lifepo4 battery pack

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Dec 29, 2016
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Lanc's, England
I just got 24 lifepo4 32650 cells, 3.2v and 6Ah each.
They suppose to last longer and be safer than li-ion.
My thought is to build a 12s2 battery pack which gives me 38.4v and just under 12Ah.
It's my first time building a battery pack, so I bought cells with screw terminals.



Most of times I don't think I need more than 12Ah but, if this is successful, I'm thinking of building a second pack and a auto switch so I can travel further when needed.
 
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Hi. I have bought some lifepo4 cells to make a similar voltage pack from a seller on ebay. He has very good feedback so I'm keeping my fingers crossed but the cells seem good and mostly very close in voltage as delivered.
Quick question- are you fitting a bms to your pack and if so, which one have you decided on?

John
 
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Joined
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Norfolk UK
Yes there's not a great choice out there. Opinions seem to be that cheaper ones are prone to failing but expensive ones are crazy prices and the programmable ones are way over my head.
My cells are much the same with no more than about .01v between any of them. I'm actually going to build a 11s 3p as it's for use with a 24v hub motor which really struggles at 24v into any headwind and runs much nicer at 36v (tried it with 3xlead acid batteries).
I'm going to run without a BMS and see how things go. I'll solder on ballance leads, use a ballance charger and monitor cell voltages each charge. I'll also fit a voltage readout/alarm on the trike to keep tabs on things while in use. Bit of a faff I know but I like to see what's happening and most of the gear I already have here for use with my drone Lipo batteries.

I was reading on Endless Sphere about the cells with screw terminals and advice was to be really careful when tightening the screws as it's easy to do damage if too tight. There is a recommended torque for tightening. I bought tabbed cells so I can solder the connections.

Would be interesting to hear how you get on with your pack. I'll post up my experiences once I get set up.

John
 
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Just to report I have my pack finished and working. I made a hard case for them from a lightweight plastic (1/4" thick solid sheet originally a sign/placard). Glued together then sheathed in epoxy soaked nylon for strength.
I hadn't quite realised how large and heavy a pack 33off 32700 cells would actually be. Difficult to find a good place to mount it on my trike. I've had to put it at the rear beside the seat and over the wheels. Not perfect but OK. I've mounted a voltmeter on the handlebars so I can monitor while riding. I charge with a RC hobby charger in two stages of 6s and 5s and can check individual P group voltages regularly.

I'd be interested to get an idea of range it will give me with pedal assistance but doubt I will often get anywhere near using it to capacity myself unless I get myself a lot fitter and more dedicated.

John
 
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Just to report I have my pack finished and working. I made a hard case for them from a lightweight plastic (1/4" thick solid sheet originally a sign/placard). Glued together then sheathed in epoxy soaked nylon for strength.
I hadn't quite realised how large and heavy a pack 33off 32700 cells would actually be. Difficult to find a good place to mount it on my trike. I've had to put it at the rear beside the seat and over the wheels. Not perfect but OK. I've mounted a voltmeter on the handlebars so I can monitor while riding. I charge with a RC hobby charger in two stages of 6s and 5s and can check individual P group voltages regularly.

I'd be interested to get an idea of range it will give me with pedal assistance but doubt I will often get anywhere near using it to capacity myself unless I get myself a lot fitter and more dedicated.

John
Due to infirmity I had to rely heavily on my e-assist and a 10AH 36V pack would give me at least 20 miles and that was using it at about 60% of max output.
The carrier for them placed a pack either side of the keel so there were 2 such packs on board so I could do 40 miles if required, with a changeover half-way.
Similarly, my "cells in a brick" battery of 20AH @ 36v would do 40miles before needing a recharge.
The bad part when touring is that you have to ensure you have a camp-site with an "electric pitch" and not mind the noise of the fans in the chargers for 4 hours while you charge them back up overnight.
It is a real bummer to know you are the lame duck needing all this "assistance" and disturbing everyone else.
 
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Hi Danny. These cells have made up a pack which, on paper, is about 18AH. Doubt the seller figures (I doubt all seller figures for everything these days) and I'll keep the charge down to 80%-90% anyway but will be plenty for me as I'll not be doing any long rides in the immediate future. This is a lovely area but the road system means I'm a bit stuck for long rides without hitting very busy traffic. Maybe I'll be able to transport our bikes further afield at some stage. Looks like the Benfleet area is less problematic and has some nice cycleways in places.

Looks like you're back to a good fitness level again now and I am hoping this summer will see me emulate your progress with regular rides round our country lanes letting me rack up the mileage and strengthen up the legs (using minimal assist (250w) against headwinds!!!)

John
 
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Looks like you're back to a good fitness level again
Sadly not, if anything I am even worse, but your kind thoughts are much appreciated. :D
 
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Oh sorry to hear that. I must have got my chronology confused. I thought you and Paul had done a foreign trip since your accident and that you were mended but guess I was wrong.
Well at least your spirit and sense of humour aren't damaged and you're still planning and building. Keep up the good work and keep posting it to give me inspiration.

John
 
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I thought you and Paul had done a foreign trip since your accident and that you were mended but guess I was wrong.
John
We did a modest trip and without incident. Despite Dan's best efforts an increase in fitness has so far eluded him.

Looks like the Benfleet area is less problematic and has some nice cycleways in places.
Sadly no it is a dreadful area built up conurbations in every direction [ except for the wet one ;) ] and no thoughts of cyclists trying to get around , roads are also deliberately NOT being maintained. I can see why gym and home gym look the only way of trying to exercise.

I assume you are in the Broads ? as the parts of Norfolk I visit can not be described as flat !

