# Updating Porsche 914, converted by previous owner



## Yabert (Feb 7, 2010)

With your short range requirement and good budget, don't hesitate to go with lithium.
A 3-4K$ battery pack will weight only 150-200 lbs and give you 20-30 miles of range.


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## onegreenev (May 18, 2012)

Yes, you would fair well with a smaller sized pack but consider a different controller too. The rest looks to be fine. You may want to check that motor as well. Racing motor? I think he was talking you up to sell the vehicle. I hope you did not spend too much on your new ride. Nice car but looks to be a bit on the rough side. It's ok but you will need to check out your components. The DC DC converter should stay. 

What is the voltage of your system? 144? 120? 96? 
What Brand of 9" motor? Warp9? Warp9 Impulse? ADC9? 

You will be a happy camper with LiFePO4 prismatic cells. I'd do at least 144 volts and 180ah cells. It is expensive yet you will still have a light pack and one that will get you a good distance. If you only drive a few miles per day then that pack could last a good 20 plus years. 

Don't go back to lead acid. 

Pete


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## Ziggythewiz (May 16, 2010)

onegreenev said:


> I'd do at least 144 volts and 180ah cells. It is expensive yet you will still have a light pack and one that will get you a good distance.


He needs a 6 mile range, and wants 20, so you recommend a $10K pack that will do ~75 miles?


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## creeg (Jul 22, 2008)

Thanks everyone-

A small pack that makes me fast and light would be great: I would prefer to get a smaller pack and not drop 10K on batteries alone, if I can avoid it.

Its a 144V system with the lead batteries, but I was hoping to go with less Volts if it will not affect performance (I have a lot to learn, I know).
Its my understanding that if I change the voltage, I need to get the controller re-calibrated to the new voltage.

I am very interested to find out what the motor is this weekend when I get a chance to crawl under it.

More info to come, appreciate all advice!


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## Ziggythewiz (May 16, 2010)

A controller can usually deal with lower voltage, but the charger will need to be re-calibrated or replaced.

By switching to lithium the car would be loads lighter, so you could actually go with lower voltage (say 120) and get the same performance (whatever that was). I think a 40 x 100AH cell pack would be great, and only blow half your budget.

What are the specs on the controller?


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## onegreenev (May 18, 2012)

Ziggythewiz said:


> He needs a 6 mile range, and wants 20, so you recommend a $10K pack that will do ~75 miles?


Yes. I say that because with the larger cells the whole thing can go further and I don't know of anyone who ONLY drives 20 miles away from home. Everyone at some time will go further. A car with a 70 mile range will allow further driving or more shorter drives without having to charge daily extending the life of the pack by a long time. 

But if you only want a short range vehicle for now that is fine but not recommended. I'd pretty much be able to say that he'd want to go further just because it will be so much fun to drive. 

My VW Roadster won't have a huge pack but then again it will not be a daily driver or all weather vehicle so a smaller pack would be perfect. I will however be able to get more than 30 miles per charge. I want enough to get to town a few times before needing a fast charge. 

My pack will be a 19.2kWh pack. 

That is in my opinion a pretty small pack.


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## Ziggythewiz (May 16, 2010)

Everyone's different. The whole point of DIY is to customize based on your needs/wants/abilities. 

15 miles would cover me 80%. 20 miles covers 95%. 25 miles covers 99%. That last 1% would require 60, 150, 2000 miles (and double the seats). 

Economics would say doubling the cost should double the utility. For most it never could.


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## creeg (Jul 22, 2008)

Awesome-

Love the discussion everyone!

I think that I will opt for a smaller pack than a 144V: if you are familiar with Los Angeles, Im very near in Culver City: pretty central to anywhere I want to go. I think a 30 mile range should be fine: for days that I have to go longer distances, I would use my ICE vehicle (not ready to give it up just yet- plus my ICE has 4WD, for snowboarding and the zombie apocalypse).

I want a car that is fast, fun to drive, can get me to Hollywood or downtown if I need it (about 7-8 miles one way), and have the ICE car as a backup. I want to ease into it (sorry if I sound like a whimp for saying that).

Much lower on the list of priorities: I have a friend who is a VW purist, who looks down on the 914 as not a real VW, not a real Porsche. So I want it to go fast enough to shut him up.

