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Reg/rec, LifePO4 problems

CR9000

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Hi guys! Pretty new on this forum!
I have a couple of questions regarding the charging system/regulator/LIFEPO4 battery.
- I am currently building a CB750 K(z) 1979 with an M-unit and all LED lights
https://ibb.co/K9nMMqr

I bought a Ultrabatt Multimighty 12200M+ 150CCA and connected this in the correct way with an 40Amp fuse to my M-unit.
After starting, I drove for 10 minutes, the next day I tried to turn over the engine and the battery shut off right away.
0V on the battery so the BMS probably secured the battery against full discharge.

I am using the Rick's Electrics Lithium Ion Reg/Rec, for CB750-1000 (€179) https://www.caferacerwebshop.com/nl/honda-cb-750-1000-lithium-ion-gelijkrichter-regela.html
In combination with the M-unit Blue and LifePo4 battery
Stator/Starting engine is original.

I measured a couple of things with the original Lead acid 14Ah battery connected (charged)
- Pulled out the ground from the ignition so the engine wouldn't ignite, turned over the starter engine for 5-7sec and had 100-110 Amps
- Measured the amperage when revving the engine and this got up to 8A load current to the battery (too much??)

Now my questions are:
- 100-110 Amps for the starting motor is normal after some research? (0,7kw starting motor)
- 8A too much for the 12v 2,5Ah LifePO4 battery? Reg/rec defect?
- Why does my 40Amp fuse reject to burn after loading it with 110Amps for 4sec??

The battery wouldn't go up to 0-30% with the optimate LifePo4 charger, so I emailed Ultrabatt and they will give me 40% discount on purchase of 2 of those batteries because 2,5Ah, equivalent of 8Ah lead acid, and the original battery was 14Ah lead acid. So they suggest putting in 2 of them minimum.
So the guys of ultrabatt think I overdid it with the starter motor and pulled more than 150A

What do you guys think of the situation?
Reg/rec?
Battery?
 
Leaning toward battery, you only have 150 amp cap on a 110 amp current. Most batteries you pick double the starting current to easily cover it. Look at cars, 500 amp battery minimum to cover up to 200 amp starter. That 14ah was picked for a reason.

You've gone too small, what so many do when you choose that type battery. These I'd be looking for 250 amp battery at the very least.

If you wired the 40 amp fuse in the 'correct' way the starter current did not go through it at all, it shunts around the fuse, you do NOT put a fuse directly in the way of the main starter amp at all. It will drag current down too much to not start correctly or more likely catch something on fire.
 
Leaning toward battery, you only have 150 amp cap on a 110 amp current. Most batteries you pick double the starting current to easily cover it. Look at cars, 500 amp battery minimum to cover up to 200 amp starter. That 14ah was picked for a reason.

You've gone too small, what so many do when you choose that type battery. These I'd be looking for 250 amp battery at the very least.

If you wired the 40 amp fuse in the 'correct' way the starter current did not go through it at all, it shunts around the fuse, you do NOT put a fuse directly in the way of the main starter amp at all. It will drag current down too much to not start correctly or more likely catch something on fire.

Thanks Amc for the quick reply!

Don't know what I am doing wrong with the 40Amp fuse below though..
Followed the M unit instructions considering the fusing.
What do u mean with 'shunts' around the fuse?
I measured around the fuse about 110Amps

Here (pretty) drawing of my 40amp fuse and link what kind of fuse.
https://ibb.co/B4mbvPM
https://mardam.mx/products/fusible-moder-repar-40a-vw-jetta-a4-audi-seat
 
You are not showing all the wiring there, there are TWO battery leads going to the solenoid, it cannot work starter otherwise. One small one switches it on and off, the other is the huge big battery cable to starter that the smaller wire connects up when on and the big cable does not fuse at all. Not familiar with M-unit other than they are worthless as they really do nothing you couldn't do with what you already had, ergo a fancy gimmick. But the unit MAY contain the main starter high amp lead in it so that you don't have the two at solenoid, it still better be standalone with no fuse or you need like 200 amp one for it.

Shunt means separately wired to go around another circuit.
 
Your link came up with 50 images and unfortunately I will not be here to weed through them as I have just elected to leave this site.

Luck.
 
40A Fuse.jpg
Here's red start wire that goes from the M-unit start output (max 30A) to the solenoid to connect the solenoid from battery to starter.
So the main power only can go through the fuse? The 15mm² wire goes to the m unit + and then goes to the solenoid, then to the motor which is grounded.
So the 100-110A doesn't go through the m unit but only passes the + pole.
 
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