Yup, but that’s not a restriction since if DVCC is being used the shunt is not even required on the battery and therefore there is no need for this new feature since the WS500 has supported moving the shunt to the alternator for years.
Yeah, it doesn’t require two current measurements, but it does require measurement of what the alternator is producing, not just what is going into the battery.
Yes, but that does not alter what I wrote: that there is no good reason, other than curiosity, for two current measurements concurrently at the WS 500, and that’s correct. I also had it verified by the designer who probably knows more about alternator regulation than any person alive. Hell, I’m just trying to save people from spending money unnecessarily!
This is a Tip, the information on how to use DVCC and the need to move the shunt is clearly provided in the Wakespeed documentation, so there is no need for me to cover every possible usage case here, so there is really no need to split the hair in four, yet again.
John, apologies for threading on this. I think it is a misunderstanding on my side, as I am confused by your remark that “…WS500 has supported moving the shunt to the alternator for years.”
I have multiple sources of charging. Ie. solar when engine is running. In your excellent article “How Batteries Charge (Multiple Charging Sources Too)” you wrote that the shunt must look at the net inflow of charge into the battery. And therefore the shunt is placed directly at the negative side of the battery.
This is also in line with the diagram of WS500 product manual page 7 where the shunt is directly placed at the battery.
Can you clarify your remark about moving the shunt to the alternator?
Note: I do not use DVCC.
You are correct, if the WS 500 is not using DVCC or some other CANBuss protocol (there are several), which replace the shunt with information sent from the BMS, the shunt must be on the battery. But in that case measuring alternator output directly is pretty much superfluous. All it would tell you would be what the alternator was outputting being the sum of the battery charging and any loads, but that’s not a useful number for the charging algorithm and only of academic interest.
Michael Guryan
October 6, 2025 12:39 pm
This might be off-topic, but is the PredictWind Datahub the same device as the OPE Tether?
I don’t know, but given how much they look alike and that PW have WS500 capability so quickly it would not surprise me. Often these boxes are generic, but probably with differences in software and probably firmware too.
David Jade
October 8, 2025 9:03 pm
There is one scenario where I have found that having an alternator shunt is useful. As mentioned it collects the amps out of the alternator regardless of any loads on the battery (whereas a battery shunt is output in minus any loads).
Heat management tends to be the Achilles heel of high output alternators, which when pushed to their limits can result in throttling of their output. If you are trying to manage maximal output by tweaking field values and other parameters, to keep an alternator happy, then being able to see what the total actual output over an hour of charging is useful (provided you can log that, as I have).
With variable battery loads, white space curves, engine rpm changes, etc. knowing the actual output can be helpful. I have found it to be a very useful datapoint on the way to tuning a system’s performance.
…Actually. I can think of a reason: to verify that we got our Whitespace programming right without turning off all loads.
That said, it’s also easy to just turn off the loads when figuring this stuff out, and also the Wakespeed app shows alternator temp, so that helps too if working on that problem. Given that, I would class having two shunts as nice to have at best, and I personally would not spend the extra money, even though I had to manage both the issues you mention.
Wakespeed’s Communication and Configuration Guide v2.6.0:
So, that’s one reason for needing to measure alternator current and not just battery current.
Hi Mark,
Yup, but that’s not a restriction since if DVCC is being used the shunt is not even required on the battery and therefore there is no need for this new feature since the WS500 has supported moving the shunt to the alternator for years.
Yeah, it doesn’t require two current measurements, but it does require measurement of what the alternator is producing, not just what is going into the battery.
Hi Mark,
Yes, but that does not alter what I wrote: that there is no good reason, other than curiosity, for two current measurements concurrently at the WS 500, and that’s correct. I also had it verified by the designer who probably knows more about alternator regulation than any person alive. Hell, I’m just trying to save people from spending money unnecessarily!
This is a Tip, the information on how to use DVCC and the need to move the shunt is clearly provided in the Wakespeed documentation, so there is no need for me to cover every possible usage case here, so there is really no need to split the hair in four, yet again.
All that said, I have added a sentence.
Let’s stop this one here too.
John, apologies for threading on this. I think it is a misunderstanding on my side, as I am confused by your remark that “…WS500 has supported moving the shunt to the alternator for years.”
I have multiple sources of charging. Ie. solar when engine is running. In your excellent article “How Batteries Charge (Multiple Charging Sources Too)” you wrote that the shunt must look at the net inflow of charge into the battery. And therefore the shunt is placed directly at the negative side of the battery.
This is also in line with the diagram of WS500 product manual page 7 where the shunt is directly placed at the battery.
Can you clarify your remark about moving the shunt to the alternator?
Note: I do not use DVCC.
Hi Pepijn,
You are correct, if the WS 500 is not using DVCC or some other CANBuss protocol (there are several), which replace the shunt with information sent from the BMS, the shunt must be on the battery. But in that case measuring alternator output directly is pretty much superfluous. All it would tell you would be what the alternator was outputting being the sum of the battery charging and any loads, but that’s not a useful number for the charging algorithm and only of academic interest.
This might be off-topic, but is the PredictWind Datahub the same device as the OPE Tether?
Hi Michael,
I don’t know, but given how much they look alike and that PW have WS500 capability so quickly it would not surprise me. Often these boxes are generic, but probably with differences in software and probably firmware too.
There is one scenario where I have found that having an alternator shunt is useful. As mentioned it collects the amps out of the alternator regardless of any loads on the battery (whereas a battery shunt is output in minus any loads).
Heat management tends to be the Achilles heel of high output alternators, which when pushed to their limits can result in throttling of their output. If you are trying to manage maximal output by tweaking field values and other parameters, to keep an alternator happy, then being able to see what the total actual output over an hour of charging is useful (provided you can log that, as I have).
With variable battery loads, white space curves, engine rpm changes, etc. knowing the actual output can be helpful. I have found it to be a very useful datapoint on the way to tuning a system’s performance.
Hi David,
True, but I think I kinda said that:
That said, it’s also easy to just turn off the loads when figuring this stuff out, and also the Wakespeed app shows alternator temp, so that helps too if working on that problem. Given that, I would class having two shunts as nice to have at best, and I personally would not spend the extra money, even though I had to manage both the issues you mention.