I will get specs on the motor and controller this weekend, and update the post.

Thanks again everyone, really appreciate it!


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## dladd (Jun 1, 2011)

creeg said:


> Much lower on the list of priorities: I have a friend who is a VW purist, who looks down on the 914 as not a real VW, not a real Porsche. So I want it to go fast enough to shut him up.


you are gonna want more than 120v then. Especially if you are planning on using low Ah cells (the lower the Ah, the higher the "C" rate for a given current). I'd say 144 minimum, or as high as you can afford to go. 

120v of 100ah cells will not be particularly quick. Not slow or anything, but you won't be 'wowing' anybody with power. just as a gross approximation, assume 40 cells sagged to 2.7 volts per cell at 500a (5C, which is pretty high). That would be (40x2.7)V x 500a = 54kW. Or approximately 72 horsepower. And that's before motor and driveline losses. Not bad, but not stunning... 

I guess the question (well, one of many  ) is how fast is fast enough to shut him up?


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## onegreenev (May 18, 2012)

120 volts minimum for a freeway vehicle and you really should have 160 or 180 AH cells. I run 100 AH cells. Not the best. What I am going to be doing is running 60 of these cells at 192 volts and turn down my max available voltage to the motor to 120 volts. Keeping the max motor amps possible of 900 amps. I will never see a full 900 but will set it for that. I will always get a good 600 to 700 amps from the batteries but that is hitting them hard. 

Basing your pack size on the distance you drive is not a good idea. Base it on your performance needs and desires. You may only need 20 miles worth but still want performance too. If you build a sports car you want sports car performance, right? 

If not why build a sports car. 

For performance you need high voltage AND high amperage and a solid motor that can handle that power. What you get in return is a car that can go further than you NEED and don't have to charge daily unless you blast around having fun in those 20 miles. 

Go with the performance aspect. If you don't now you will want to later and there is no need to buy your stuff twice. Right? 

Pete


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## skooler (Mar 26, 2011)

I disagree with onegreenev.

You dont *need* energy for performance, you need power. There is a huge difference. Often what happens is that when you have a lot of energy available, the power available also goes up.

I'm assuming your motor is DC series - I would reccomend going for the highest voltage possible and limiting the voltage in the controller.

You need to know the difference between battery volts&amps and motor volts&amps. A decent controller will convert battery volts into motor amps. So you can have more motor amps than battery amps but you can never have more motor voltage than battery voltage. Power is power but higher voltage means that you can use more of it when you need it.

Don't forget that it is very rare to pull full volts and amps at the same time.
amps = torque (i.e when pulling off)
volts = RPM (i.e when going fast)

I would reccomend going for something like a Soliton 1 or Jr (400 & 200 HP respectively) and a high voltage, low AH battery pack.

Based on your range requirements (20 miles) worst case is about 350WH/mile for your car. 

350WH/mile*20miles = 7000w (7KWH) 
You cant cycle batteries 100% so make 7KWH 80% of the total capacity
7KW/0.8 = 8.75KWH

So maybe 50 *60 AH cells for 160v total? (9.6KWH?) should cost about $4,000 maybe you could go higher voltage by adding more cells if you have the budget.

Hope this helps 

Cheers,

Mike


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## tylerwatts (Feb 9, 2012)

I agree with Skooler.

When you consider the difference between battery output and motor input you understand that what one greener is saying and what ziggy sausage both valid, when you understand that you have both when one is battery output and the other is motor input.

So my advice would be like skooler says. And I would recommend looking at the new grey CALB cells with higher C ratings these would allow a small pack to output higher amps at higher voltages (motorway) and give excellent MOTOR current at low speed acceleration!

And theSplitons are very nice controllers. Lets see what creek finds in the car first, look forward to hearing it sir!


