battery packs

[betty boop]

any experience of these ? - my lead sealed 40AH Ring booster pack has died and thinking of replacing it but these look so good? I know Nick? added a link recently if anyone has it handy?

http://www.amazon.co.uk/gp/product/B00M1OUBES?*Version*=1&*entries*=0

[Bigplumbs]

That does indeed look nice. Cant seem to see where it states the Mha capacity. If it keeps its charge and it should as it is Lithium then it would be very usefull on a boat

Dennis

[Ianfs]

Thing is with these starter packs is that whilst they can provide quite high currents, they often cannot do it for that long. The batteries in them don't actually store that much energy say 10-15Ah which would run a typical single headlight bulb for say 2-3 hours. A typical car battery 65-80ah would be more like 10-15~ hours, or a 110ah boat leisure battery around 20 hours. Also what is not mentioned is they are deeply affected by being cold. It could be that whilst a good car battery has enough to start cold one of these little things if left in the glove box may not.
Just FYI

This quote is from an earlier post on the subject, just thought it might be worth mentioning!

[annageek]

I made a post about these on YBW forums, but I can't seem to find it.

Up until recently, I worked as an electronic engineer for a battery company. The company makes high-end boost packs (the ones used by people like the AA) and wanted to better understand these new-breed of lithium based products. As a result, I did a thorough benchmark test, followed by a full tear down and finally some abusive / destructive testing. The It wasn't exactly the same battery pack, but I am certain they're all much the same.

Performance wasn't as good as stated... but it was quite good nonetheless. However, it was easy to over load the pack, causing the internal lithium battery to become destroyed. The test I performed used a very heavy overload was meant to destroy the pack. As such, it failed quickly and without much drama. However, due to the battery chemistry used (LiCoO2), a more modest overload (the type that would occur if the pack was legitimately used on too big/stubborn an engine) then the failure mode may actually involve fire and/or explosion.

LiCoO2 doesn't like being stored at temperature. Keeping it in a boat or car during the UK summer will lead it to seeing temperatures of up to as much as 50degC. At this temperature, a fully charged battery will drain to virtually zero charge is as little as a month. If the battery is over discharged, then it will become permanently useless (won't recharge properly) and in worse case scenarios, can be hazardous to recharge. Talking of temperature, from a bout 5degC downwards, LiCoO2 isn't very good at supplying current. Below zero, this starter pack will be useless. As a point of reference, lead-acid batteries are rated for cold cranking amps (CCA) down at -18degC.

There is also no over-discharge protection on the engine start output, so if you were trying to start a really stubborn engine, then after a few seconds, the battery would be exhausted and quite probably over-discharged to destruction. The unit that I tested contained an 11.1V nominal (3-series cell) 3Ah (despite claiming to be 12Ah!) cell pack. My car has a 1.8L petrol engine and under starting, required an average of about 190A to keep it turning over. Allowing for typical inefficiency(about 30%), and assuming the pack was fresh off charge, I'd get about 40s of cranking my Astra before the pack became junk. On a much larger engine with perhaps 350A average cranking current, then you get barely 20s.

A reasonable quality lead-acid starter pack is more reliable, more capable, safer and will last a lot longer (if looked after reasonably well) Sure, it's bigger and heavier but unless you are REALLY pushed for space or weight, then just put up with these negatives. When you come to rely upon it, a lead-acid battery pack is more likely to work whereas a lithium one may let you down.

My opinion sounds quite biased, but it really is my own opinion. I have no affiliation with any battery companies any more... just in case you wondered!

[_Ed_]

Annas post is so spot on I really couldn't put it better if I tried.