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Old 19-10-2013, 06:13   #16
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Re: Solar Power and Battery Monitor Shunt Questions

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Originally Posted by monte View Post
warning, dont use the % of charge as an indication of battery charge. Always use the voltage reading. % of charge is calculated from amps in/amps out a coefficient #
After a few days of not plugging in it can be way off. Hopefully yours is calibrated closely.

Solar has a nasty habit of resetting battery monitors to full especially early and late in the day, or when over-cast. Solar or wind can replicate a shore charger or alternator in float mode with low voltage and low current.

I hear the same thing very often ("My batteries are full by noon.") and this is often far from the truth because the battery monitor was sent into a false reset by the solar...

These monitors reset on: current, time at current, voltage time at voltage....


Xantrex XBM
:

"When the battery voltage is above a certain level during a predefined time while the charge current is below a certain level during the same time, the battery can be considered as fully charged. These voltage and current levels as well as the predefined time are called charged parameters.

In general for a 12 V lead acid battery, the voltage charged parameter is 13.2 V and the current charged parameter is 2.0% of the total battery capacity (for example, 4 A with a 200 Ah battery). A charged parameter time of 4 minutes is sufficient for
most battery systems.


Please note that these parameters are very important for correct operation of your Xantrex Battery Monitor, and must be set appropriately in the corresponding Functions."


What they fail to mention is that these "charged parameters" can easily be replicated by solar or wind and can trick the monitor into re-setting to 100% well before the bank is even close.

With solar or wind I recommend reprogramming the monitor to not auto-synch and instead to rely on manual resets when "know full" by using the net accepted current at absorption voltage method.
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Old 19-10-2013, 07:48   #17
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Re: Solar Power and Battery Monitor Shunt Questions

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Originally Posted by Maine Sail View Post

In general for a 12 V lead acid battery, [B]the voltage charged parameter is 13.2 V and the current charged parameter is 2.0% of the total battery capacity (for example, 4 A with a 200 Ah battery). A charged parameter time of 4 minutes is sufficient for
most battery systems.
Those parameters will result in a very early synchronisation as you say. However, the principal of resetting the monitor when the charging current has dropped to low level and the battery voltage is high is still sound.

If the parameters are changed to 14.2 v with 1-1.5% for 4 mins you have an automatic system that will sync the battery monitor at a sensible point. (Not quite a 100% for the purists but close enough)

Its a pity the battery monitor people do not always make the equipment as adjustable as it should be
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Old 19-10-2013, 08:19   #18
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Re: Solar Power and Battery Monitor Shunt Questions

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Originally Posted by noelex 77 View Post
Those parameters will result in a very early synchronisation as you say. However, the principal of resetting the monitor when the charging current has dropped to low level and the battery voltage is high is still sound.

If the parameters are changed to 14.2 v with 1-1.5% for 4 mins you have an automatic system that will sync the battery monitor at a sensible point. (Not quite a 100% for the purists but close enough)

Its a pity the battery monitor people do not always make the equipment as adjustable as it should be
Raising the synch voltage can certainly help it re-set more reliably but I still find manual resets very easy and more reliable with solar or wind.

Leaving any monotor at the factory defaults for auto-sync with solar or wind results in counting errors so if you want to maintain auto synch then re-programing will be necessary.
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Old 19-10-2013, 13:19   #19
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Quote:
Originally Posted by noelex 77 View Post
Those parameters will result in a very early synchronisation as you say. However, the principal of resetting the monitor when the charging current has dropped to low level and the battery voltage is high is still sound.

If the parameters are changed to 14.2 v with 1-1.5% for 4 mins you have an automatic system that will sync the battery monitor at a sensible point. (Not quite a 100% for the purists but close enough)

Its a pity the battery monitor people do not always make the equipment as adjustable as it should be
I'm currently struggling with precisely this battery monitor settings issue with the following setup:
- Xantrex LinkPro battery monitor (actually a TBS E-Xpert Pro, but same product as far as I can tell)

- 220Ah AGM battery (small as for racing boat, no loads at shore as not a live aboard, no fridge, etc)

- Steca 15A 2-stage PWM solar regulator (PR 1515) connected to 2x Chinese-made solar panels (125W each)

The Steca regulator's float voltage is 13.9V (14.4V bulk charging), which is not programmable. It enters float above battery voltage of 12.7V (bulk charge for 11.7-12.7V), so it should be at float most of the time at dock.

I previously set the Xantrex synchronization settings as follows:

- Voltage: 13.7V (I was worried about voltage drop from regulator to battery because of smallish cabels, though they are next to each other)
- Charge acceptance: 2% (4.4amps)
- Time: 240secs

In practice, with these settings the battery monitor is currently never equalizing at "Full" (at dock under the daily sun of the Canaries, no loads, occasional running of engine, no shore-power...), but that may be because the battery appears partly dead (still checking but it's discharging way too fast).

