Hollis H-160 DPV Upgrade

[jvanostrand]

For A123 20A batteries in a 12-serial configuration (like what I did) you'll want to PWM the voltage down. I'm not sure the motor can take the full 42 volts. Using any other method of voltage regulation (like a resistor, or a simple voltage regulator) would dissipate too much heat and would take battery life with it.
With 8 cells in series, which would be about the 24V, you could remove the controller entirely and find something to use as an on/off switch. Then'd you'd be in 2nd speed all the time. You'd have to sense yourself when the power begins to die and stop using it to keep the batteries healthy.

 

[SHADOW/LAFD]

Thanks for all the great input! The direct wiring would be simple as long as I maintain the low volt on/off switching and 24 volt battery. The existing controller/driver is unreliable on my six H-160’s. Your upgrade would make these machines the best option if it was not so expensive. Thank you for sharing your knowledge!
Best,
Shadow

 

[jvanostrand]

The main cost is in the cells, then the charger (maybe $75.) The components for the controller are cheap and you can reuse the expensive Anderson connectors from the old controller and charger. I think the various electronics components cost about maybe $40 IIRC. I spent a little money on getting strong AL rods and cutting threads. Then a few dollars on Delrin plastic for the battery cover. I went with 12 cells and I wanted the DPV to be in good trim so I added more lead to the nose and added three 1.5" ABS pipe "buoyancy" cells to the side. They act as torque dampeners and keep the back end up. Now if I drop the tow bolt snap the DPV floats while the snap stays on the bottom. If I let go of the DPV it hangs there perfectly in the water. It's really nice having it balanced.

If you don't feel up to taking the time to learn everything you need to build a controller try looking for a local "maker space" or "hack lab". There will be an enthusiast there that will be able to do it.

 

[tbone1004]

@jvanostrand expensive anderson connectors? they're like $5 per set for the pp75 big ones....

 

[SharkyFr]

For A123 20A batteries in a 12-serial configuration (like what I did) you'll want to PWM the voltage down. I'm not sure the motor can take the full 42 volts. Using any other method of voltage regulation (like a resistor, or a simple voltage regulator) would dissipate too much heat and would take battery life with it.
With 8 cells in series, which would be about the 24V, you could remove the controller entirely and find something to use as an on/off switch. Then'd you'd be in 2nd speed all the time. You'd have to sense yourself when the power begins to die and stop using it to keep the batteries healthy.

Dear John

I'm planning make a lithium battery using 18650 cells, in you experience with this dpv electronics and motor...

do you think I can use a 8s 18650 with a 29.6v nominal (33.6v with 4.2v cells)?

not sure if a 7s setting would be sufficient for engine / electronics performance.

Regards.

 

[jvanostrand]

Dear John

I'm planning make a lithium battery using 18650 cells, in you experience with this dpv electronics and motor...
do you think I can use a 8s 18650 with a 29.6v nominal (33.6v with 4.2v cells)?
not sure if a 7s setting would be sufficient for engine / electronics performance.

Regards.

The original battery pack has 23 NiMH cells which means the controller and motor are used to about 30v. I'm not an expert but I don't think you'll burn anything out at 33.6v. There's usually lots of head room in electronics.

The controller has a protection system, it shuts off when it reaches a low battery threshold and then will only operate in 1st speed from that point on. I don't know what voltage triggers it but the NiMH cells generally operate to 1.1v or 1.0v safely. So it's cutting out at 23v to 25.3v.

You should check the cells you are using to see what the safe disacharge voltage is. The controller will shut off around 3.0v so you should be fine. I think Li-Ion can go to 2.5v depending on chemistry.

There are a few things you need to consider.

1/ The battery you create should be about the same weight as the original. The DPV needs to be neutral in the water, so if your battery weighs less you have to add lead. If your battery weighs more you'll need to add some buoyancy somehow (like extending the hull, or strapping empty tubes to the outside like I did.)

The one reason I didn't choose 18650s was that each cell has a metal case and all that metal adds up. I wanted to extend run time so I wanted more amp-hours (Ah) than the 15 Ah original. If you are just trying to replace the existing battery, you could look at 26650 cells or the larger 32650 lifepo cells. You should be able to get more capacity will less metal.

2/ Amp-hours is a lie. The H-160 is supposed to be a 16Ah DPV, but if you look at the cells they are stamped 15Ah. Likewise batteries you buy from online sources often inflate the Ah capacity. I haven't checked in a while but the light-green Panasonic NCR18650A was the best going and tested accurately at its rating of 3000mAh. I see Panasonic now has a higher capacity 3,600mAh NCR18650G. Avoid the cheap cells, they advertise unrealistic Ah and usually deliver way less than even 2400mAh.

3/ You need to decide between protected cells and unprotected cells. Protected cells have circuitry that prevent them from discharging too low. The controller in the DPV does that, the battery doesn't have to. If you choose a protected cell then you're DPV will die if it reaches cut-off voltage. The protection circuit won't help if the DPV is flooded because the water will short circuit around it.

Best of luck.

 

[SharkyFr]

Thanks a lo

The original battery pack has 23 NiMH cells which means the controller and motor are used to about 30v. I'm not an expert but I don't think you'll burn anything out at 33.6v. There's usually lots of head room in electronics.

The controller has a protection system, it shuts off when it reaches a low battery threshold and then will only operate in 1st speed from that point on. I don't know what voltage triggers it but the NiMH cells generally operate to 1.1v or 1.0v safely. So it's cutting out at 23v to 25.3v.

You should check the cells you are using to see what the safe disacharge voltage is. The controller will shut off around 3.0v so you should be fine. I think Li-Ion can go to 2.5v depending on chemistry.

There are a few things you need to consider.

1/ The battery you create should be about the same weight as the original. The DPV needs to be neutral in the water, so if your battery weighs less you have to add lead. If your battery weighs more you'll need to add some buoyancy somehow (like extending the hull, or strapping empty tubes to the outside like I did.)

The one reason I didn't choose 18650s was that each cell has a metal case and all that metal adds up. I wanted to extend run time so I wanted more amp-hours (Ah) than the 15 Ah original. If you are just trying to replace the existing battery, you could look at 26650 cells or the larger 32650 lifepo cells. You should be able to get more capacity will less metal.

2/ Amp-hours is a lie. The H-160 is supposed to be a 16Ah DPV, but if you look at the cells they are stamped 15Ah. Likewise batteries you buy from online sources often inflate the Ah capacity. I haven't checked in a while but the light-green Panasonic NCR18650A was the best going and tested accurately at its rating of 3000mAh. I see Panasonic now has a higher capacity 3,600mAh NCR18650G. Avoid the cheap cells, they advertise unrealistic Ah and usually deliver way less than even 2400mAh.

3/ You need to decide between protected cells and unprotected cells. Protected cells have circuitry that prevent them from discharging too low. The controller in the DPV does that, the battery doesn't have to. If you choose a protected cell then you're DPV will die if it reaches cut-off voltage. The protection circuit won't help if the DPV is flooded because the water will short circuit around it.

Best of luck.

thanks so much for your comments.

Yes I have see the oem cells are saft vh fl xp 15A, Hollis lies about 16A.

I have a little experience making batteries for dpv, I have modify for friends some silent submerge dpv and now I have a h-160, I'm familiar with buoyancy and trim settings with new battery upgrades.

I will use genuine samsung cells and I planning use a bms in the battery in order to protect and manage the charge and discharge (not sure how works the hollis electronics with nimh and how to extrapolate to lithium) I will use 2.85v as shut off voltage.

my idea is to keep the original battery case to ensure water tightness and lighting connection.

The modification project is to prepare H-160 as a backup DPV for cave diving.

 

[sdalcher]

jvanostrand,

Thank you for sharing your knowledge and experience.

 

[Marc G]

Morning, I see from your post that you are the person to visit with about Hollis electronics. We have two H160's that we have upgraded the batteries in but are strugling with getting a good match on the electronics. If you could share your electronic topography that would be greatly appreciated. We are using a friends Scubaboard account but could be reached more easily at dan@divetech.ca. Thanks again for any help you can share.

Dan