Paul
 
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Hi Paul. I used to visit Danny's area often since I had a boat moored in the Dauntless yard for a while. I confess I never did much other than visit the yard but recognised odd bits of Danny's cycle journey he put up on a vid. That particular route looked quite pleasant as I recall.

I'm about 7 miles west of Kings Lynn just before the Sutton Bridge. I'm just North of the A17 which is a heavily used main route east to west with commercial traffic thundering along the single carriageway at all times. North of me is The wash and rivers east and west. Most of this area is quite flat and pleasant for cycling but although not too built up it is very busy on the roads all round. My few encounters with cars and larger vehicles have given me an instant inferiority complex while trundling along at 10mph with impatient drivers eager to get by.

I don't know of any cycle paths hereabouts and an internet search didn't show much either.

I'm happy in my immediate surrounding area at the moment with lots of lanes and back roads to explore. Mybe later I'll get more adventurous.

John
 
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Hi Paul. I used to visit Danny's area often since I had a boat moored in the Dauntless yard for a while. I confess I never did much other than visit the yard but recognised odd bits of Danny's cycle journey he put up on a vid. That particular route looked quite pleasant as I recall.
IIRC it is the ONLY ride he has complete with poor surfaces and in the summer wall to wall holiday makers !

I can ride from home to Boston on quite roads and railway tracks 74 miles plenty of stops and very little traffic.

We did it from Fledborough Viaduct to Boston and back just over 100 miles after small detours in Lincoln and Woodall Spa for food , managed the old CTC standard of 8 hours cycling [ just ] however due to many eating/watering stops it took us almost 14 hours overall

I'm about 7 miles west of Kings Lynn just before the Sutton Bridge. I'm just North of the A17 which is a heavily used main route east to west with commercial traffic thundering along the single carriageway at all times. North of me is The wash and rivers east and west. Most of this area is quite flat and pleasant for cycling but although not too built up it is very busy on the roads all round. My few encounters with cars and larger vehicles have given me an instant inferiority complex while trundling along at 10mph with impatient drivers eager to get by.

I don't know of any cycle paths hereabouts and an internet search didn't show much either.

I'm happy in my immediate surrounding area at the moment with lots of lanes and back roads to explore. Mybe later I'll get more adventurous.

John
I use the A17 a lot as we holiday in Norfolk quite a bit , first off is breakfast at Holbeach and then on to the coast [ usually ] no further than Weybourne , this year we will pass through heading into Suffolk via Swaffam anther ' favourite place '.
I only think I have reached Norfolk when I cross Sutton Bridge ! Is there still a cafe there ? always been meaning to visit if the Aurora @ Holbeach should be closed :)

Paul
 
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8 hours? Hells teeth I'm puffing like an old train after 8 minutes. My Dad died the other year just as I was retiring and getting my leg sorted. It would have been great to cycle to him a few times a week rather than use the car. About 2 miles each way along back roads would have helped with my leg and fitness level.

There's a cafe/restaurant called 'Pippas Pantry' at Sutton Bridge. As you get to the roundabout before the Bridge turn left down towards Sutton Bridge/Long Sutton and it's a few hundred yards on the right. Doesn't look much from outside but it's apparently really nice inside and serves great food. Haven't been there yet but it's somewhere we've intended to visit.

We often pass by or through Holbeach heading for Springfields retail outlet in Spalding. One of Joan's favourite places- I hate it! Discovered last year there's a scrap metal dealer in Holbeach and he has a pile of scrap bikes you can sort through. Not exactly a treasure trove but reasonable selection and at scrap prices £5-£10 for a car full.

I lived in Suffolk near Haverhill for many years before moving to Maldon Essex then up to Aberdeenshire Scotland. Then 16yrs ago back 'daan saaf' and found my perfect home here and soon after, my perfect wife (Don't tell her I said that!).

If you do pass this way sometime you're more than welcome to stop by for a cuppa and a toasted sarny or whatever. We're easy to find and only half a mile off the A17 so not far out of your way.

John
 
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8 hours? Hells teeth I'm puffing like an old train after 8 minutes. My Dad died the other year just as I was retiring and getting my leg sorted. It would have been great to cycle to him a few times a week rather than use the car. About 2 miles each way along back roads would have helped with my leg and fitness level.
It was on a fast 2 wheeled recumbent , I needed all the help I could get as one was about 20 years younger than me and his son 40 !

I could also out eat them !
I beat them to the cafe and before my stuff came out they left the cafe to inform me there was no cheese cake left !
I said I know I ordered the last piece , oh and apple pie and ice cream , all on the same plate !

There's a cafe/restaurant called 'Pippas Pantry' at Sutton Bridge. As you get to the roundabout before the Bridge turn left down towards Sutton Bridge/Long Sutton and it's a few hundred yards on the right. Doesn't look much from outside but it's apparently really nice inside and serves great food. Haven't been there yet but it's somewhere we've intended to visit.
The I have heard of I suspect , we have also been to the garden centre a couple of times and that 50's diner down near Gypsy Bridge [ I think it's called that ] ?

Discovered last year there's a scrap metal dealer in Holbeach and he has a pile of scrap bikes you can sort through. Not exactly a treasure trove but reasonable selection and at scrap prices £5-£10 for a car full.
Alas the car is always full of holiday stuff , although once I squeezed a dismantled BMX in [ scrap ] however i got it and a pair of 14mm axled wheels for a £10.

If you do pass this way sometime you're more than welcome to stop by for a cuppa and a toasted sarny or whatever. We're easy to find and only half a mile off the A17 so not far out of your way.
Very kind of you to offer , I wish the roads were better it would make a nice ride out , camp the night and return the next day.

Paul
 
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