Battery Vehicle Society

MalcolmB wrote:If you want a relatively inexpensive runabout with less than say 30 miles range, lead still makes excellent sense. If you're looking for better performance and/or longer range then it's worth doing the sums for your particular application to see whether lithium would make a better choice. The relative merits vary widely depending on your needs.

This is the key really isn't it? What the vehicle is used for?

I'm a firm believer in using vehicles differently to the current norm which is that you have one car that does all your journeys. Well more and more housholds now have multiple cars and the majority of the journeys are short distances with few people in the the vehicle. Yet there's been a profusion of 7 seater people carriers which is just ludicrous to my mind. I know people will say having more than one car is too but give it a try you'll soon see it makes a lot of sense in fact and you can actually do without the big family car after all. Which is where we come in on the EV front and the battery question. Do you really need your EV to have a range of over 40 miles ?

I think the Chevy Volt (or is it GM Volt) with the 40 mile EV range then over to Range extender petrol will be the real answer and for them to be investing hundreds of millions into this kind of platform confirms this thought to my mind.

PHEV wrote: Personally I've not found any lead that will do 10c without sagging terribly,

However, 10C out of a Lithium is only about 1 to 2C out of an average Lead Acid (Based on 10Ah Li cells versus say an 85Ah Pb).

I agree that you'll get a lot of sag at 10C - but for most car type apps, you are probably not going to be drawing more than about 4C, versus 30C out of your Lithium cells so it's barely a fair comparison.

For Bikes and light vehicles, I can see the advantage - but I just don't see that it adds up for heavier vehicles.

Si

You won't get 10C out of these lithium batteries, but then you're not likely to need it either
http://www.thunder-sky.com/products_en. ... d2=&page=3

I must admit, the thundersky 160Ah cell looks a good choice for car use, at 3C this gives you 480A, which should be all thats needed for most light weight cars, a few of the Australians are using these packs now and seem to be pretty happy, cost is also getting very good on them now

Paul

Interesting, but what are the thundersky batteries?

They reckon them to be good for 3000 cycles at 70% DOD, which smacks of LiFePO4, but they recommend a charge voltage of 4.25 volts.

Has anyone got the lowdown on these and the prices?

Cheers,
Nino.

nino500 wrote:Has anyone got the lowdown on these and the prices?

Cheers,
Nino.

Haven't got the lowdown on the spec, but I did enquire about the prices of the 90ah cells last week. A mere $135 per cell. At $2700 to power my planned trike I suddenly found the £100 worth of lead acid off ebay really very very attractive!

Hope I'm not too far off topic. I will be needing a lead acid pack for my car and would welcome any advice as to where to source AGM style batteries. I need 160-200ah 156v and my controller pulls up to 500 battery amps (1000 motor amps). Could a gel battery ever be man enough?

My take on the lithium/lead debate is that lithium is too expensive if you need high amperage.

Derek

Hi Derek,

As a general rule of thumb a AGM can deliver more amps than a gel but a gel can be cycled to a greater DOD before affecting battery life.

Have a look at http://www.secbattery.com. Their "red top" battery might interest you. I found them quite helpful and they have a very detailed spec sheet for their batteries, its a small link at the bottom left corner of the page after you click on a specific battery range. I am using their front terminal gel cells and have been happy with them.

Thanks Greg

We exchanged a few emails a while back and you gave me that link. I phoned them at the time to get an idea on price, but the price of lead was very high at the time so they were fairly expensive. I'll definitely try them again though. The difference in price between gel and agm was not much but I just worry that gel might not supply enough amps or may sag a lot, extra cycle life sounds appealing however. I think you are most probably correct to point to the red top.

Derek

For anyone who is interested. Sec battery quoted £150 +vat per battery for 160ah 12v red tops. 10 week delivery.
Thats £2300 for a pack (156v 160ah).

Does that sound ok ?