To get the battery monitor to synchronize better using your advice above (assuming functional batteries), should I consider increasing the Xantrex settings to 13.9V or even beyond? Or focus instead on lowering charge acceptance limit to 1% or 1.5%?
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Old 19-10-2013, 14:05   #20
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Re: Solar Power and Battery Monitor Shunt Questions

Generally solar controllers do not talk to plain battery monitors. To get the % aright, you must set your monitor so that every time your bat hits a given voltage / amperage, the monitor will re-sett the % counter.

Our monitor takes in at least the following: bat capacity, charge factor, 'full' voltage, 'full' amps in when charged.

It seems to work very well and I can see the % resets daily.

b.
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Old 19-10-2013, 14:07   #21
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Re: Solar Power and Battery Monitor Shunt Questions

For everyone installing a battery monitor: The "Gotcha Algorithm" thread, a "MUST READ"

Link-series Charging Algorithms -- The "Gotcha" Factor!

DEFAULTS are factory settings that are made to be modified to suit your setup.
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Old 19-10-2013, 14:13   #22
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Re: Solar Power and Battery Monitor Shunt Questions

Quote:
Originally Posted by galacticair View Post

I previously set the Xantrex synchronization settings as follows:

- Voltage: 13.7V (I was worried about voltage drop from regulator to battery because of smallish cabels, though they are next to each other)
- Charge acceptance: 2% (4.4amps)
- Time: 240secs
Set the voltage to where the solar regulator falls back on absorption. This will work.

Example:

Say your solar regulator charges till 14.5 hit, then falls back on 13.7.

Set bat monitor %full point reset to 14.5 (NOT 13.7).

Some monitors can also use %full point by charge amperage. The logic operator is sometimes AND (good!) and on other makes OR (bad;-()

I let the amps well alone when charging by solar only.

Cheers,
b.
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Old 19-10-2013, 14:37   #23
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Re: Solar Power and Battery Monitor Shunt Questions

What about the Sterling battery monitor? I need to install a battery monitor and this one is currently at the top of the list as I'm also planning on a Sterling charger. The Sterling monitor seems to be just an AH counter. I think there is no automatic reset, but it's hard to tell from the instructions. There is also no Peukert effect parameters. It seems a good compromise since I'm planning to switch to LiFePo in a couple of years and I think it will adapt to these. Any thoughts or experience with the Sterling battery monitor?
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Old 19-10-2013, 15:23   #24
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Re: Solar Power and Battery Monitor Shunt Questions

Quote:
Originally Posted by galacticair View Post
I'm currently struggling with precisely this battery monitor settings issue with the following setup:
- Xantrex LinkPro battery monitor (actually a TBS E-Xpert Pro, but same product as far as I can tell)

- 220Ah AGM battery (small as for racing boat, no loads at shore as not a live aboard, no fridge, etc)

- Steca 15A 2-stage PWM solar regulator (PR 1515) connected to 2x Chinese-made solar panels (125W each)

The Steca regulator's float voltage is 13.9V (14.4V bulk charging), which is not programmable. It enters float above battery voltage of 12.7V (bulk charge for 11.7-12.7V), so it should be at float most of the time at dock.

I previously set the Xantrex synchronization settings as follows:

- Voltage: 13.7V (I was worried about voltage drop from regulator to battery because of smallish cabels, though they are next to each other)
- Charge acceptance: 2% (4.4amps)
- Time: 240secs

In practice, with these settings the battery monitor is currently never equalizing at "Full" (at dock under the daily sun of the Canaries, no loads, occasional running of engine, no shore-power...), but that may be because the battery appears partly dead (still checking but it's discharging way too fast).

To get the battery monitor to synchronize better using your advice above (assuming functional batteries), should I consider increasing the Xantrex settings to 13.9V or even beyond? Or focus instead on lowering charge acceptance limit to 1% or 1.5%?
If you are not reaching the battery monitor reset parameters of battery voltage above 13.7v with less than 4.4A going into the battery. It means that the absorption charging phase of 14.4v terminates before the current drops to below 4.4A.

The conclusion is that the that the absorption phase is terminating too early.

The solution is to increase the absorption time if this is possible with your regulator.

Default absorption time is quite variable between about 1 and 3 hours.
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Old 19-10-2013, 15:27   #25
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Re: Solar Power and Battery Monitor Shunt Questions

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it's hard to tell from the instructions
Well, you sorta answered your own question.

We are using a Tri-Metric. Look into their instructions. I think they tell everything and anything one wants to know about how their unit operates and what it can/cannot do for the user.

