# Pondering which gauges to get....



## sailfish11 (Sep 15, 2007)

Hello all,

I'm at the point in my conversion where I'm starting to think about which gauges I'm going to get. I'm wondering what gauges are the 'essential' ones. I'm converting a '65 Mustang and I'm using 98 LiFePo4 batteries. 

My dash has a five gauge instrument cluster (Speedo, Fuel, Oil, Temp, and Amps). Obviously, the only one of those I can still use is Speedo. I'd like to keep the look somewhat stock, so I'm thinking about going to a gauge company to get some custom made. Westach.com has some nice looking gauges and they say they can customize them. I've seen that Electro Automotive has some Westachs for sale and I may use some of them, but my pack will be 313.6V and some of EA's gauges won't work.

So which ones would people recommend? I'm thinking the probable candidates are:

Ammeter
Temp of battery pack (or maybe just highest cell temp)
'Fuel' (SOC -- something like total voltage as a percentage?)

What else might I want?


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## dtbaker (Jan 5, 2008)

I got the LED bar type 'fuel' gauge, which is just a calibrated voltmeter. Maybe it can be calibrated for your voltage as well. people tell me it is less distracting than trying to watch digital numbers or small needles. The needle type voltmeters tend to bounce all over with bumps anyway.

I got a 0-500 ammeter for the HV side, and a 50-150 voltmeter. The voltmeter I am seriously considering switching out for a 0-50 ammeter to keep tabs on the LV side of things. I need to make sure that auto accessories don't blow my dc-dc convertor!

I found a cheap three meter 'pillar mount' bracket at jcwhitney that looks like it'll stick right on the driver's side pillar and I won't have to mess with the dash at all other than find the dash light and ground wires.

d


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## Bottomfeeder (Jun 13, 2008)

I understand your problem. I'm converting a '64 Triumph Spitfire, and the digital gauges would look too out of place. I called up Westach and got the exact gauges I needed. They were very helpful. I haven't tested anything yet, as I'm still wiring up the car, but they look great. This photo makes them stick out more, they really blend in with the car in real life.

I replaced my Temp gauge with 0-500 Amps and fuel with State-of-Charge. If you tell them exactly what voltages are 100% and 20% they can make you a custom SOC gauge. I had mine made upside down for better visibility and added a chrome bezel to match my existing gauges. Don't forget a light kit for each gauge. Give them a call. A quote is free.


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## dtbaker (Jan 5, 2008)

looks nice bottomfeeder.... are you going to hook the tach back up?

And a more general question for the electrical experts is...... how hard would it be to use the ICE fuel level wire hanging loose from the removed fuel tank, and customize a settable voltage level from the HV battery pack to read E-F ? It would be cool to not have to buy a fuel gauge at all....


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## Bottomfeeder (Jun 13, 2008)

I have a mechanical tach, but I will change it out for an electric tach from a later model. Then I will get the tach going again via a Hall Effect sensor. I just bought a sensor from EV Source for the end of the motor, but getting the vehicle moving will be my first priority.

I think you'll have to look at how your fuel gauge operates. It's always possible to design a circuit that will convert your high voltage to a signal that the fuel gauge can read, but it could be time consuming for someone who doesn't regularly design circuits. Do you have any electically oriented friends and something to bargain with?


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## dtbaker (Jan 5, 2008)

Bottomfeeder said:


> It's always possible to design a circuit that will convert your high voltage to a signal that the fuel gauge can read, but it could be time consuming for someone who doesn't regularly design circuits. Do you have any electically oriented friends and something to bargain with?


I can weld, but have nobody local I know of to trade skills with.  I am hoping some smart ee type can figure out a generic 'settable' black box that people like me could just wire in to the HV side. If it would be cheaper than the pre-fab led fuel gauge.....


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## ElectriCar (Jun 15, 2008)

I'm using the PakTrakr in mine but it's a lead acid pack. It will monitor each individual battery, gives amps with additional sensor, pack voltage and more. Also alerts you of problems with individual batteries before they destroy adjacent batteries. Check out the link, it's really something!

With this thing, I'll have a fuel gauge, pack voltage, individual battery status as needed and pack current. It' s less than $400 I think and you don't need a shunt, only the current sensor.

RE the factory gauges, I found the sensor leads for my temp gauge which goes from 100-260. One guy suggested I use it to monitor my controller temp which is more crucial than the motor temp. 

On my 91 S10, the sensor wire is a single dark green wire coming from the driver side of the harness. The other connection of the sensor is the engine block or chassis ground. You need to know the type of sensor your vehicle uses, most likely a thermistor. 

Take an ohm meter if you can find the sensor and take an ohm reading. The S10 sensor will read 2252ohms at 77 deg F and decrease in ohms as you warm it. Here's the one I'm going to try and use on my controller. Electrically it will work but don't know yet where to mount it.

I also found the oil pressure gauge wire which is a single brown wire. Cut loose, the oil pressure gauge maxes out at 80. Ground it and it falls to 0. Don't quite know how I can use it yet.

I don't have an amp guage or tach but I plan to buy a tach and figure out how to make it work.

Best of luck!


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## sailfish11 (Sep 15, 2007)

Thanks for the suggestions everyone. I'm trying to keep the look somewhat stock so I want to stay away from the LED or digital gauges. I should also add that my BMS includes a touch panel LCD (that I will hide in my console) that displays:
Voltage of each battery cell 
Current of the whole battery pack 
Temperature of each 10-cell pack 
Total voltage of the battery pack (V) 
Remaining energy (Ah and kWh) 
The highest cell voltage and cell ID 
The lowest cell voltage (cell ID) 
Highest and temperature and corresponding sample point 

The reason I still want to add analog gauges is to keep the dash useful, while still looking stock. Plus the LCD panel will be in the console, on a low line of sight. I don't want to be looking down there too often. So I wanted to replace the four ICE gauges with others that were more useful.

I should also add that mine is an AC system.

So I'm thinking of:
Ammeter (something like -150 to +150, for regen)
SOC
Low Voltage meter (for aux battery)
Temp (I like the suggestion of monitoring the controller temp)


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## sailfish11 (Sep 15, 2007)

Bottomfeeder said:


> I replaced my Temp gauge with 0-500 Amps and fuel with State-of-Charge. If you tell them exactly what voltages are 100% and 20% they can make you a custom SOC gauge. I had mine made upside down for better visibility and added a chrome bezel to match my existing gauges. Don't forget a light kit for each gauge. Give them a call. A quote is free.


Bottomfeeder -- great conversion project. I was originally going to convert an '80 Triumph (I already own), but decided I wanted my EV to be a more practical daily driver (the Spit would never work in NY winters).

For your SOC, it's hard to tell from the picture, but it looks like it goes from 1 to 10? I guess that means you look at it as a percentage? I wonder, for dtbaker, if Westach would print up a face showing E to F instead.

Alternatively, since gauge sizes are fairly standard, you could just have Westach make you a regular SOC gauge for your voltage and then once it arrives try to swap out its face with your stock one.


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## Bottomfeeder (Jun 13, 2008)

Harsh winters would definitely take the practicality out of the Spitfire. Mine came with a hardtop, so the vehicle will be useful even during the cool winters we have.

My SOC does indeed go from 1 to 10 (x10%). I guess that's standard for Westach gauges. I would've preferred a different demarcation, but it's fine as is. It's worth asking if you can send in your gauge and have them do a professional job of it. It's probably not that difficult for them to put the face on their gauge, or conversely stuff your gauge with their innards. They seemed helpful over the phone...


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## RKM (Jun 9, 2008)

sailfish11 said:


> Thanks for the suggestions everyone. I'm trying to keep the look somewhat stock so I want to stay away from the LED or digital gauges. I should also add that my BMS includes a touch panel LCD (that I will hide in my console) that displays:
> Voltage of each battery cell
> Current of the whole battery pack
> Temperature of each 10-cell pack
> ...


Sailfish11,

Does this BMS control the charge and discharge state of each cell? That is, will it bypass charge around cells that reach a max voltage and allow the remainder of the pack to reach full charge, then shut down the charger? Will it reduce power or shut down the controller if a low voltage point is passed by a cell? The website, doesn't suggest that it does this. It appears that it monitors the state of cells but doesn't necessarily protect from over/under charge.

Thanks.

Rob


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## sailfish11 (Sep 15, 2007)

RKM said:


> Sailfish11,
> 
> Does this BMS control the charge and discharge state of each cell? That is, will it bypass charge around cells that reach a max voltage and allow the remainder of the pack to reach full charge, then shut down the charger? Will it reduce power or shut down the controller if a low voltage point is passed by a cell? The website, doesn't suggest that it does this. It appears that it monitors the state of cells but doesn't necessarily protect from over/under charge.
> 
> ...


Thanks for pointing this out! It turns out that their BMS does protect from over/under charge, but it does NOT do balancing!!! I've got my order with them on hold while I investigate this. Since my system will have 98 batteries I think need balancing, although I must admit to a certain amount of ignorance on this subject.... I'll start another thread to investigate (since my search for 'balancing' turned up way too many off-topic posts).

So now I'm back in the hunt for a good BMS....


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## tj4fa (May 25, 2008)

I bought the Westach 0-150VDC and 0-400VDC Amp analog gauges. 

The voltmeter's graduations were too small for me to read so I bought a cheap $10- 0-200VDC digital one off eBay and scabbed it in today. It helps me see how many volts are left in the pack when I stop at a stoplight.

I've seen a ham radio guy take a wattmeter out of a ham radio and use it. It shows the two needles crossing between amps and volts and it sounds like it gives him a better indication of SOC. 



















(Don't panic over my 170Volt reading. I turned the ignition on while recharging a few minutes ago to see the charging voltage on the pack).


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## sailfish11 (Sep 15, 2007)

sailfish11 said:


> Thanks for pointing this out! It turns out that their BMS does protect from over/under charge, but it does NOT do balancing!!!


After an exhaustive discussion on this topic, I've decided to keep the BMS and charger from Elite. It turns out the charger will do an adequate job of keeping the cells balanced and the controller will provide some protection as well.

So that part of the conversion is back on track -- now I'm back to deciding on which analog gauges to put in my dash!

I've decided I want an SOC, ammeter, and a low voltage meter (to monitor aux battery voltage). I have four gauges on my dash (not including speedo), so I need to chose one more.

I'm thinking it would be nice to have some sort of temp gauge, either for the batteries or the controller. Any thoughts on which would be more important?


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## tj4fa (May 25, 2008)

Is this the type gauge pack in your Mustang (or would it fit)?

http://cgi.ebay.com/ebaymotors/MUST..._trkparms=65:1|39:1|240:1318#ebayphotohosting


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## sailfish11 (Sep 15, 2007)

Yup -- that's the one I have in my car. So now I'm just trying to replace the four smaller gauges with ones more relevant to the EV.


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## tj4fa (May 25, 2008)

I've heard where you can get thermistors (whatever they are) and drive your existing gauges like your temperature and fuel gauge.

If you have any idiot lights like check engine or oil pressure, you might be able to hook up your motor over-temp to one so you don't drive too long running hot and burn up your motor.


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## dtbaker (Jan 5, 2008)

tj4fa said:


> I've heard where you can get thermistors (whatever they are) and drive your existing gauges like your temperature and fuel gauge.


It WOULD be cool to recalibrate the existing water temp gauge (my car just has anidiot light though).... but I dunno how to do it and digging behind the dash is not something I want to do.... I am considering a temp gauge for controller and/or motor but have not settled on anything yet.

The ADC 8" motor has a built in 'over-temp' circuit wired in, so I will probably just run that up to a red light or something.


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## sailfish11 (Sep 15, 2007)

I agree it would be cool to repurpose the original gauges to EV meters, but it would be tricky.

Fuel (E to F) = SOC
Temp (C to H) = Controller Temp
Amps (D to C) = ammeter (discharge to charge, since I'll have regen)

But then the tricky gauge would be:
Oil (L to H) = ???

I could see if Westach could produce another face for the gauge, but it would be difficult to precisely match the others. I could just leave the gauge in there I suppose and not have it hooked to anything. Or I could use the oil gauge as my aux battery voltmeter and not change the face (just let it read L to H, and I would know what it means).

Any other ideas?


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## sailfish11 (Sep 15, 2007)

So, now I've decided NOT to go with the BMS and charger from Elite. I'm going to use the BMS from EV-Power, and a Manzanita Micro PFC-20 charger.

I think the EV-Power BMS is a better system than the one from Elite (which, as it turns out) is really nothing more than a battery _monitoring_ system.

But now I don't get that fancy LCD screen that came with the Elite BMS....


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