Find Kaput Electric Scooter Will Salvage SLA Batteries for Cluster Rocket Model Rocket Launch System

[brockrwood]

Found a Razor brand “E175” electric scooter near the dumpster.

(I know. Dumpster salvage item. I am old. Dignity means less and less to me.)

I could not get the scooter to go, so I just salvaged these two 12V, 5Ah, sealed lead acid batteries out of it. (And a few other useful electronic parts.)

I am trying to charge these up to see if they still work. So far so good.

It looks like I need to charge them up to at least 13.38V to get a full charge. That takes a long time at 125mA constant current.

 

[Cape Byron]

(I know. Dumpster salvage item. I am old. Dignity means less and less to me.)

What is this ‘dignity’ of which you speak?

 

[brockrwood]

Weird charge curve on these batteries. They charge from 11.2 volts to 12.2 volts fairly quickly. Then they charge very slowly from 12.2 volts to about 13.7 volts. Then they charge fairly quickly up to 14.7 volts.

This is with a constant current of 125 mA being applied.

Once you take them off the charger, the voltage drops, fairly quickly, all the way down to 12.7 volts.

Is this normal behavior for a sealed lead-acid battery?

 

[0011001100]

That's how lead acid batteries are. However, a real test would be to watch the voltage under load. If they sag too much under a small-modest load (2-3 amps) then they most likely have degraded and aren't going to be very useful with only a fraction of the rated capacity left.

 

[SolarYellow]

I bet that even degraded, they'll launch the heck out of a bunch of rockets. Maybe not mega-clusters, but lots of singles and more modest clusters.

ETA: Making rockets and rocket paraphernalia out of free stuff is cool. Nothing wrong with pulling it out of a dumpster, unless you had to get biohazard all over yourself to do it.

 

[brockrwood]

I bet that even degraded, they'll launch the heck out of a bunch of rockets. Maybe not mega-clusters, but lots of singles and more modest clusters.

That’s what I was thinking. These are probably fine to launch a bunch of low power Estes rockets, using Estes black powder engines and igniters as long as I don’t try to launch cluster engine model rockets.

Still, if these batteries are degraded I will be a little disappointed. I mean, four fresh AA alkaline batteries will ignite an Estes black powder motor using an Estes type igniter. You don’t need to lug around a heavy 12V, 5Ah SLA battery for that.

I guess these batteries would be good for igniting engines using just a good, old piece of nichrome wire. You need an oomphy current to get those hot. I have several spools of nichrome wire to use up before I die. It will take a lot of launches.

Anyway, the only way to find out what sort of life these batteries have left in them is to charge ‘em up and try ‘em out!

@0011001100

 

[cbrarick]

question: Where is the BMS for this battery?
I was able to find on the vision website it's a AGM battery
But you're using a dell computer charger (for lithium batteries) as a power source.

IDK much about AGM batteries but wonder about the safety of mixing charger and battery types, especially where the charger was never designed to charge that battery type. part of the problem may be that. In this day of walmart cheap chargers, why not one designed to charge a AGM battery?

 

[Handeman]

I bet that even degraded, they'll launch the heck out of a bunch of rockets. Maybe not mega-clusters, but lots of singles and more modest clusters.

ETA: Making rockets and rocket paraphernalia out of free stuff is cool. Nothing wrong with pulling it out of a dumpster, unless you had to get biohazard all over yourself to do it.

I have no doubt you are right.

Years back, a friend gave me a motorcycle battery that wouldn't start his Harley because it had a bad cell. I used that to launch LPR/MPR with up to 4 engine clusters for years. Usually only charged it once a season.