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Desperately needing help!
I have 2 Victron 330ah batteries charging via Smart BMS 12/100 with 80 amp fuse.
While driving or idle, I never get more than 40 amp charging (in the app, it says around 50% of alternator power) From my Promaster 2020 with 220 amp alternator. Never went higher,
Why don’t I see around 70 amp of charging?
I have seen a few posts with similar issues, but never a clear answer.
Thx, I really hope someone can point me in the right direction.
I ran into similar issues with my CL12/100. I have a Transit with Dual 250a. The CL12/100 is extremely sensitive to voltages.
In order to get 100% charge current, it seems to need at least 0.5v more on the alternator side when charging. (see attached photos) When the CL12/100 is charging it usually sees ~0.2v lower than my voltage meter on the starter battery. In the photos below my starter battery was showing 14.04v
If you are able to adjust your consistent alternator voltage, i found that above 14.4v is what the CL12/100 seems to want.
Also, only use the Victron Brand 32v mega fuses, its calibrated for them. I tried a few other 125a mega's and most were 10a less output.
The photo you shared, the house battery should be at 100% or in absorption at 14.19v. So it shouldn't be a high current %. Also, at 6% current output you're not pulling any real power from the alternator, so it shouldn't drop the alternator voltage.
What is the CL12 showing for the alt/starter voltage when your house battery is below 13.3v?
My fix was a setting on the ford to get the voltage higher from the alternator, i don't know promasters so i can't help in that domain.
The CL12 isn't a B2B charger, the CL12 is a current limited pass through, which uses ~0.5v of the input voltage.
A B2B charger will have a 100% output with the input above 13.6v, since it can step up/increase the output voltage.
Some possibilities:
- There is a DC-DC booster installed in between the alternator and the smart BMS.
- The wiring between the alternator - BMS - battery is to thin, reducing the current.
- The charge current settings in the smart BMS need to be changed.
Thx for your input
There is no DC to DC booster in between the alternator and the BMS, and the cable was able to charge at 80 amps before the BMS was installed.
I will post a picture of the BMS charge settings when I get home, but I believe it was at 14.2v.
Ok, I can confirm:
- there are no DC-DC booster installed between the alternator and BMS
-the wiring coming from the alternator to the Smart BS is 4 awg size
-the charge current settings is set at 14.2v in the Smart BMS settings see picture below
What settings should be changed to what?
Any help would be appreciated :-)
Image Caption
So your images show that the alternator is at 14.43V and the battery is 14.19V measured at the BMS terminals. If you alternator would only supply 80A at 14.43V without the BMS, then adding the BMS will reduce the charge rate due to the extra resistance added to the charging circuit. You can not add resistance and expect the same performance. I suggest you try a larger control fuse because this will have a lower resistance and may help. Secondly, get your multimeter out when charging and measure the voltage drop from the stud on the alternator to the alternator stud on the BMS and from the battery stud on the BMS t the battery stud on the battery. If either of these shows any appreciable voltage drop then check the nuts are tight, the crimps are tight and consider larger cabling. On this type of circuit it is not the rating of the cable that is important, but the voltage drop and having larger cables will reduce voltage drop.
I will relook at the terminals and screws and make sure everything is tight and try a 100 amp MEGA fuse.
These readings were when the battery was full.
When it is at say 80% SOC, it still does not charge at more than 45 amps. (With an 80 amp MEGA fuse)
