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Battery pack update..
#11
(05-21-2017, 10:30 PM)Sleepster Wrote:
(05-21-2017, 09:25 PM)justMongo Wrote:
(05-21-2017, 07:04 PM)Ockrocket Wrote: When I turned the machine on it showed a 0.4 of a volt drop on start up, and then stabilised to 0.2 of a volt when running... it was showing a battery level of 11.2  volts with the machine running when I turned it off and swapped back to mains power. 

Not sure what you're saying here.  Do you mean the current draw was 0.4 Ampere on start; and 0.2 Ampere running??
Seems too low for current draw with a 12 Volt machine...  Or do mean the Voltage dropped from X Volts by that much?


I think he's saying that the battery voltage dropped by 0.4 volts when the machine was started up. When a load is applied to a battery the battery voltage drops. Then, after the machine had started up and the fan was running at a steady speed, the voltage was only 0.2 volts less than what it was when the machine was turned off.

Give that man a Kewpie Doll.  Grin

Yes, only talking about voltage drop on the digital volt meter I bought that plugs in to the second cig. lighter socket, just useless observation seeing as I had the new 'gizmo' showing it.  Rolleyes

I haven't bothered to get out my multimeter to test current draw/amps and so forth, I will leave that to others who understand it better.. I'm just a basics man when it comes to electrics. 

In my personal experience 11.2 volts has proven to be far from a 'dead flat battery' [just try shorting one out and then tell me if it is dead.. ask me how I know  Oh-jeez I had to put out the fire when I did it  Unsure  ] ... though it may be the technical experts who design them deem it so.  Dont-know

If I don't have an early start tomorrow I may run it off the battery again tonight, if I have to wake up to swap to mains it won't worry me as long as I have a later alarm in the morning.
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#12
Not going to let me forget that altercation with the tree are you Mongo..  Laugh-a-lot

SS, no I don't have to use the heated hose and humidifier, just thought I'd test under maximum load conditions. 

Sleepster, yes I was looking at solar panels yesterday... but a size small enough to pack on the bike is of limited use for recharging as much/more than the CPAP takes out. 

I'm going to enquire with people who no more about using two or three small panels to get the total I need for recharging though.
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#13
What are you using to recharge the battery? I would think a discharged battery could pull significant amps off your motorcycle charging system if you don't regulated it.
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#14
Sleeprider..

The battery will just recharge off the auxiliary wiring socket, the same as my phone and GPS do.

It will only charge at the voltage the alternator puts out for the main battery and the rest of the electrics.. 14.4 volts when I checked it the other day with the new cig. lighter USB/volt meter gizmo. 

It is only current going in, not amperage load coming out [as in starting the engine], so no need for heavy cabling to charge it.
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#15
(05-22-2017, 07:38 PM)Ockrocket Wrote: It is only current going in, not amperage load coming out [as in starting the engine], so no need for heavy cabling to charge it.

What limits the charging current when the alternator is at 14.4 V and the discharged battery is at 11.4 ?
I smell smoke!
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#16
(05-22-2017, 07:59 PM)justMongo Wrote:
(05-22-2017, 07:38 PM)Ockrocket Wrote: It is only current going in, not amperage load coming out [as in starting the engine], so no need for heavy cabling to charge it.

What limits the charging current when the alternator is at 14.4 V and the discharged battery is at 11.4 ?
I smell smoke!

What JustMongo and I are trying to say is that when a deep cycle battery is discharged, it will consume as much power as it can draw from the bike stator. This current (regardless of voltage) can be much higher than the wire connector you have used to connect the battery can safely handle.  You need to regulate the battery charge to prevent a fire and potentially damaged battery.  You don't want that thing to recharge faster than 2-4 amps  at 12-14 Volts, or you will cause the battery to out-gas and be damaged. A discharged battery is a huge load on the electric system, and charging it too fast is harmful to the bike's electrical system and the battery.
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#17
I will speak to my electrickery expert friend then... he has qualifications and degrees in automotive/domestic/airconditioning and computer electronics wiring.

I'm also going to query him on the solar aspect as well.
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#18
(05-22-2017, 09:29 PM)Sleeprider Wrote: What JustMongo and I are trying to say is that when a deep cycle battery is discharged, it will consume as much power as it can draw from the bike stator. This current (regardless of voltage) can be much higher than the wire connector you have used to connect the battery can safely handle.  You need to regulate the battery charge to prevent a fire and potentially damaged battery.  You don't want that thing to recharge faster than 2-4 amps  at 12-14 Volts, or you will cause the battery to out-gas and be damaged.  A discharged battery is a huge load on the electric system, and charging it too fast is harmful to the bike's electrical system and the battery.

Suppose there's no extra battery attached and the bike's battery has been discharged to 11 volts. You somehow manage to start the bike. How would this situation be any different than the one where you connect the extra battery that's been discharged to 11 volts?

It would seem to me that the bike's regulator would limit the current flow so that the battery won't charge too fast. Of course repeatedly charging that huge extra battery will shorten the life of the bike's stator, perhaps even destroying it the first time you try to charge the battery. But I don't see how the battery could be damaged.
Sleepster
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#19
In the case where there is one battery (the primary), and it is at very low charge, the alternator is self regulating for current. Voltage must be regulated by controlling current to the rotor winding. Stator current is regulated by the limited current supplied at low RPMs. At higher RPMs where the alternator could produce higher current, the higher frequency of the 3-phase stator winding limits current by its inductive reactance. (Frequency is proportional to RPM; and Inductive Reactance is proportional to frequency) The primary battery is connected with heavy gauge wire.

Ock wants to charge via an AUX power socket likely using smaller gauge wire.

With the well charged primary battery in place, there would be a large unregulated surge from the primary to the (dead) AUX battery. If fused, then the fuse likely blows. If not fused, and the wire gauge is small, it will heat any small gauge wire. Perhaps melt it. I think that AUX power socket on the bike is intended as a low power supply to use with cell phone chargers, et cetera. Likely the AUX power socket is fused; and the worse that happens is a blown fuse. But, then there's no charger for the secondary battery.
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#20
JM is right on target. The biggest danger is posed by using too small wire, or failing to fuse the line. It's also important to consider where power it tapped, and grounding. A discharged starting battery can suffer extreme damage if it is not properly restored. Starting the bike and using an unregulated charging system will put too much current on the battery, potentially causing internal damage and venting. Small starting batteries like on a motorcycle are ideally charged at relatively low amperage. The rule of thumb is that you should never charge a battery at more than one-tenth its rating in amp hours. Meaning that a 20-amp battery should be charged at no more than 2 amps over a 10-hour period. A 12 amp battery should be charged no faster than 1.5 amps. This rate can be exceeded on a motorcycle with a depleted batter that is jump started. So jump starting is strictly for emergencies, and really should be avoided in favor of slow-recharging. Jump starting and subsequent fast charging of the battery is a leading cause of battery damage and early battery failure and charging a dead battery with the stator at full power, can burn out the regulator or diodes by overheating them.
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