Honda CBR XX Forum banner

LiFePo4 batteries and Regulator upgrade

7K views 51 replies 6 participants last post by  Mallow1 
#1 · (Edited)
I'm starting this thread to pull together and update the excellent advice I've read on this site, some of which goes decade+ back (re mosfet regulators) and still seems to be valid, but now becoming even more important as LiFePo4 batteries get more powerful and (relatively) cheaper.
 
#2 · (Edited)
My case:
I'm on a 97 carbie. Ran lead acid bat for first 15 yrs. Changed to Shorai LiPo last 8 years regularly swapping between two bats (using a Shorai bespoke charger) and ridden regularly. No battery tender. I've killed them both.

I've only needed to change a faulty r/r (regulator/ rectifier) once. I can't remember if that included upgrading to mosfet but may explain me killing my Shorais if not mosfet!

Mosfet is better tech which from what I've read, smooths the function of the r/r stepping the balance from fully recharging the battery to fully dispersing unwanted generated AC/DC to ground (resulting in less heat dissipation). Old tech was all or nothing (full on recharge or sudden full on heat generation). Extremes (esp sudden heat = not great for batteries or electrics). Mosfet can gradually change the balance of the two and mode of coping with excess current.

Now as we switch to LEDs (headlights, tail lights, indicators, dash bulbs etc) we reduce our ampage needs (at the cost of making the heat dissipation topic harder for the r/r increasimg risk of burning them or the stator out faster).

Yet on the other hand we add more power hungry ancils to power as we ride along (esp heated grips, seat, clothing, GPS, satnav, phone, bluetooth, USB ports etc). That eats up excess power.

Taken to an extreme that may results in the bat not being recharged fully so your potentially dead for next time you hit the starter button! So a balance is needed between the two and one solutuon (as yet) doesn't necessarily fit all as we all have dif mods/ upgrades).

Added to that LiFePo4 bats bring creater power to the table (and mine even has a built in jump start function so in theory I've got a back up solution to too many mods draining my bat).

However LiFePo4 need a gentler charging profile than lead acid and Mosfet seem best suited to provide that else you kill you expensive battery quicker or worse have it explode! Ouch!
 
#3 · (Edited)
I've just bought an Antigravity 16Ah 480 CCA LiFePo4 so need to protect the bike and bat from the downsides of each other while maintaining the upsides.

So R/R choice:
From what I've read a Shindengen FH012AA mosfet R/R will do spec wise and ought to physically fit a carbie (on left side poss with bracket mod). It is rated at 50A max. It seems to have a great reputation with users on this site and Jack comes well recommended as a supplier (inc kits). I'll add a link in a mo.

So is my old wiring good enough to cope with <10s of up to 480 CCA? Fuse choice upgrade too?

I'm very interested to hear if there is better recommendations out there that will still physically fit (I'm mindful of stories of cheap knockoffs, advice to attach direct to the battery, go for hi as poss max amp capacity, improved grounding (inc use of heat paste) to help with heat loss and waterproofing connectors).

Thoughts, corrections, updates advice and R/R recommendations all welcome (and truly needed)

Rgds Mallow1
 
#7 ·
Hi Adey,

Obvs the two are different but I'm finding difficulty google comparison between the two re tech specs & user insight. Most of what I find is back in 2018 when 847 was pretty new with limited user feedback and limited OEM uptake. Really great to hear you've had no problems but what would be the advantage of the 847 over the 20AA? Why'd you go the full hog roast?

Any insight re comparison appreciated?
 
#6 ·
I'd say your wiring should be fine.
The positive lead from the battery to the starter relay, then from the relay to the starter is a heavy lead.
The relay is just a "heavy switch" to connect the battery to the starter, there are no fuses in this line.
The 30amp fuse on the starter relay is the main fuse, from the battery lead into the relay, it supplies a feed to the ignition switch.
The ignition switch, switched on, supplies power to the smaller fuses to protect specific circuits.
 
#8 ·
I'd say your wiring should be fine.
The positive lead from the battery to the starter relay, then from the relay to the starter is a heavy lead.
The relay is just a "heavy switch" to connect the battery to the starter, there are no fuses in this line.
The 30amp fuse on the starter relay is the main fuse, from the battery lead into the relay, it supplies a feed to the ignition switch.
The ignition switch, switched on, supplies power to the smaller fuses to protect specific circuits.
Thanks Punts… I was about to settle down with the wiring diagram to appraise the situ. While the antigravity comes with it's own built in BMS (battery management system) capable of putting the bat into "sleep mode" if it drops beneath a threshold voltage, I've been a long time user of "PriorityStart" so I'm overly complicating my life working out if this is now redundant or if not, where to stick it in a new set up.

Great to know you think the wiring is up to coping with the higher CCA. Thanks.
 
#10 ·
Mallow, the whole thing is counter intuitive, less electrical load makes the R/R work harder, and visa versa. The harder it works the hotter it gets. If you convert to all LED, then you are making the (standard issue or FH020AA) R/R work harder. This is where the 847 differs, in that instead of sending excess electrical energy to ground through some kind of resistance, it creates an open circuit instead. As you probably know, with any electrical component, heat is your enemy.
 
#11 ·
Fizzy, yer it get the diametrisity of the situ.

