Lowering Battery Temps (Fan Mod)

[howson]

Guest (Jim),
Based on some of your posts about battery temperature I dug into the BMV-712's history on my setup and was shocked to find the chart below (over the last month):


That's not good. There are some serious temperature spikes. I'm thinking about getting the fans shown below and configuring to "push" and "pull" through my battery box. The fans will turn on (and off) through a Solid State Relay triggered by the BMV-712 based on temperature.


Would appreciate reading your .02.

gbkims (Gene)--you know I want your input, too.

Everyone else is also more than welcome to chime in if they know of a better solution or have a question. (Sometimes a question will lead to more research which results in a better solution!)

Howard

[Guest]

howson Howard,

I think this is a good solution and have also been looking at thermostatically controlled fans if ventilating my single battery box does not get the job done. Depending on battery mounting, I could see where stacking batteries could develop a significant amount of heat on the top battery. Wouldn't it be nice to be able to liquid heat and cool them?

Jim

[gbkims]

Howard,

Push-Pull via 712's relay into a DC SSR sounds good
I used 120mm fans in my computer cases back in the day.
Moved good amount of air and quiet compared to 80/92mm fans I started out with.

You might try something like Cooler Master MFX-B2NN-18NPK-R1 https://www.amazon.com/Cooler-Master.../dp/B086HNZWD7
This type of grill for the fans https://www.amazon.com/AC-Infinity-V.../dp/B010FBZZFS

[Guest]

howson Howard,

In the 9 Aug to around 15 Aug would you have been doing deeper discharges and re-charges?

Jim

[howson]

howson Howard,

In the 9 Aug to around 15 Aug would you have been doing deeper discharges and re-charges?

Jim

Hmmm...this may have been when I was playing with the EasyStarts and figuring out how to get the air conditioner to run off the inverter (again). They weren't long runs. If the temp spikes did coincide with the usage, that reinforces the need for ventilation!

--break--

gbkims , Cooler Master is a good name. Their products usually get good reviews in MaximumPC magazine. The AV Cabinet Cooling setup has one advantage--the 5-speed adjustable power supply. I'll be able to tweak the speed of the fans based on the cooling results (or noise level).

Today I'll be doing some measuring to see if they will fit. I'll update this thread as I progress through this project.

Howard

[Guest]

I would definitely go with the low cost of air cooling first, but if the discharge and charging is excessive and battery mounting is tight, liquid cooling may provide an additional benefit. The problem we also face with these battery designs is the lack of thermal conductivity of the cells with the case. So it will be interesting how well convection cooling will work on these case designs. A call to BB may also help where they may have information on the rate of energy transfer and what spacing and cooling they would recommend between the batteries in a multiple battery system.

Jim

[Country Campers]

Howard

If I recall your battery bank is in the pass thru , correct? If so where will you get fresh air? Meaning circulating air in a confined space will only heat up the air. I realize the cooling will only be used in certain circumstances.

Brian

[howson]

Howard

If I recall your battery bank is in the pass thru , correct? If so where will you get fresh air? Meaning circulating air in a confined space will only heat up the air. I realize the cooling will only be used in certain circumstances.

Brian

Good question--I've been thinking along the same lines. I think what I'm going to do is use my Elitech temperature & humidity data logger tool to record the temps in the pass-thru while the BMV is recording battery temps. I'll do a "spiral development" approach to the problem, meaning if an easy-to-implement solution doesn't work I'll proceed on to the next level. First I'll need a solid way to measure results, so I can accurately assess cause and effect.

If only TucsonJim lived closer--he's good at this kind of testing!

[TucsonJim]

howson

I was just thinking. I wonder if you could put a vent grill in the floor of your closet, and then place a fan under it to pull cool air from the bedroom down into the pass through. It seems like it would be very easy to do.

Jim

[howson]

howson

I was just thinking. I wonder if you could put a vent grill in the floor of your closet, and then place a fan under it to pull cool air from the bedroom down into the pass through. It seems like it would be very easy to do.

Jim

That is definitely an option. It would have to work like a dryer vent, though, to exclude the possibility of hot air rising into the bedroom from the passthru when the fan wasn't on.

[TucsonJim]

That is definitely an option. It would have to work like a dryer vent, though, to exclude the possibility of hot air rising into the bedroom from the passthru when the fan wasn't on.

A simple manual closure would work just fine.

https://smile.amazon.com/RV-Designer...825271&sr=8-35

Jim

[Guest]

Guys,

This is a great discussion. Yes data acquisition would be valuable here to understand if the heat rejection of the batteries would result in a reasonable level of heating in the passthrough. This will tell you if there is enough air volume to provide cooling and still maintain reasonable temperatures. A couple ways to get around this if heating is too high is to have the fans cooling a battery box, and to also have a fan to pull in fresh air into the passthrough and pass this air out through a vent similar to the one we use for the range in our rigs. The flap could be closed for cold weather or for travel.

The other option is liquid cooling where its easy to transfer heat from the batteries to the atmosphere outside the passthrough with an external cooler with fan and a small circulating pump with a battery cooling plate.

https://www.modine.com/markets/liqui...battery-plate/

Jim

[Guest]

howson Howard,

I am not seeing the long term temperature logging on my BMV 712. Curious how your getting this output?

Jim

[howson]

howson Howard,

I am not seeing the long term temperature logging on my BMV 712. Curious how your getting this output?

Jim

Edit: I had written earlier that the BMV can record on an SD card. I'd confused the BMV with the CCGX. Sorry!

The way I do it is through the VRM Portal. Data is uploaded to Victron every few minutes with the status of my system. I can access the data as long as there's an internet connection.

Under the ADVANCED tab there are multiple different parameters I can access depending on the device chosen. (There's 10 "widgets" for the BMV available through the portal.) One of the parameters, aka "widgets", is the temperature history.




Gotta go walk dogs (they are barking their heads off) but the BMV manual has info starting in par 3.5...

3.5 History data
The BMV stores events which can be used at a later date to evaluate
usage patterns and battery health.
Select the history data menu by pressing ENTER when in normal mode
(see section 4.3).

[howson]

Guest

Well darn--I was wrong in my earlier post. The BMV itself does not store temp data, but it does through the portal. That's quite odd. I can't find any method of storing (or retrieving) temperature data without going through the VRM portal, which (I think) requires a GX device (like my CCGX)

I looked through the VictronConnect app (no luck) and through the BMV itself (also no luck).

Sorry!

From the manual: