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diy solar

Traditional Battery Case for 280ah Cells

I bought 2 of the battery boxes one arrived on good condition the other has a deep indentation of a nut in the battery post. Talking to the company to see if they can ship a new battery box top. Must of happened when they threaded the hole for the screw and went to deep.
 

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Mike Jordan said:
I've had that thought several times. Have you searched through any measurements?
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Indeed I have checked. I can definitely find one that would fit 4 cells of the 280 AH variety.

I was wondering if anyone knows or can think of any downside?
 
Gazoo said:
I do recall someone using a cooler. I think the only problem is the thickness of the walls if intending to use battery posts. Of course there are several ways around that. For example one could use Anderson connectors to connect between the battery and an inverter.

I do think a cooler would be fairly sturdy. A box that won't flex on the bottom would be good to prevent stress on the cells terminals. If it flexes, throw in a 3/4 inch plywood in the bottom then you should be good to go.
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Good point Gazoo. I don't think you need 3/4 inch though. The plastic bottoms and sides are fairly sturdy, and I think that 1/4 inch would be sufficient.
 
Mark44 said:
Good point Gazoo. I don't think you need 3/4 inch though. The plastic bottoms and sides are fairly sturdy, and I think that 1/4 inch would be sufficient.
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I keep thinking 8 cells because that's what I have. I know coolers are fairly sturdy and I agree 1/4 inch plywood might do the trick. My only concern is any flexing on the bottom which would cause the cells to shift and put stress on the terminals.

The other thing I thought of is heat build up if running the BMS hard for long periods with the cooler cover attached. But other than that and the thickness of the walls I think a cooler is a great idea. I have seen one member house all of his equipment in milk crates...lol. And there is nothing wrong with that either...simple and effective. I have been looking at the Arko-Mills stuff too. But the rated weight capacity needs to be taken into consideration.

I also found this 20 gallon Husky box at Home Depot. Unfortunately the inside width is 13 inches and I need 14 inches. I measured it myself. It would work if I installed the cells on their flat side but I really don't want to do that. Husky also makes a 12 gallon version of the same box. They have a rated weight capacity of 500lb's and 200lb's respectively.

No doubt plywood would be a good idea for any case. Even the metal ones sold by Amy and others. The reason I don't want to go with a metal case is because it's much easier to drill holes in plastic and mount things.
 
Gazoo said:
I keep thinking 8 cells because that's what I have. I know coolers are fairly sturdy and I agree 1/4 inch plywood might do the trick. My only concern is any flexing on the bottom which would cause the cells to shift and put stress on the terminals.

The other thing I thought of is heat build up if running the BMS hard for long periods with the cooler cover attached. But other than that and the thickness of the walls I think a cooler is a great idea. I have seen one member house all of his equipment in milk crates...lol. And there is nothing wrong with that either...simple and effective. I have been looking at the Arko-Mills stuff too. But the rated weight capacity needs to be taken into consideration.

I also found this 20 gallon Husky box at Home Depot. Unfortunately the inside width is 13 inches and I need 14 inches. I measured it myself. It would work if I installed the cells on their flat side but I really don't want to do that. Husky also makes a 12 gallon version of the same box. They have a rated weight capacity of 500lb's and 200lb's respectively.

No doubt plywood would be a good idea for any case. Even the metal ones sold by Amy and others. The reason I don't want to go with a metal case is because it's much easier to drill holes in plastic and mount things.
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Point one, stress on the terminals and cell walls is a big no-no for sure. Yu are correct, my first set up will be 12 volt 4 cells, so I think that thinner ply is good. But your point is valid once i turn to 24V systems.

I am of two minds on the heat thing. First, the heat could be good in cooler climes. Might eliminate the need for a heating pad. Second, everything I see and read, including Will's reviews, indicates that ambient temperature for LIFEPOP4 batteries should not likely exceed 30c or 80f. This assumes that you are not running at a rate where the discharge is so high that you create heat. I think my use case will be OK and that the cooler walls will tend to mediate temperature in both directions. I can always put a temp probe in the box.

The link looks good! I may choose to go this route (check Walmart for storage totes). However right now I am leaning toward the cooler idea as a test/prototype.

I too am hesitant on metal, since it is a conductor, and subject to either electrolysis, or corrosion. Plywood does sound like a great alternative, not to say inexpensive, but looking at prices, buying a cooler off-season, may actually be less expensive than plywood, and comes with that cool handle! :cool:

Thanks for your great feedback. I really like these conversations, as I learn and am able to make decisions in stages when people like you choose to share their opinions and experience!
 