The stator just pumps out the juice. That juice needs to go somewhere. Options being:
a) recharge battery (until full) NB amp/ voltage profiles important re type of battery
b) run bikes electric requirements when running inc all ancils
c) dump excess (if any) somewhere, typically to bats -ve terminal/ ground and/or dumped as heat.

The R/R ensures that AC from the stator is:
1) converted to DC
2) manages the voltage of the resulting DC to within a specific range (old tech suited to lead acid bats, latest suited to inc LiFePo4 requirement; the two being potentially different)
3) supplies a-c above

Old-school tech does that in binary (all or nothing) manner. Mosfet does that gradually. Result is mosfet copes with more types of bat types (inc LiFePo4) and runs cooler.

Have I got that right so far?
 
#13 · (Edited)
From other threads the SH847 will fit an FI bird over on the OEM location (right hand side) and for carbies (and some early FIs) it is tighter but will still fit in the OEM location on the left hand side.

Beestoys posted a template for a bracket to do the job on the LHS (inc a note saying the bracket allows for a touch of tilt away from the subframe to help achieve the best fit).

PBZ
So sorry this took so long to get to you

View attachment 120463
 
#15 ·
LMAO… 😂 You're prob not wrong there. If I get really really bored sometime I'm sure we could calc a theoretical approximation and see how far we'd have to ride for the higher price of the SH847 to pay for itself via that dynamic! It's prob going to pay for itself in longer stator, battery and its own lifespan way quicker!
 
#17 · (Edited)
Great explanation (see link below) of charging stages and voltages of Sealed Lead Acid (SLA) batteries versus Lithium/ LiFePo4 ones. Reason why I'm being cautious is a lot of lithium RRs say "not for SLA use, lithium only". My concern is if my lipo fails for whatever reason then I may wish to throw in a good old SLA without having to swap RR too. So can I find an RR spec'd to cope with the two safely.


Basically the explanation says Lithiums should not be exposed to a charging voltage greater than 15.7 volts (damage or worse) and ideally not allowed to drop beneath 12.5 volts (NB at 11v potentially unrecoverable deep discharge). Prudent range therefore seems to be 13.7-14.7 volts so a lot of RR manufacturers aim to have 'set point voltage" at 14-14.2v +/- 0.2v

So it looks like an RR set at 14.5v isn't quite ideal for either type of battery but could cope with both SLA and Lithium without damageing either so long as it's a quality one (i.e. swift to respond to voltage spiking outside that value).

Now my battery choice has a built in BSM (battery management system) which affords an extra degree of protection against brief periods of too hi or too low voltages for an RR operating normally (though not 100% bullet proof against RR failure).

The final piece of the picture therefore I think is to ensure the RR can cope with sustained hi RPMs without failure (bearing in.mind our BB's, are Jap "screaming crotch rockets" who red line at 11k rpm not USA "Hardly Dangerous" low reving easy riders). So for example FH020AA (mosfet parallel shunt) and SH847 (SCR series shunt) can whereas an SH775 can't and is reported as prone to fail at hi RPMs.

Gosh… who knew this was so intricate a selection process!
 
#18 · (Edited)
Well Mallow
I'll add a one real world experience. I have on 2 occasions deep cycled my shoria. once with the SH12 and again with the 847. It's still I. here and working. I do on occasions see 14.7 on my volt meter. But my amps at freeway will actually swing negative. This leads creadance to your observations of the R/R uncoupling. I saw the same action out of the SH12. It doesn't go a large negative typically at 42 4500 rpm it's - 3.5 to - 3.7 amps. Total draw on the system as I have it configured is 11 amps. The SH12 would do the same, at lower surface streets it will swing closer to zero. This leads creadance to the postulation again that it uncouples to the demand. My reasoning based on the 2 meters readings is that I see amperage dropping less negative because stator output drops off at lower rpm. But myvoltage stays rock solid at 14.6.
 
#19 ·
So far the SH847 still seems to be undisputed top dog.

Great to hear your real-world observations are in line with the info I'm digging up to educate myself before I splash more cash.

It's even proving hard to find alternative series r/r units to compare the SH847 against. I do now think the "Hot Shot Series" label on the Rick's units I looked at refers to the range of products not the tech (series v shunt).

So pleased your typos get as bad as mine😱! I tend to have to repeatedly edit my posts ten fold to make them vaguely readable from my initial fat finger typos, auto corrects and just bad spelling! I need another 🍺🍷🥃
 
#26 ·
Mallow
Here's the pics of my install Judging by the sheathing and the fact that I typically a stator every 30,000 miles because I ride in a oven most of the year. These leads are factory sheathed and wire colored and are long enough to reach the R/R in the NORMAL location LOL.

130644
130645
 
  • Like
Reactions: Mallow1
#28 ·
You might want to swap out the breaker he supplies in his kit. Thinking because if everything being converted to LED it burned out. I swapped over to a little fuse low profile JCASE cartridge fuse for the main. It's designed for high current applications.
Cartridge Fuses
Provide increased time delay and low voltage drop to protect high current circuits and handle inrush currents.
Cartridge Fuses
 
#30 ·
Finally saved my pennies up and ordered a SH847. Now it's great re stator and temp etc but is set at 14.5v output (not as LiFePo/ Lithium friendly as a 14.1v set point). Any way to reset it or an add on a minor gizmo between it and my battery to tweak that small difference?

Prob not (or not worth the effort) and prob my Antigravity bat will cope anyway but no harm asking.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top