahr cells from Carl http://www.evequipmentsupply.com and have been testing them -- they seem to be doing well at 10C rates.
Hi, can you send the request to my email box : [email protected]
yes, our 14Ah is new.
Thank you
Candy
 

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Discussion Starter · #53 ·
hello all

just wanted to say that all is good on the new pack. for the about the last 3 weeks it has been in the teens and 20's in the morning and about 32 deg f at the end of the day. the pack seems to work good even when it is 10 deg f. there is some loss but way less than lead acid.

we just ordered another 48 pack from carl for the new truck. we have the electrical specs on the new motor and hopfully monday we will have the mechanical demensions. it will be 72 volt, at 94.1 % eff. and A good chance we will have the first built unit by the end of janurary.

as soon as we get all the demensions and specs we will post them.

as far as the hi power batteries we are very pleased, like we said we just ordered another set. we had issuses with the first pack and hi power stood behind them and made it right.

i like very much dealing with a company that takes care of its customers. that how we run our business everyday.

thanks
kevin
topeka electric motor inc
ev designs dept
 

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If I ordered tomorrow could they ship before the holidays or do I have to wait for your 10 days off?:)
Dear Sir :
What kind battery pack are you looking for ?
do you know what is Hipower's advantages ? and do you know why Kevin Constant's battery pack can work so great ?
We are different from other suppliers, because we well select and match the battey pack , which will take us one week time.
that means in the same battery pack, there is closer inner resistance, capacity, volt tolerance, etc.
thank you
Candy
 
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