I am trying an experiment. At work I borrowed with permission 4 12V 9A SLA AGM batteries and connected them in series to make a 48V 9A battery pack. I then connected a power cable that will connect to the charging port on my Condor and a second cable for charging the battery pack. The battery pack weighs about 20 pounds and fits easily in my seat bucket. I rode around tonight and climbing hills is a lot faster and getting up to speed is faster too. But also my range has been greatly increased. So now my Condor has a total of 29A of battery power instead of just 20A. I do charge the battery packs separately. but they are connected in parallel when in the Condor. I am going to buy them to use permanently because they work so well.

Ken Finch

Well that sounds great! Just out of curiosity how much do the 4 batteries cost? My ebike supports 2 batteries. My main one is a 48v 20ah lithium battery. I just to rebuild the SLA pack under my seat. Just want to use it as an emergecy backup.

...climbing hills is a lot faster and getting up to speed is faster too.

Good stuff Ken. What you have now is a "stiffer" pack. In other words you have spread the load across more batts which reduces the Peukert factor (lower voltage seen under high current draw aka voltage "sag" = lower RPMs from the motor) that you usually see(feel) with the old/smaller Ah pack... So yah, stronger acceleration and hill climbing...

And Vic... when you ask about cost, whatever figures you hear ya can offset with some savings. Because the original pack is not taxed as much, you'll see more cycles/longer life...

BTW the more Ahs added do not translate directly as more range. ie 20% more Ah does not provide exactly 20% more range. `Cause the extra weight requires more power to accelerate and also adds more rolling resistance to the tires, all else equal.

LoCk

http://www.ctv.ca/ser...

I came across this article. It's about electric cars. But if they made it so ebike could also be charged it would be amazing.

Well I will be asking about the cost today at work, because I borrowed them and have not purchased them yet.

Thanks Lock, Well to offset the weight factor I removed the 20 or so pounds of tools I was carrying at all times in my rear trunk. Thus I replaced the 20 pounds of weight in my rear trunk with 20 pounds of batteries under my seat so there is not really a weight penalty.

And if it offsets the needed replacement of the main battery pack by a few months in the future then that is a un-calculated bonus as well.

Ken Finch

Ken
Good stuff!

Does just connecting the new pack to the charging port then put the two sets of battery packs in series?

Also, would it be possible/difficult to set it up so both packs are charged simultaneously off one charger?

I'll drop by the store one day to have a look at your good work.

Connecting the battery pack to the Condors charging port connects that pack in parallel with the main pack making it electrically one large 48V 29A battery pack.

Ken Finch

Well I disassembled the extra battery packs temporary assembly (vinyl tape holding the batteries together) and reassembled the pack with industrial strength Scotch double sided mounting tape and glue for a permanent assembly. I then re wired it with spade quick connects and put it back in my Condor. It will now be a daily used battery pack on my Condor. I am now in the long term testing phase of this experiment. Phase 1 (performance and range test) surpassed my expeditions by a wide margin. As soon as I can find some 25A Diodes I will be installing them so I will not have to electrically disconnect the battery packs when I park my Condor.

Ken Finch

As soon as I can find some 25A Diodes I will be installing them so I will not have to electrically disconnect the battery packs when I park my Condor.

Ken, would you elaborate here please. In *theory* (so often inadequate in practice eh?) diodes would deal with circumstances where the two packs are at different voltage levels... not different Ah sizes. The packs you have paralleled start out "in step" at 48V and you are charging and discharging together, so in a perfect world the batts would age all at the same rate and voltage levels would stay in step. In your case your original "broken in" pack has been paralleled with fresh lead, so I can see where perhaps you can expect an inbalance in voltage levels with time...

I know that the "Big Boys" with their EV cars are careful to specify batteries that all come from the same batch (date code), and that even given this, on close inspection they do reject a new battery or two as falling slightly "off spec" compared to the others in the delivery...

So where exactly are you installing these diodes and what purpose will they serve please?

tks
Lock

Well when I turn off and park my Condor I do not want my 20A pack discharging into the 9A pack. So the diodes will prevent the voltage from flowing from the main pack to the extra pack. That way the voltage flows out of the 9A pack into the 20A pack then from the 20A pack to my Condors Controller, but the voltage will not flow in the reverse. When I charge the packs I remove both packs and bring them in my house or at the store. I then charge them separately with two separate chargers.

Ken Finch