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## onegreenev (May 18, 2012)

100ah cells just don't supply a high amount of current. I can with a 120 volt system get briefly 600 amps from my cells but the voltage drops like a rock. So I am not seeing 120 volts to my motor. I may have 600 amps but not the voltage. Even at 156 volts the pack sags quite a bit. It is interesting to talk about but in reality you will need to use pretty high amperage to get any decent performance out of your system while accelerating. With that in mind it is better to have as high of voltage as your motor will handle. With DC it is not very high. With AC it is easier because the motor has no arcing issues associated with it. With DC you work in a low voltage arena and high amperage arena. I can go to 192 volt system buy my motor won't handle that. So I turn it down. Being that I have 60 cells instead of the normal 38 allows me to run higher currents without much of a problem. Yes you can do that but you'd still need to buy 60 100 ah cells. If you can't and need to run 120 volts or 144 volts get the larger capacity cells which will allow you to operate them in a high capacity easier. You will need some good amperage to move your vehicle to speed. I highly abuse my cells and intended them to be abused. Not something you want to do on a daily basis. 100 AH cells are fine if you intend to have a pile of them. Still it costs a hefty amount. With 38 100 ah cells the voltage sags real low. I have sagged to under 2 volts under load. Ouch. Not a good thing. With 60 cells I did not sag nearly as far. Still it hits hard. Reality is far different than paper.


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## dougingraham (Jul 26, 2011)

Have you driven a lithium battery electric sports car? If not find someone in your area that will let you drive their car. This will change what you want in your ride.

I wouldn't think of lowering the voltage. You will be disappointed if you do. If anything find out what the voltage limit on the motor controller is and size the voltage of the pack to match that. Then select the capacity of the cells to get the range you want. If you lower the voltage you will limit the usable RPM range of the motor. This will cause you to have to shift more often. I suggest raising the voltage only because you will probably need to replace the charger anyway because of the switch to lithium so this isn't a negative. At the least keep the 144 volts. That would keep everything else in the car happy like the DC-DC and any instrumentation that is in place.

I knew I needed about 12 miles average and on my longer days 20 miles. But I built a pack that could do 80+ miles because it took a pack that size to make the car fun to drive. More fun than when the car was ICE powered. Now I find myself doing drives just for the fun of it. And when I do I am glad I have that 80 miles of range because I would be having range anxiety otherwise. You are lucky that you don't need to deal with a heater. You might want a little larger pack if you decide you need AC.

I knew I only needed 20 miles to cover my 99%. But I am really glad I built it to do more. My hat will be off to you if you can restrain yourself to building a 20 mile range car.


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## onegreenev (May 18, 2012)

> Then select the capacity of the cells to get the range you want.


If he selects the 60ah cells he won't have the ampere capacity needed for decent performance without hitting the cells too hard. With 100 AH cells and a constant 3C (300 amps) is fine for cruising but under load that can jump to 700 or higher amperage and those 60ah cells just won't live well.

So it is not entirely true to find the voltage then pick the size pack for your distance. Voltage and Amperage are tied together pretty tightly. He might consider getting a controller that will allow a high voltage pack like up in the 250 volt range then limit the motor voltage to like 144 or 156 volts then he might get away with 60 AH cells. But you still need a whopping amount of them. It allows you to limit your sag and allow your motor to better utilize the voltage so when you are accelerating you WILL have nearly if not all the voltage to the motor that your motor can handle and not sag to some super low voltage. I can sag a 120 volt pack down to about 76 volts with no trouble. That is like driving a 76 volt car at 600 amps on acceleration. The car is limited on rpm with the low voltage and also provides less power and requires more shifting. Use 192 volts and limit to 120 and I put nearly if not all 120 volts plus 600 amps into the motor and the performance is good. Still not a race car but it is good and for the VW better than stock by a long shot. 

The Synkromotive, WarpDrive, Soliton 1 and Jr and Zilla will allow voltage limiting. My controller will only allow a max of 192 nominal volts for my system. Lower than the others but still quite good. Price is excellent too.


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## creeg (Jul 22, 2008)

Hi Everyone-

So Im trying not to get too excited, but I have 2 controllers (looks like he gave me a spare). And they are not GE controllers. They are Motorola controllers. It says "experimental" on them. However, it also looks like they are from the 1990s.

The motor has NO markings on it at all, so I have no idea what it is. Im hoping that someone can tell me by looking at the pictures, attached.

I took some shots of the extra controller that is not in the car, with a measuring tape so you can see the dimensions.

I also tried to get a bunch of shots of the motor, including some shots into the opening of the motor- maybe seeing whats in there will help with identification.

Thanks everyone for all your help, I really appreciate it and am very grateful.


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## creeg (Jul 22, 2008)

Here are some more shots of the motor.


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## skooler (Mar 26, 2011)

creeg said:


> Here are some more shots of the motor.


