7moore7

Finally...

The one advantage I can see to making your own is sizing- this thing is still quite a bit wider than the A123 cell packs... Probably actually an advantage on most bikes as the battery wont' be flying around in the case, but if you need space it makes a little difference.

But the price is damn nice.

Tweety

It's been discussed already in this thread...

https://www.superhawkforum.com/forum...po4#post291074

I'll say it again, I dislike the fact that it's obviously 8 cells divided in two parallel strings of four, instead of pairing them first... This is proven by the fact that there is a 5 pin "BMS port"...

And obviously they are planning to sell "Battery Management System" chargers for a decent sum, to "properly" care for your battery... Ie balance it to death...

But there is one very, very good reason why I agree with them that you should have a special charger... Not the balancer, but the charger... Because it saves them the trouble of dumb-asses charging it incorrectly on their battery tender and then complaining...

The price is right, the construction probably sound, but design wize probably a wrong choice, but

skokievtr

what charger would u recommend for dyi and this battery?

Tweety

It's got two wheels, handlebars and a seat... Any other charger that comes near the battery is just going to screw things up...

Either you run that bike to start it, or jump it, and then take a long ride... Then the battery is charged...

If you however don't like that idea and really want to use a charger, the dumbest charger possible is the best one... 14.4V 1-5A and nothing else... No intelligent charging, no charge curves, nothing of that nonsense...

And using a battery tender of any sort on a LiFePo4 battery is stupid as it just destroys the battery...

skokievtr

how r these type of batteries on the VTRs electrical system?

It may sound dumb but I thought there is a relationship between the battery & VR-R with cine wave frequencies & reflections back & forth. I have the original non-finned OE VR-R (knock on plastic) on my 97 with +60k miles on it. However years ago I bedded the VR-R in heat sink compound against the frame and bonded a CPU heat sink to the VR-Rs "outside side". The heat sink has an integral 12V fan powered when the ignition switch is on. I also run more accessories than OE on the puny 280 watts available. Given the vehicles OE system draws about 13+ amps (a bit more at higher revs of the 280 / 12.85V = 21.8+/- available), I've never had issues (again knock on plastic) with the VR-R getting too hot.

Just curious...

Just

Tweety

Well, the honest answer... Not that great...

This is a repeat performance, I have explained this before, so you get the short version, longer available through search...

A LiFePo4 cell has a nominal voltage of 3.3V and charge voltage is 3.4-3.6V... 4 cells make a 12V pack, with a nominal voltage of 13.2 V and charge voltage 13.6-14,4V...

Now, if you charge each cell to 3.6V you are top-filling them, and you are affecting balance (read the long version, see thread above) and instead optimal charge would be to about 3.45-3.5V... That works out to 13.8-14V on a pack... (This is why a 14.4V charger which is common is OK, but not the best)

The OEM R/R (fins or no fins, doesn't matter) will when new and in good shape give you roughly 14V +/- 0.1-0.2V or so... So at that point it's pretty optimal as a charger... The problem is, it varies a lot depending on RPM... And when it ages it starts varying even more wildly...

So as a result if your charging system is marginal to begin with, ie there is a problem and you use this type of battery, you get problems... mikstr had problems with his pack, and his bike works fine with a standard battery, so his bike was probably marginal...

However with a Mosfet type R/R (Yamaha as an example) you get a stable charge voltage independant on RPM, and in most cases they are right smack dab on 14V... Ie as close to optimal as possible...

Last thing... Not acting as a seller (I don't like that myself)... The first thing anybody should do if considering this type of battery is to get yourself an onboard voltmeter, that will tell you the voltages while riding... Not just stick one on there while idling on the stand... That tells you a lot about your charging system, and if you need fixing it, not just to use this type of battery, but in general...

There are several types, LCD/LED numerical display, LED bargraph, or even a dial... All works... I prefer not to look at one, so I use my own design, two warning LED's... No LED = OK!, a LED is lit = NOT OK!... I sell them, and the design is in the knowledgebase...

Oh, as a side note for those that have bought or made mine... That one is optimised for the SLA/GEL batteries, so it won't tell you if you go below charge voltage on the LiFePo4 cells... I have made another version (a few components have changed) that works for the LiFePo4 packs...

skokievtr

I forgot to mention, I do have an on-board volt meter. Its a LED bar graph type (http://www.visualinstruments.com/) and reads no more than 14v at idle (lowest OE current draw state) and lower at higher revs of course. I should note though that the VM is connected to a switched + wire up near the instruments so voltage read there is lower than at the battery due to current drop over a 2.5+ foot long probably 18 or even 20 gauge wire. I have not compared this VM to my multimeter reading at the battery. Voltage at battery at idle is +14v but does not fluctuate much until revs are raised.

Would you suggest replacement of the OE VR-R with a Yamaha unit, and if so what year & model?

Tweety

How large steps does that voltmeter measure? If it's measuring fine enough to tell, and your bike stays above 13.6V at all times you are fine as you are... If not, a Yamaha R/R with either partno "5JW-81960-00-00" or "4JH-81960-01-00" will work just fine... It fit's a whole lot of bikes, a reverse partno search at Ronayes gives you a long list...

skokievtr

It reads in .5v increments but never reads much above 13v or so at idle or constant speed and lower on average at higher and fluctuating revs (again connected to a thin gauge + wire of a loaded circuit well away from the battery.

It appears 4JH-81960-01-00 can be had new from RA for about $70. Not bad and I know how to connect it.

thanks. I guess its time to bite the bullet and replace the OE VR-R as one of my winter projects along with re-wire my headlight power loom with 16 gauge wire instead of 18 (similar to the Eastern beaver kit), and replace my headlight modulator with this unit http://www.ridesafer.com/ProductDetails.asp?ProductCode=LM0030 because it can be wired with my own 16 gauge wire via my HL loom. Most other HLm come pre-wired with light gauge wire.