[Woodsmith]

Originally Posted by cliftonts

I was thinking of just using a cheap second hand set of lead acids, probably wouldn't cost more than about £100. For testing it doesn't matter if they only make it to the end of the drive.

Simon Rafferty of X-Eng powered his electric Freelander using scrap batteries. He approached his local scrap yard and asked to see all their Optima red top batteries. He tested each and bought all the good ones for £3 each with a sell back of £2 each when he is done with them.
£1 per battery isn't a bad deal. He gave me four from his collection to run my tractor with.
When I get the trike built I will run that with the same pack to get it road legal before switching to 144V or lithium.

[cliftonts]

Originally Posted by Ziggythewiz

If you're just trying to get to the end of the drive, start by recycling batteries for others. I managed to get a dozen from posting on craigslist and freecycle. Even though they were all old and mostly starter batteries just using half of em I was able to get the car down the road (should have turned around sooner) and didn't have to pay any core charges when I got my real batteries.

What do you mean by core charges?

[Ziggythewiz]

I don't know how things work over there. Here when you buy nearly anything automotive related you have to give 'em an old one to reman/recycle or pay a core charge. For batteries it's $9 a pop, so that would have been over 10% of my original battery pack bill if I had not collected a bunch to turn in.

[cliftonts]

Originally Posted by Ziggythewiz

I don't know how things work over there. Here when you buy nearly anything automotive related you have to give 'em an old one to reman/recycle or pay a core charge. For batteries it's $9 a pop, so that would have been over 10% of my original battery pack bill if I had not collected a bunch to turn in.

Ah we have that on some things but not on others.

[cliftonts]

Originally Posted by Woodsmith

Simon Rafferty of X-Eng powered his electric Freelander using scrap batteries. He approached his local scrap yard and asked to see all their Optima red top batteries. He tested each and bought all the good ones for £3 each with a sell back of £2 each when he is done with them.
£1 per battery isn't a bad deal. He gave me four from his collection to run my tractor with.
When I get the trike built I will run that with the same pack to get it road legal before switching to 144V or lithium.

The local scrap yard here charge £20 per battery. Just out of interest you say 'switching to 144v or lithium' so how would you configure the vehicle for testing exactly?

[Woodsmith]

Originally Posted by cliftonts

The local scrap yard here charge £20 per battery. Just out of interest you say 'switching to 144v or lithium' so how would you configure the vehicle for testing exactly?

Everything on the vehicle works on 12v except for the motor and controller so all that stays the same. Even the contactors should be 12v coils.

The controller, if it is a Soliton or the Open Revolt kit (don't know about others), will run on 12V for testing IIRC. I was planning on using the Open Revolt and initially running 48V, or 72V, to get it to the test centre for inspection and then when I know it is all legal and safe I would then replace the pack with 144V lithium.

If you have a look at Skooler's RX8 conversion thread he is currently testing the car's functions on 36V with the batteries balanced on the front of the car and connected with jump leads.

[cliftonts]

Originally Posted by Woodsmith

Everything on the vehicle works on 12v except for the motor and controller so all that stays the same. Even the contactors should be 12v coils.

The controller, if it is a Soliton or the Open Revolt kit (don't know about others), will run on 12V for testing IIRC. I was planning on using the Open Revolt and initially running 48V, or 72V, to get it to the test centre for inspection and then when I know it is all legal and safe I would then replace the pack with 144V lithium.

If you have a look at Skooler's RX8 conversion thread he is currently testing the car's functions on 36V with the batteries balanced on the front of the car and connected with jump leads.

I see. It sounds like there are several stages to the conversion then. While we're waiting for my finances to catch up with my ambition we've been discussing the finer details here. For instance the rev counter, temperature and fuel gauges will of course become redundant. I assume these will work via varying voltages or pulses. If their any way these can be rewired so they are taking an input about, say, the battery levels or the revs of the motor? It would be pretty cool if it were possible to get every gauge doing something again.

Also I did see a kit offering solar panels too. I'm rather dubious about the benefits and whether they'd be work the expense. Do you think a decent sized panel on the roof would provide a worthwhile relief for the batteries? Perhaps offsetting use of the stereo, heater fans etc?

[cliftonts]

Originally Posted by gottdi

Kit! Which kit did you look at that got you thinking about converting? I'd say steer away from kits but you can use them as reference to figure out what you need. You apparently have time to source parts and possibly a good used forklift motor too. You might consider buying a good adaptor and I'd for sure go with a clutch even if your transmission can shift OK with out one. The clutch is there for a reason.

The kits I first saw were on http://www.avt.uk.com/. I was just saying to a friend today that there's never any guarantee a kit has all the best parts for a given conversion, and that using this forum as a knowledgebase I should be able to work out what's best.

Some vehicles can only safely hold so much excess weight. Most cars can't safely hold much. It is a real issue. Many conversions with lead acid are way over the safe limits of the weight holding capacity of the vehicle and its suspension components. It is not always the suspension components that determine the vehicle capacity. Being a unibody the body must be able to withstand the weight too. Any cracks in the metal will be a huge issue. Unibody cars can crack around suspension components and cause loads of issues.

It's a Mk3 Golf, I don't know what they build them out of but they are indestructible! Our plan is to replace the bonnet and wings with fibreglass or other lightweight replacements and make weight savings wherever possible. I won't be doing this until after the conversion is complete as I want a baseline to be able to say 'I've done all this and it's extended the range by xx miles'

Plan your build well and we will be glad to help. Don't buy things willy nilly. Be sure you need something before you buy it. Lay out your plan and then do what you need one bit at a time. Prep your vehicle first, buy your batteries last.

I'm actually sat here right now using other people's conversion stories to put together a shopping list.

Voltage: 120 minimum for a vehicle the size you are considering. 144 or 156 or more if you can but with lead acid you may be limited to 120 because of excess weight needed to be safely carried around. With lithium the sky is pretty much the limit. There is a limit of course but you can stuff in enough to get a quick vehicle and one that will have reasonable range.

How do the voltages work? I've seen you can run at 12 for testing and people seem to be discussing many voltages as options for the same kit. So is it a case that I could use 3 lithium batteries to give me 12 volts with pathetic range and then add 1 more to run at 15v, 2 more to run at 18v? Or do we need to stick to the figures people are quoting? 48v, 72v, 96v, 144v etc. What's the maximum we can go to?

Thanks to everyone for their comments. It's giving me a lot to think about. New questions keep popping up and I'm beginning to view certain aspects of it in new ways.

[CrazyAl]

Originally Posted by cliftonts

How do the voltages work? I've seen you can run at 12 for testing and people seem to be discussing many voltages as options for the same kit. So is it a case that I could use 3 lithium batteries to give me 12 volts with pathetic range and then add 1 more to run at 15v, 2 more to run at 18v? Or do we need to stick to the figures people are quoting? 48v, 72v, 96v, 144v etc. What's the maximum we can go to?

Although what I'm about to say does not answer your question directly (and in parts a bit off on a tangent), it is something to keep in mind when working things out.
There is a relationship between power (P), voltage (V) and amps (I) as expressed in this formula:
P = V * I
where P is measured in Watts (W)
V in volts (V)
I in amps (A).

So if for example, you have a 48 volt system and 200 amps is being pulled,
power is 48V * 200A = 9600 W = 9.6KW
If you double the voltage (and keep the amps), then 96V * 200A = 19600W = 19.6KW

Another thing to think about is that if hypothetically for arguments sake you only needed 9.6KW, by running 96 volts, then you only need 100 amps to get the same power as if you were running 48 volts at 200 amps.
ie. 48V * 200A = 96V * 100A = 9600W = 9.6KW

However, with the higher voltage and lower amps, the cables don't have to be as thick compared to lower voltage and higher amps.
Thick cables = more weight.
That is one reason why it is desirable to have higher voltages.
The maximum voltage you can go up to is dependent on things like how much voltage the controller, electric motor, etc can handle.
With an Electric Motor, I've been told the thickness of the winding determines the maximum current and the insulation of the winding governs the maximum voltage it can handle.

Keep in mind that motors and controllers typically have a continuous current rating and peak current rating which you need to keep in mind. They can only run at peak current for a very short time - need to look at documentation for controller and motor for what that time is.

[cliftonts]

Keep in mind that motors and controllers typically have a continuous current rating and peak current rating which you need to keep in mind. They can only run at peak current for a very short time - need to look at documentation for controller and motor for what that time is.

It's a tricky one alright. Finances force you to need fewer batteries initially but then you're forced to either shoulder the extra weight of the cables or rewire once you're upped your voltages.

As for the motor, their's a fair chance I'll end up with a second hand motor so what do I do if it was stripped from something like a fork lift and there is no documentation?