My house bank currently has two ACDelco Voyager M30HMF batteries with a
reserve capacity of 115Ah each. These batteries are a couple of years
old but have only ever been lightly discharged and kept fully charged
all the time.

I would like to increase the size of the house bank but am not sure what
the implications are of mixing batteries of different ages. I understand
that different technologies cannot be mixed but I believe these are just
sealed wet cells. Does the fact that they are sealed mean I cannot use
standard wet cells? I guess the charge rate of the whole bank will be
limited by the sealed cells in this case.

What are the groups thoughts on the best options to double the size of
the house bank? I calculate that would keep me going for a 2-3 days
without having to crank the engine and never get close to the 50%
discharge point.

Am I best getting another couple of voyager batteries or should I look
at other options such as golf cart batteries?

Thanks,

Steve

Steve wrote in :

My house bank currently has two ACDelco Voyager M30HMF batteries with a
reserve capacity of 115Ah each. These batteries are a couple of years
old but have only ever been lightly discharged and kept fully charged
all the time.

They'll still be less Ah than new. At two years old, they're already past
halfway in their useful life. If you Ah tested them, you'd probably find
they were 70-80 Ah at this age with your light use. "Local Action", caused
by imperfections of other metals in the lead plates, eats away at the acid
capacity (which limits Ah) from the instant the battery is loaded with
electrolyte. It consumes the acid.


I would like to increase the size of the house bank but am not sure what
the implications are of mixing batteries of different ages. I understand
that different technologies cannot be mixed but I believe these are just
sealed wet cells. Does the fact that they are sealed mean I cannot use
standard wet cells? I guess the charge rate of the whole bank will be
limited by the sealed cells in this case.

Old batteries have less intrinsic voltage than new batteries with fresh
acid loads. If you leave the charger in the boat on all the while it's
stored, it matters little as the automatic charger will feed it more
electrons as they fight each other. However, if you store the boat with
old batteries in parallel with new batteries, the new batteries will try to
charge the old batteries, who can't use it, and it will, eventually, kill
them all. Under load, both sets of batteries are straining, pulling the
load as they can. Ah, but there's a big problem. The new batteries have a
larger Ah capacity than the old batteries. So the old batteries run down
faster, cycling deeper than the new batteries, exacerbating the problem as
you tear up the old batteries with deeper cycling.

So, don't do it. Dump them all and replace them all with new, SAME Ah
CAPACITY, batteries so these things don't happen. If you have the room,
why not stop paralleling little 115Ah trolling motor batteries and install
just ONE, large capacity battery NOT in parallel, like a couple of L-16 6V
monsters in series. Series batteries don't suffer from the swinging
discharging-each-other storage problems of parallelling little batteries.
They'll take more vertical space, so you have to have a tall place to put
them, but they make up for it in using less sq ft of deck space. Two L-16
in series more than doubles your current 230Ah capacity and reduces the
number of cells to maintain and fail from 24 to 6...reducing the failure
mode, significantly. L-16s are commercial batteries made to last, not
trolling motor batteries made to sell to consumers. The come with
convenient caps so you can actually service them with DISTILLED water,
instead of some bogus "maintenance free" sales gimmick, which means
"replace me when I need only need a little water".

Never leave different batteries in parallel without the charger, different
technologies or not. There will ALWAYS be stronger batteries charging
weaker batteries in a parallel network, a constant struggle which kills
them all. If you eliminate this parallel nonsense, you eliminate this
effect whenever they are stored uncharging.


What are the groups thoughts on the best options to double the size of
the house bank? I calculate that would keep me going for a 2-3 days
without having to crank the engine and never get close to the 50%
discharge point.

Two large 6V monsters in series. Larger the better.

Six 8,250 Ah submarine cells is best if you can solve the storage problem.
Each cell is 3' x 4' x 6' and weighs over half a ton. You'll only have to
charge them every 3 years...(c; Can it float 4 tons? Sure would make it
ride smooth until the waves are over the bow..... Leave the 1000A charger
on the dock to save 800# of extra weight.


Am I best getting another couple of voyager batteries or should I look
at other options such as golf cart batteries?


Golf cart batteries are a very economical way to get fairly good capacity.
But, one set of golf cart batteries is only 50Ah more than what you've got
now, but without the parallel discharge problem. L16s will double it but
are much more expensive. 4 golf cart batteries is about one set of L16s in
capacity...series parallel connected. Lionheart is using 4 L16s in series
parallel with constant trickle charging at the dock (10A) for house power
for all the toys.

Here's one dealer's comments:

"TROJAN L16HC

6 volts 395 amp-hrs 130 lbs
720-016 Trojan L16 $209
(L) 11 5/8 in. (W) 7 in. (H) 16 11/16 in.
The Trojan L16HC is a tougher deep cycle battery usually used in fork
lifts or industrial floor scrubbers. If you insist on a larger, somewhat
more robust battery for your bank, the Trojan L16HC is a good choice.

It has been redesigned, and is a much better value than in the past.
First, its capacity has been increased to 395 amp-hours from 350 amp-hours.
Second, it has been given a new Polyon case complete with carrying handles
and a new Trestle design for higher strength and durability.
The L16HC has the same patented Multi-Rib separators, extra thick glass
mats and Alpha Plus paste as the T-105 Life expectancy for the L16Hc is
approximately 850 deep cycles. This is longer than the 750 deep life cycles
for the T-105, but the L16HC still comes out about 20% more expensive per
watt stored over its rated life. The other major disadvantage is that the
L16HC is heavy. It requires at least two people to carry each one. Rough
handling could be a major reason for shorter life (damaged or weakened
plates), so be extra careful when transporting any battery and the L16HC in
particular because of its weight."

Weigh 4 trolling motor batteries together. Two L16HC weigh in at 260
pounds, about as much as Aunt Jemima. Note the difference in weight caused
by the difference in LEAD in them. Wonder what the trolling motor
batteries left out? Think 4 trolling motor batteries REALLY equal the
400AH capacity of two L16HC beasts in series? NOT!

Plug your ears when salesmen start talking about why you should pay $400
for some exotic 130AH geewhiz battery....(c;

Larry,

I really should have been able to work that one out myself! Just getting
lazy I guess. It's just so easy to ask!

Everything you say makes sense so I guess I will just put up with the
small bank knowing that it probably wont last very long since I will
probably be taking it to 50% discharged and beyond quite often.
Especially since the capacity could be significantly lower than the
230Ah I thought I had. When they do pack up I will look at a big
capacity non-parallel solution that allows water to be added as you have
suggested. I was a bit shocked at the weight of the Trojan batteries but
I guess they just have better plates which are lead after all (44lb/KWh
for Voyager vs 55lb/KWh for the Trojan). I am not sure I am ready to
have 260lb of battery in the boat yet although just imagine what you
could run off nearly 800Ah capacity! I can just imagine sitting there
with the air conditioner running to cool it down because you have the
electric bar heaters on! Well a couple of hours anyway.

Thanks,

Steve

Larry W4CSC wrote:
Steve wrote in :


My house bank currently has two ACDelco Voyager M30HMF batteries with a
reserve capacity of 115Ah each. These batteries are a couple of years
old but have only ever been lightly discharged and kept fully charged
all the time.


They'll still be less Ah than new. At two years old, they're already past
halfway in their useful life. If you Ah tested them, you'd probably find
they were 70-80 Ah at this age with your light use. "Local Action", caused
by imperfections of other metals in the lead plates, eats away at the acid
capacity (which limits Ah) from the instant the battery is loaded with
electrolyte. It consumes the acid.


I would like to increase the size of the house bank but am not sure what
the implications are of mixing batteries of different ages. I understand
that different technologies cannot be mixed but I believe these are just
sealed wet cells. Does the fact that they are sealed mean I cannot use
standard wet cells? I guess the charge rate of the whole bank will be
limited by the sealed cells in this case.


Old batteries have less intrinsic voltage than new batteries with fresh
acid loads. If you leave the charger in the boat on all the while it's
stored, it matters little as the automatic charger will feed it more
electrons as they fight each other. However, if you store the boat with
old batteries in parallel with new batteries, the new batteries will try to
charge the old batteries, who can't use it, and it will, eventually, kill
them all. Under load, both sets of batteries are straining, pulling the
load as they can. Ah, but there's a big problem. The new batteries have a
larger Ah capacity than the old batteries. So the old batteries run down
faster, cycling deeper than the new batteries, exacerbating the problem as
you tear up the old batteries with deeper cycling.

