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I believe your advice is a good recommendation. I just can’t resist fiddling with this though. My hope is that a better battery solution would put less load on the engine. Drag racers have long disabled their alternators to gain a few HP. Hypermilers have found no alternator can gain 5%. So hoping small, light battery will charge fast to reduce load. Worst case, I learn a few things and loose some money in the process. Best case, I learn a few things, and save money in fuel and less frequent battery replacements.
Maxwell BCAP0350. Capable of 170 amps max, but will deliver 840 amps if shorted. Max continuous at 40C is 34 amps. 350 farad capacity. 2.7V max
Probably not necessary with your recommended set up, but seems it would lighten the stress on the ANR’s.
I went ahead and ordered 20 of the ANR18650’s and the balancing circuit. I already have 21 of the Boostcaps, but want to start with just 1P6S.
Not sure how I will keep them balanced. I will monitor voltage real time. If imbalance happens, I will have a quick connection for 6 LED’s. I would like to leave the LED’s connected full time, but my testing shows they bring the voltage down to low. Need to do more research on that. Also need to find a solution to keep them and the ANR’s cooler than the engine compartment.
Due to the low storage capacity, I will carry a booster pack and jumper cables for back up.
Well, according to what I can see in the lygte-info.dk review of the APR18650M1A, these ladies seem to feature no higher than 30mΩ of internal resistance. A 4S5P pack should exhibit a combined maximum of 24mΩ minus cell and terminal interconnection losses. The cap string is about 19'2mΩ minus losses so, it should bump the effective cranking power by up to 187'5 instant amps.
Should be good for at least a 2.0 litre (122ci) otto engine, maybe a tad bigger, if properly built.
How are you planning on the battery assembly? I have a really smart idea using neodymium magnets and thin copper sheet, minimizing losses and doing away with any need for spot welding.
I’m a long time and current owner of dual purpose, dirt, 4 wheeler and sport bikes. I’m not sure if you have electric start or not but the battery is usually there so that the headlight and controls can operate without the engine running.
The best solution may be to get a compact lead acid gel battery for an automatic power supply or a garage door opener. They will love the 14.5 volt no load output. It is easy to create space under the seat and drop a plastic bucket or tray in to strap the battery down. Swap out some terminals and you should be just fine.
The lead acid battery will probably cost about $20 to $30, which is likely less expensive than anything else you’ll come up with.
Well, if you're after minimizing losses, that is done by minimizing the power lost in the cranking power supply by maintaining a sufficiently high load/supply impedance, thereby avoiding the loss of cranking power which otherwise is spent killing your under-specced battery. This part seems 0K for that setup.
Additionally, battery and capacitor drainage does matter also, as these little losses will have to be compensated feeding extra fuel for the alternator's duty. With regards to this, maybe this is not that good.
However, this setup should be very reliable and deep cycle derived damage resistant, whereas any standard lead cranking battery will suffer damage if deep cycled (my venerable Ibiza GT TD petrolero's battery became mostly useless after a couple of deep cycles).
Use a nice low viscosity 5W30 synthetic oil: that reduces losses. :-)
Honestly, I think motorbikes benefit more than cars with LiFePO4 batteries due to the effective reduced wheight and space gained. What ImA4Wheelr is going to build, in fact, is the kind of setup zeremefico would really enjoy for that R1 or most other big bikes, and it would seamlessly work in quite cold climates.
For those winters in Montana, Canada, etc. where your nominal 490 CCA battery surrenders, I’d slam a nice pack of LiFePO4s (4S5P AMR26650s) and maybe a good setup of boostcaps in parallel with the factory lead battery for KaBOOM cold cranking power and much reduced additional wheight compared to any 1000+ CCA lead acid monster. Seems reasonable.
On my car the idle speed is noticeably higher (250-300RPM) with the supercaps alone as compared to the fresh fully charged lead acid battery alone. Indicates the lead acid is taking a significant amount of charge current even after it's full.
Guess your car engine isn’t diesel…
Time to sell DC-DC boost converters to properly feed these poor spark plug coils, extra horsepower! LOL!
That thing you say… well, it has a reason. Fact is, the output from the vehicle regulator is actually a bit above what these 6S lead acid tanks are supposed to take, all of it was designed to be that way because of their inherent overcharge tolerance, among other things.
Hey, these are good news for LiFePO4 equipped Otto engines, as the LiFePO4s shouldn’t leech that much current, way less in fact.
Great thing to tell to my friend who owns a pair of bikes. Sick!
I don’t have anything more to add to this conversation. I just wanna know where adnj gets a gel-filled lead acid for $20 to $30. I was in my local auto parts store recently and watched a guy buy a small gel-filled battery for over $90!
I purchased 20 cells to go 5P4S. Unfortunately, the cells were not adequately packed and 3 sustained damage in transit. The vendor says he/she will pack them better going forward and has 3 replacement cells in route to me with a tracking number. Vendor has been very responsive.
Test of the cells indicates they have a very flat discharge curve and produce high current and then basically fall flat on their faces. Pretty sweet really. Plus, much safer.
In the mean time, I will build a 4P4S pack with 6S BoostCaps parallel. To balance the BoostCaps, I'm going to try 2S Ni-Mh parallel to each cap. I haven't seen this anywhere, so I will be actively monitoring the BoostCaps and spot checking the Ni-mh and LiFePo4's.
One cell didn’t look too bad, but when I tested it, it only had 179mAh. The other 2 cells had enough damage to the top of the cells that they seemed too much of a short and leak hazard for my taste.
Max voltage for 3S LiPo’s is 12.6 volts. Typical car regulator cuts out at 14.4 volts.
4S LiFePo4 are cutting it close with a max voltage of 14.4v, but they are supposed to be a bit overcharge tolerant and the BMS will drain them down starting at 3.6 volts/cell (but at a slow rate). Just in case, I will have to monitor for issues in this regard.
I didn't think LiPo's/IMR's/INR's etc.would have much punch (or mAh's stored) 3.6V.
LiFePo4 cells at 3.6v are fully charged and capable of 150 amps (30 x 5P) continuous and 325 amp bursts.
LiFePo4 cells are good down to 2V. So more operating margin.
Finally, the 6S BoostCaps are the real stars of the show. Capable of 170 amps max, but will deliver 840 amps if shorted. Max continuous at 40C is 34 amps. More than enough for the surge to get the starter motor started (which is when most of the current is needed).