Mark44 said:
I can always put a temp probe in the box.
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Or buy a BMS that has a temp probe attached to it. Overkillsolar BMS's are popular. I have the 24 volt version and it came with two temp probes. The 12 volt version comes with at least one temp probe, I don't think it comes with two. The high and low temps can be programmed, as can everything else.
 
Mark44 said:
Everything I see and read, including Will's reviews, indicates that ambient temperature for LIFEPOP4 batteries should not likely exceed 30c or 80f. [86F]
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<30*C/86*F should be a very healthy and conservative limit. From what I have read, at <0.5C and especially at <0.25C cell temperature should be within a few degrees of ambient.
I think my use case will be OK and that the cooler walls will tend to mediate temperature in both directions. I can always put a temp probe in the box.
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My uneducated guess is that you are right. But I don't know enough to have an educated guess. I have seen rough calculations of how to determine how many Watts a heating pad needs to be to heat batteries in an insulated box. I suppose this math could be done in reverse to figure out the effect an insulated box would have on heat generated from the batteries and BMS if you could figure out a rough figure for how much energy was being converted to heat within the box. OR... you could just try it and see, and not overthink everything like I do :)
 
@Mark44 and @Gazoo I've been thinking about a cooler as mentioned above. I would think a cooler would be more supportive than the HD totes. In an RV application like mine, I do not think there would be enough energy movement in the batts to cause the cells to heat. I am thinking about attaching the BMS on the outside of the cooler to negate a BMS heat trap. But if you guys find a good solution, post pics :cool:
 
Mike Jordan said:
@Mark44 and @Gazoo I've been thinking about a cooler as mentioned above. I would think a cooler would be more supportive than the HD totes. In an RV application like mine, I do not think there would be enough energy movement in the batts to cause the cells to heat. I am thinking about attaching the BMS on the outside of the cooler to negate a BMS heat trap. But if you guys find a good solution, post pics :cool:
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A temp controlled fan....lol. It could be mounted in a cooler to keep everything neat and the BMS inside the cooler but I think it would be somewhat of a pain.
 
Gazoo said:
A temp controlled fan....lol. It could be mounted in a cooler to keep everything neat and the BMS inside the cooler but I think it would be somewhat of a pain.
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Actually Gazoo, that is almost exactly what I was thinking. The BMS will disperse a limited amount of heat, but I assume since my discharge rate is likely to be .25C to .4 C it should not play a large roll. I was actually worried more from a heat perspective in terms of keeping the battery box warm enough, as opposed to cooling it.

I will be spending a lot of time north of 49, and likely to experience 32f or lower from time to time. But the idea of including a fan on the side of the cooler that is regulated by a temp probe is way cool!

My whole objective starting this thread was to investigate how to keep the battery box temperature as constant as possible, hoping to avoid the need for either cooling or heating! Everyone here is pushing my limits and I love it. You have inspired me to try some things I was not thinking of!

So I need to ask another question. Completely in the ditch as it is not about cases. If I need to move the question would someone please tell me where to put it?

I am considering an inexpensive power supply from a server, as the base for a charger. Does anyone know if that type of power supply can be pushed to a voltage that would work with a LIFEPO4 battery? With such high amperage, I am concerned about trying to use a buck/boost converter to get 13.4 for absorption. So I need the brain trust to weigh in!
 
Mark44 said:
So I need to ask another question. Completely in the ditch as it is not about cases. If I need to move the question would someone please tell me where to put it?

I am considering an inexpensive power supply from a server, as the base for a charger. Does anyone know if that type of power supply can be pushed to a voltage that would work with a LIFEPO4 battery? With such high amperage, I am concerned about trying to use a buck/boost converter to get 13.4 for absorption. So I need the brain trust to weigh in!
Click to expand...
I suggest searching "server power supply" "meanwell power supply" "computer power supply" maybe "HP power supply" etc on the forum, there have been a number of discussions on this in the past 4 months or so. I don't recall what subforums or where exactly or I would give you a direct link, but it shouldn't be too hard to search for.
 
Dzl,

Thanks for the direction, I will search as you suggest. Thanks again.
 
Mark44 said:
That ain't fancy, That's freaking awesome! I can only hope mine looks half as nice as this. Way to go Tim0Shel a thing of beauty and lloks hella durable!(y);)
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Thank you for your kind words!!! One thing I can tell you from experience is keep it simple not so much looks make it functional as possible and its too easy to overthink things for sure. I am starting to put so much in it I have designed some 3D prints to extend the rear of the case for all fusing and wiring. Hope this will provide room in the top half of the case for inverter to fit. My issue is finding one to fit in the size I want.
 
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