I sometimes use Link on bigger boats and I do not like it too much but it too does whatever the instructions say it will.

If a meter is very basic, no wonder its instructions are very short.

b.
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Old 19-10-2013, 15:34   #26
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Re: Solar Power and Battery Monitor Shunt Questions

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Originally Posted by Maine Sail View Post
Raising the synch voltage can certainly help it re-set more reliably but I still find manual resets very easy and more reliable with solar or wind.
.
I think manual resets are a good idea, but you still need to decide on some parameters that you are going to use to perform the reset.

If the battery monitor is adjustable then you can program these same parameters into an automatic reset. Works for me (with the limitation that it is resetting a fraction before 100% if you are really picky)

Usually I agree 100% with all your posts so perhaps I am missing something
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Old 19-10-2013, 16:50   #27
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Re: Solar Power and Battery Monitor Shunt Questions

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Originally Posted by noelex 77 View Post
If you are not reaching the battery monitor reset parameters of battery voltage above 13.7v with less than 4.4A going into the battery. It means that the absorption charging phase of 14.4v terminates before the current drops to below 4.4A.

The conclusion is that the that the absorption phase is terminating too early.

The solution is to increase the absorption time if this is possible with your regulator.

Default absorption time is quite variable between about 1 and 3 hours.
Not your fault, but I don't quite understand your explanation (same as Barnakiel's response above). To be honest, PWM charging has me pretty confused... It seems straightforward when I see the explanations online, but I get lost when trying to interpret the charging cycle with my system.

Can you lay out exactly what happens if the absorption phase terminates too early?
=> I would think that voltage would then drop from 14.4V to 13.9V (Steca regulator float setting), while current may still be a bit high >2% (4.4A) since absorption ideally should have continued longer. But eventually, the battery should charge up and amps will go <2%, which given voltage of 13.9V is still >13.7V synchronization setting on the Xantrex LinkPro, the LinkPro should now auto-synchronize...
What am I not getting right?

Steca solar regulator manual is also not helping me, since it doesn't refer to any absorption phase, just a "boost" phase. Is this sometimes synonymous with absorption stage?

Specficially, does anyone understand what the Steca's specs below mean in terms of the charging pattern I should be seeing?
(1) Data on final charge voltage (Gel battery)
- Normal charging (float): 13.9 V
- Boost charging (boost) for 2h: 14.4V => IS THIS ABSORPTION?
- Equalisation charging for 2h: 14.7V

(2) Charge control activation: Activation thresholds of the different charging modes
- Normal charging: ≥ 12.7 V => this seems quite low for a "float" setting
- Boost charging: 11.7 V 12.7 V
- Equalisation charging: < 11.7 V

Steca is a German company, but the terminology above doesn't seem to be a translation issue (their German manual uses the same terms of "normal (float)" and "boost" charging).

Any explanations would be much appreciated...!
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Old 19-10-2013, 17:20   #28
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Re: Solar Power and Battery Monitor Shunt Questions

Ideally the absorption stage terminates and drops back to float when the battery return amps drop back to about 1 to 2% at the absorption voltage.
If this was the case your battery monitor would reset to 100% right at the end of the absorption stage. This does not happen in your system so the charge current must be higher than 4.4A.

As you have set your synchronisation voltage below the float voltage (which I would not recommend) When your regulator drops back to float the synchronisation criteria should be immediately met. As they are not it indicates that even at a float voltage of 13.9v the battery is still accepting more than 4.4A

There are only two possibilities I can think of:
1.The batteries are a long way from 100% charged. Therefore your absorption time needs to be longer.
2. The batteries are stuffed (A highly technical term that usually results in wallet opening ) I think this is the most likely cause. You settings should be causing the monitor to sync early if the batteries were in good condition.

The bulk (or boost) stage is strictly speaking the stage before absorption where the battery voltage is still rising, but I think by "boost" in your instructions really mean "absorption"
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Old 19-10-2013, 22:00   #29
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Re: Solar Power and Battery Monitor Shunt Questions

Thanks for the heads up Monte, I'll double check that. Neko. I have the Outback set for 24v panels to a 12v system with AGM batteries of about 560AH. It does the rest by itself. Nice piece of equipment.

Cheers, Bill
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Old 20-10-2013, 06:24   #30
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Re: Solar Power and Battery Monitor Shunt Questions

Sure thing if for whatever reason your charging set-up (solar or otherwise) does not reach the monitor re-set %full point (Volts, Amps or combined), the %full info will work but its accuracy will degrade overtime. That's the point beyond the %full re-set point on the monitor.

If you are under the sun, try pushing to the re-set point with the genset or alt, once. If you still cannot get there then your batteries may be too big, to old, or else your charging capacity is inadequate.

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