Blue Seas ML ACR 7622 questions

[luthj]

Comparing the amount of time most drive to 24hr 365 float charging is is disingenuous at best. The reality is that running with an alternator at 14.2 to 14.4 volts continuously will not cause any long-term harm to a healthy battery. In the case of batteries they get routinely cycled below 40% DOD it will increase their lifespan.

If desired many alternators can be modified with a relay and a diode. This will allow operation via switch to change between normal and boosted alternator voltage.

 

[john61ct]

Many battery mfg are fine with higher voltage to speed up deep cycle charging while actively cycling.

Just don't leave it there when not.

Example, Trojan recommend 14.82V then a drop to 14.7V for absorption, but this is for when you have plenty of time to recharge. The part most miss is that this voltage guidance is qualified by stating: "*If charging time is limited, contact Trojan Technical Support for assistance."

If you contact them, and get someone who knows something, they will tell you that for shortening run times, an absorption of 14.8V - 15.0V is optimal Even an absorb of 14.7V will help the bank last longer than 14.6V but 14.8 - 15V is even better.

 

[DaveInDenver]

Comparing the amount of time most drive to 24hr 365 float charging is is disingenuous at best.

It's not disingenuous to consider that (1) most of the time you barely discharge a battery just starting your engine that you really don't need to bulk at levels like 15 V to force much current and (b) most people are driving considerable lengths of time on the highway where the RPMs will be up and that +0.7 V bump will take the normally slightly low voltage to sufficiently damaging absorption/float. Of course doing it here and there following a weekend running a battery down with a fridge isn't gonna hurt anything and is probably really what you want to do. But if the other 5 days of the week you're driving an hour to & from work on the Interstate that sort of consistent stressing may be just as damaging long term as under voltage was. Adding a relay to switch the diode in and out is a clever solution. It's a manually operated multi-stage charger, intelligence provided by the knucklehead behind the wheel.

 

[DaveInDenver]

Many battery mfg are fine with higher voltage to speed up deep cycle charging while actively cycling.

Just don't leave it there when not.

Example, Trojan recommend 14.82V then a drop to 14.7V for absorption, but this is for when you have plenty of time to recharge. The part most miss is that this voltage guidance is qualified by stating: "*If charging time is limited, contact Trojan Technical Support for assistance."

If you contact them, and get someone who knows something, they will tell you that for shortening run times, an absorption of 14.8V - 15.0V is optimal Even an absorb of 14.7V will help the bank last longer than 14.6V but 14.8 - 15V is even better.

It depends on the requirements and specifics, but usually under a quick charge scenario the elevated voltage is done from a deep discharge (which I mentioned before is usually *not* the case with a starting battery) with no current limit but is time dependent and the battery can't be left indefinitely at the high voltage without current limit.

Plus don't neglect temperature compensation, which is absolutely critical to life of a battery. Voltage and current recommendations are at ideal of usually 20 °C and must be adjusted. Since under hood temperatures are going to be elevated you can't use 15 V unless ambient is cool enough that the battery is 20 °C (68 °F). Odyssey, for example only because that's what I have, says for cyclic use the ideal bulk quick charge is 14.7 V at 25 °C and the compensation is 24 mV per °C. If you believe their guidelines you should be at 14.1 V at the height of summer, when a battery could easily see 50 °C and 15 V would be a winter charging voltage since that would require the battery be 15 °C.

Point I would forward is that Toyota and most manufacturers make decisions that are the least potentially damaging baseline which work most places. Undercharging in Minneapolis is safer than overheating in Phoenix. One shortens the life, the other may cause venting and explosion. So adjusting from stock needs to be done knowing margins. Just sticking a diode in the sense line may be fine for your climate but it's not always going to be safe.

 

[DaveInDenver]

Kinda silly added complexity too. Regulating sensor lead draws what, less than 20mA ? It cant be much...

I can't imagine so, 20 mA strikes as at least the right order.