Lead acid

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Joined
May 13, 2017
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263
Anyone using lead acid batteries on there solar install?

T105 trojan

6v 225ah they are 130 each local here

The 18650 way, with bateries from recyclers and not counting your time is the cheapest. But i figure if i buy good 18650s at a dollar a piece, lead acid is cheaper.
 

jesusangel

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Joined
May 28, 2017
Messages
277
Hi, first this battery is for golf cars, for power systems they recommend Trojan T-105-RE, specifications of last one say that in a 100 hours discharge you can get 250AH (1.5KWh) it sounds weird for a lead acid, but they state it's a true deep cycle. I think if you discharge the battery until that level many times its live will be shorter. Nobody recommeds to discharge a lead acid battery more than 50%.

If these number are true (100% DoD), yes, to get 1.5KWh at 2000mAh you need 200 18650s, a little more expensive, but you are no considering life of batteries, lead acid batteries usually have shortest life (# of cycles).

If you must buy I will considere LiFePo batteries, they will cost 2 times more but life is at least double of lead, and usable energy is double too. So the cost is half.

Regards
 
Joined
May 13, 2017
Messages
263
LiFeYPo4 lyp , dont use lfp lifepo. (Notice the y in the name)

If i used lithium it would be the 18650 cells.
 

owitte

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Oct 19, 2016
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I'm using 6 of those (sorry, it's a german shop), bought them, before I thought about using 18650s. From my experience, they're ok as long as you don't need too much power. I noticed a heavy voltage drop on higher loads (>1kW), which caused my inverter to switch back to grid (assuming the batteries are empty). Then, the batteries recovered quite fast, voltages rised, which made the inverter switch back to battery and so on every minute...

Since a few months, I'm using them together with my 18650 Powerwall and it's working great (see here), but as soon as I have enough capacity with 18650s, I'll through the LAs out and sell them.

Hope this hepls, have sun :)
Oliver
 
Joined
Jun 22, 2017
Messages
18
I was looking at something similar as well. Perhaps replacing a set of golf cart batteries with DIY 18650's. A relative has to replace is LA's every two years at a cost of around $1,100. But, that cart is probably discharged 90%-100% regularly. Perhaps it needs a cutoff circuit... Anyway, I figure, if I can get the same capacity out of 18650's, they will surely last longer. What I don't know, are the LA capacities measure to 50% drain, or 100%? I am assuming 100%.
 
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May 13, 2017
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263
Something is wrong with the cart.
Unless there buying walmart car batteries.

I live in the golf cart capital and eveyone gets 7-12 years.
 
Joined
Jun 22, 2017
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1958greyhound said:
Something is wrong with the cart.
Unless there buying walmart car batteries.

I live in the golf cart capital and eveyone gets 7-12 years.

That is possible, I don't know much about them. On his, they are almost always fully discharged. 48v, and after about 2 years he is lucky to get 10-15 minutes from the batteries.
 
Joined
Jun 22, 2017
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1958greyhound said:
yup you have to keep the charger pluged in when your not driving

It is always plugged in per the dealer. They said that was the reason they went though so many, but it hasn't helped the past 5 years. Possibly a charging issue then...
 

Korishan

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Jan 7, 2017
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Or his discharging all the way and not making sure the electrolyte is filled. A dry LA will die quickly, too.

And, just alike any other battery, an LA that is SOC is <50% repeatedly will dramatically decrease the batteries life span. If they are constantly discharging that far, maybe they should have a gauge on it with a limiter on output once the batteries get below 60% so they can limp it back in to get charged.
It's also possible there is a parasitic leak somewhere as well.
 

Korishan

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Jan 7, 2017
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Depends on the cart. When I worked at the college, they were just direct connection through a few switches and a pedal. Nothing fancy. And we drove them most of the day and plugged in at night, and the batteries last years. But, note, they were 6V deepcycle batteries. So that might be the difference. Two in series, and I dunno what in parallel, I'm thinkin 4 strings

I think the reasoning behind it is they are Lead Acid. They drop in voltage faster than lithiums as they are used, so it's quite noticeable when they are needing a charge. However, if you do a lot of start/stop with time for the batteries to recover, you can push them much farther than if they were just driven continuously.

Put a solar panel on the roof with a PWM charger and that might help alleviate the battery replacement so often.
 

daromer

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Oct 8, 2016
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Joined
Jul 8, 2017
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I have 2 Voltmaster 270Ah AGM battery running my Tiny house since 01/06/16.
On the moment they start to go down since (01/04/17) i'm using a washing theDaewoo DWD-M301WP Mini Drum Washing Machine drops the voltage down from 13.8 floating to 11.9 volts. So i'm going to build a LiFo battery pack with enough capacity.
 
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