So, don't do it. Dump them all and replace them all with new, SAME Ah
CAPACITY, batteries so these things don't happen. If you have the room,
why not stop paralleling little 115Ah trolling motor batteries and install
just ONE, large capacity battery NOT in parallel, like a couple of L-16 6V
monsters in series. Series batteries don't suffer from the swinging
discharging-each-other storage problems of parallelling little batteries.
They'll take more vertical space, so you have to have a tall place to put
them, but they make up for it in using less sq ft of deck space. Two L-16
in series more than doubles your current 230Ah capacity and reduces the
number of cells to maintain and fail from 24 to 6...reducing the failure
mode, significantly. L-16s are commercial batteries made to last, not
trolling motor batteries made to sell to consumers. The come with
convenient caps so you can actually service them with DISTILLED water,
instead of some bogus "maintenance free" sales gimmick, which means
"replace me when I need only need a little water".

Never leave different batteries in parallel without the charger, different
technologies or not. There will ALWAYS be stronger batteries charging
weaker batteries in a parallel network, a constant struggle which kills
them all. If you eliminate this parallel nonsense, you eliminate this
effect whenever they are stored uncharging.


What are the groups thoughts on the best options to double the size of
the house bank? I calculate that would keep me going for a 2-3 days
without having to crank the engine and never get close to the 50%
discharge point.


Two large 6V monsters in series. Larger the better.

Six 8,250 Ah submarine cells is best if you can solve the storage problem.
Each cell is 3' x 4' x 6' and weighs over half a ton. You'll only have to
charge them every 3 years...(c; Can it float 4 tons? Sure would make it
ride smooth until the waves are over the bow..... Leave the 1000A charger
on the dock to save 800# of extra weight.


Am I best getting another couple of voyager batteries or should I look
at other options such as golf cart batteries?



Golf cart batteries are a very economical way to get fairly good capacity.
But, one set of golf cart batteries is only 50Ah more than what you've got
now, but without the parallel discharge problem. L16s will double it but
are much more expensive. 4 golf cart batteries is about one set of L16s in
capacity...series parallel connected. Lionheart is using 4 L16s in series
parallel with constant trickle charging at the dock (10A) for house power
for all the toys.

Here's one dealer's comments:

"TROJAN L16HC

6 volts 395 amp-hrs 130 lbs
720-016 Trojan L16 $209
(L) 11 5/8 in. (W) 7 in. (H) 16 11/16 in.
The Trojan L16HC is a tougher deep cycle battery usually used in fork
lifts or industrial floor scrubbers. If you insist on a larger, somewhat
more robust battery for your bank, the Trojan L16HC is a good choice.

It has been redesigned, and is a much better value than in the past.
First, its capacity has been increased to 395 amp-hours from 350 amp-hours.
Second, it has been given a new Polyon case complete with carrying handles
and a new Trestle design for higher strength and durability.
The L16HC has the same patented Multi-Rib separators, extra thick glass
mats and Alpha Plus paste as the T-105 Life expectancy for the L16Hc is
approximately 850 deep cycles. This is longer than the 750 deep life cycles
for the T-105, but the L16HC still comes out about 20% more expensive per
watt stored over its rated life. The other major disadvantage is that the
L16HC is heavy. It requires at least two people to carry each one. Rough
handling could be a major reason for shorter life (damaged or weakened
plates), so be extra careful when transporting any battery and the L16HC in
particular because of its weight."

Weigh 4 trolling motor batteries together. Two L16HC weigh in at 260
pounds, about as much as Aunt Jemima. Note the difference in weight caused
by the difference in LEAD in them. Wonder what the trolling motor
batteries left out? Think 4 trolling motor batteries REALLY equal the
400AH capacity of two L16HC beasts in series? NOT!

Plug your ears when salesmen start talking about why you should pay $400
for some exotic 130AH geewhiz battery....(c;

1