Re: Battery pack replacement at 4 Years boating

Myles Twete

Yeah Cal, be careful with battery maintainers.

I bought two GEN4 “Genius” multi-battery charger/maintainer blocks---one with 4 outputs, one with 3 outputs.  I hooked them up 4 years ago to 14 golf-cart 6v batteries on my 1920 Milburn after driving the Milburn to a new storage facility.  They’re good for 10amps output, so I was pretty excited about using these as both charger and maintainer.  Well, that was November.  I didn’t make a trip to the storage facility to check on these and then by late January I was having coronary bypass surgery, so I didn’t get around to checking on the old car until April or so.  Well, I got there to find the car not plugged in, which upset me a bit, but when I found the car wouldn’t really budge under its own power, I later realized that all the cells were very dried out.  I literally added about 8 gallons of distilled water to the cells in the car that day.  So  I think they were pretty dang dry.

Anyway, I have since spent a lot of time at times getting these batteries back up to snuff (now 9 years old) and a year ago easily drove the car 16 miles to Fairview a couple times where I worked at the time.  With CV19 and a funky 2020, I haven’t gotten the car out much or paid much attention to it (again)---at least this time it is in my driveway under cover, so…anyway, I found that even without charging the batteries in months, the cells were quite dried out.  I added about 3gallons of water just to get the levels up a ways above the tops of the plates.  And I’ve been blasting the batteries with some good charge to wake them back up (desulfating), which I’m pretty confident will bring them up pretty well for 9-yr old lead-acid.  Last year after doing this, I checked the electrolytes and found them disappointing until I really hit the batteries with some serious current (50amps charging).  After, every cell was reading in the GOOD range.  So I’m going thru that again---I know the drill…


This will likely be the last I will be using lead-acid.  My boat pack is all lithium as is of course my 2011 THINK (same batteries).  And I’m likely to be replacing the Milburn pack with the same lithium batteries in the coming weeks/months.  It’s funny though---these lithium batteries are actually slightly older (2010) than the lead-acid batteries in the Milburn now.  Still, except for the 1-in-50 or so cell pairs that are leaky, droopy or otherwise drift low before the others, the minimal maintenance requirements for the lithium pack really make it a big plus.  I can literally go months without checking my pack on my boat and I know that it is ready to go when I get out there next…that was never the case before.


Surplus lithium car batteries/modules of many stripes are out there.  I considered buying an entire THINK pack recently (at ½ the price I paid for one a few years ago), but just don’t have the room to dissect it---and I only need 4 of 8 of the pack’s modules for my Milburn…and I know where I can get these locally, so not much incentive.


Anyway, with your stressed batteries, Cal, add water to them if you can (hard to do with AGM) then give them some good hard charging currents, but watch them (and smell them) to make sure they aren’t overheating and emitting hydrogen sulfide.


And if anyone is looking for up to 14 golf cart batteries that have low # of cycles but 9years old, let me know---I can give you a sweet deal.




From: [] On Behalf Of Electri-Cal
Sent: Sunday, November 8, 2020 2:56 PM
Subject: [oregoncoots] Battery pack replacement at 4 Years boating


Just as a note on battery life.  The oldest pack of 2 bi-Mart # 27 deep cycles would have hit 4 years in December this year.   Those came from my cabin cruiser to Surprise -- so I'm going by the sale stickers on the case.  That's fine as I probably powered up too fast a lot over the years.  What I would say is that I got good service from them with no problems, at a price of under $100 bucks each.   Planning on doing the next oldest pair soon, then I'll be ready for the coming season with max. cruise range.   That's a reasonable cost for electric boating, with zero other problems.

The why now ?? Question.  I had a malfunction on my trickle charger, it shorted out somehow, and just maintained a full on trickle for about a week, 24-- 7 on .  Overloaded the cells to death, than sat there with warm batteries way too long,  First time for that, but it was on my 4 battery pack so all need replaced before any major use.  For now i'll use the old 2 battery and 2 packs system, like over several years.  Sending back the 24v.  battery minder for service, find out what went wrong.

Just a note for battery cost ideas, be seeing you ---- Cal

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