Battery monitor

[countrykids]

My current battery monitor is a voltmeter and a chart to tell me percent batteries are full. Looking around it appears there are devices that would do a better job and provide other info as well.
What are you using for a battery monitor? Trimetric and Victron are two that are mentioned and I expect there are others.
Thanks for your input.

[Harvey51]

Hi ktmrfs - I enjoyed your post and thinking. I am interested in the extra features you found on the Trimetric battery monitor.

It seems to me that the battery monitor and battery charge controller ought to be combined so charging is smart - higher voltage and current when the state of charge is low and lower when near full charge. I know charge controllers are supposed to do that but how can they do it well without knowing the state of charge?

It would be nice to have more aggressive charging on vehicles, too. We drive ours such short distances that they don't fully charge after a start. Then the current drawn by computer, remote radio, etc overnight often pulls the battery down to an unhealthy state. The alternator is more than capable of recharging fully in half an hour but I don't think it knows it needs to. I live in a cold climate so this is a serious problem.

[ktmrfs]

Harvey51 wrote:
I took the lowest cost route - under $25 from China via eBay.
eBay battery monitor
I got the 20 or 30 amp version and had some trouble connecting heavy wires - had to use short lengths of AWG 12. Other than that, no problem. Works very well and it is very nice to always have the % of full charge for my batterys. Recommended.

I installed one of these in daughters in-law's trailer. Since he didn't have an inverter, we used the 100A version.

One point, you need at least the 50A shunt for most applications, since all the charging current must pass through the shunt. So, my advice is to get a shunt with some margin based on your max charging current or max discharge current. A 100A or 200A should suffice in most cases. and at least by the 100A shunt, it has an external shunt much easier to connect to.


Great value for the bucks, and for them (and us) it gives an accurate enough indication of battery state of charge. In my trailers I have the Trimetric, but that was before the one above was available. In reality I think the one above is a much better value for the $ and perfectly adequate for Most applications. and easier to wire in than the trimetric.

Now the trimetric does have features these ebay units don't have, but again in bang for the buck, it's a great deal and does the important job.

[Harvey51]

We always boondock.
Part of it is my determination not to waste another pair of batteries by relying on the over optimistic voltage method confused by surface charge. Plus it is just nice to know when I need to be careful with electricity use.

[mike-s]

What problem are you trying to solve?

Do you boondock for days and need to know your status (and what are you going to do about it, other than to leave early), or is it just an AR thing to see numbers (very common)?

What you're doing now is fine for the former, not so much for the latter.

[MrWizard]

X2 ^
i put the same meter, higher amps version in the Safari, great tool for the price

i have one i'm going to install in this RV (the bounder)

[Harvey51]

I took the lowest cost route - under $25 from China via eBay.
eBay battery monitor
I got the 20 or 30 amp version and had some trouble connecting heavy wires - had to use short lengths of AWG 12. Other than that, no problem. Works very well and it is very nice to always have the % of full charge for my batterys. Recommended.

[Smitty77]

Not familiar with Victron, or have personal experience with those that own it. But, they do have a good following and reputation.

The Trimetric brand I've friends that are very pleased with their results. And I've ready many heavy into Boon Docking that won't leave home without a Trimetric.

I know more from firsthand friends, and from reading positive input about Trimetric, so that is the way I'd lean if shopping.

That being said, I a do have almost a full Magnum coach. MS2812 with AGS/SBC/ARC-50/BMK - the only unit I have not Magnum, is the MidNite Classic150 Solar Controller. Magnum did come out with the PT-100 Controller a few months after my install, so if doing this today, I'd do a real close comparison between the PT-100 and the Classic150. In the above mix, the BMK is the measurement, of course thru a Shunt, that also requires a display module too.

Happy hunting,
Smitty

[hedge]

another happy Victron owner, I had to add the dongle to mine... jealous of the new model with it included.

[ependydad]

Victron BMV-702 with the added Bluetooth dongle OR buying the BMV-712 which has Bluetooth connectivity built-in. It's great to grab my phone and take a quick glance. I didn't even mount the included monitor.

[bacil]

THESE, they are marine oriented but are great we have them in charter boats (some of them). I like that it shows all the information (load and charge in the same time). I will probably put it to our RV as soon as we get it.

[2oldman]

Victron BMV-700. Displays on your smartphone.