Never see right voltage charging #'s with sh775 and Lithium

[GabrielGoes]

The SH775 isn't a smart charger - the charging regulation is a property of the combination of the set-point voltage the regulator is at and the battery coming up on voltage as it charges. When the battery voltage reaches the same as the reg output, charging effectively ceases. Current won't flow when the voltage points are equal.
That's all there is to it.
However, on modern ECU-controlled engines and charging systems incorporated, all that above doesn't necessarily apply, as cunning design can make the regulation do stuff that is far more clever than older setups.

are you sure? i don't doubt you, but would like to see this on paper some how. The research i've done mentions that the SH775 specifically detects a full battery and throws the extra load to an open circuit. Another thing is if i charge my battery and run the charging test, she'll only show in the mid 13v range whereas if i let the battery sit a while, or drain it some, then repeat the test, i get the high end of 13v's and 14v's to show on my meter.

[Cipher]

are you sure? i don't doubt you, but would like to see this on paper some how. The research i've done mentions that the SH775 specifically detects a full battery and throws the extra load to an open circuit. Another thing is if i charge my battery and run the charging test, she'll only show in the mid 13v range whereas if i let the battery sit a while, or drain it some, then repeat the test, i get the high end of 13v's and 14v's to show on my meter.

Did you test AC output if each stator leg.
my bike specs. 75VAC at 5000 rpm.

[Nessism]

are you sure? i don't doubt you, but would like to see this on paper some how. The research i've done mentions that the SH775 specifically detects a full battery and throws the extra load to an open circuit. Another thing is if i charge my battery and run the charging test, she'll only show in the mid 13v range whereas if i let the battery sit a while, or drain it some, then repeat the test, i get the high end of 13v's and 14v's to show on my meter.

I've been buying and selling SH775's for a little while now, and before sending them out, I hook them up to my bike and verify function. My bike doesn't get ridden very much these days, and the battery often runs down, and when testing charging voltage with a depleted battery, the charge voltage across the battery will hang at about 14 VDC. If I stop, and fully charge the battery, then the bike will show 14.5 VDC across the battery when reving to 5000 rpm. What this means in terms of function is unclear to me, I just know it to be true on my bike.

[Grimly]

are you sure? i don't doubt you, but would like to see this on paper some how. The research i've done mentions that the SH775 specifically detects a full battery and throws the extra load to an open circuit.

Yes, it opens the circuit from the stator, which was always the sensible way of doing it, but it wasn't feasible back in the 70s and 80s, because we didn't have teh necessary robust (and cheap) components to do it that way.
What I'm referring to ^^^ up there, when the output voltage meets the battery, it's not a smart device, never has been.

[GabrielGoes]

Yes, it opens the circuit from the stator, which was always the sensible way of doing it, but it wasn't feasible back in the 70s and 80s, because we didn't have teh necessary robust (and cheap) components to do it that way.
What I'm referring to ^^^ up there, when the output voltage meets the battery, it's not a smart device, never has been.

Thanks for the input, Okay m8 I'll have to take the 13.8 as it is lol. If it starts becoming problematic I have 2 more stators from known good bikes.

one things for certain is that LifPo4 lithium have a circuit board built in to stop charging once charged so therefore I just went with AGM

[salty_monk]

I've been using a Shorai with an SH775 for a while without problems. Before I switched it out it had one of the FHA12 or whatever the number is shunt Mosfet types. Also not a problem with the Shorai.
The biggest issue with the Lithium is parasitic drain. They don't have a lot of real capacity so a drain brings them down to a level where there can be permanent damage quite quickly. It's worth having one of the BMS chargers that can manage/balance the individual cells.

On a SHorai you can actually measure the individual cells with a meter in the plug socket if you're careful with the pins....

[Who Dat?]

... The research i've done mentions that the SH775 specifically detects a full battery and throws the extra load to an open circuit. ...

I deal a bit with vehicular electrics and have to smirk a bit at comments like this.

Besides the stator inputs and the ground wire, there is exactly ONE wire attached to the r/r. It is usually attached to the battery, but not always directly. When the r/r "detects a full battery", where is this "open circuit" that will recieve the extra load? And, if it's an "open circuit", there is nothing there to accept that "extra load".

By the way, the r/r does not provide a "load", it looks for one. A load is a demand, like a headlight or ignition system.

As others have mentioned, when the difference between charging output and the battery voltage gets less and less, so does the charging rate, the charge is not sent to another location.

[pdqford]

^^^^^^^. what he said! Thank You.

If you look at Nessism’s diagram of the recommended way to wire the SH775, or the wiring diagram for most Suzuki’s,, the output of the R/R (the red wire) goes to a junction feeding two parallel circuits. One side of the junction goes through the fuse box and to the battery. The other side of the junction goes to the main harness to power up the rest of the electrical system. I mean, how would the R/R know which one of the two parallel circuits contains the battery?

For example, if your Stator is capable of putting out, say 14.3 volts, but the regulator has thyristors that dump to ground at, say 13.8 volts, 13.8V, is the most voltage you will see anyplace in the power side of the system, assuming no voltage drop due to poor connections, etc. I have read that these newer thyristors are capable of dumping up to 2000 times per second, spreading the stator load as opposed to having a shunt regulator just locking onto ground.

Aside: I retired from my full time job back in 1995 and then five years latter I took every automotive electrical/electronics course out local community college offered.. (Hey, when you are a senior citizen there is no tuition for these courses!) After two years of free courses I sat for the ASE exam in Auto Electronics and one in Auto Drivability, passing both! What I did learn that electricity is electricity. Doesn’t matter if it Auto, Bike, Boat, etc. and that I only know a small fraction about electricity.

Now, back to your regularly scheduled thread.

[salty_monk]

I was lucky enough to be with Posplayr on one of the early days of figuring out these Series RR's. Pretty interesting when you see them on a scope, it makes it pretty easy to understand what's happening. It's one of the few ways to see the "smoke" before it escapes

[niclpnut]

When I first identified the polaris units (775) as a series regulator, I've been running them ever since and they have maintained 14.5v with agm or lithium batteries.

[pdqford]

Good to know. .