Poor Man's Trimetric?

I have the one in the first post, second link, only mine is the 25 amp version.
It has served well for a whole year now. I don't know how accurate the amp readings are but I'm pleasantly surprised that the amp hour tracking is so good I have never needed to reset it - it reads the 188 amp hours I set as the battery capacity when I start a trip fully charged - and comes right back to 188 after we get home and the solar panel tops up for a day or two.

Come to think about it, charge is not lost as easily as energy. I wouldn't buy the one that measures KWH's because you would have to put more KWHs into a battery than you took out to recharge it because you take out energy at a lower voltage than you must charge with. If it really measures energy (volts x amps x seconds) rather than charge it would be a poor indicator of state of charge.

My complaint was that the wire terminals on the device are too small - I could use only 14 gauge wires. Hopefully the higher amperage model has heavier connectors.

MrWizard wrote:
i use a Turnigy RC power meter to measure watts , watt hrs, amp hrs, peak watt, peak amps

its in between the solar charge controller and the batteries

its rated for a peak of 130amps, but that is short time RC motor load
not microwave baking a potato or 200amp charger

its good as long as continuous load/charge is less than 65 amps

and it only measures one way

so you need two if you want to read power use and power charge
it does not do add & subtract "tally" tracking

oops !!!

i use a Turnigy RC power meter to measure watts , watt hrs, amp hrs, peak watt, peak amps

its in between the solar charge controller and the batteries

its rated for a peak of 130amps, but that is short time RC motor load
not microwave baking a potato or 200amp charger

its good as long as continuous load is less than 65 amps

landyacht318 wrote:
That ammeter your linked only reads Loads or sources, not both at once. It will read Zero amps on a 100 amp load when it is wired to read charging amperage.

Actually twisting the voltage and Amperage calibration pots was quite difficult as any pressure on the mini pots skewed the readings for a couple seconds after one removed all pressure from it, and while they appear to be phillips head, I had to use a very small flat heat in one of the 4 crosses to turn them.

Sorry to be a negative Nancy.

Shirley you aren't a Nancy.

So I will have to choose or get two! My priority by far is the battery charging amps. Thanks for the warning on that.

We'll see how it works out. Lives don't depend on the results, but it would be nice if it actually does what I want.

That ammeter your linked only reads Loads or sources, not both at once. It will read Zero amps on a 100 amp load when it is wired to read charging amperage.

Actually twisting the voltage and Amperage calibration pots was quite difficult as any pressure on the mini pots skewed the readings for a couple seconds after one removed all pressure from it, and while they appear to be phillips head, I had to use a very small flat heat in one of the 4 crosses to turn them.

Sorry to be a negative Nancy.

landyacht318 wrote:
we posted only 3 minutes apart so I do not know if you saw my post.

But what you decided on is the 200 amp version of the 100 amp version I employed and found to be inaccurate at low currents. I'd have to assume the 200 amp version is even more so at low currents.

I was never able to get it calibrated so it would read both 38 and 1.5 amps accurately, in fact anything under 1.5 amps could not be calibrated correctly. It would read 0.0 amps when 0.78 amps were still flowing.

That 9 dollar meter might cause 100$ worth of headaches.

Real amps accuracy doesn't matter for my purpose and the amps will not be making up an AH count so they don't matter for an accurate count there. I will check the accuracy against the usual amps I have seen on the Tri for various things to make sure it is in the ball park though. The voltage is cross-checked with other voltmeters so I will know if it reads high or low and by how much.

I just want the ammeter for when battery charging at 100a or so to make sure the charger(s) are running properly at start up, and to see when amps are tapering to my target for turning off the generator. Eg 5 amps per battery is approx. 90% SOC, so at 20 amps with the four 6s.

Also I look at the amps to see that the inverter is behaving right when I turn on the microwave or something.

we posted only 3 minutes apart so I do not know if you saw my post.

But what you decided on is the 200 amp version of the 100 amp version I employed and found to be inaccurate at low currents. I'd have to assume the 200 amp version is even more so at low currents.

I was never able to get it calibrated so it would read both 38 and 1.5 amps accurately, in fact anything under 1.5 amps could not be calibrated correctly. It would read 0.0 amps when 0.78 amps were still flowing.

That 9 dollar meter might cause 100$ worth of headaches.

I decided to save my brain from all that watts stuff, and get this for the 5er ( I don't need an AH counter there, but I do want the V and the A to 200a) and put the Trimetric in the TC for its AH counter, which I am used to.

Thanks for the good input everyone.


http://www.ebay.ca/itm/DC-0-300V-200A-Shunt-Voltage-Current-Panel-Meter-Digital-LED-Voltmeter-Ammeter-/271729368180?hash=item3f44551c74:g:~~0AAOSwc0FUqBWS

I thought I saw something on Amazon, but it was the same as your first link.

Check out this' monitor' if you want a laugh, but maybe the voltage enjoying types will like it for the warm and fuzzies having no basis in reality:

http://www.amazon.com/SMAKN%C2%AE-Battery-Indicator-Capacity-Meter-Blue/dp/B00UY9PY44/ref=pd_sim_469_67?ie=UTF8&refRID=1H7EKCWKT3XMXM6GP2M7

Could you install another correct Shunt and some twisted pair leads for the trimetric and swap it to the TC any easier?

I assume new leads would require a rezeroing of the trimetric with zero loads on each swapping to achieve any accuracy in amp readings.


It appears this problem has no inexpensive solution.

I had one ammeter with the same shunt shown in your links, and its resolution on 1.5 amp loads or less was quite poor.

I think for the accuracy you seek, something requiring the Deltec 500 amp shunt or similar might be required.

On a side note I often see on other forums how people with portable 12v compressor chest style fridges recommend turning the fridge off overnight and then claim they only lose 1 or 2 internal degrees in 8 hours. If this was the actually accurate, and not just an internet claim, then it is likely cold enough outside to barely require refrigeration at all.

My 1.8 cubic foot 12v compressor fridge's consumption really declines to about 7.5 AH in 24 hours when average temps are mid to high 50's, but climbs upto the 24Ah range at close to 80f and will be closer to 34AH at 90f.

I put this 64 AH maximum wattmeter on the input leads to know this:

http://www.amazon.com/GT-Power-Analyzer-Consumption-Performance/dp/B00C1BZSYO/ref=pd_sim_422_31?ie=UTF8&refRID=0CDNR1CH8CRFT3PYZFXX

When it exceeds 64AH, it flips back to zero and starts recounting.

Wish I could help, but other than having another shunt and the ability to swap the trimetric easily from rig to rig, I think you are in the two trimetric camp.

Wait, this might be helpful:
http://www.cruisersforum.com/forums/f14/low-cost-battery-monitor-137003.html