You can get Link 10s with the serial port. When you call Xantrex support, ask about this. They also sometimes have factory refurbished Link 10s for sale.

Here’s a basic metering question: how do I know what scale to get for an ammeter?

Do I just match it to the max current of the controller? If so, what if you’re running a contactor controller or controller bypass?

I think batteries have a max current output based on their internal resistance. Maybe the battery specs will give s short-out current. I reckon, for example that when I fit my bypass, i won’t exceed 500A with my motor and Trojans. what makes me think this is that it’s actually only a small part of the rev range where I can get the controller’s max output (about 325A) most of the rev range only pulls obout 200A at full throttle. so I think the controller is not limiting the current by much. Also, and here’s the clincher – I have a 500A fuse! I have ordered my bypass contactor so I’ll be able to tell you by feb / march time what happens to the current for me. Meanwhile, you could do worse than reading EV dragster pages like John Wayland’s as to how they get their high currents and what limits them.

Thanks James. Leads me to the next question (with preamble).

Preamble: regardless of what my actual max current limit may be, I’d really prefer to have a gauge with a small scale because it has better ‘resolution’ for taking accurate readings at a glance. (Also, hopefully, most of the time, we’re pulling low amps, right?)

Question: what happens if I pick say a 200A ammeter, and occasionally draw much more than that (eg. full accel)? Do I have to buy another one each time? :)

I don’t think a mechanical meter will be damaged by a bit of over-deflection. It may eventually go out of calibration if the overdeflection is too much. Mine overdeflects backwards by up to 50A when I am regenerating.
The actual currents in the meter and the forces involved in deflecting it are low. so the danger is probably bending the needle and that seems unlikely. Anyone feel free to tell me I’m wrong here!

My meter is 0-450A and I think that is a good sort of scale for my voltage (96V) if you ar erunning a higher voltage you might need smaler scale.

You could also get round the ammeter problem by using the small scale ammeter for the controller and allowing the bypass to bypass the ammeter shunt. It will then read approx 0A when you are bypassed. you might like another small ammeter for the bypass current however, or you won’t know!

James, have you talked about your controller bypass here yet? I’d sure be interested to know how you’re going about it.

I have a new wiring diagram for the Zapi which my EV supplier sent to me which includes a bypass controller.

The Zapi contrller has a specific pin out for the bypass contactor so It decides when to apply the bypass. This is good because it means I don’t have to put an extra switch at the end of throttle travel which I would otherwise have to do. (Maybe I am mistaken on this point). I can email you the diagram, but it may only apply ot the Zapi. Essentially the bypass controller shorts out the PWM switching so that the series motor end up connected directly to the battery.

I’m told the Zapi controller is very fussy and I guess it probably throw an error if you tried to bypass it manually.

The old GE EV-1 controller that came with the forklift also has a bypass circuit. But we will likely start by trying out a small Curtis first.

If the Curtis will move the car adequately, adding a bypass to it would be an idea. I thought you might be doing a similar “home brew” upgrade, so the OEM schematic won’t apply here, but thanks anyway.

After waiting 10 weeks! for Electric Transport to quote shipping of a Link10 emeter I discovered a local supplier of Xantrex equipment. The latest gage is called the XBM (Xantrex Battery Monitor I suppose). Judging from the tech spiel it looks pretty sophisticated but only works for the pack as a whole. There is an RJ12 connector on the back for hooking up the optional software interface with isolated RS232 port. The software looks interesting but I can’t afford that at the moment…

I emailed tech support about ‘remoting’ the buttons of the link 10 so that I could mount it in the sealed intrument cluster. They suggested simply soldering momentary push switches in parallel with the ones on the circuit board – I suppose that could also be done with the new XBM too.

Hi Nick

On a slightly different subject, I fitted the controller bypass and invited my EV supplier Robert to come and set it up. It’s funny. I found the controller was turned right down ( level 4/9) and that’s why it was not performing well. The controller is working really well now, giving me good low revs acceleration but it never seems to actuate the bypass controller which I spent 100 pounds (GBP) on. Oh well! My verdict, if you have a Zapi H2 don’t bother with the bypass, just turn it up to the maximum setting if you want the the power.

You are right about the guarantee but sometimes ya just gotta do these things. I have a friendly electronics tech who could to do it for me but I can’t even figure out how to open the XBM anyway (without a knife at least)! If I can’t remote the buttons to mount it in the enclosed instrument console I will just have to mount it on the dash. I will likely move the radio lower down the console and use the free slot for the XBM and maybe some other indicators etc.

As far as I can tell from a good reading of the manual the XBM is pretty much the same as the link 10 except for the fact that it takes all of its power from the traction pack (with optional prescaler of course). There are only 3 wires for the voltage sense and 2 wires for current. The price wasn’t too painful either.

I am just about to wire in the current sense wires to the shunt and need a query answering. I was contemplating using CAT 5e network cable (4 twisted pairs) but the wires are very small. I thought maybe a good idea would be to wire 4 wires together (1 from each pair) and then connect the other 4 wires together. This gives 4 parallel twisted pair connections and the wires are now big enough to connect to a ring crimp terminal. Does anyone see an issue with this?

I think it’ll be OK if the wire isn’t too long and if the impedance of your ammeter is nice and high.

I used (an still using) CAT5 to measure voltages. Quite long lengths of wire (3-4m) and I was only using the single strands. When I used a low impedance voltmeter (my bargraph in “bar” mode rather than “dot” mode) then it drew lots of current (around 100mA) and there was a slight voltage drop over the CAT5. If you do what you are suggesting, you would proabably avoid the voltage drop and everything will be fine. Anyone disagree?

Well – I just blew up a voltage prescaler!!! On reading the manual it does say that it will be destroyed if you reverse the polarity – and they mean it. A chunk flew across the garage!

Anyway, how have others connected the link10 meter? I have a small DC/DC isolator for the 12v supply and obviously a new prescaler but there is only one -ve connection for both the 12v and voltage sense connections. The manual also shows the 2 -ve’s on the same terminal – is this correct?

Hi Nick

I will go out and check my e-meter wiring for you soon.

I have 2 -ve wires on the same terminal. It’s the end terminal. It’s on the left if you look at the back of the e-meter. There are no other terminals with 2 wires. I also have a prescaler.

Hope this helps.

Hi Nick,

Here’s the schematic of the emeter wiring on the Mazda.