SLA Solution????

[Bilko130]

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Hi Folks,

This is my first posting so please be gentle with me......

I'm going to try to give you some background into my rationale for a SLA solution and I would like any, and all comments.

I have a journey of some 4 miles (there & back) to complete, to work, every 5-6 days. My journey there, without assistance would be bliss,(all downhill) but the journey back would be a "killer" as I am not a bike rider. However, the costs of running a car for such a small amount of distance make an E-Bike, the almost the perfect solution. It will no doubt help with the ever increasing healthy living lifestyle, I need to invest in as an overweight 40 something......

I have been given an E-Bike that needs some "attention". It is a "Sunlova Sport Classic" and having looked around, can't find anything like this bike. The battery pack supplied with it has no identification plates, with just a kettle lead output, and a XLR style input for charging. The charger is missing, as is the rear carrier rack for the bike, but the battery carrier with lock and keys, is complete. It's a "project"....

My question is...

Am I being unrealistic to expect a home made SLA battery pack (3x12v 12/15 ah) to cope with the daily trawl?

As a "technician" (mechanic) for some 20+ years, I can wield a soldering iron, crimp connections, and have all the tools, parts, etc; available by hook, or by crook....

Dont think I need Lithium-Ion, Li-Po, etc, as range seem unimportant. Just something to help me up those damn hills.....

I would be really interested in anyone's comments who has attempted a similar situation with SLA's. Charging will be via a 12v charger, with batteries rewired every night, if needed, with a c-tek XS3600 battery charger. A more elegant solution would be a bonus suggestion....

Any comments on a re-cell solution fror my dud battery would be fab....

Sorry to blabber on, but all suggestions are welcome.

My thanks in advance,

Bilko130

 

[ace_bridger]

Hi Bilko,

I've just bought a 36V 250W Powabyke Mk1 which, by my calculations will draw 7A max. I'm making two battery packs from 12V 7.5 Ah SLA batteries (I bought 10 of them for £100 on eBay!). The first pack will be 36V 7.5 Ah and the second will be 36V 15 Ah (3 SLAs for the first and 6 for the second).

By my calcs the smaller pack should run the motor for an hour at 15 mph so if I assume 70% efficiency I would hope to get 10 miles or so. My commute is 10 miles so we'l see if I can manage it on the little pack or whether or not I need the bigger one.

In the short term I plan to recharge using my cheapo 12V charger and rewire in parallel until I buy a 36V 2A charger off eBay...they sell for about £20 or less.

In terms of life, the SLAs should have a usable life of about 300 cycles (from full charge to empty and back) but if I use my larger 15 Ah pack to do my commute then the pack will be drained less so should have a longer life.

My packs are currently just gaffer taped together and connected with automotive wire (17A). Be sure to add an inline fuse to stop things catching fire and I don't see why a homemade SLA should be any less good than these SLA packs you can buy. I've made two packs, as above, for £100 plus bits I had lying around and a £2.50 keetle socket from Maplin

Good luck

Adam

 

[ace_bridger]

Took mine on a test run to work and back today and rode for an hour with no pedalling and covered 12 miles out of my 7.5 Ah pack. Fairly flat run with two hills but will equal ascent and descent.

 

[Bilko130]

Hello Adam (ace_bridger),

Thanks for the reply.

Really glad I posted my question on here as I thought I was being a bit of a pratt!....

Been looking on ebay at batteries and I've found 3x 12v 12/15 ah batteries for around £70 quid delivered, so it seems you had a bargain with the 10 you bought!!!

I'm also intending to buy a 12v c-tek charger and rewire to charge the batteries, so that's made me feel a bit better about it.

If they last a year at the above price, it's a damn sight better than the £1000-£1500 quid a year to run my car!

Think I'm gonna go for it, and see what comes of it.

I actually can't wait to have a go with the bike & see what its like.

Will post here and let you know when the "Beast" is up & running....

Again, thanks for the reply.

Bilko130

 

[pepston]

Hi.
I`ve just shoved all the bits and gubbins from an old Electroped Roadstar onto a cheap supermarket bike and it works really well. I bought 3 lead acid gel batteries 12v/12ah for £60 and am having to charge them up seperately as I dont have a 36v charger yet!!! The manufacturer of the batteries tells me that if they become fully discharged they can be recharged up to 500 times so I think yours may well last over a year. My batteries will cope with just under an hour unassisted on the flat but a range of at least 30 miles assisted even with a killer hill. Cheap transport or what??? I have saved a fortune in running costs already and really don`t need a car anymore. Good luck with the project.
regards, Steve