Li Ion batteries

There's a lot on this in the archives. My summary:

1. There are now several happy Members. They seem to work fine in 7s and cold weather (by UK standards) hasn't been a problem.
2. They're very light and very expensive.

I'd be prepared to fit one, but don't think they're worth it... yet. I'd be very wary of one that didn't have known provenance and previous reports.

Jonathan

What do people make of this product:

http://www.kitcardirect.co.uk/ultrabatt-lithium-battery-728-grams.html

I couldn’t see any technical data for the battery.  Jonathan, could you advise on what Ah battery one would need for a 2.0l Duratec fitted with a isolator/battery master switch? Occasional weekend/dry weather use, currently stored in the garage over the winter and fired up for a short run up to temp about once a month.

Kind regards,

I don't have a good answer, but let's see if we can creep up on that.

But first the warnings:

1. The two widely quoted figures represent the amount of energy deliverable from the battery, typically measured in Ah (happy to argue about units and whether this is "energy" or "charge"), and the maximum current that can be delivered eg at cranking, typically measured in A. But I don't think that the way these are measured is particularly consistent between manufacturers, I have never seen an independent test for this sort of battery, and at least two suppliers actually use incorrect (rather then merely deprecated) units. 
2. Current drain at rest varies considerably between 7s. And some 7s live on *conditioning chargers, some have isolator switches, and some use nothing at all: this is crucial when considering how much energy needs to be stored and Andrew has worked through some of the numbers.

Here goes:

1. The Magneti Marelli MM-ION-15 is rated at 32 Ah and 540 A cranking.
2. The Varley Lithium Li5 is rated at 5.5 Ah and 335 A cranking.
3. What battery do Caterham fit for your sort of Duratec? I'll then look up the spec for that.

Jonathan

​* Some conditioning chargers now claim to be optimised for lithium batteries, but I don't know how much this matters.

Thanks for looking into this Jonathan... My car currently has a Banner battery fitted, although I can’t get you the current spec as I’m out of the country at present but will be able to look soon.  The car is a 2009 R500 Duratec however I’m not the first owner, I purchased it in September 2017 from Caterham as an approved used Seven.

If there are any recommended batteries for a reasonable price I’d consider swapping to something lighter in mass, just so long as it is a suitable spec and can be securely held in place.

I'm really pleased with my Skyrich 15Ah Lithium battery, which only cost £150 ish from memory. Mind you, with no immobiliser on my trusty XFlow I don't have a problem leaving it for weeks anyway. An isolator switch might be good on a more modern car, but the weight saving per £ is unbeatable.

Current Banner is 35Ahr

https://www.ebay.co.uk/itm/JMT-Lithium-Ion-Battery-HJTX20H-FP-For-Kymco-MXU-700-i-4x4-LOF-2015/302153486236?hash=item4659c04f9c:g:OnAAAOSw9-FZ4OLe

This was £138 when I bought mine 

High compression Duratec is no problem for it   

The Magneti Marelli MM-ION-15 is rated at 32 Ah and 540 A cranking.
The Varley Lithium Li5 is rated at 5.5 Ah and 335 A cranking.

Skyrich YT9B-BS / HJT9B-FP-S: 15 Ah, 190A.
JMT Lithium Ion Battery HJTX20H-FP: 7 Ah, 420 A.

The storage capacity on the Varley and Skyrich look low. Any experiences in practice, please, with details of how the 7 is kept, see post #6? (Thanks, Oliver.)

Jonathan

PS: To the tune of "If I had a Hammer"... "If we had a wiki... "