Lead Acid vs. Lithium Based vs. Nimh and other Batteries

[dogman dan]

Yeah, some drill nicads are cheese. I remember trying the skill brand ones once on a kit that came with several tools. Those ones pooped out in less than 6 months, not even that hard used. The cheapo charger that came with them may have been part of the problem. Makita 9v nicads have always seved me well, those are the 15 year old ones I mentioned. Lately, for about 4 years now, I use a 24v Black and Decker drill and those have lasted fine, the oldest 4 year old ones still kicking. There are grades of nicads though, so they are not all identical. The ones I got from ebikes -ca have made me pretty happy.

Again, my theory on what kills, or causes "memory" in nicads is partial charging and then running em dead, which may only drill 2 holes, but still counts as a cycle. Leaving them on trickle chargers too long can be a problem too. Good chargers that turn themselves off is crucial.

 

[torker]

Yea I think the chargers might have a lot to do with it, and the cheap cells. I just read a pdf from Jaycar I think and it explained things very well. I wish tool batteries had a standard mating connection per voltage. It would force manuf. to make a better product if they knew people could use any battery they wanted. I am tempted to go door to door asking people for their old tool batteries, maybe offer them a couple bucks. I might get all kinds of good cells :wink: I wonder if I could get a good smart/ multivoltage charger and use it on my tool batts? I'd have to use alligator clips to change between charger bases but it might be worth it. I'd rather throw away a few walwarts than all my old drills etc..

 

[RTLSHIP]

I own 4 36v 12 ah SLA packs and a 48v lifepo4 pack. One of those 36v packs is actually a Greensaver Silcone battery pack. This silicone pack weighs around 30lbs but does provide very good range. I can be taken down to 35
volts without damage. Sulfation is less of a an issue.

 

[mrzed]

Now.... if we can only steal Toyota Prius batteries and reverse engineer their battery management software....

In order to get 150000 average Km out of the packs, they apparently design the BMS to not discharge below 50% or charge above 80% - not exactly eBike material. Light hybrids are a totally different beast from EV's, that's one of the big reasons.

Back on topic, have to agree that SLA still works for the puttering around town set. NiMH is IMO all the disadvantages of NiCad with the added disadvantage of having 1/3 or less of the charge cycle capacity.

The way I see it:

SLA for low cost/short distance (and I mean really short)
LifePo4 if you can afford it and/or for long distance/light weight
NiCad slots right in between

All the other chemistries offer some combo of short shelf life and/or too few charge cycles.

 

[onemintyulep]

I have just replaced 24V/12Ah SLA by 24V/10Ah of LiMn. From 8.2kg to 2.4kg. The difference uphill is enourmous. No more voltage sag On the other hand the SLA were only 25€ for the 2, and the LiMn I could not even tell you where to get them from.