Absorb voltage between controllers. Ts45, Ps-30

jimbuck

I’m installing a pwm system for approximately 30A of solar. It will be a 12v @ 220Ah FLA bank. I’ve been looking at charge controllers here in the uk and can get a Tristar ts45 for £190 without temp sensor. A pro star ps30 with internal sensor (older model) for £189. If the system was MPPT then I could get a victron 100/30 for £195. (Pwm seems expensive) Looking at the two Morningstar controllers, I am drawn to the Ts45 as i can set the absorption voltage to 14.8. Why did Morningstar set the ps-30 at 14.4? Is this ok? For example if I had the same identical setup (array, bank etc) what would be the effect of charging my battery with the lower absorption voltage of the ps-30? Just a slower charge time? I’m going to be using crown or Trojan batteries which recommend 14.8v absorb but I see others in here happily using the pro star-30.

Thanks, Jim

Photowhit

I think we have moved to somewhat higher voltages recently. I use to use 14.4 equivalent (28.8 on a 24 volt system) with off brand golf cart batteries and I believe it was common and in the range for flooded lead acid batteries. 

Here in the state, Trojans do tend to last longer, but aren't as cost efficient in the long run, at least when you might expect to get 7 years out of them compared to 5 out of generic GC batteries. I'm seeing people suggesting you might well get 10+ years out of T105RE's now, so I might suggest then for someone who is experienced with off grid systems. 

If you are new to off grid systems and can get a generic at around 1/2 the price, I'd suggest that. While flooded lead acid batteries are resilient, first time solar users tend to make mistakes and kill their first set of batteries.

jimbuck

Thanks photowhit, I’ve had a small 200w system for a couple of years feeding a 115Ah battery. I’ve been charging at 14.8 with a 13.4 float. I’m just curious as to why people still use ps-30’s etc with their lower setpoint. I’m unclear if it matters to a GC battery from crown/Trojan.

Photowhit

It might also have to do with having a single controller that can charge Flooded and AGM batteries without fear of over charging. Agm can't deal well with voltages of around 15 volts, that will kill them over time.

mcgivor

@jimbuck Since you are looking for a controller, have you considered the Morningstar eco pulse, which isavailable in the UK for about half the price you have posted,  30A including meter, it appears to be similar as the PS.

jimbuck

@Photowhit, that’s a point but I think the ps-30has a dual for fla, sealed selection. I think I’ve ruled it out anyway.

@mcgivor, I have never seen that controller before, it looks like a nice simple controller, has 14.7 setting and also a custom setting. I can only find it in 1 store here which is a supplier so I have enquiried about an account. If I can’t get hold of one then i will probably lean towards a Ts-45

Jim

Estragon

I think my TriStars can be set for up to 15v absorb (L16 preset), and can also do custom setting if needed via PC software. One nice thing about them is they have big heat sinks and no fans, which means one less part to make noise and eventually fail.

You can charge at lower voltage for longer, but this is often impossible with solar. I imagine it would be a problem pretty much anywhere in the UK much of the year. Might work okay for a summer cottage or caravan though.

jimbuck

I just posted a reply and it only displays the first 3 lines of the post? I’ve tried to copy and paste it into the comments box and still 3 lines?

Jim

mike95490

jimbuck said:    I just posted a reply and it only displays the first 3 lines of the post? I’ve tried to copy and paste it into the comments box and still 3 lines      Jim

That happens on other forums,  Try using a plain text editor such as Notepad (windows' basic editor).  Formatted text does not always paste well

jimbuck

Thanks, I typed into the leave s comment box and it chopped 90% off the message. Luckily I copied it first do to past experience. I put it in notepad and chopped it up and then tried to paste it, same thing. I’m using an iPhone.

Jim

jimbuck

Yes here in the uk we need to make the most of the few sun hours we get in a day (or week) I think over panelling to a degree helps on those days where cloud is passing in front of the sun. I’m fortunate that I only use about 400wh a day. Charging at 14.8 will be a more efficient use of the sun hours than attempting a longer charge at 14.4.
I’m jealous of those of you in more sunny climates. Jim

jimbuck

Finally

littleharbor2

jimbuck said:

Thanks, I typed into the leave s comment box and it chopped 90% off the message. Luckily I copied it first do to past experience. I put it in notepad and chopped it up and then tried to paste it, same thing. I’m using an iPhone.

Jim

You've brought the problem over from that "other" solar forum. 

BB.

Jim, when you post with a desk top computer, the forum can save your in progress typing (browser crash, to click somewhere else accidently, etc.).

Go to the forum page:

http://forum.solar-electric.com/discussions

And look for the "My Drafts" link on the right, down a bit from the top of the page (if the system has no saved drafts, the button will not be there). Just click on My Drafts and you can pick which post you wish to continue on.

The Mobile version of the software does save you drafts, but does not display "My Drafts" on the the mobile site.

-Bill

jimbuck

Thanks bill, I did some changes to the paragraphs and it eventually posted. It does say draft saved every now and then. I’ve only got the phone, no pc so i’m making sure I copy as I go.

@littleharbour
I’ll try and bring something good next time

BB.

On my Android phones, three dots upper right, click and find the "request desktop site" check box. Click on that, and you can find your "Drafts" folder on one of the main pages (to the right with other "useful" links). Click on that, and you will (hopefully) find your last draft post(s).

Or, if I leave the comment page and come back (sometimes hit "refresh" too), I will usually get my lost comment back too.

-Bill

jimbuck

Thanks again Bill, I don’t have the 3 dots but can eventually get it to work with a combination of refreshing and pasting.

Jim