Southend Meet


#1

Ok let’s kick this thing off. Thought it probably deserved its own thread so post all relevant info in here.


(system) #2

Ill be up for it, twizy being delivered Friday and then wrapped early next week


(mender) #3

195 miles so five 3 hour charges from here :S
Have fun!


Greetings from Germany
(osbrook) #4

Me too. How about one nearer you? Not so far for aminorjourney, ecofunkytravel. I’ll trailer my Twizy there behind my motor home so I have some where to stay, just charging to sort while there.


(mender) #5

Sounds like a great idea-location suggestions anyone? Leominster!

From me in Leominster, Ecofunkytravel is 45 miles away in Brecon and aminorjourney 80 miles away in Bristol.
I know of two other Twizy local owners (not on the forum-give me time!); Russel in Bromyard near Leominster and Ian in Aymestrey near Leominster-he charges his off his own HEP plant on the river Lugg!

Anyone is most welcome to charge at my place :wink:


Greetings from Germany
(ecofunkytravel) #6

Although I’m nervous about encouraging folks to see a Twizy as a viable for long distance travel, it does pose an interesting mathematical problem. Say the Twizy charges at a steady rate of 16mph. If you crawl along at 16mph then re-charge for an hour you would do 16 miles in two hours, or 8mph. If you Twiz at 48mph, and do 48 miles in an hour, it will take 3 hours to recharge, so you would do that 48 miles in 4 hours, or average 12mph. 32 miles at 32mph would take 2 hours to recharge, 10.6mph. And so on.

But things aren’t actually that simple, because even if the Twizy did re-charge at a linear rate, and it doesn’t, it certainly doesn’t discharge at the same rate at 8mph as it does at 48mph. So if you did 48 miles at 48mph, it will take you longer to re-charge because you’ll have used more energy.

If we had the data, we could work out (as Tesla have for their long distance charge station network in the U.S) what the optimum spacing and speed are to cover an arbitrarily long trip in the minimum time. Some lithium battery charge profiles show maximum take up rate between about 20% and about 90% of capacity, for example. You can see something like that with a Twizy if you monitor the charger wattage at different charge levels. It usually starts at a steady 2200 watts but as it gets into the 90’s the wattage drops to below 1000, and for the final 3% to about 375 watts.

So you might make swifter long distance progress if you recharge only to 90% (or until the wattage drops from 2200) and then went on your way. And you might also find that a slower speed than flat out actually increases your average speed for trips over your battery capacity. It certainly does for the Tesla.


(mender) #7

Interesting-I noticed that charging from 40-50% is much quicker than 90-100%, which backs that up.

Yes, going 40-45mph and not 52 gets you there slower, but recharge is quicker-I wonder how this works out in real life with the difference in discharge rates? I tend to blitz locally when near to recharge and do the full discharge run at 40-52mph so I can get the whole way and recharge while seeing friends.
My longest journey in a day was 101 miles which was planned well to spend time eating or seeing friends while it needed charging.

Mine is outside my house when not in use and I like to keep it full so I can do the full discharge long journey I need when I want to, but I seem to start the recharge from either 81% or 88% an awful lot, usually after a school run and a few errands-I wondered why this top up took ages!
I wonder if this is damaging to the battery, like with a mobile phone which seems to prefer full discharge and full recharge rather than constant top ups?


(osbrook) #8

There is a thread on battery charging. But it came to an end when AminorJourney with real life experience and the Wiki on Lithium batteries said different things. Lithium Batteries should not be left discharged, so if you flatten them or get close then they should be re-charged as soon as possible. Lithium batteries unlike NiCads can be topped up. Now what was been said by Nikki is don’t top off every time but let it get down to say 65%. While various web sites say the batteries prefer little and often - like you do. ie. 300 deep discharges or several thousand top ups.

But damage to the battery when rented doesn’t matter.


(system) #9

It’s probably worth a little reclarification from me:

So…

I don’t think we should be topping the Twizy battery packs up every time we do a trip, although I do now (on average) charge once a day… However, I try not to let my Twizy sit at either fully charged, or fully discharged, for a long period of time.

Our Leaf is now at 25k miles, with no discernible loss in battery capacity or range. Wherever possible, we try to keep the battery in the 20-80 percent range, although it is now getting two 100 percent charges a day (due to there being colder mornings and my wife wanting to stay warm on those 80 mile round-trip commutes! :slight_smile:

When it comes to Twizy charging too, I’ve discovered that SOCs less than 10 percent result in REALLY long charge times. IMHO, it’s better to drive from full to say 2 bars, and then recharge. I suspect it’s quicker overall, thanks to the delta in charging times.

However, back to the topic at hand: an event/meetup.

I’d love the idea of a meetup. I’d of course, suggest we look at a ZCW location, but I’m also open to suggestions.

40 miles is ideal for me, but I think 80 miles is doable, provided it’s on a Sunday (I work on a Saturday teaching band). I’d also, of course, need to find somewhere in-between to charge up. Referencing above, I think two charging slots is the ideal :slight_smile:


(mender) #10

Interesting points on charging on this thread-cheers :wink:

Mine gets 80-100% most days, then 2-100% once a week-hope this is ok for the batteries.
Time will tell-but as Osbrook rightly points out-they are rented so it does not matter.
Effectively we are the guinea pigs for the ZE product range and our usage data and problems will be useful to Renault in the longer term.


(osbrook) #11

Over on the German Twizy site they state that the batteries age quicker if left at 100% SOC (State of Charge) and that the Twizy batteries cannot be completely discharged as there is always 13% left to protect the battery. So the battery is not 7KW but 6.1KW useable.

If the car is being left while (you go on holiday) leave it at 60%SOC so there is room for any self discharge but the battery is not full.


Greetings from Germany
(mender) #12

Thanks for this-may start leaving the 80% to run to 60% to 40% on the school runs, then charge fully before the long weekly run.
Problem is that sometimes I just want to go for a long run without planning. Hmmm.


(ecofunkytravel) #13

It’s true that any battery damage that isn’t the result of abuse would be covered, but Renault aren’t guaranteeing the battery to offer 100% of its initial capacity for the length of the contract . So if we’re talking about charging modes that preserve capacity then it will matter if you want to maximise battery capacity for as long as possible.


Greetings from Germany
(mender) #14

(system) #15

I really agree with all of that :slight_smile:


(mender) #16

This is what makes a forum so useful to its users.

Cheers to all for the posts and to James for getting the site so well sorted :wink:


(KoenVdH) #17

Maybe also interesting to look at the sales figures you can find here.
Using that we should be able to calculate how many Twizy’s are in your “battery range” neighborhood.
Let’s say 5% of the owners would like to meet up.
My estimate is that we have to take a train to meet…
Anyway the sales figures are also interesting, [FONT=Lucida Grande]7891 Twizy’s are sold in Europe year to date.
[/FONT]


(mender) #18

Very interesting link with figures-how on earth did you get access to that?!


#19

Looks like this information is freely available if you know where to look. Strange, as when I asked Renault for sales figures on Twitter they said they did not give sales figures out. So we have 233 Twizys in the UK so far that we know of. Not bad I suppose what with the dreadful summer and winter approaching. I think Spring 2013 is when we’ll see the Twizy really take off.


(mender) #20

Just a thought: if there are 221 Renault dealers in the UK, and most should have a demo on the go, does that mean that the only Twizys in the UK are those and ours on the forum? :lol:

I guess these figures are sold not registered then :S or you would have the highest percentage of owners to forum members of any car in the world :wink: