Batrium Configuration Question

Dr. Dickie

Member
Joined
Sep 23, 2020
Messages
126
As I prepare to get my battery and new solar set-up together, I run through scenarios in my head.
As I understand it, the biggest difference between the Batrium Watchmon 4 with longmods and the Watchmon 5 without longmons is, the Watchmon 4 allows for 28 Ah a day of balancing, while the Watchmon 5 only allow for 6 Ah adjacent a day (along with easier wiring, which does not concern me).
Since I am putting my battery in a steel box, and I am in Florida, one of my biggest concerns is temperature. Where I am, the highest highs in the summer are about 95oF. My plan is to rig a fan system with temperature control--pulling air low in the box where the battery is, and exhausting it out the top (outside). SO, it does not make sense to me to use the Watchmon 4 with 14 longmons inside the box on the battery, whereas I could mount the Watchmon 5 (which dissipates the heat from the unit rather than the longmons) above the battery near the heat exhaust port at the top of the box.
I only plan a max amp draw of about 0.5 amp per cell (4 kW max, with a 14s160p system where 18650 are 2.6 Ah rated capacity) under max rare conditions, so I really do not believe that I would need more than 6 Ah a day to balance the packs-_I know those are two different things, but I do not plan on a large drawdown in capacity during normal operation--so I do not expect a serious unbalance to occur.
Is there any other considerations that I am missing (advantages of Watchmon 4 over Watchmon 5)?
Thanks
 

Wolf

Well-known member
Joined
Sep 25, 2018
Messages
1,390
I went with the Watchmon 4 because it allows me to expand my battery to more than just (1) 14s80p battery. I may be wrong but watchman 5 is somewhat limited to the amount of actual packs in series. I will in the long run have (4) 14s80p batteries which means 56 longmont sensors.
I believe the Watchmon5 can sort of accommodate that with a master/ slave configurations. Oops I mean primary/secondary.
The Watchmon 4 does it natively and all that needs to be done is add the longmons to the loop.
Wolf
 

OffGridInTheCity

Well-known member
Joined
Dec 15, 2018
Messages
1,476
Agree with @Wolf and would add some key thoughts to help the discussion forward :) I have 2 x WM4 + Expansions.

- WM5 is limited to 15s - so its no good for LifePO4 which needs 16s for 48v nominal. So if you ever want to switch out your battery bank from lithium-ion to lifepo4 you'd be out of luck.
- WM5 does allow multiple 15s 'sets'... @LithiumSolar (a.k.a. @Mike) did an excellent youtube showing this -

- WM4 - Some cool/unique things about WM4 + longmons.... is that you can put more than 1 longmon on a battery and amplify balancing OR you can put the longmons together a bit away from the actual packs if you needed to for some special reason. Its *very flexible* in these reqards.

Balance current - WM4 significantly more capable than WM5 BUT.... a healthy system doesn't need balance at all. So you might say its more of a matter of time - e.g. WM4 is faster but WM5 should be able to do the job just fine with more patience.

Heat - I'm not sure that heat from balancing - e.g. remember that a healthy battery doesn't even need balancing except touch ups for a few days every few months - is something to overly stress about. My longmons get hot to the touch but its 'point heat' rather than radiating/heater type heat. In WM4/longmon you can actually set the max temp for the longmons - I set mine at 55C - to limit the effect a bit (and do slower balancing). I wonder if you can do the same for WM5.
 
Last edited:

Dr. Dickie

Member
Joined
Sep 23, 2020
Messages
126
Ahh, no good for LiFePO4, I think that is a deal breaker, as I plan to go that route down the road, and if I am dropping a grand I want to make it capable. Ahh, and I can set temp, so if I have some problems I can adjust.
Thanks Wolf and OffGridinTheCity, that is what I needed to know.
 
Top