It's definitely a brushed DC Motor.

Are the cables going into it all the same size? If so I'm 99% sure it will be series wound DC.

Your controller looks like it says 172v on the side.

What is the diameter of the motor? looks around 9".

The adapter plate looks well made so I think you are fine on the motor side of things, does it have a clutch? Controller looks good too.

Pete,

If he were to run at higher voltage (172v) and limit the motor to say 120v, he wont need to have as much current available from the cells as the controller can compensate (read my post above). Battery amps and motor amps are not the same. It is also very rare that you need to use all of the volts available while pulling max amps.

essentially the controller can convert volts to amps but not amps to volts. therefore, having more volts available makes more power available when you need it.

Of course there is a fairly linear correlation between energy and power but not much energy is needed for this car.


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## Yabert (Feb 7, 2010)

Cool! IGBT 900A controller with 172v (?) limit. And your motor seem to be an ADC-FB1-4001 9''. http://www.kta-ev.com/AMD_Motor_FB1_4001A_28_5HP_p/amd-fb1-4001a.htm
Not the best one, but a good one.
This good cumbo will move your lightweight car very well.

Unlike what greenev said, the new Calb CA 60Ah seem able to supply 10-12C (600-720A)briefly without suffer too much.
I think a 48S (154v nominal) 1P (60Ah) (only 215 lbs) will give you pretty good performance with over 200 lbs-ft of torque from start and around 90-100 Kw of peak power.


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## onegreenev (May 18, 2012)

> Unlike what greenev said, the new Calb CA 60Ah seem able to supply 10-12C (600-720A)briefly without suffer too much.


I am quite aware of what the cells can provide. Have you watched your sag under load? The lower the AH rating of the cell the less it can provide with minimal sag. You do want the voltage to the motor as high as you can so you can go further before needing to shift. 

Skooler,

With the controllers he has available to him (the ones that came with the car) he has little choice about being able to limit the voltage to the motor. Most old controllers can't do that. So he needs to either run at his motors best voltage and being it looks like an early ADC I highly doubt he would be able to sustain 172 volts. I would also not go over that 172 volts fully charged. Excellent, an early IGBT controller that can dish out some serious amps. Got me wondering if this is the model that got the wheels turning for the building of the Soliton 1 which some believe to be the first real controller that used IGBT modules. 

I still stand that he should NOT use 60ah cells in a performance vehicle. And if performance is not the objective why build on a performance vehicle.


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## onegreenev (May 18, 2012)

I am aware of the budget limitations. I am quite aware of the controller issue and you are limited to what you have on hand. Changing to lithium will require a new charger. Other than that most every thing else can remain the same. I know you may want a short distance vehicle but any vehicle can be a short distance one. You can still build it for longer distances and then just drive it short distances. It is not a waste as it can increase the life of your pack 10 fold. Don't fully charge it and don't fully discharge it. Drive in the safe zone only. You may not even have to charge daily. 

So lets say your limited to 144 volts or you limit yourself to 120 volts. You have few choices. At 144 volts you have to have 45 cells that is still $4,000 bucks of cells and a small pack. Yes the CALB cells can give out some amazing power. If your going to limit yourself then move up to the 100AH cells. They can provide more amperage better than the 60AH CALB. That will be $6,700 for that pack. 

Bottom balance your pack and get a smart charger and let it stop your charge at like 3.5 volts each. Get an AH counter and amp meter and volt meter and when you are at your low end just be sure you stop before your car stops. Since you won't have a controller that can limit your voltage. 

That is assuming the two controller you have are fully manual which looks to be the case. 

One more thing. If you decide you don't want that Motorola controller I'd like to buy it from you. More for wanting to see how its built than any thing else. 

Pete


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## skooler (Mar 26, 2011)

Pete,

Being an IGBT controller it will also be PWM - which will limit the voltage to the motor.

I'm sure Tesseract will chime in eventually and confirm ;-) therefore going to the highest voltage supported makes a LOT of sense


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## onegreenev (May 18, 2012)

Looks like things are pretty manual on that from the photos. Might limit via a trim pot but most new controllers require a computer to configure. Like the Synkromotive, WarpDrive and the Soliton and Zilla. 

Being an IGBT does not exclusively mean it will limit voltage.


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## creeg (Jul 22, 2008)

skooler said:


> It's definitely a brushed DC Motor.
> Are the cables going into it all the same size? If so I'm 99% sure it will be series wound DC.
> 
> What is the diameter of the motor? looks around 9".
> ...


Answers to the above questions:

1) Yes, I think the cables are all the same size.
2) Yes, I think its a 9". I tried to get a tape measure up there to confirm, and didnt do a very good job: but it was around 9", which correlates with what the previous owner says.
3) I think it has a clutch, as there is still a shifter in the car that goes into gear.

Thanks guys!


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## creeg (Jul 22, 2008)

Hey, what do these stand for?

IGBT controller 
PWM

I dont know those abbreviations.

Thanks


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## Ziggythewiz (May 16, 2010)

creeg said:


> 3) I think it has a clutch, as there is still a shifter in


Doesn't mean anything. Many of us go clutchless, but still have the shifter. I can change gears, just don't use a clutch to do it. Just try the clutch pedal and see what it moves. (My pedal's still in but not attached to much)


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## dougingraham (Jul 26, 2011)

creeg said:


> Hey, what do these stand for?
> 
> IGBT controller
> PWM
> ...


IGBT = Insulated Gate Bipolar Transistor. It is a kind of power switch generally favoring higher voltages these days. MOSFETs are considered better devices to use up to 200-300 volts and IGBT's are considered better above that voltage for most switching applications. There are special cases where one is preferred over the other outside those ranges. In the 90's the crossover point was about 50 volts less which explains why this controller uses IGBT with the voltage limit it has.

PWM = Pulse Width Modulation. This is used to drive the gate of the switching device(s) in order to control the flow of energy. Depending on the topology you can increase voltage, decrease voltage, or limit current.


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## dougingraham (Jul 26, 2011)

skooler said:


> Pete,
> 
> Being an IGBT controller it will also be PWM - which will limit the voltage to the motor.
> 
> I'm sure Tesseract will chime in eventually and confirm ;-) therefore going to the highest voltage supported makes a LOT of sense


A buck regulator type switching supply which is what we are talking about can only reduce the voltage. Reducing the voltage will have the side effect of reducing the current. The Soliton 1 which I am familiar with can limit based on throttle position, motor voltage, motor current, battery voltage, battery current, and slew rate. With this Motorola controller it looks like the only adjustable setting is motor current.

A light foot on the throttle will be the only way to limit motor voltage if that is necessary because of the use of a battery pack with a voltage higher than is acceptable to the motor. The controller could do this but was not designed with this feature in mind.


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## tomofreno (Mar 3, 2009)

skooler said:


> ..It is also very rare that you need to use all of the volts available while pulling max amps...


 It is if you only consider vehicles using the higher voltage controllers like a Zilla or Evnetics, but actually max'ing volts and current at the same time is more common than not, since by far most ev's were made with the older controllers which were more like 144V nominal, max 500A in the 1970's through early 2000's.


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## creeg (Jul 22, 2008)

So it sounds like I would benefit from a new controller, as this one is outdated and wont provide the level of control I need, yes?


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## creeg (Jul 22, 2008)

This is going to eat up my budget very quickly. Yikes!


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## Yabert (Feb 7, 2010)

creeg said:


> So it sounds like I would benefit from a new controller


Yes!



> as this one is outdated


Yes!




> and wont provide the level of control I need


Not necessarily!
You will need to try it. Adjustable amps output is a good thing to protect motor and battery (100A to 900A based on the picture).


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## creeg (Jul 22, 2008)

Yabert said:


> You will need to try it. Adjustable amps output is a good thing to protect motor and battery (100A to 900A based on the picture).


Ok, so I should give this one a try, spend my money on batteries and other necessities, and then if this controller is too boring, switch up.

this Thread, comparing 500a to 1000a was very informative, but might as well give it a shot with the controller I have since it is already installed.

http://www.diyelectriccar.com/forums/showthread.php/500a-vs-1000a-81512.html


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## dtbaker (Jan 5, 2008)

creeg said:


> Hi,
> I have a Porsche 914 that had been converted already by the previous owner. this is my first post about it!
> 
> 
> ...


stick with 144v to minimize changes. you can probably get the Zivan re-programmed for Lithium.... if you go with a 144v (45cells) at 100ah you'll have more range than you really need, but the capacity of the cells will support the occasional hard acceleration made possible if you upgrade your controller to something modern like a Soliton Jr. or Zilla capable of 600-1000 amp output.


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## creeg (Jul 22, 2008)

So I just talked to a friend who has some matched Li-poly batteries for sale:

100 qty
100 ahr
3.4 nominal (didnt get the peak)

He wants $100/cell, with $18 per BMS.
Would sell the whole kit for $10k (which I have absolutely no way of paying for right now)

He said I could run them in parallel as 2 sets of 50 cells to get more off-the-line speed.

I think he said they are Hihon brand?

Man, I wish I could afford to do something like that, but I dont see having that kind of money for a while.


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## creeg (Jul 22, 2008)

It looks like new comparable batteries are in the range of $100 to $150 (if Im looking at this right), so dont know if that is such a great price.


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## tylerwatts (Feb 9, 2012)

Creeg do you have details of the batteries? What brand and model? 100aH Li-Po could have very significant peak current potential, 20-30C rates would be too much for your motor, or give your batts a very easy time. Need details to know whether that price is unreasonable. Obviously a lot of money. Also, is that each battery is 3.4V and max 100A output? Needs bit clearer info.


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## creeg (Jul 22, 2008)

Tyler, 
I have sent an email to get more details. Will let you know when I get them.

Thanks!


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## creeg (Jul 22, 2008)

Ok, got some details on the batteries:

100 qty of the HP-PW-100AH. 
The BMS are voltage clampers that I had made that bolt on to the top of the cells. 
They have 2 big resistors that start clamping at 3.65 volts.
See attached PDF.


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## skooler (Mar 26, 2011)

creeg said:


> Ok, got some details on the batteries:
> 
> 100 qty of the HP-PW-100AH.
> The BMS are voltage clampers that I had made that bolt on to the top of the cells.
> ...


Not a good deal in my opinion.


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## dtbaker (Jan 5, 2008)

creeg said:


> Ok, got some details on the batteries:
> 
> 100 qty of the HP-PW-100AH.
> The BMS are voltage clampers that I had made that bolt on to the top of the cells.
> ...



hhhmmmm, the hi-power cells are reputed to have lower C rating than CALB or some of the other prismatics, and reports I am recalling from memory is that the internal resistance is a little higher and people have reported more of a spread in values in a given batch. Second consideration is that home-build cell-shuntBMS may well provide more risk than protection. If they clamp while charger is in CA, they might overheat and start a fire, or if they fail 'on' due to vibration or mechanical short, they can drain a cell in a hurry.

If you can get the cells at a killer discount, and don't expect to push them hard with high-amp draw, it might be worth it.... otherwise, save up and get a pack of the new CALBs.


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## creeg (Jul 22, 2008)

Thanks guys-

I kind of had a feeling that these may not be worth it. 

Appreciate the help.


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## creeg (Jul 22, 2008)

Ok, 
I finally finished the schematics for my Porsche, please see attached PDF.

There are still some connections that I need to figure out (they end in a "?").
There are a bunch of terminated connections that look like they SHOULD go somewhere, but they do not go anywhere right now. 

So I want to see if anyone can look this over, see if it looks right, and what I need to reconnect or change in the disconnected wires.

For those that have not read the history of this car: it was converted and working prior to my owning it. The batteries died and the previous owner sold it to me. 
I would like to get a minimal charge in the batteries to see if the wheels will turn, just to confirm that it is all working. I have it on jacks, so the wheels dont need to bear any load: just turn.

I want to make sure I get it all figured out before I start looking into battery options and spending the big money.

I realize that my schematics are probably not the most aesthetically pleasing diagrams you have ever seen: please offer any advice on a way I can clean it up.

Thank you!


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## dougingraham (Jul 26, 2011)

Mostly your schematic makes sense. The rear battery positive appears to go to the kill switch. That is normal. The rear battery negative connection should go to the middle battery positive. And then the middle battery negative goes to the junction box on the firewall where it connects to the controller negative and the charger negative. What you show there is not clear at all and if your schematic is accurate the only battery the car was running on was the middle one. There is also the odd wire from the kill switch to the motor that doesn't make sense. I would double check the battery cables and label the schematic with positive and negative leads coming out of the batteries.

