Here are some criteria that I find to be very important when buying
an Ah counter type battery monitor
If it does not have an adjustable Peukert, walk away.
Some manufactures have decided that they already know the "Peukert" of your batteries... Trust me they don't always know this.
When emailed and asked very technical questions surrounding how they internally calculate for Peukert they either simply don't reply or send you some gobeldy gook answer that means it will NOT be an accurate monitor
unless you get very lucky and your bank has the same Peukert as the BM maker decided is the right one.
The Xantrex monitors (made by TBS Electronics) and the Victron monitors both allow for adjusting the Peukert. Philippi monitors also allow for this.
This is why a battery monitor without an adjustable Peukert will add up counting errors significantly faster. These are two banks I recently installed.
Bank #1 400Ah TPPL AGM
- Peukert 1.11
Apply a 10A load for 8 hours / Peukert Corrected Load = 9.27A X 8 = 74 Ah's used
Bank #2 370Ah L16 Flooded Deep Cycle
- Peukert 1.55
Apply a 10A load for 8 hours / Peukert Corrected Load = 7.13A X 8 = 57Ah's used
You can easily see why a battery monitor with a one size fits all Peukert will not be very accurate.
As of yet my emails to Smart Gauge have gone unanswered as to whether this technology will work on LiFePO4
. I would expect that it could but it instills little confidence when the company won't even answer an email
with a simple yes or no answer.. Balmar
, the US Importer, does not know the answer either...
With ANY Ah counting battery monitor proper programming and frequent manual resets when "known full" are the best way to keep them accurate.
How do you know when the bank is really full? Simple, fire up the motor
, turn all loads OFF and set the BM to the amp screen
. If the battery bank is taking less than 2% of its 20 hour capacity rating, at 14.2V+, it is full enough
to do a manual reset.
Many BM's are tricked into resetting before the banks are actually full and solar
can cause this to happen. This creates counting errors which only get worse with time unless you manually reset often, when known full
... They are only as smart as the person using & programming them allow them to be...
Here's an example. I was working on a boat last Wed with a Xantrex Link-Pro. The boat also has solar. The BM was blinking "FULL".. When I fired up the motor
the 315Ah bank was accepting 25A - 28A of charge current
. 2% would mean a charge acceptance of under 7A for this bank. The monitor had been tricked into resetting to full based on solar and it was not "FULL".... I see this quite frequently...
Ah counting BM's are NOT a fuel
gauges are pretty fool proof, when sitting level. Battery monitors are more like looking at your fuel gauge when heeled. You need to be smart enough to know what you are seeing may not be true and smart enough to actually keep on top of it so it can be as accurate as possible..
I won't name brands (there are plenty of them who pray on unsuspecting boaters) but I will say to please avoid BM's that do not allow you to program your own Peukert #, if you actually care for your monitor to be as accurate as it can be...