Cheap battery alternitives to SLA?

Well, my SLAs were half dead anyway, and after yesterdays ride, one of them started spitting acid out the seams while I was riding. I still had 10 miles of range, but I'm generaly of the oppinion that acid spitting batteries are a bad thing.

I went to replace the batterys, but the local battery supplier is back ordered on them. a few calls around and it looks like everyone is backordered on SLA 10 amp. I can order them from a few places, but the cost of shipping a 10 pound brick of lead is as much as the cost of the battery.

So, since I realy need a whole new battery pack, I guess its time to get away from SLA. The problem is, this clsoe to Christmas, my budget is in the SLA range. I was running 48v, 10 amps with 7 amps usable when the SLA were good. What else is out there on tyhe cheap side to power my bike?

Energy Drinks?

Currently nothing beats SLA for startup costs. If you are willing to invest for longer term payback the other chemistries (Li variants) start to make sense.

(I'd love to be proven wrong on the above, but I'm not holding my breath)

Well theres the harbor freight thread a few lines down from this one... but even that isn't as cheap as a good deal on SLAs. And theres more wiring and work to get it set up and charge them.

I had forgotten about Vanilla Ice's harbor freight battery thread. Could make for a reasonable step up from SLA with the right DIY spirit. The right charger setup is a concern, but with the charger and a drill thrown in for $5 more it's a nice deal.

Did we confirm the drill/charger/battery $15 deal was the same voltage and battery capacity as the $10 battery? I thought the batteries had different shapes based on the pictures I saw, but I didn't research it any further.

Theres a few different bats that look very similar so be careful you get 1700mah ones!! They are the sale ones. I think theres some 1200 and 1500 mah ones too. IIRC none of the different ones will slot in to the same charger/tools. I have two 1200mah 18v tools that are like 2mm off from sharing each others 18v bats. Very stupid...

Theres a walk in sale right now for $13.99 for bat/drill/charger, but I'm not sure if its the 1700mah one. If you go SLA, you can try the rage case deals. 8a ones for $11 each if you buy 8 pieces. Not sure if they are ebike friendly, or what shipping runs though.

With 18V, 1.7Ah, you could run a 3sx5p setup for 54V x 8.5Ah at $150 for batteries. Chargers would be extra and you can't wire Ni based cells in parallel for charging, only in serial...figure on a boatload of chargers.

I know you gain a weight advantage for your extra $$$. What does the longevity (distance) picture look like for the change?

Just wondering if anyone knows what the C rating might be for these batteries?

Herrsprocket said:

Just wondering if anyone knows what the C rating might be for these batteries?

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Sub-C nicads are usually rated for 10C, like these 1.8ah Sub-C's:
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=274
It's hard to find larger-size nicads rated for more than 3-5C.

Sounds like these win. at 30 amps my bike uses, thats only 3.5C load on the packs. So whats a good cheap but fast way to charge up 15 packs at once?

I was thinking what I'd do is hacksaw the drills in half and epoxy the bat receptacle halves together some how in rack/frame bags. Bats click in securely so you could even mount some sidewerds. Then you retain the OE cell cases and charge them with the OE chargers. Thats the lazy way, but it may not be possible to do depending on your frame and how you want everything placed. 15 is a lot of them.

I still had 10 miles of range, but I'm generaly of the oppinion that acid spitting batteries are a bad thing.

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Where exactly is the acid coming out? Is it on top where they glue the top on? If your only using one charger to charge all 4 in series, it may be that the batteries aren't balanced to each other to well anymore causing excessive voltage and gassing, causing the acid to come out. You might just need to get (2) 24 volt chargers to cut down on the voltage so the charging inbalance is less severe. Or charge with 12 volt in parallel somehow.

Also, I accidently pulled part of the top off on one of my sla's using some strong tape. I just taped it back on and its been ok.

its spitting up out of a square vent hole on the top edge of the cover.the cover is heat sealed on. Its spitting up when I ride, not when I charge, and it seems to be doing it only when its voltage drops way below the other 3 bricks.
I charge with a 48V chrger, but it doesn't spit up then. I keep tabs on the volatges before and after I ride. SLA tend to self balance, if they are within a volt or two before charging.


The Nicads would be the perfect answer, with only one problem. I need to find a way to charge them cheaply in a reasonable amount of time. that means I need 15 chargers, or 5 - 54volt chargers. The drill/charger pack comes with the 1.3 amp battery. They had them at the store here, but not the spare 1.7 packs. The drill package doesn't say, but the battery part number matched the 1.3 volt spare pack's part number. So buying the drill package doesn't make sense. I need another sorce for chargers.

