Your method, of using an additional battery with a switch, is the only solution that I have seen.
Thanks for confirming that, at least I am on the right lines!
Do you know if there are any plans to expand on the default models built into VeSys?
I tried modelling an alternator by using a battery set at 28 Volts with a very low internal resistance and a relay controlled by the warning light signal to energise it. This was charging a four x 12 Volt battery system (series / parallel), also there was a battery equalizer in there which provided +12V to one of the batteries if system voltage exceeded 26.65 Volts (so that a communications installation was happy. I was trying to optimise a charging system to cope with long periods of engine-off operation. Unfortunately the simulation couldn't cope - Dave Botting told me that the design package was only intended to work with one battery - has this been changed?
Batteries cannot be put in series in VeSys, well they can physically but you'll get odd simulation results
To answer your question about multiple batteries, Dave was probably referring to multiple batteries in the same circuit because it is quite common on multi-volatage designs to have multiple batteries.
VeSys 2.0 can support multiple batteries in simulations. Support for this does have a performance impact so is not enabled by default, but can be turned on in the preferences.
If we were working on vehicles that were dual voltage i.e. 12v and 24v would you need to enable the multiple batteries in the preferences or is it possible to represent the 12v systems within one diagram and 24v in another and so possibly dodging the issue of multiple batteries?
I guess the other question is how big a performance hit is it to have mulitple batteries?
I can't seem to find the preferences for enabling multiple batteries, I have looked through all of the project preferences for VeSys Design - any ideas?
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I'll merge your two questions in one response....
The settings are in the analysis settings (Analysis->Tools->Object Manager... Edit->Settings) from memory, which configures analysis for an individual user. I must admit it is a while since I was working very actively with Analysis and this feature was added back in 1996. However, I believe the performance issues were involved with managing the grounding of the multiple batteries, rather than the multiple voltage sources (so combined 12v and 24v should not be an issue, just add two voltage sources with the required voltages).
As for performance, there are a number of factors. Firstly, computers are a lot faster than they used to be, and the default setting may not be as much of an issue as it was when the functionality was added. However, because the analysis functionality can be applied to very large systems in CHS (whole aircraft in some cases) we had to be aware of scaling issues that may simply not be present for VeSys 2.0.
Analysis & Simulation is a very hot topic at the moment (busier than ever this month), but I will ask Muhammad Askar (the TME responsible for Analysis) to put together a short document with instructions and some recommendations and place it in the forum (FAQ section? Opinions very welcome).
Thanks for the detailed answer and you were quite right it was under one of the menu's in the Object Manager - good memory especially on a Saturday morning!
I think the issue with multiple batteries in VeSys Classic was similar to the one you described as you always had to ground the battery (hence you can't put them in series). If any performance issues are only related to battery grounding I don't think it'll cause a problem for the vast majority of simulation we are involved in.
Let's not ask difficult questions like "Why are we doing this on a Saturday morning?" lol!
VeSys & VeSys 2.0 essentially use the same SPICE simulator (tweaks in both cases, but a common ancestor is not hard to trace back to) so it's not surprising there were common challenges. As you say, in most cases it's not an issue, which is perhaps (you really would think I could remember) a good reason to leave the default off.
I think (and this perhaps relates to your other question in a different thread) that Analysis is one of the areas of biggest increases in functionality in VeSys 2.0 and we should really cross link to some of the articles in the CHS section that highlight the new capabilities.