On the motor controller the 12V common and +12volt must be connected up to the 12V of the car, probably the a switched output. The connections to the relay (this is a precharge contactor) are not clear either. It looks like they put in an interlock to maybe prevent the precharge contactor from closing if the charger is active.

You have a lot of it documented though and I am sure this was a lot of work. If you can clear up the confusion with the heavy cables going to the batteries a bit I dont see why you couldn't plug in the charger and see what happens.


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## Ziggythewiz (May 16, 2010)

It would help to label the wires pos or neg...I think the ??s on the battery pack go to the charger, but hard to tell from how the banks don't appear to be wired.


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## Salty9 (Jul 13, 2009)

I would use red electrical tape around the positive wires at junction points. Red is fairly commonly used for positive leads.


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## creeg (Jul 22, 2008)

Thanks everyone-

Im going to try to get a look at it this weekend and post a revised schematic.


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## creeg (Jul 22, 2008)

hi Everyone-

Ok, I followed the advice, and have checked the wires: the schematic was incorrect around the batteries. I simplified it, so I only have one pack (of the 3) hooked up (the rear pack).
I then tried to charge those batteries, and the charger is giving me the "Audible message + RED flash" which indicates "Battery disconnected or not in conformity. (Verify the connection and the nominal voltage). "

Could the batteries be too far gone to get a charge in them? They were at the end of their life when I bought the car 4 or 5 years ago.

Also, attached is an updated schematic.

Thank you


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## Ziggythewiz (May 16, 2010)

What voltage are the batteries you have connected, and what is the charger programmed for? I wouldn't expect any charger to work with 1 of 3 battery banks connected.


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## dtbaker (Jan 5, 2008)

Ziggythewiz said:


> What voltage are the batteries you have connected, and what is the charger programmed for? I wouldn't expect any charger to work with 1 of 3 battery banks connected.



exactly.... most chargers that have a fixed final output voltage also have have a minimum voltage programmed they expect to see, or they error out. This prevents the from trying to take fewer batteries up to the original final voltage....


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## dougingraham (Jul 26, 2011)

Did you simplify the schematic or did you rewire around the middle battery? The charger probably is expecting a minimum voltage.

Or you may need to close the Kill switch to actually connect the charger to the batteries. Best practice is to have nothing connected to the batteries on the battery side of the kill switch except for a fuse. So to either charge or drive you need to close that switch.

All that being said the batteries may be too far gone. I would put a volt meter across each battery and note the voltage. If these are 12V batteries you can charge them individually with an automotive type battery charger. If they are 6volt batteries you can charge them with the 6volt setting on the charger or charge two as a pair.

If they are 12V batteries and the voltage is much below 10 and has been this way for several months they are probably not going to be usable.

If any of the batteries turn out to be usable then you can swap them around and make a low voltage pack that you could use to drive around the block. You may need assistance configuring the controller to accept a lower voltage.

Good luck!


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## creeg (Jul 22, 2008)

Thanks Ziggy-

So it sounds like I need to get all the batteries hooked up and try it with all of them. Otherwise I would need to get the charger reprogrammed to test it out.

I am missing some of the batteries, so I may have to figure out an alternate solution. 

My first goal is to determine if everything works: I want to get the wheels to turn (while up on jackstands) to confirm that I have a viable vehicle. 

Does anyone have a suggestion on how I can do that, keeping in mind that I am missing some of the original batteries? Is there a way I can just hook up a couple new, charged, batteries (and not use any of the old ones) to see if they will turn the wheels?

Could I charge some of the old batteries individually with a single-battery charger to get enough juice to test it?

Please advise.

Thank you


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## Ziggythewiz (May 16, 2010)

creeg said:


> Could I charge some of the old batteries individually with a single-battery charger to get enough juice to test it?


Yes. If you can charge enough of them for the controller to be happy you can run at a lower voltage. The controller may just run slow, or not turn on at all if you don't have enough voltage.


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## Zapped 914 (Jul 3, 2013)

Creeg,
I just picked up on this thread, don't know if it is still being used.
Where did you end up with your 914?
Curiously, I too have a 914 that was set up for lead and needs batteries. Not sure which way to go.
-1974 Porsche 914
-Kostov 11" 192v motor
-Auburn Scientific Grizzly controller
-Was setup with 16 12v Optimas


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