So the perfect solution all comes down to how to charge these?

Falconev has a 10Ah 36V pack for $375 including charger

Drunkskunk said:

The Nicads would be the perfect answer, with only one problem. I need to find a way to charge them cheaply in a reasonable amount of time... So the perfect solution all comes down to how to charge these?

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How fast do you need to charge?

If you make 12V packs you can use auto chargers (2A/10A/20A/50A). Make sure you have thermal cutoff in addition to the standard FLA charger.

Xyster should be able to tell you how to setup 12v 8500mah packs for charging. In the other thread he mentioned diodes or something.

vanilla ice said:

Xyster should be able to tell you how to setup 12v 8500mah packs for charging. In the other thread he mentioned diodes or something.

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A search will find the specifics discussed in other threads. Basically, separate each series-string with either diodes (like high power schottky diodes), switches or un-plugable connectors that can be all disconnected for charging, then reconnected for discharging. In the case of diodes of course, the connecting/disconnecting is automatic, based on the direction of current flow.

All-Battery seems to almost always have 30 Nimh F cells at 14ah on Ebay for $345 shipped. The picture is for untabbed, but the small print says tabbed is an option.
That would get a single string of 30 cells for 36v 14ah for building a relatively uncomplicated-easy to charge pack. Not as cheap as the HF Nicads, but a lot simpler option with pretty good ah.

(Newbie here. Been lurking for 2 or 3 months now. Y'all influenced me into buying a 408 front hub motor with a 36v 20 amp controller. Sucked another one in. It's a blast. I'm looking to upgrade batteries myself pretty soon. Trying to wait for better availability/ testing of the LifePo4 chemistry. But If I can't wait, those All-Battery F cells might be the ticket since I'm not confident enough to tackle 150 or 200 of the sub C Nicads right now.)

Thanks for being a good natured bunch of guys. Y'all make learning fun. (Yeah, I'm from the South-but everyone should use "Y'all"---great word

mate I did think about using those f cells when i was first looking at ebikes..but the draw rate on them sucks...i think its 1C, not even enough power for a 20amp controller

Well, more checking before I ordered from Harbor freight. the battery pack in the store weighed around 2 pounds. I borrowed a displayed meat scale. That means in the case, the Nicads would weigh 30 pounds. not so great. and my mattery rack would only hold 8 of them, in the space of 4 SLAs. I would need to build a whole new battery rack, or seperate out all 15 packs into individual cells. Still Very cost effective, but labor intinsive, and the cost of the chargers is still an issue.

Still, at $165+tax and shipping, its not a bad deal, the only other hangup is charging. I'm used to a 4 hour max charging time, usualy done in 2-3 hours, and a single charger small enough to take with me. that means I can recharge while eating someplace, or take it to work and charge there, or get in 3 or 4 rides in a day. I'd need to be able to charge the Nicads up in, we'll double the time, say 8 hours, and with a charging system I could carry with me, and use in public without someone thinking I had a bomb.

And thats were the Nicads fail, is in the charging problems. If there was a one cord solution that could charge these, it would make up for the other drawbacks, but without esentualy building my own charger from scratch, there isn't a way that I can find to charge all the cells in a short time with something that would be portable and cheap.



So I've found another solution maybe. For around $400 (to 600) I can load up on Lipo. TrueRC.com builds some big Lipo packs that will charge off high production RC battery chargers. In there custom pack section, they have some 8 amp and 12 amp batteries as well. I've delt with them before on small batteries, and been real happy with them.

There must be RC chargers to handle your NiCd config.

So what did you decide on? Staying SLA? HF nicads? The doc $0 method? If you could find a 54v charger that was affordable it'd make things easier. I'm not sure such a beast exists.

Well, for the moment I'm stuck with Acid spitting SLA. a week of research and I still couldn't come up a way to charge 3s5p worth of 18 volt Nicads cheaply and quickly.

I'd say those F cells look pretty good. The spec sheet says 6.5mohms so they should be good for 35 amps. the 'standard rate' means the rate they test the cycle life at. Definatly worth building your own pack and learning about whats involved as people have had problems with the premade packs. Also worth getting a couple of cells first and testing them.

oh and welcome to the forum Larry

Drunkskunk said:

Well, for the moment I'm stuck with Acid spitting SLA. a week of research and I still couldn't come up a way to charge 3s5p worth of 18 volt Nicads cheaply and quickly.

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Make a "Tampon" out of a small piece of rag and some tape to catch the acid. Then you can change it every once in a while. Then you can keep using them.