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Old 08-02-2016, 13:30   #76
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Re: Batteries Went Dead Overnight - Beginner

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Originally Posted by skipmac View Post

Charging. Net necessarily a lot more complicated that FLA but very different and requires more attention to the process or you can destroy the batteries. I read that LiFePO prefer to be fully charged then stop. Discharged fully before recharging. So you have to watch the SOC and only charge at the right time and only to the right state. FLA you can recharge or top off the batteries whenever it's convenient. Got a nice, sunny day? Max out your solar. Tied up at the dock every day or so, top off the batteries and maybe run an EQ cycle.

Plus I see some recommending fairly complex battery monitoring systems, some saying you don't need them.
I was hoping these were what I was going to use till I read this. Now IDK. So they will develop a memory like the old Ni Cads or not charging and discharging just kills them immediately?
Sounds like using a solar charging system and with normal for a boat or motor home use it would be next to impossible to maintain them properly.

This is sad news.
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Old 08-02-2016, 13:33   #77
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Re: Batteries Went Dead Overnight - Beginner

All good reasons to have the old fashioned wet cell golf cart batteries, even if you don't take care of them very well you get a lot of value and use for the price. I wonder if anyone has even tried to say this? Just maybe:

Battery Craziness
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Old 08-02-2016, 13:35   #78
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Re: Batteries Went Dead Overnight - Beginner

Batteries in 12 easy lessons:

Real world. From a "battery research" guy, and one who installs, tests, and uses batteries 24/7.

1. Flooded LA batteries are still in 2016 the best bang-for-the-buck, and the best choice for most cruising sailors;

2. With caveats, AGMs could be OK, too, but are more pricey, less tolerant of abuse, and more tricky to maintain. But, to really take advantage of their properties, you may need to completely revise your charging system and plan;

3. For some sailors, gels make a lot of sense, but are more expensive;

4. LiFePO batteries are very expensive, but when systems are well chosen, installed, and monitored may be a good choice;

5. Firefly batteries look very good. Expensive, but good experience so far. Unfortunately, they only come in Group 31 size so far;

6. Most boats are way underprovisioned with charging capability. You can't have too much charging capability. More is better. Less will cost you money over the long term, especially if you depend too much on mechanical means;

7. Solar panels are an excellent investment, when paired with a reliable MPPT or PWM controller;

8. Wind generators are good, too, but are sometimes a hassle to install, maintain, and control;

9. Among the several ways to monitor state-of-charge (SOC), the Smart Guage is perhaps the best and ONLY reliable means; amp counters need constant calibration (which on the average boat they don't get), and can be very misleading;

10. The ONLY reliable way to measure the residual capacity of your batteries is by using a controlled 20-hour discharge test; expensive inductance meters can approximate, perhaps better than other tests, but cannot match the accuracy of a 20-hour test;

11. Specific gravity tests on FLAs may be good for identifying deficient cells and need for equalization, but they do NOT relate to battery capacity; and

12. Larger battery banks are better than smaller ones for several reasons: lower cycling levels, faster charging, increased available AH, etc.

... in a nutshell :-)

Bill
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Old 08-02-2016, 13:43   #79
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Re: Batteries Went Dead Overnight - Beginner

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Originally Posted by Salty Mike View Post
I was hoping these were what I was going to use till I read this. Now IDK. So they will develop a memory like the old Ni Cads or not charging and discharging just kills them immediately?
Sounds like using a solar charging system and with normal for a boat or motor home use it would be next to impossible to maintain them properly.

This is sad news.
I don't know if LiFePOs develop memory but for whatever reason they don't respond well to partial charge and partial discharge. Maybe one of the LiFePO experts will weigh in with the why and wherefore.

My main objection, because they are very expensive up front a screw up can be very painful. I am not saying that they are hypersensitive to lots of different use and abuse issues, but there are a few things that will kill them dead rather quickly. Considering the cost, that would ruin not just my day but maybe even the entire month.
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